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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ca4cac4c74e849a4ebd276dce9bbf56ef368d232 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]849<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
850 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]851 like this can be merged with other constants if they have the same
852 initializer. Note that a constant with significant address <em>can</em>
853 be merged with a <tt>unnamed_addr</tt> constant, the result being a
854 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]855
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856<p>A global variable may be declared to reside in a target-specific numbered
857 address space. For targets that support them, address spaces may affect how
858 optimizations are performed and/or what target instructions are used to
859 access the variable. The default address space is zero. The address space
860 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]865<p>An explicit alignment may be specified for a global, which must be a power
866 of 2. If not present, or if the alignment is set to zero, the alignment of
867 the global is set by the target to whatever it feels convenient. If an
868 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]869 alignment. Targets and optimizers are not allowed to over-align the global
870 if the global has an assigned section. In this case, the extra alignment
871 could be observable: for example, code could assume that the globals are
872 densely packed in their section and try to iterate over them as an array,
873 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]874
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875<p>For example, the following defines a global in a numbered address space with
876 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]878<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]879@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]880</pre>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
884
885<!-- ======================================================================= -->
886<div class="doc_subsection">
887 <a name="functionstructure">Functions</a>
888</div>
889
890<div class="doc_text">
891
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]892<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893 optional <a href="#linkage">linkage type</a>, an optional
894 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]895 <a href="#callingconv">calling convention</a>,
896 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#paramattrs">parameter attribute</a> for the return type, a function
898 name, a (possibly empty) argument list (each with optional
899 <a href="#paramattrs">parameter attributes</a>), optional
900 <a href="#fnattrs">function attributes</a>, an optional section, an optional
901 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
902 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]904<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
905 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a possibly empty list of arguments, an optional alignment, and an
911 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]913<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]914 (Control Flow Graph) for the function. Each basic block may optionally start
915 with a label (giving the basic block a symbol table entry), contains a list
916 of instructions, and ends with a <a href="#terminators">terminator</a>
917 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]919<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 executed on entrance to the function, and it is not allowed to have
921 predecessor basic blocks (i.e. there can not be any branches to the entry
922 block of a function). Because the block can have no predecessors, it also
923 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]925<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]928<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929 the alignment is set to zero, the alignment of the function is set by the
930 target to whatever it feels convenient. If an explicit alignment is
931 specified, the function is forced to have at least that much alignment. All
932 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]933
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]934<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
935 be significant and two identical functions can be merged</p>.
936
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]939define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
941 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
942 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
943 [<a href="#gc">gc</a>] { ... }
944</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]945
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]946</div>
947
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]948<!-- ======================================================================= -->
949<div class="doc_subsection">
950 <a name="aliasstructure">Aliases</a>
951</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]952
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
955<p>Aliases act as "second name" for the aliasee value (which can be either
956 function, global variable, another alias or bitcast of global value). Aliases
957 may have an optional <a href="#linkage">linkage type</a>, and an
958 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]960<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]961<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]962@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]963</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]964
965</div>
966
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]967<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]968<div class="doc_subsection">
969 <a name="namedmetadatastructure">Named Metadata</a>
970</div>
971
972<div class="doc_text">
973
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]974<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]975 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]977
978<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]979<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]980; Some unnamed metadata nodes, which are referenced by the named metadata.
981!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]982!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]983!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]984; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]986</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]987
988</div>
989
990<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]991<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]993<div class="doc_text">
994
995<p>The return type and each parameter of a function type may have a set of
996 <i>parameter attributes</i> associated with them. Parameter attributes are
997 used to communicate additional information about the result or parameters of
998 a function. Parameter attributes are considered to be part of the function,
999 not of the function type, so functions with different parameter attributes
1000 can have the same function type.</p>
1001
1002<p>Parameter attributes are simple keywords that follow the type specified. If
1003 multiple parameter attributes are needed, they are space separated. For
1004 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1005
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1006<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1007declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1008declare i32 @atoi(i8 zeroext)
1009declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1010</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1013 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1014
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1015<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1020 should be zero-extended to the extent required by the target's ABI (which
1021 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1022 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1023
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1024 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1025 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1026 should be sign-extended to the extent required by the target's ABI (which
1027 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1028 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that this parameter or return value should be treated in a
1032 special target-dependent fashion during while emitting code for a function
1033 call or return (usually, by putting it in a register as opposed to memory,
1034 though some targets use it to distinguish between two different kinds of
1035 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1036
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1037 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1038 <dd><p>This indicates that the pointer parameter should really be passed by
1039 value to the function. The attribute implies that a hidden copy of the
1040 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 is made between the caller and the callee, so the callee is unable to
1042 modify the value in the callee. This attribute is only valid on LLVM
1043 pointer arguments. It is generally used to pass structs and arrays by
1044 value, but is also valid on pointers to scalars. The copy is considered
1045 to belong to the caller not the callee (for example,
1046 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1047 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1048 values.</p>
1049
1050 <p>The byval attribute also supports specifying an alignment with
1051 the align attribute. It indicates the alignment of the stack slot to
1052 form and the known alignment of the pointer specified to the call site. If
1053 the alignment is not specified, then the code generator makes a
1054 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1056 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1057 <dd>This indicates that the pointer parameter specifies the address of a
1058 structure that is the return value of the function in the source program.
1059 This pointer must be guaranteed by the caller to be valid: loads and
1060 stores to the structure may be assumed by the callee to not to trap. This
1061 may only be applied to the first parameter. This is not a valid attribute
1062 for return values. </dd>
1063
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1064 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1065 <dd>This indicates that pointer values
1066 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1067 value do not alias pointer values which are not <i>based</i> on it,
1068 ignoring certain "irrelevant" dependencies.
1069 For a call to the parent function, dependencies between memory
1070 references from before or after the call and from those during the call
1071 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1072 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1073 The caller shares the responsibility with the callee for ensuring that
1074 these requirements are met.
1075 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1076 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1077<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1078 Note that this definition of <tt>noalias</tt> is intentionally
1079 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1080 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1081<br>
1082 For function return values, C99's <tt>restrict</tt> is not meaningful,
1083 while LLVM's <tt>noalias</tt> is.
1084 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1085
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1086 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This indicates that the callee does not make any copies of the pointer
1088 that outlive the callee itself. This is not a valid attribute for return
1089 values.</dd>
1090
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1091 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This indicates that the pointer parameter can be excised using the
1093 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1094 attribute for return values.</dd>
1095</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1096
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1097</div>
1098
1099<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1100<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1101 <a name="gc">Garbage Collector Names</a>
1102</div>
1103
1104<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1106<p>Each function may specify a garbage collector name, which is simply a
1107 string:</p>
1108
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1109<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1110define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1111</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1112
1113<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1114 collector which will cause the compiler to alter its output in order to
1115 support the named garbage collection algorithm.</p>
1116
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1117</div>
1118
1119<!-- ======================================================================= -->
1120<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1121 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122</div>
1123
1124<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1125
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126<p>Function attributes are set to communicate additional information about a
1127 function. Function attributes are considered to be part of the function, not
1128 of the function type, so functions with different parameter attributes can
1129 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1130
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1131<p>Function attributes are simple keywords that follow the type specified. If
1132 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1133
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1134<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1135define void @f() noinline { ... }
1136define void @f() alwaysinline { ... }
1137define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1139</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1140
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1141<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1142 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1143 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1144 the backend should forcibly align the stack pointer. Specify the
1145 desired alignment, which must be a power of two, in parentheses.
1146
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This attribute indicates that the inliner should attempt to inline this
1149 function into callers whenever possible, ignoring any active inlining size
1150 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1151
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1152 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1153 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame]1154 meaning the function can be patched and/or hooked even while it is
1155 loaded into memory. On x86, the function prologue will be preceded
1156 by six bytes of padding and will begin with a two-byte instruction.
1157 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1158 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1159
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1160 <dt><tt><b>inlinehint</b></tt></dt>
1161 <dd>This attribute indicates that the source code contained a hint that inlining
1162 this function is desirable (such as the "inline" keyword in C/C++). It
1163 is just a hint; it imposes no requirements on the inliner.</dd>
1164
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1165 <dt><tt><b>naked</b></tt></dt>
1166 <dd>This attribute disables prologue / epilogue emission for the function.
1167 This can have very system-specific consequences.</dd>
1168
1169 <dt><tt><b>noimplicitfloat</b></tt></dt>
1170 <dd>This attributes disables implicit floating point instructions.</dd>
1171
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1172 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1173 <dd>This attribute indicates that the inliner should never inline this
1174 function in any situation. This attribute may not be used together with
1175 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1176
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1177 <dt><tt><b>noredzone</b></tt></dt>
1178 <dd>This attribute indicates that the code generator should not use a red
1179 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1180
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This function attribute indicates that the function never returns
1183 normally. This produces undefined behavior at runtime if the function
1184 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1185
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This function attribute indicates that the function never returns with an
1188 unwind or exceptional control flow. If the function does unwind, its
1189 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1190
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1191 <dt><tt><b>optsize</b></tt></dt>
1192 <dd>This attribute suggests that optimization passes and code generator passes
1193 make choices that keep the code size of this function low, and otherwise
1194 do optimizations specifically to reduce code size.</dd>
1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the function computes its result (or decides
1198 to unwind an exception) based strictly on its arguments, without
1199 dereferencing any pointer arguments or otherwise accessing any mutable
1200 state (e.g. memory, control registers, etc) visible to caller functions.
1201 It does not write through any pointer arguments
1202 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1203 changes any state visible to callers. This means that it cannot unwind
1204 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1205 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1206
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute indicates that the function does not write through any
1209 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1210 arguments) or otherwise modify any state (e.g. memory, control registers,
1211 etc) visible to caller functions. It may dereference pointer arguments
1212 and read state that may be set in the caller. A readonly function always
1213 returns the same value (or unwinds an exception identically) when called
1214 with the same set of arguments and global state. It cannot unwind an
1215 exception by calling the <tt>C++</tt> exception throwing methods, but may
1216 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1217
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function should emit a stack smashing
1220 protector. It is in the form of a "canary"&mdash;a random value placed on
1221 the stack before the local variables that's checked upon return from the
1222 function to see if it has been overwritten. A heuristic is used to
1223 determine if a function needs stack protectors or not.<br>
1224<br>
1225 If a function that has an <tt>ssp</tt> attribute is inlined into a
1226 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1227 function will have an <tt>ssp</tt> attribute.</dd>
1228
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This attribute indicates that the function should <em>always</em> emit a
1231 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1232 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1233<br>
1234 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1235 function that doesn't have an <tt>sspreq</tt> attribute or which has
1236 an <tt>ssp</tt> attribute, then the resulting function will have
1237 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1238</dl>
1239
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1240</div>
1241
1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1244 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1245</div>
1246
1247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1250 the GCC "file scope inline asm" blocks. These blocks are internally
1251 concatenated by LLVM and treated as a single unit, but may be separated in
1252 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1253
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1254<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1255module asm "inline asm code goes here"
1256module asm "more can go here"
1257</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1258
1259<p>The strings can contain any character by escaping non-printable characters.
1260 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1262
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263<p>The inline asm code is simply printed to the machine code .s file when
1264 assembly code is generated.</p>
1265
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1266</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1267
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="datalayout">Data Layout</a>
1271</div>
1272
1273<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1276 data is to be laid out in memory. The syntax for the data layout is
1277 simply:</p>
1278
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1279<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1280target datalayout = "<i>layout specification</i>"
1281</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282
1283<p>The <i>layout specification</i> consists of a list of specifications
1284 separated by the minus sign character ('-'). Each specification starts with
1285 a letter and may include other information after the letter to define some
1286 aspect of the data layout. The specifications accepted are as follows:</p>
1287
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1288<dl>
1289 <dt><tt>E</tt></dt>
1290 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 bits with the most significance have the lowest address location.</dd>
1292
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1294 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 the bits with the least significance have the lowest address
1296 location.</dd>
1297
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1298 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1299 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300 <i>preferred</i> alignments. All sizes are in bits. Specifying
1301 the <i>pref</i> alignment is optional. If omitted, the
1302 preceding <tt>:</tt> should be omitted too.</dd>
1303
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1304 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1305 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1306 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1307
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1308 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1309 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1310 <i>size</i>.</dd>
1311
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1313 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1314 <i>size</i>. Only values of <i>size</i> that are supported by the target
1315 will work. 32 (float) and 64 (double) are supported on all targets;
1316 80 or 128 (different flavors of long double) are also supported on some
1317 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1320 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1321 <i>size</i>.</dd>
1322
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1323 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1324 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1325 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1326
1327 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1328 <dd>This specifies a set of native integer widths for the target CPU
1329 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1330 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1331 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1332 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1334
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1335<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1336 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337 specifications in the <tt>datalayout</tt> keyword. The default specifications
1338 are given in this list:</p>
1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340<ul>
1341 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1342 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1343 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1344 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1345 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1346 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1347 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1348 alignment of 64-bits</li>
1349 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1350 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1351 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1352 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1353 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1354 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1355</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1356
1357<p>When LLVM is determining the alignment for a given type, it uses the
1358 following rules:</p>
1359
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360<ol>
1361 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1362 specification is used.</li>
1363
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1364 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1365 smallest integer type that is larger than the bitwidth of the sought type
1366 is used. If none of the specifications are larger than the bitwidth then
1367 the the largest integer type is used. For example, given the default
1368 specifications above, the i7 type will use the alignment of i8 (next
1369 largest) while both i65 and i256 will use the alignment of i64 (largest
1370 specified).</li>
1371
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1372 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1373 largest vector type that is smaller than the sought vector type will be
1374 used as a fall back. This happens because &lt;128 x double&gt; can be
1375 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1377
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1378</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1379
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1380<!-- ======================================================================= -->
1381<div class="doc_subsection">
1382 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1383</div>
1384
1385<div class="doc_text">
1386
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1387<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1388with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1389is undefined. Pointer values are associated with address ranges
1390according to the following rules:</p>
1391
1392<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1393 <li>A pointer value is associated with the addresses associated with
1394 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1395 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1396 range of the variable's storage.</li>
1397 <li>The result value of an allocation instruction is associated with
1398 the address range of the allocated storage.</li>
1399 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1400 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1401 <li>An integer constant other than zero or a pointer value returned
1402 from a function not defined within LLVM may be associated with address
1403 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1404 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1405 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1406</ul>
1407
1408<p>A pointer value is <i>based</i> on another pointer value according
1409 to the following rules:</p>
1410
1411<ul>
1412 <li>A pointer value formed from a
1413 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1414 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1415 <li>The result value of a
1416 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1417 of the <tt>bitcast</tt>.</li>
1418 <li>A pointer value formed by an
1419 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1420 pointer values that contribute (directly or indirectly) to the
1421 computation of the pointer's value.</li>
1422 <li>The "<i>based</i> on" relationship is transitive.</li>
1423</ul>
1424
1425<p>Note that this definition of <i>"based"</i> is intentionally
1426 similar to the definition of <i>"based"</i> in C99, though it is
1427 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1428
1429<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1430<tt><a href="#i_load">load</a></tt> merely indicates the size and
1431alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1432interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1433<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1434and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1435
1436<p>Consequently, type-based alias analysis, aka TBAA, aka
1437<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1438LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1439additional information which specialized optimization passes may use
1440to implement type-based alias analysis.</p>
1441
1442</div>
1443
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1444<!-- ======================================================================= -->
1445<div class="doc_subsection">
1446 <a name="volatile">Volatile Memory Accesses</a>
1447</div>
1448
1449<div class="doc_text">
1450
1451<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1452href="#i_store"><tt>store</tt></a>s, and <a
1453href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1454The optimizers must not change the number of volatile operations or change their
1455order of execution relative to other volatile operations. The optimizers
1456<i>may</i> change the order of volatile operations relative to non-volatile
1457operations. This is not Java's "volatile" and has no cross-thread
1458synchronization behavior.</p>
1459
1460</div>
1461
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1462<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1464<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1466<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1468<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1469 intermediate representation. Being typed enables a number of optimizations
1470 to be performed on the intermediate representation directly, without having
1471 to do extra analyses on the side before the transformation. A strong type
1472 system makes it easier to read the generated code and enables novel analyses
1473 and transformations that are not feasible to perform on normal three address
1474 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1475
1476</div>
1477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1478<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1479<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1480Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1482<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1483
1484<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1485
1486<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1488 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1489 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1490 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1491 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1492 </tr>
1493 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1494 <td><a href="#t_floating">floating point</a></td>
1495 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1496 </tr>
1497 <tr>
1498 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499 <td><a href="#t_integer">integer</a>,
1500 <a href="#t_floating">floating point</a>,
1501 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1502 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1503 <a href="#t_struct">structure</a>,
1504 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1505 <a href="#t_label">label</a>,
1506 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1507 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1508 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 <tr>
1510 <td><a href="#t_primitive">primitive</a></td>
1511 <td><a href="#t_label">label</a>,
1512 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1513 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1514 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1515 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1516 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517 </tr>
1518 <tr>
1519 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1520 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1521 <a href="#t_function">function</a>,
1522 <a href="#t_pointer">pointer</a>,
1523 <a href="#t_struct">structure</a>,
1524 <a href="#t_pstruct">packed structure</a>,
1525 <a href="#t_vector">vector</a>,
1526 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1527 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1528 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1529 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1530</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1531
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1532<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1533 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1534 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1536</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1540
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1541<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1542
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1543<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1544 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1545
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1546</div>
1547
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1548<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1549<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1550
1551<div class="doc_text">
1552
1553<h5>Overview:</h5>
1554<p>The integer type is a very simple type that simply specifies an arbitrary
1555 bit width for the integer type desired. Any bit width from 1 bit to
1556 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1557
1558<h5>Syntax:</h5>
1559<pre>
1560 iN
1561</pre>
1562
1563<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1564 value.</p>
1565
1566<h5>Examples:</h5>
1567<table class="layout">
1568 <tr class="layout">
1569 <td class="left"><tt>i1</tt></td>
1570 <td class="left">a single-bit integer.</td>
1571 </tr>
1572 <tr class="layout">
1573 <td class="left"><tt>i32</tt></td>
1574 <td class="left">a 32-bit integer.</td>
1575 </tr>
1576 <tr class="layout">
1577 <td class="left"><tt>i1942652</tt></td>
1578 <td class="left">a really big integer of over 1 million bits.</td>
1579 </tr>
1580</table>
1581
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1582</div>
1583
1584<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1585<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1586
1587<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1588
1589<table>
1590 <tbody>
1591 <tr><th>Type</th><th>Description</th></tr>
1592 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1593 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1594 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1595 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1596 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1597 </tbody>
1598</table>
1599
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1600</div>
1601
1602<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1603<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1604
1605<div class="doc_text">
1606
1607<h5>Overview:</h5>
1608<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1609
1610<h5>Syntax:</h5>
1611<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1612 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1613</pre>
1614
1615</div>
1616
1617<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1618<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1619
1620<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1621
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<h5>Overview:</h5>
1623<p>The void type does not represent any value and has no size.</p>
1624
1625<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626<pre>
1627 void
1628</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1629
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1630</div>
1631
1632<!-- _______________________________________________________________________ -->
1633<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1634
1635<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1636
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1637<h5>Overview:</h5>
1638<p>The label type represents code labels.</p>
1639
1640<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1641<pre>
1642 label
1643</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1644
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1645</div>
1646
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1647<!-- _______________________________________________________________________ -->
1648<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1649
1650<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1651
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1652<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1653<p>The metadata type represents embedded metadata. No derived types may be
1654 created from metadata except for <a href="#t_function">function</a>
1655 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1656
1657<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1658<pre>
1659 metadata
1660</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1661
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1662</div>
1663
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1664
1665<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1669
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1670<p>The real power in LLVM comes from the derived types in the system. This is
1671 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1672 useful types. Each of these types contain one or more element types which
1673 may be a primitive type, or another derived type. For example, it is
1674 possible to have a two dimensional array, using an array as the element type
1675 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1676
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1677
1678</div>
1679
1680<!-- _______________________________________________________________________ -->
1681<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1682
1683<div class="doc_text">
1684
1685<p>Aggregate Types are a subset of derived types that can contain multiple
1686 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1687 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1688 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1689
1690</div>
1691
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1692<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1693<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1695<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1696
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1697<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1699 sequentially in memory. The array type requires a size (number of elements)
1700 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1701
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1702<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1703<pre>
1704 [&lt;# elements&gt; x &lt;elementtype&gt;]
1705</pre>
1706
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1707<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1708 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1709
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1710<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1711<table class="layout">
1712 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1713 <td class="left"><tt>[40 x i32]</tt></td>
1714 <td class="left">Array of 40 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[41 x i32]</tt></td>
1718 <td class="left">Array of 41 32-bit integer values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>[4 x i8]</tt></td>
1722 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1723 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725<p>Here are some examples of multidimensional arrays:</p>
1726<table class="layout">
1727 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1728 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1729 <td class="left">3x4 array of 32-bit integer values.</td>
1730 </tr>
1731 <tr class="layout">
1732 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1733 <td class="left">12x10 array of single precision floating point values.</td>
1734 </tr>
1735 <tr class="layout">
1736 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1737 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1738 </tr>
1739</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1740
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1741<p>There is no restriction on indexing beyond the end of the array implied by
1742 a static type (though there are restrictions on indexing beyond the bounds
1743 of an allocated object in some cases). This means that single-dimension
1744 'variable sized array' addressing can be implemented in LLVM with a zero
1745 length array type. An implementation of 'pascal style arrays' in LLVM could
1746 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756<p>The function type can be thought of as a function signature. It consists of
1757 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1758 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1759
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1761<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1762 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1763</pre>
1764
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1765<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1766 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1767 which indicates that the function takes a variable number of arguments.
1768 Variable argument functions can access their arguments with
1769 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1770 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1771 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1774<table class="layout">
1775 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1776 <td class="left"><tt>i32 (i32)</tt></td>
1777 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1778 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1779 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1780 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1781 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1782 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1783 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1784 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1785 </td>
1786 </tr><tr class="layout">
1787 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1788 <td class="left">A vararg function that takes at least one
1789 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1790 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1791 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1792 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1793 </tr><tr class="layout">
1794 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1795 <td class="left">A function taking an <tt>i32</tt>, returning a
1796 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1797 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1798 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1799</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1801</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1804<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1806<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1809<p>The structure type is used to represent a collection of data members together
1810 in memory. The packing of the field types is defined to match the ABI of the
1811 underlying processor. The elements of a structure may be any type that has a
1812 size.</p>
1813
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1814<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1815 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1816 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1817 Structures in registers are accessed using the
1818 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1819 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1821<pre>
1822 { &lt;type list&gt; }
1823</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1825<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1826<table class="layout">
1827 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1828 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1829 <td class="left">A triple of three <tt>i32</tt> values</td>
1830 </tr><tr class="layout">
1831 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1832 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1833 second element is a <a href="#t_pointer">pointer</a> to a
1834 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1835 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1836 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1839</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1842<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1843</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1844
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1845<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1846
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1847<h5>Overview:</h5>
1848<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1849 together in memory. There is no padding between fields. Further, the
1850 alignment of a packed structure is 1 byte. The elements of a packed
1851 structure may be any type that has a size.</p>
1852
1853<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1854 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1855 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1856
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1857<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1858<pre>
1859 &lt; { &lt;type list&gt; } &gt;
1860</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1861
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1862<h5>Examples:</h5>
1863<table class="layout">
1864 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1865 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1866 <td class="left">A triple of three <tt>i32</tt> values</td>
1867 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1868 <td class="left">
1869<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1870 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1871 second element is a <a href="#t_pointer">pointer</a> to a
1872 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1873 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1874 </tr>
1875</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1876
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1877</div>
1878
1879<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1880<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1881
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1882<div class="doc_text">
1883
1884<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1885<p>The pointer type is used to specify memory locations.
1886 Pointers are commonly used to reference objects in memory.</p>
1887
1888<p>Pointer types may have an optional address space attribute defining the
1889 numbered address space where the pointed-to object resides. The default
1890 address space is number zero. The semantics of non-zero address
1891 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1892
1893<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1894 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1895
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1896<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1897<pre>
1898 &lt;type&gt; *
1899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1900
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1901<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1902<table class="layout">
1903 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1904 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1905 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1906 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1907 </tr>
1908 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1909 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1910 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1911 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1912 <tt>i32</tt>.</td>
1913 </tr>
1914 <tr class="layout">
1915 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1916 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1917 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1918 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1921</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1922
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1924<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1925
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1926<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1927
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1929<p>A vector type is a simple derived type that represents a vector of elements.
1930 Vector types are used when multiple primitive data are operated in parallel
1931 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1932 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1934
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1935<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1936<pre>
1937 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1938</pre>
1939
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1940<p>The number of elements is a constant integer value larger than 0; elementtype
1941 may be any integer or floating point type. Vectors of size zero are not
1942 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1944<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1945<table class="layout">
1946 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1947 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1948 <td class="left">Vector of 4 32-bit integer values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1952 <td class="left">Vector of 8 32-bit floating-point values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1956 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1957 </tr>
1958</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1960</div>
1961
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1962<!-- _______________________________________________________________________ -->
1963<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1964<div class="doc_text">
1965
1966<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1967<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1968 corresponds (for example) to the C notion of a forward declared structure
1969 type. In LLVM, opaque types can eventually be resolved to any type (not just
1970 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971
1972<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1973<pre>
1974 opaque
1975</pre>
1976
1977<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978<table class="layout">
1979 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1980 <td class="left"><tt>opaque</tt></td>
1981 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1982 </tr>
1983</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1984
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1985</div>
1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<!-- ======================================================================= -->
1988<div class="doc_subsection">
1989 <a name="t_uprefs">Type Up-references</a>
1990</div>
1991
1992<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1995<p>An "up reference" allows you to refer to a lexically enclosing type without
1996 requiring it to have a name. For instance, a structure declaration may
1997 contain a pointer to any of the types it is lexically a member of. Example
1998 of up references (with their equivalent as named type declarations)
1999 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000
2001<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2002 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2003 { \2 }* %y = type { %y }*
2004 \1* %z = type %z*
2005</pre>
2006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2007<p>An up reference is needed by the asmprinter for printing out cyclic types
2008 when there is no declared name for a type in the cycle. Because the
2009 asmprinter does not want to print out an infinite type string, it needs a
2010 syntax to handle recursive types that have no names (all names are optional
2011 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
2013<h5>Syntax:</h5>
2014<pre>
2015 \&lt;level&gt;
2016</pre>
2017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2018<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2019
2020<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2021<table class="layout">
2022 <tr class="layout">
2023 <td class="left"><tt>\1*</tt></td>
2024 <td class="left">Self-referential pointer.</td>
2025 </tr>
2026 <tr class="layout">
2027 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2028 <td class="left">Recursive structure where the upref refers to the out-most
2029 structure.</td>
2030 </tr>
2031</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2032
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2034
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2035<!-- *********************************************************************** -->
2036<div class="doc_section"> <a name="constants">Constants</a> </div>
2037<!-- *********************************************************************** -->
2038
2039<div class="doc_text">
2040
2041<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043
2044</div>
2045
2046<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2047<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049<div class="doc_text">
2050
2051<dl>
2052 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2054 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055
2056 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2057 <dd>Standard integers (such as '4') are constants of
2058 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2059 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2060
2061 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2062 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2063 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2064 notation (see below). The assembler requires the exact decimal value of a
2065 floating-point constant. For example, the assembler accepts 1.25 but
2066 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2067 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2068
2069 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2070 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2072</dl>
2073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2074<p>The one non-intuitive notation for constants is the hexadecimal form of
2075 floating point constants. For example, the form '<tt>double
2076 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2077 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2078 constants are required (and the only time that they are generated by the
2079 disassembler) is when a floating point constant must be emitted but it cannot
2080 be represented as a decimal floating point number in a reasonable number of
2081 digits. For example, NaN's, infinities, and other special values are
2082 represented in their IEEE hexadecimal format so that assembly and disassembly
2083 do not cause any bits to change in the constants.</p>
2084
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2085<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2086 represented using the 16-digit form shown above (which matches the IEEE754
2087 representation for double); float values must, however, be exactly
2088 representable as IEE754 single precision. Hexadecimal format is always used
2089 for long double, and there are three forms of long double. The 80-bit format
2090 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2091 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2092 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2093 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2094 currently supported target uses this format. Long doubles will only work if
2095 they match the long double format on your target. All hexadecimal formats
2096 are big-endian (sign bit at the left).</p>
2097
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2098<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099</div>
2100
2101<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2102<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2103<a name="aggregateconstants"></a> <!-- old anchor -->
2104<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2105</div>
2106
2107<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2109<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2111
2112<dl>
2113 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2114 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2115 type definitions (a comma separated list of elements, surrounded by braces
2116 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2117 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2118 Structure constants must have <a href="#t_struct">structure type</a>, and
2119 the number and types of elements must match those specified by the
2120 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2121
2122 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2170<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2171@X = global i32 17
2172@Y = global i32 42
2173@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2174</pre>
2175
2176</div>
2177
2178<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2179<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2180<div class="doc_text">
2181
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2182<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2183 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2184 Undefined values may be of any type (other than '<tt>label</tt>'
2185 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2187<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 program is well defined no matter what value is used. This gives the
2189 compiler more freedom to optimize. Here are some examples of (potentially
2190 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2191
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2192
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2193<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2194 %A = add %X, undef
2195 %B = sub %X, undef
2196 %C = xor %X, undef
2197Safe:
2198 %A = undef
2199 %B = undef
2200 %C = undef
2201</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2202
2203<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2204 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2205
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2206<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2207 %A = or %X, undef
2208 %B = and %X, undef
2209Safe:
2210 %A = -1
2211 %B = 0
2212Unsafe:
2213 %A = undef
2214 %B = undef
2215</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2216
2217<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2218 For example, if <tt>%X</tt> has a zero bit, then the output of the
2219 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2220 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2221 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2222 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2223 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2224 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2225 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2226
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2227<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2228 %A = select undef, %X, %Y
2229 %B = select undef, 42, %Y
2230 %C = select %X, %Y, undef
2231Safe:
2232 %A = %X (or %Y)
2233 %B = 42 (or %Y)
2234 %C = %Y
2235Unsafe:
2236 %A = undef
2237 %B = undef
2238 %C = undef
2239</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2240
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2241<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2242 branch) conditions can go <em>either way</em>, but they have to come from one
2243 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2244 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2245 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2246 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2247 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2248 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2250<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2251 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2252
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2253 %B = undef
2254 %C = xor %B, %B
2255
2256 %D = undef
2257 %E = icmp lt %D, 4
2258 %F = icmp gte %D, 4
2259
2260Safe:
2261 %A = undef
2262 %B = undef
2263 %C = undef
2264 %D = undef
2265 %E = undef
2266 %F = undef
2267</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2268
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2269<p>This example points out that two '<tt>undef</tt>' operands are not
2270 necessarily the same. This can be surprising to people (and also matches C
2271 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2272 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2273 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2274 its value over its "live range". This is true because the variable doesn't
2275 actually <em>have a live range</em>. Instead, the value is logically read
2276 from arbitrary registers that happen to be around when needed, so the value
2277 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2278 need to have the same semantics or the core LLVM "replace all uses with"
2279 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2280
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2281<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2282 %A = fdiv undef, %X
2283 %B = fdiv %X, undef
2284Safe:
2285 %A = undef
2286b: unreachable
2287</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2288
2289<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2290 value</em> and <em>undefined behavior</em>. An undefined value (like
2291 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2292 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2293 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2294 defined on SNaN's. However, in the second example, we can make a more
2295 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2296 arbitrary value, we are allowed to assume that it could be zero. Since a
2297 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2298 the operation does not execute at all. This allows us to delete the divide and
2299 all code after it. Because the undefined operation "can't happen", the
2300 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2301
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2302<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2303a: store undef -> %X
2304b: store %X -> undef
2305Safe:
2306a: &lt;deleted&gt;
2307b: unreachable
2308</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2309
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2310<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2311 undefined value can be assumed to not have any effect; we can assume that the
2312 value is overwritten with bits that happen to match what was already there.
2313 However, a store <em>to</em> an undefined location could clobber arbitrary
2314 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2315
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2316</div>
2317
2318<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2319<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2320<div class="doc_text">
2321
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2322<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2323 instead of representing an unspecified bit pattern, they represent the
2324 fact that an instruction or constant expression which cannot evoke side
2325 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2326 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2327
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2328<p>There is currently no way of representing a trap value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2329 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2330 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2332<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2333
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2334<ul>
2335<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2336 their operands.</li>
2337
2338<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2339 to their dynamic predecessor basic block.</li>
2340
2341<li>Function arguments depend on the corresponding actual argument values in
2342 the dynamic callers of their functions.</li>
2343
2344<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2345 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2346 control back to them.</li>
2347
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2348<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2349 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2350 or exception-throwing call instructions that dynamically transfer control
2351 back to them.</li>
2352
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2353<li>Non-volatile loads and stores depend on the most recent stores to all of the
2354 referenced memory addresses, following the order in the IR
2355 (including loads and stores implied by intrinsics such as
2356 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2357
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2358<!-- TODO: In the case of multiple threads, this only applies if the store
2359 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2361<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2362
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2363<li>An instruction with externally visible side effects depends on the most
2364 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2365 the order in the IR. (This includes
2366 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2367
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2368<li>An instruction <i>control-depends</i> on a
2369 <a href="#terminators">terminator instruction</a>
2370 if the terminator instruction has multiple successors and the instruction
2371 is always executed when control transfers to one of the successors, and
2372 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2373
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame^]2374<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2375 instruction if the set of instructions it otherwise depends on would be
2376 different if the terminator had transfered control to a different
2377 successor.</li>
2378
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2379<li>Dependence is transitive.</li>
2380
2381</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2382
2383<p>Whenever a trap value is generated, all values which depend on it evaluate
2384 to trap. If they have side effects, the evoke their side effects as if each
2385 operand with a trap value were undef. If they have externally-visible side
2386 effects, the behavior is undefined.</p>
2387
2388<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2389
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2390<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2391entry:
2392 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2393 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2394 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2395 store i32 0, i32* %trap_yet_again ; undefined behavior
2396
2397 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2398 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2399
2400 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2401
2402 %narrowaddr = bitcast i32* @g to i16*
2403 %wideaddr = bitcast i32* @g to i64*
2404 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2405 %trap4 = load i64* %widaddr ; Returns a trap value.
2406
2407 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2408 %br i1 %cmp, %true, %end ; Branch to either destination.
2409
2410true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2411 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2412 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2413 br label %end
2414
2415end:
2416 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2417 ; Both edges into this PHI are
2418 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2419 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2420
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame^]2421 volatile store i32 0, i32* @g ; This would depend on the store in %true
2422 ; if %cmp is true, or the store in %entry
2423 ; otherwise, so this is undefined behavior.
2424
2425 %br i1 %cmp, %second_true, %second_end
2426 ; The same branch again, but this time the
2427 ; true block doesn't have side effects.
2428
2429second_true:
2430 ; No side effects!
2431 br label %end
2432
2433second_end:
2434 volatile store i32 0, i32* @g ; This time, the instruction always depends
2435 ; on the store in %end. Also, it is
2436 ; control-equivalent to %end, so this is
2437 ; well- defined (again, ignoring earlier
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2438 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2439</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2440
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2441</div>
2442
2443<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2444<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2445 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2446<div class="doc_text">
2447
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2448<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2449
2450<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2451 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2452 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2453
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2454<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2455 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2456 comparisons against null. Pointer equality tests between labels addresses
2457 results in undefined behavior &mdash; though, again, comparison against null
2458 is ok, and no label is equal to the null pointer. This may be passed around
2459 as an opaque pointer sized value as long as the bits are not inspected. This
2460 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2461 long as the original value is reconstituted before the <tt>indirectbr</tt>
2462 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2463
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2464<p>Finally, some targets may provide defined semantics when using the value as
2465 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2466
2467</div>
2468
2469
2470<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2471<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2472</div>
2473
2474<div class="doc_text">
2475
2476<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2477 to be used as constants. Constant expressions may be of
2478 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2479 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2480 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2481
2482<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2483 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2484 <dd>Truncate a constant to another type. The bit size of CST must be larger
2485 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2486
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2487 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2488 <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]2489 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2490
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2491 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2492 <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]2493 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2494
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2495 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496 <dd>Truncate a floating point constant to another floating point type. The
2497 size of CST must be larger than the size of TYPE. Both types must be
2498 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2499
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501 <dd>Floating point extend a constant to another type. The size of CST must be
2502 smaller or equal to the size of TYPE. Both types must be floating
2503 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2504
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2505 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2506 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2507 constant. TYPE must be a scalar or vector integer type. CST must be of
2508 scalar or vector floating point type. Both CST and TYPE must be scalars,
2509 or vectors of the same number of elements. If the value won't fit in the
2510 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2511
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2512 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2513 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2514 constant. TYPE must be a scalar or vector integer type. CST must be of
2515 scalar or vector floating point type. Both CST and TYPE must be scalars,
2516 or vectors of the same number of elements. If the value won't fit in the
2517 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2518
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2520 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2521 constant. TYPE must be a scalar or vector floating point type. CST must be
2522 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2523 vectors of the same number of elements. If the value won't fit in the
2524 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2525
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2526 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2527 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528 constant. TYPE must be a scalar or vector floating point type. CST must be
2529 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2530 vectors of the same number of elements. If the value won't fit in the
2531 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2532
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2533 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2534 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2535 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2536 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2537 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2538
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2539 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2540 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2541 type. CST must be of integer type. The CST value is zero extended,
2542 truncated, or unchanged to make it fit in a pointer size. This one is
2543 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2544
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2545 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2546 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2547 are the same as those for the <a href="#i_bitcast">bitcast
2548 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2549
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2550 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2551 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2552 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2554 instruction, the index list may have zero or more indexes, which are
2555 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2556
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2557 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2558 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2559
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2560 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2561 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2562
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2563 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2564 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2565
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2566 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2568 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2569
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2570 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2571 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2572 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2573
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2574 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2575 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2576 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2577
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2578 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2579 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2580 constants. The index list is interpreted in a similar manner as indices in
2581 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2582 index value must be specified.</dd>
2583
2584 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2585 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2586 constants. The index list is interpreted in a similar manner as indices in
2587 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2588 index value must be specified.</dd>
2589
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2590 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2591 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2592 be any of the <a href="#binaryops">binary</a>
2593 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2594 on operands are the same as those for the corresponding instruction
2595 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2596</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2597
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2598</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2599
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2600<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2601<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2602<!-- *********************************************************************** -->
2603
2604<!-- ======================================================================= -->
2605<div class="doc_subsection">
2606<a name="inlineasm">Inline Assembler Expressions</a>
2607</div>
2608
2609<div class="doc_text">
2610
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2611<p>LLVM supports inline assembler expressions (as opposed
2612 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2613 a special value. This value represents the inline assembler as a string
2614 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2615 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2616 expression has side effects, and a flag indicating whether the function
2617 containing the asm needs to align its stack conservatively. An example
2618 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2619
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2620<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2621i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2622</pre>
2623
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2624<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2625 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2626 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2627
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2629%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]2630</pre>
2631
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2632<p>Inline asms with side effects not visible in the constraint list must be
2633 marked as having side effects. This is done through the use of the
2634 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2635
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2636<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2637call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2638</pre>
2639
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2640<p>In some cases inline asms will contain code that will not work unless the
2641 stack is aligned in some way, such as calls or SSE instructions on x86,
2642 yet will not contain code that does that alignment within the asm.
2643 The compiler should make conservative assumptions about what the asm might
2644 contain and should generate its usual stack alignment code in the prologue
2645 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2646
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2647<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2648call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2649</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2650
2651<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2652 first.</p>
2653
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2654<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2655 documented here. Constraints on what can be done (e.g. duplication, moving,
2656 etc need to be documented). This is probably best done by reference to
2657 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2658</div>
2659
2660<div class="doc_subsubsection">
2661<a name="inlineasm_md">Inline Asm Metadata</a>
2662</div>
2663
2664<div class="doc_text">
2665
2666<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2667 attached to it that contains a list of constant integers. If present, the
2668 code generator will use the integer as the location cookie value when report
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2669 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2670 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2671 source code that produced it. For example:</p>
2672
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2673<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2674call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2675...
2676!42 = !{ i32 1234567 }
2677</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2678
2679<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]2680 IR. If the MDNode contains multiple constants, the code generator will use
2681 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]2682
2683</div>
2684
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2685<!-- ======================================================================= -->
2686<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2687 Strings</a>
2688</div>
2689
2690<div class="doc_text">
2691
2692<p>LLVM IR allows metadata to be attached to instructions in the program that
2693 can convey extra information about the code to the optimizers and code
2694 generator. One example application of metadata is source-level debug
2695 information. There are two metadata primitives: strings and nodes. All
2696 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2697 preceding exclamation point ('<tt>!</tt>').</p>
2698
2699<p>A metadata string is a string surrounded by double quotes. It can contain
2700 any character by escaping non-printable characters with "\xx" where "xx" is
2701 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2702
2703<p>Metadata nodes are represented with notation similar to structure constants
2704 (a comma separated list of elements, surrounded by braces and preceded by an
2705 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2706 10}</tt>". Metadata nodes can have any values as their operand.</p>
2707
2708<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2709 metadata nodes, which can be looked up in the module symbol table. For
2710 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2711
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2712<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2713 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2714
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2715<div class="doc_code">
2716<pre>
2717call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2718</pre>
2719</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2720
2721<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2722 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2723
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2724<div class="doc_code">
2725<pre>
2726%indvar.next = add i64 %indvar, 1, !dbg !21
2727</pre>
2728</div>
2729
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2730</div>
2731
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2732
2733<!-- *********************************************************************** -->
2734<div class="doc_section">
2735 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2736</div>
2737<!-- *********************************************************************** -->
2738
2739<p>LLVM has a number of "magic" global variables that contain data that affect
2740code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2741of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2742section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2743by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2744
2745<!-- ======================================================================= -->
2746<div class="doc_subsection">
2747<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2748</div>
2749
2750<div class="doc_text">
2751
2752<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2753href="#linkage_appending">appending linkage</a>. This array contains a list of
2754pointers to global variables and functions which may optionally have a pointer
2755cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2756
2757<pre>
2758 @X = global i8 4
2759 @Y = global i32 123
2760
2761 @llvm.used = appending global [2 x i8*] [
2762 i8* @X,
2763 i8* bitcast (i32* @Y to i8*)
2764 ], section "llvm.metadata"
2765</pre>
2766
2767<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2768compiler, assembler, and linker are required to treat the symbol as if there is
2769a reference to the global that it cannot see. For example, if a variable has
2770internal linkage and no references other than that from the <tt>@llvm.used</tt>
2771list, it cannot be deleted. This is commonly used to represent references from
2772inline asms and other things the compiler cannot "see", and corresponds to
2773"attribute((used))" in GNU C.</p>
2774
2775<p>On some targets, the code generator must emit a directive to the assembler or
2776object file to prevent the assembler and linker from molesting the symbol.</p>
2777
2778</div>
2779
2780<!-- ======================================================================= -->
2781<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2782<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2783</div>
2784
2785<div class="doc_text">
2786
2787<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2788<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2789touching the symbol. On targets that support it, this allows an intelligent
2790linker to optimize references to the symbol without being impeded as it would be
2791by <tt>@llvm.used</tt>.</p>
2792
2793<p>This is a rare construct that should only be used in rare circumstances, and
2794should not be exposed to source languages.</p>
2795
2796</div>
2797
2798<!-- ======================================================================= -->
2799<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2800<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2801</div>
2802
2803<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2804<pre>
2805%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2806@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2807</pre>
2808<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.
2809</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2810
2811</div>
2812
2813<!-- ======================================================================= -->
2814<div class="doc_subsection">
2815<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2816</div>
2817
2818<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2819<pre>
2820%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2821@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2822</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2823
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2824<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.
2825</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2826
2827</div>
2828
2829
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2830<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2831<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2832<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2833
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2834<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2836<p>The LLVM instruction set consists of several different classifications of
2837 instructions: <a href="#terminators">terminator
2838 instructions</a>, <a href="#binaryops">binary instructions</a>,
2839 <a href="#bitwiseops">bitwise binary instructions</a>,
2840 <a href="#memoryops">memory instructions</a>, and
2841 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2842
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2843</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2845<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2846<div class="doc_subsection"> <a name="terminators">Terminator
2847Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2848
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2849<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2851<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2852 in a program ends with a "Terminator" instruction, which indicates which
2853 block should be executed after the current block is finished. These
2854 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2855 control flow, not values (the one exception being the
2856 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2857
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2858<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2859 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2860 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2861 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2862 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2863 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2864 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2865 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2869<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2870<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2871Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2872
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2873<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2876<pre>
2877 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]2878 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2879</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2881<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2883 a value) from a function back to the caller.</p>
2884
2885<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2886 value and then causes control flow, and one that just causes control flow to
2887 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2888
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2889<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2890<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2891 return value. The type of the return value must be a
2892 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2895 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2896 value or a return value with a type that does not match its type, or if it
2897 has a void return type and contains a '<tt>ret</tt>' instruction with a
2898 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2900<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2901<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2902 the calling function's context. If the caller is a
2903 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2904 instruction after the call. If the caller was an
2905 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2906 the beginning of the "normal" destination block. If the instruction returns
2907 a value, that value shall set the call or invoke instruction's return
2908 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2909
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2910<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2911<pre>
2912 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2913 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2914 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]2915</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2917</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2919<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2920
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2921<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924<pre>
2925 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]2926</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2929<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2930 different basic block in the current function. There are two forms of this
2931 instruction, corresponding to a conditional branch and an unconditional
2932 branch.</p>
2933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2934<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2935<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2936 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2937 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2938 target.</p>
2939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2940<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2941<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2942 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2943 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2944 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2946<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2947<pre>
2948Test:
2949 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2950 br i1 %cond, label %IfEqual, label %IfUnequal
2951IfEqual:
2952 <a href="#i_ret">ret</a> i32 1
2953IfUnequal:
2954 <a href="#i_ret">ret</a> i32 0
2955</pre>
2956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2957</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2958
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2959<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2960<div class="doc_subsubsection">
2961 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2962</div>
2963
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2964<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2965
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2967<pre>
2968 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2969</pre>
2970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2971<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2972<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]2973 several different places. It is a generalization of the '<tt>br</tt>'
2974 instruction, allowing a branch to occur to one of many possible
2975 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2977<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2978<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2979 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2980 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2981 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2984<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2985 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2986 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2987 transferred to the corresponding destination; otherwise, control flow is
2988 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2989
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2991<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2992 <tt>switch</tt> instruction, this instruction may be code generated in
2993 different ways. For example, it could be generated as a series of chained
2994 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2995
2996<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2997<pre>
2998 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2999 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3000 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3001
3002 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3003 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3004
3005 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3006 switch i32 %val, label %otherwise [ i32 0, label %onzero
3007 i32 1, label %onone
3008 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3009</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3010
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3011</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3012
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3013
3014<!-- _______________________________________________________________________ -->
3015<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3016 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3017</div>
3018
3019<div class="doc_text">
3020
3021<h5>Syntax:</h5>
3022<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3023 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]3024</pre>
3025
3026<h5>Overview:</h5>
3027
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3028<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3029 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3030 "<tt>address</tt>". Address must be derived from a <a
3031 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3032
3033<h5>Arguments:</h5>
3034
3035<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3036 rest of the arguments indicate the full set of possible destinations that the
3037 address may point to. Blocks are allowed to occur multiple times in the
3038 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3039
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3040<p>This destination list is required so that dataflow analysis has an accurate
3041 understanding of the CFG.</p>
3042
3043<h5>Semantics:</h5>
3044
3045<p>Control transfers to the block specified in the address argument. All
3046 possible destination blocks must be listed in the label list, otherwise this
3047 instruction has undefined behavior. This implies that jumps to labels
3048 defined in other functions have undefined behavior as well.</p>
3049
3050<h5>Implementation:</h5>
3051
3052<p>This is typically implemented with a jump through a register.</p>
3053
3054<h5>Example:</h5>
3055<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3056 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3057</pre>
3058
3059</div>
3060
3061
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3062<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3063<div class="doc_subsubsection">
3064 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3065</div>
3066
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3067<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3069<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3071 &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]3072 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073</pre>
3074
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3075<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3076<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077 function, with the possibility of control flow transfer to either the
3078 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3079 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3080 control flow will return to the "normal" label. If the callee (or any
3081 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3082 instruction, control is interrupted and continued at the dynamically nearest
3083 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3084
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3085<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3086<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3087
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3088<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3089 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3090 convention</a> the call should use. If none is specified, the call
3091 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3092
3093 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3094 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3095 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3096
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3097 <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]3098 function value being invoked. In most cases, this is a direct function
3099 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3100 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3101
3102 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3103 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3104
3105 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3106 signature argument types and parameter attributes. All arguments must be
3107 of <a href="#t_firstclass">first class</a> type. If the function
3108 signature indicates the function accepts a variable number of arguments,
3109 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3110
3111 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3113
3114 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3116
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3117 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3119 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3120</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3121
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3122<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<p>This instruction is designed to operate as a standard
3124 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3125 primary difference is that it establishes an association with a label, which
3126 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3127
3128<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3130 exception. Additionally, this is important for implementation of
3131 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3133<p>For the purposes of the SSA form, the definition of the value returned by the
3134 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3135 block to the "normal" label. If the callee unwinds then no return value is
3136 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3137
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3138<p>Note that the code generator does not yet completely support unwind, and
3139that the invoke/unwind semantics are likely to change in future versions.</p>
3140
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3141<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3142<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3143 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3144 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3145 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3146 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3147</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3148
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3150
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3151<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3152
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3153<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3154Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3156<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3157
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3158<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3159<pre>
3160 unwind
3161</pre>
3162
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3163<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3164<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165 at the first callee in the dynamic call stack which used
3166 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3167 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3168
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3169<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3170<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171 immediately halt. The dynamic call stack is then searched for the
3172 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3173 Once found, execution continues at the "exceptional" destination block
3174 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3175 instruction in the dynamic call chain, undefined behavior results.</p>
3176
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3177<p>Note that the code generator does not yet completely support unwind, and
3178that the invoke/unwind semantics are likely to change in future versions.</p>
3179
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3180</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3181
3182<!-- _______________________________________________________________________ -->
3183
3184<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3185Instruction</a> </div>
3186
3187<div class="doc_text">
3188
3189<h5>Syntax:</h5>
3190<pre>
3191 unreachable
3192</pre>
3193
3194<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3195<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196 instruction is used to inform the optimizer that a particular portion of the
3197 code is not reachable. This can be used to indicate that the code after a
3198 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3199
3200<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3201<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3203</div>
3204
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3205<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3206<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3208<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209
3210<p>Binary operators are used to do most of the computation in a program. They
3211 require two operands of the same type, execute an operation on them, and
3212 produce a single value. The operands might represent multiple data, as is
3213 the case with the <a href="#t_vector">vector</a> data type. The result value
3214 has the same type as its operands.</p>
3215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3216<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3217
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3218</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3220<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3221<div class="doc_subsubsection">
3222 <a name="i_add">'<tt>add</tt>' Instruction</a>
3223</div>
3224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3225<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3227<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3228<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3229 &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]3230 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3231 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3232 &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]3233</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3235<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3236<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3237
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3238<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3239<p>The two arguments to the '<tt>add</tt>' instruction must
3240 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3241 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3242
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3243<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3244<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3245
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3246<p>If the sum has unsigned overflow, the result returned is the mathematical
3247 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]3248
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3249<p>Because LLVM integers use a two's complement representation, this instruction
3250 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3251
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3252<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3253 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3254 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3255 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3256 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3261</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3263</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3265<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3266<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3267 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3268</div>
3269
3270<div class="doc_text">
3271
3272<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3273<pre>
3274 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3275</pre>
3276
3277<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3278<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3279
3280<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3281<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3282 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3283 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3284
3285<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3286<p>The value produced is the floating point sum of the two operands.</p>
3287
3288<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3289<pre>
3290 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3291</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3292
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3293</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3295<!-- _______________________________________________________________________ -->
3296<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3297 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3298</div>
3299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3300<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3301
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3302<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3304 &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]3305 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3306 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3307 &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]3308</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3309
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3310<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3311<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3312 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3313
3314<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3315 '<tt>neg</tt>' instruction present in most other intermediate
3316 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3318<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319<p>The two arguments to the '<tt>sub</tt>' instruction must
3320 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3321 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3323<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3324<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3325
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3326<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3327 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3328 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330<p>Because LLVM integers use a two's complement representation, this instruction
3331 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3332
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3333<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3334 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3335 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3336 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3337 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3338
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3339<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3340<pre>
3341 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3342 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3343</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3345</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3346
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3347<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3348<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3349 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3350</div>
3351
3352<div class="doc_text">
3353
3354<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3355<pre>
3356 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3357</pre>
3358
3359<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3360<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3361 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3362
3363<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364 '<tt>fneg</tt>' instruction present in most other intermediate
3365 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3366
3367<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3368<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3369 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3370 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3371
3372<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3373<p>The value produced is the floating point difference of the two operands.</p>
3374
3375<h5>Example:</h5>
3376<pre>
3377 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3378 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3379</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3381</div>
3382
3383<!-- _______________________________________________________________________ -->
3384<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3385 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3386</div>
3387
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3388<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3390<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3391<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3392 &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]3393 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3394 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3395 &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]3396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3398<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3399<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3401<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402<p>The two arguments to the '<tt>mul</tt>' instruction must
3403 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3404 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3405
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3406<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409<p>If the result of the multiplication has unsigned overflow, the result
3410 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3411 width of the result.</p>
3412
3413<p>Because LLVM integers use a two's complement representation, and the result
3414 is the same width as the operands, this instruction returns the correct
3415 result for both signed and unsigned integers. If a full product
3416 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3417 be sign-extended or zero-extended as appropriate to the width of the full
3418 product.</p>
3419
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3420<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3421 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3422 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3423 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3424 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3425
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3426<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3430
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3431</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3432
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3433<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3434<div class="doc_subsubsection">
3435 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3436</div>
3437
3438<div class="doc_text">
3439
3440<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441<pre>
3442 &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]3443</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3445<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3447
3448<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3449<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3451 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3452
3453<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3454<p>The value produced is the floating point product of the two operands.</p>
3455
3456<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3457<pre>
3458 &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]3459</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3461</div>
3462
3463<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3464<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3465</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3466
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3467<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3468
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3471 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3472 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3473</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3475<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3476<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3477
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3478<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3479<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3481 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3482
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3483<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3484<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3485
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3486<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3487 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3488
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3489<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3491<p>If the <tt>exact</tt> keyword is present, the result value of the
3492 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3493 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3494
3495
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3496<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497<pre>
3498 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3499</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3501</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3503<!-- _______________________________________________________________________ -->
3504<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3505</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3507<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3509<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3511 &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]3512 &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]3513</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3514
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3515<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3516<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3517
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3518<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3519<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3520 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3521 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3522
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3523<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524<p>The value produced is the signed integer quotient of the two operands rounded
3525 towards zero.</p>
3526
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3527<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3529
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3530<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531 undefined behavior; this is a rare case, but can occur, for example, by doing
3532 a 32-bit division of -2147483648 by -1.</p>
3533
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3534<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3535 <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]3536 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3537
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3538<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539<pre>
3540 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3541</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3542
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3543</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3545<!-- _______________________________________________________________________ -->
3546<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3549<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3551<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3552<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3553 &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]3554</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3555
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556<h5>Overview:</h5>
3557<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3559<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3560<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3562 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3563
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3564<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3565<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3567<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3568<pre>
3569 &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]3570</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3572</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3573
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3574<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3575<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3576</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3578<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3579
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3580<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3581<pre>
3582 &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]3583</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3584
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3585<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3587 division of its two arguments.</p>
3588
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3589<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3590<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3592 values. Both arguments must have identical types.</p>
3593
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3594<h5>Semantics:</h5>
3595<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3596 This instruction always performs an unsigned division to get the
3597 remainder.</p>
3598
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3599<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3600 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3601
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3602<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3604<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3605<pre>
3606 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3607</pre>
3608
3609</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612<div class="doc_subsubsection">
3613 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3614</div>
3615
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3616<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3617
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3618<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3619<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3620 &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]3621</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3622
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3623<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3624<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3625 division of its two operands. This instruction can also take
3626 <a href="#t_vector">vector</a> versions of the values in which case the
3627 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3628
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3629<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3630<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3632 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3633
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3634<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3635<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]3636 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3637 <i>modulo</i> operator (where the result is either zero or has the same sign
3638 as the divisor, <tt>op2</tt>) of a value.
3639 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3641 Math Forum</a>. For a table of how this is implemented in various languages,
3642 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3643 Wikipedia: modulo operation</a>.</p>
3644
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3645<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3646 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3647
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3648<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649 Overflow also leads to undefined behavior; this is a rare case, but can
3650 occur, for example, by taking the remainder of a 32-bit division of
3651 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3652 lets srem be implemented using instructions that return both the result of
3653 the division and the remainder.)</p>
3654
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3655<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656<pre>
3657 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3658</pre>
3659
3660</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3662<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3663<div class="doc_subsubsection">
3664 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3665
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3666<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3667
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3668<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3669<pre>
3670 &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]3671</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3672
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3673<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3675 its two operands.</p>
3676
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3677<h5>Arguments:</h5>
3678<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3680 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3681
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3682<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683<p>This instruction returns the <i>remainder</i> of a division. The remainder
3684 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3685
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3686<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3687<pre>
3688 &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]3689</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3691</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3692
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3693<!-- ======================================================================= -->
3694<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3695Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3697<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698
3699<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3700 program. They are generally very efficient instructions and can commonly be
3701 strength reduced from other instructions. They require two operands of the
3702 same type, execute an operation on them, and produce a single value. The
3703 resulting value is the same type as its operands.</p>
3704
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3705</div>
3706
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3707<!-- _______________________________________________________________________ -->
3708<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3709Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3710
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3711<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3713<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3715 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3716 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3717 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3718 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3719</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3720
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3721<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3723 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3724
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3725<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3727 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3728 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3729
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3730<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3732 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3733 is (statically or dynamically) negative or equal to or larger than the number
3734 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3735 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3736 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3737
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3738<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3739 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]3740 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3741 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3742 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3743 they would if the shift were expressed as a mul instruction with the same
3744 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3745
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746<h5>Example:</h5>
3747<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3748 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3749 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3750 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3751 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3752 &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]3753</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3754
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3755</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3757<!-- _______________________________________________________________________ -->
3758<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3759Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3760
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3761<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3763<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3764<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3765 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3766 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3767</pre>
3768
3769<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3771 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3772
3773<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3774<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3775 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3776 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3777
3778<h5>Semantics:</h5>
3779<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3780 significant bits of the result will be filled with zero bits after the shift.
3781 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3782 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3783 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3784 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3785
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3786<p>If the <tt>exact</tt> keyword is present, the result value of the
3787 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3788 shifted out are non-zero.</p>
3789
3790
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3791<h5>Example:</h5>
3792<pre>
3793 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3794 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3795 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3796 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3797 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3798 &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]3799</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3800
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3801</div>
3802
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3803<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3804<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3805Instruction</a> </div>
3806<div class="doc_text">
3807
3808<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3809<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3810 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3811 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3812</pre>
3813
3814<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3815<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3816 operand shifted to the right a specified number of bits with sign
3817 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3818
3819<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3820<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3821 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3822 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3823
3824<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825<p>This instruction always performs an arithmetic shift right operation, The
3826 most significant bits of the result will be filled with the sign bit
3827 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3828 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3829 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3830 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3831
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]3832<p>If the <tt>exact</tt> keyword is present, the result value of the
3833 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
3834 shifted out are non-zero.</p>
3835
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3836<h5>Example:</h5>
3837<pre>
3838 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3839 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3840 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3841 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3842 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3843 &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]3844</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3846</div>
3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3849<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3850Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3851
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3852<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3854<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3855<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3856 &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]3857</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3858
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3859<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3861 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3863<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3864<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3866 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3867
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3868<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3869<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3870
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3871<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3872 <tbody>
3873 <tr>
3874 <td>In0</td>
3875 <td>In1</td>
3876 <td>Out</td>
3877 </tr>
3878 <tr>
3879 <td>0</td>
3880 <td>0</td>
3881 <td>0</td>
3882 </tr>
3883 <tr>
3884 <td>0</td>
3885 <td>1</td>
3886 <td>0</td>
3887 </tr>
3888 <tr>
3889 <td>1</td>
3890 <td>0</td>
3891 <td>0</td>
3892 </tr>
3893 <tr>
3894 <td>1</td>
3895 <td>1</td>
3896 <td>1</td>
3897 </tr>
3898 </tbody>
3899</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3902<pre>
3903 &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]3904 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3905 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3907</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3908<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3909<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911<div class="doc_text">
3912
3913<h5>Syntax:</h5>
3914<pre>
3915 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3916</pre>
3917
3918<h5>Overview:</h5>
3919<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3920 two operands.</p>
3921
3922<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3923<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3924 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3925 values. Both arguments must have identical types.</p>
3926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3927<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3928<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3929
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3930<table border="1" cellspacing="0" cellpadding="4">
3931 <tbody>
3932 <tr>
3933 <td>In0</td>
3934 <td>In1</td>
3935 <td>Out</td>
3936 </tr>
3937 <tr>
3938 <td>0</td>
3939 <td>0</td>
3940 <td>0</td>
3941 </tr>
3942 <tr>
3943 <td>0</td>
3944 <td>1</td>
3945 <td>1</td>
3946 </tr>
3947 <tr>
3948 <td>1</td>
3949 <td>0</td>
3950 <td>1</td>
3951 </tr>
3952 <tr>
3953 <td>1</td>
3954 <td>1</td>
3955 <td>1</td>
3956 </tr>
3957 </tbody>
3958</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3960<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961<pre>
3962 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3963 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3964 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3965</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3967</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3969<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3970<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3971Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3972
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3973<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3975<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976<pre>
3977 &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]3978</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3980<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3982 its two operands. The <tt>xor</tt> is used to implement the "one's
3983 complement" operation, which is the "~" operator in C.</p>
3984
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3985<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3986<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3988 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3990<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3991<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3992
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3993<table border="1" cellspacing="0" cellpadding="4">
3994 <tbody>
3995 <tr>
3996 <td>In0</td>
3997 <td>In1</td>
3998 <td>Out</td>
3999 </tr>
4000 <tr>
4001 <td>0</td>
4002 <td>0</td>
4003 <td>0</td>
4004 </tr>
4005 <tr>
4006 <td>0</td>
4007 <td>1</td>
4008 <td>1</td>
4009 </tr>
4010 <tr>
4011 <td>1</td>
4012 <td>0</td>
4013 <td>1</td>
4014 </tr>
4015 <tr>
4016 <td>1</td>
4017 <td>1</td>
4018 <td>0</td>
4019 </tr>
4020 </tbody>
4021</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4022
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4023<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024<pre>
4025 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4026 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4027 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4028 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4029</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4031</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4032
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4033<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4034<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4035 <a name="vectorops">Vector Operations</a>
4036</div>
4037
4038<div class="doc_text">
4039
4040<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041 target-independent manner. These instructions cover the element-access and
4042 vector-specific operations needed to process vectors effectively. While LLVM
4043 does directly support these vector operations, many sophisticated algorithms
4044 will want to use target-specific intrinsics to take full advantage of a
4045 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4046
4047</div>
4048
4049<!-- _______________________________________________________________________ -->
4050<div class="doc_subsubsection">
4051 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4052</div>
4053
4054<div class="doc_text">
4055
4056<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4057<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4058 &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]4059</pre>
4060
4061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4063 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4064
4065
4066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4068 of <a href="#t_vector">vector</a> type. The second operand is an index
4069 indicating the position from which to extract the element. The index may be
4070 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The result is a scalar of the same type as the element type of
4074 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4075 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4076 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4077
4078<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4079<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4080 &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]4081</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4083</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4084
4085<!-- _______________________________________________________________________ -->
4086<div class="doc_subsubsection">
4087 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4088</div>
4089
4090<div class="doc_text">
4091
4092<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4093<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4094 &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]4095</pre>
4096
4097<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4098<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4099 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4100
4101<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4102<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4103 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4104 whose type must equal the element type of the first operand. The third
4105 operand is an index indicating the position at which to insert the value.
4106 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4107
4108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4109<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4110 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4111 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4112 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113
4114<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4115<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4116 &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]4117</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4118
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4119</div>
4120
4121<!-- _______________________________________________________________________ -->
4122<div class="doc_subsubsection">
4123 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4124</div>
4125
4126<div class="doc_text">
4127
4128<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4129<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4130 &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]4131</pre>
4132
4133<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4135 from two input vectors, returning a vector with the same element type as the
4136 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4137
4138<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4140 with types that match each other. The third argument is a shuffle mask whose
4141 element type is always 'i32'. The result of the instruction is a vector
4142 whose length is the same as the shuffle mask and whose element type is the
4143 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4144
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The shuffle mask operand is required to be a constant vector with either
4146 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4147
4148<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4149<p>The elements of the two input vectors are numbered from left to right across
4150 both of the vectors. The shuffle mask operand specifies, for each element of
4151 the result vector, which element of the two input vectors the result element
4152 gets. The element selector may be undef (meaning "don't care") and the
4153 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4154
4155<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4156<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4157 &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]4158 &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]4159 &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]4160 &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]4161 &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]4162 &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]4163 &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]4164 &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]4165</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4166
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4167</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4168
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4169<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4170<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171 <a name="aggregateops">Aggregate Operations</a>
4172</div>
4173
4174<div class="doc_text">
4175
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4176<p>LLVM supports several instructions for working with
4177 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4178
4179</div>
4180
4181<!-- _______________________________________________________________________ -->
4182<div class="doc_subsubsection">
4183 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4184</div>
4185
4186<div class="doc_text">
4187
4188<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4189<pre>
4190 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4191</pre>
4192
4193<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4194<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4195 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4196
4197<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4198<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4199 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4200 <a href="#t_array">array</a> type. The operands are constant indices to
4201 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4202 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4203 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4204 <ul>
4205 <li>Since the value being indexed is not a pointer, the first index is
4206 omitted and assumed to be zero.</li>
4207 <li>At least one index must be specified.</li>
4208 <li>Not only struct indices but also array indices must be in
4209 bounds.</li>
4210 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4211
4212<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4213<p>The result is the value at the position in the aggregate specified by the
4214 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4215
4216<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4217<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4218 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4219</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4220
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4221</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4222
4223<!-- _______________________________________________________________________ -->
4224<div class="doc_subsubsection">
4225 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4226</div>
4227
4228<div class="doc_text">
4229
4230<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4231<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4232 &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]4233</pre>
4234
4235<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4236<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4237 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4238
4239<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4241 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4242 <a href="#t_array">array</a> type. The second operand is a first-class
4243 value to insert. The following operands are constant indices indicating
4244 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]4245 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246 value to insert must have the same type as the value identified by the
4247 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4248
4249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4251 that of <tt>val</tt> except that the value at the position specified by the
4252 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4253
4254<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4255<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4256 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4257 %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]4258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4260</div>
4261
4262
4263<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4264<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4265 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4266</div>
4267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4268<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4269
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270<p>A key design point of an SSA-based representation is how it represents
4271 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4272 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4275</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4277<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4278<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4279 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4280</div>
4281
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4282<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4283
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4284<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4285<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4286 &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]4287</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4289<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4290<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291 currently executing function, to be automatically released when this function
4292 returns to its caller. The object is always allocated in the generic address
4293 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4295<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296<p>The '<tt>alloca</tt>' instruction
4297 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4298 runtime stack, returning a pointer of the appropriate type to the program.
4299 If "NumElements" is specified, it is the number of elements allocated,
4300 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4301 specified, the value result of the allocation is guaranteed to be aligned to
4302 at least that boundary. If not specified, or if zero, the target can choose
4303 to align the allocation on any convenient boundary compatible with the
4304 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4306<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4307
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4308<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4309<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4311 memory is automatically released when the function returns. The
4312 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4313 variables that must have an address available. When the function returns
4314 (either with the <tt><a href="#i_ret">ret</a></tt>
4315 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4316 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4318<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4319<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4320 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4321 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4322 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4323 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4324</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4326</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4327
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4328<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4329<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4330Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4332<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4334<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4336 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4337 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4338 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339</pre>
4340
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4341<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4342<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4344<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4346 from which to load. The pointer must point to
4347 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4348 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4349 number or order of execution of this <tt>load</tt> with other <a
4350 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4351
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4352<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353 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]4354 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355 alignment for the target. It is the responsibility of the code emitter to
4356 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4357 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4358 produce less efficient code. An alignment of 1 is always safe.</p>
4359
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4360<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4361 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4362 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4363 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4364 and code generator that this load is not expected to be reused in the cache.
4365 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4366 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4367
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4368<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369<p>The location of memory pointed to is loaded. If the value being loaded is of
4370 scalar type then the number of bytes read does not exceed the minimum number
4371 of bytes needed to hold all bits of the type. For example, loading an
4372 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4373 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4374 is undefined if the value was not originally written using a store of the
4375 same type.</p>
4376
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4377<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4378<pre>
4379 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4380 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4381 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4384</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4385
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4386<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4387<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4388Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4389
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4391
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4392<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4394 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>
4395 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]4396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4398<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4399<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4401<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4403 and an address at which to store it. The type of the
4404 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4405 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4406 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4407 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4408 order of execution of this <tt>store</tt> with other <a
4409 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410
4411<p>The optional constant "align" argument specifies the alignment of the
4412 operation (that is, the alignment of the memory address). A value of 0 or an
4413 omitted "align" argument means that the operation has the preferential
4414 alignment for the target. It is the responsibility of the code emitter to
4415 ensure that the alignment information is correct. Overestimating the
4416 alignment results in an undefined behavior. Underestimating the alignment may
4417 produce less efficient code. An alignment of 1 is always safe.</p>
4418
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4419<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4420 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4421 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4422 instruction tells the optimizer and code generator that this load is
4423 not expected to be reused in the cache. The code generator may
4424 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4425 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4426
4427
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4428<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4430 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4431 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4432 does not exceed the minimum number of bytes needed to hold all bits of the
4433 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4434 writing a value of a type like <tt>i20</tt> with a size that is not an
4435 integral number of bytes, it is unspecified what happens to the extra bits
4436 that do not belong to the type, but they will typically be overwritten.</p>
4437
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4438<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439<pre>
4440 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4441 store i32 3, i32* %ptr <i>; yields {void}</i>
4442 %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]4443</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4444
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4445</div>
4446
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4447<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4448<div class="doc_subsubsection">
4449 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4450</div>
4451
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4452<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4453
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4454<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4455<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4456 &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]4457 &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]4458</pre>
4459
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4461<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4462 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4463 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4464
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4465<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4466<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4467 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4468 elements of the aggregate object are indexed. The interpretation of each
4469 index is dependent on the type being indexed into. The first index always
4470 indexes the pointer value given as the first argument, the second index
4471 indexes a value of the type pointed to (not necessarily the value directly
4472 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4473 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4474 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4475 can never be pointers, since that would require loading the pointer before
4476 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4477
4478<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]4479 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4480 integer <b>constants</b> are allowed. When indexing into an array, pointer
4481 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]4482 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4483
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4484<p>For example, let's consider a C code fragment and how it gets compiled to
4485 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4486
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4487<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4488struct RT {
4489 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4490 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4491 char C;
4492};
4493struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4494 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4495 double Y;
4496 struct RT Z;
4497};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4498
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4499int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4500 return &amp;s[1].Z.B[5][13];
4501}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4502</pre>
4503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4504<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4505
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4506<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4507%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4508%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4509
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4510define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4511entry:
4512 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4513 ret i32* %reg
4514}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4515</pre>
4516
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4517<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4518<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]4519 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4520 }</tt>' type, a structure. The second index indexes into the third element
4521 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4522 i8 }</tt>' type, another structure. The third index indexes into the second
4523 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4524 array. The two dimensions of the array are subscripted into, yielding an
4525 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4526 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4527
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4528<p>Note that it is perfectly legal to index partially through a structure,
4529 returning a pointer to an inner element. Because of this, the LLVM code for
4530 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4531
4532<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4533 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4534 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4535 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4536 %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]4537 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4538 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4539 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4540 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4541</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4542
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4543<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4544 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4545 base pointer is not an <i>in bounds</i> address of an allocated object,
4546 or if any of the addresses that would be formed by successive addition of
4547 the offsets implied by the indices to the base address with infinitely
4548 precise arithmetic are not an <i>in bounds</i> address of that allocated
4549 object. The <i>in bounds</i> addresses for an allocated object are all
4550 the addresses that point into the object, plus the address one byte past
4551 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4552
4553<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4554 the base address with silently-wrapping two's complement arithmetic, and
4555 the result value of the <tt>getelementptr</tt> may be outside the object
4556 pointed to by the base pointer. The result value may not necessarily be
4557 used to access memory though, even if it happens to point into allocated
4558 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4559 section for more information.</p>
4560
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561<p>The getelementptr instruction is often confusing. For some more insight into
4562 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4563
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4564<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4565<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4566 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4567 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4568 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4569 %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]4570 <i>; yields i8*:eptr</i>
4571 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4572 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4573 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4574</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4576</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4578<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4579<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4580</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4582<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4583
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4584<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585 which all take a single operand and a type. They perform various bit
4586 conversions on the operand.</p>
4587
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4588</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4589
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4590<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4591<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4592 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4593</div>
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597<pre>
4598 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4599</pre>
4600
4601<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4603 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4604
4605<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4606<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
4607 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4608 of the same number of integers.
4609 The bit size of the <tt>value</tt> must be larger than
4610 the bit size of the destination type, <tt>ty2</tt>.
4611 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612
4613<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4614<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4615 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4616 source size must be larger than the destination size, <tt>trunc</tt> cannot
4617 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4618
4619<h5>Example:</h5>
4620<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4621 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4622 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4623 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
4624 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4625</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4627</div>
4628
4629<!-- _______________________________________________________________________ -->
4630<div class="doc_subsubsection">
4631 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4632</div>
4633<div class="doc_text">
4634
4635<h5>Syntax:</h5>
4636<pre>
4637 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4638</pre>
4639
4640<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4641<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4643
4644
4645<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]4646<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
4647 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4648 of the same number of integers.
4649 The bit size of the <tt>value</tt> must be smaller than
4650 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4652
4653<h5>Semantics:</h5>
4654<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]4655 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4656
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4657<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]4658
4659<h5>Example:</h5>
4660<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4661 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4662 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]4663 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4664</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4666</div>
4667
4668<!-- _______________________________________________________________________ -->
4669<div class="doc_subsubsection">
4670 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4671</div>
4672<div class="doc_text">
4673
4674<h5>Syntax:</h5>
4675<pre>
4676 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4677</pre>
4678
4679<h5>Overview:</h5>
4680<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4681
4682<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4683<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
4684 Both types must be of <a href="#t_integer">integer</a> types, or vectors
4685 of the same number of integers.
4686 The bit size of the <tt>value</tt> must be smaller than
4687 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4689
4690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4692 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4693 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4694
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4695<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]4696
4697<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4698<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4699 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4700 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]4701 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4702</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4703
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4704</div>
4705
4706<!-- _______________________________________________________________________ -->
4707<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4708 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4709</div>
4710
4711<div class="doc_text">
4712
4713<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4714<pre>
4715 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4716</pre>
4717
4718<h5>Overview:</h5>
4719<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4721
4722<h5>Arguments:</h5>
4723<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4725 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]4726 <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]4727 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4728
4729<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4731 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732 <a href="#t_floating">floating point</a> type. If the value cannot fit
4733 within the destination type, <tt>ty2</tt>, then the results are
4734 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4735
4736<h5>Example:</h5>
4737<pre>
4738 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4739 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4740</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4742</div>
4743
4744<!-- _______________________________________________________________________ -->
4745<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4746 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4747</div>
4748<div class="doc_text">
4749
4750<h5>Syntax:</h5>
4751<pre>
4752 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4753</pre>
4754
4755<h5>Overview:</h5>
4756<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]4757 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4758
4759<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4760<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4761 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4762 a <a href="#t_floating">floating point</a> type to cast it to. The source
4763 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764
4765<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4766<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767 <a href="#t_floating">floating point</a> type to a larger
4768 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4769 used to make a <i>no-op cast</i> because it always changes bits. Use
4770 <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]4771
4772<h5>Example:</h5>
4773<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]4774 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
4775 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4776</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4777
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4778</div>
4779
4780<!-- _______________________________________________________________________ -->
4781<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4782 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4783</div>
4784<div class="doc_text">
4785
4786<h5>Syntax:</h5>
4787<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4788 &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]4789</pre>
4790
4791<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4792<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4794
4795<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4797 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4798 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4799 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4800 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4801
4802<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4803<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4804 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4805 towards zero) unsigned integer value. If the value cannot fit
4806 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4808<h5>Example:</h5>
4809<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4810 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4811 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4812 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4813</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4814
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4815</div>
4816
4817<!-- _______________________________________________________________________ -->
4818<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4819 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4820</div>
4821<div class="doc_text">
4822
4823<h5>Syntax:</h5>
4824<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4825 &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]4826</pre>
4827
4828<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4829<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4830 <a href="#t_floating">floating point</a> <tt>value</tt> to
4831 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4832
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4833<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4835 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4836 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4837 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4838 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4839
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4840<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4841<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4843 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4844 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4845
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4846<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4847<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4848 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4849 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4850 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4851</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4852
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4853</div>
4854
4855<!-- _______________________________________________________________________ -->
4856<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4857 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4858</div>
4859<div class="doc_text">
4860
4861<h5>Syntax:</h5>
4862<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4863 &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]4864</pre>
4865
4866<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4867<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4868 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4869
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4870<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4871<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]4872 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4873 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4874 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4875 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4876
4877<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4878<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4879 integer quantity and converts it to the corresponding floating point
4880 value. If the value cannot fit in the floating point value, the results are
4881 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4882
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4883<h5>Example:</h5>
4884<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4885 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4886 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4887</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4889</div>
4890
4891<!-- _______________________________________________________________________ -->
4892<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4893 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4894</div>
4895<div class="doc_text">
4896
4897<h5>Syntax:</h5>
4898<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4899 &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]4900</pre>
4901
4902<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4904 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4905
4906<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4907<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]4908 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4909 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4910 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4911 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4912
4913<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4914<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4915 quantity and converts it to the corresponding floating point value. If the
4916 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4917
4918<h5>Example:</h5>
4919<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4920 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4921 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4922</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4924</div>
4925
4926<!-- _______________________________________________________________________ -->
4927<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4928 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4929</div>
4930<div class="doc_text">
4931
4932<h5>Syntax:</h5>
4933<pre>
4934 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4935</pre>
4936
4937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4939 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4940
4941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4943 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4944 <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]4945
4946<h5>Semantics:</h5>
4947<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4948 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4949 truncating or zero extending that value to the size of the integer type. If
4950 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4951 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4952 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4953 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4954
4955<h5>Example:</h5>
4956<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4957 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4958 %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]4959</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4961</div>
4962
4963<!-- _______________________________________________________________________ -->
4964<div class="doc_subsubsection">
4965 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4966</div>
4967<div class="doc_text">
4968
4969<h5>Syntax:</h5>
4970<pre>
4971 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4972</pre>
4973
4974<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4975<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4976 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4977
4978<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4979<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4980 value to cast, and a type to cast it to, which must be a
4981 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4982
4983<h5>Semantics:</h5>
4984<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4985 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4986 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4987 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4988 than the size of a pointer then a zero extension is done. If they are the
4989 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4990
4991<h5>Example:</h5>
4992<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4993 %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]4994 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4995 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4996</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4998</div>
4999
5000<!-- _______________________________________________________________________ -->
5001<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5002 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5003</div>
5004<div class="doc_text">
5005
5006<h5>Syntax:</h5>
5007<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5008 &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]5009</pre>
5010
5011<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5012<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5014
5015<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5017 non-aggregate first class value, and a type to cast it to, which must also be
5018 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5019 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5020 identical. If the source type is a pointer, the destination type must also be
5021 a pointer. This instruction supports bitwise conversion of vectors to
5022 integers and to vectors of other types (as long as they have the same
5023 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5024
5025<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5026<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5028 this conversion. The conversion is done as if the <tt>value</tt> had been
5029 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5030 be converted to other pointer types with this instruction. To convert
5031 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5032 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5033
5034<h5>Example:</h5>
5035<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5036 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5037 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5038 %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]5039</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5041</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5042
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5043<!-- ======================================================================= -->
5044<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5046<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5047
5048<p>The instructions in this category are the "miscellaneous" instructions, which
5049 defy better classification.</p>
5050
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5051</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5052
5053<!-- _______________________________________________________________________ -->
5054<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5055</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5057<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5058
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5059<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5060<pre>
5061 &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]5062</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5063
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5064<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5065<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5066 boolean values based on comparison of its two integer, integer vector, or
5067 pointer operands.</p>
5068
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5069<h5>Arguments:</h5>
5070<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071 the condition code indicating the kind of comparison to perform. It is not a
5072 value, just a keyword. The possible condition code are:</p>
5073
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5074<ol>
5075 <li><tt>eq</tt>: equal</li>
5076 <li><tt>ne</tt>: not equal </li>
5077 <li><tt>ugt</tt>: unsigned greater than</li>
5078 <li><tt>uge</tt>: unsigned greater or equal</li>
5079 <li><tt>ult</tt>: unsigned less than</li>
5080 <li><tt>ule</tt>: unsigned less or equal</li>
5081 <li><tt>sgt</tt>: signed greater than</li>
5082 <li><tt>sge</tt>: signed greater or equal</li>
5083 <li><tt>slt</tt>: signed less than</li>
5084 <li><tt>sle</tt>: signed less or equal</li>
5085</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5086
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5087<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5089 typed. They must also be identical types.</p>
5090
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5091<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5092<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5093 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5094 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]5095 result, as follows:</p>
5096
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5097<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5098 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5099 <tt>false</tt> otherwise. No sign interpretation is necessary or
5100 performed.</li>
5101
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5102 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5103 <tt>false</tt> otherwise. No sign interpretation is necessary or
5104 performed.</li>
5105
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5106 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5107 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5108
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5109 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5111 to <tt>op2</tt>.</li>
5112
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5113 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5114 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5115
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5116 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5118
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5119 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5120 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5121
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5122 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5123 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5124 to <tt>op2</tt>.</li>
5125
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5126 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5127 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5128
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5129 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5130 <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]5131</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5132
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134 values are compared as if they were integers.</p>
5135
5136<p>If the operands are integer vectors, then they are compared element by
5137 element. The result is an <tt>i1</tt> vector with the same number of elements
5138 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5139
5140<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5141<pre>
5142 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5143 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5144 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5145 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5146 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5147 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5148</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5149
5150<p>Note that the code generator does not yet support vector types with
5151 the <tt>icmp</tt> instruction.</p>
5152
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5153</div>
5154
5155<!-- _______________________________________________________________________ -->
5156<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5157</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5159<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5160
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5161<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162<pre>
5163 &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]5164</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5165
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5166<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5167<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5168 values based on comparison of its operands.</p>
5169
5170<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]5171(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5172
5173<p>If the operands are floating point vectors, then the result type is a vector
5174 of boolean with the same number of elements as the operands being
5175 compared.</p>
5176
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5177<h5>Arguments:</h5>
5178<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5179 the condition code indicating the kind of comparison to perform. It is not a
5180 value, just a keyword. The possible condition code are:</p>
5181
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5182<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5183 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5184 <li><tt>oeq</tt>: ordered and equal</li>
5185 <li><tt>ogt</tt>: ordered and greater than </li>
5186 <li><tt>oge</tt>: ordered and greater than or equal</li>
5187 <li><tt>olt</tt>: ordered and less than </li>
5188 <li><tt>ole</tt>: ordered and less than or equal</li>
5189 <li><tt>one</tt>: ordered and not equal</li>
5190 <li><tt>ord</tt>: ordered (no nans)</li>
5191 <li><tt>ueq</tt>: unordered or equal</li>
5192 <li><tt>ugt</tt>: unordered or greater than </li>
5193 <li><tt>uge</tt>: unordered or greater than or equal</li>
5194 <li><tt>ult</tt>: unordered or less than </li>
5195 <li><tt>ule</tt>: unordered or less than or equal</li>
5196 <li><tt>une</tt>: unordered or not equal</li>
5197 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5198 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5199</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5201<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202 <i>unordered</i> means that either operand may be a QNAN.</p>
5203
5204<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5205 a <a href="#t_floating">floating point</a> type or
5206 a <a href="#t_vector">vector</a> of floating point type. They must have
5207 identical types.</p>
5208
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5209<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5210<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211 according to the condition code given as <tt>cond</tt>. If the operands are
5212 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5213 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5214 follows:</p>
5215
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5216<ol>
5217 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5218
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5219 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5220 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5221
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5224
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5227
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5228 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5229 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5230
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5231 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5232 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5233
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5234 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5235 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5236
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5237 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5238
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5239 <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]5240 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5241
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5242 <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]5243 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5244
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5245 <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]5246 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5247
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5248 <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]5249 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5250
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5251 <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]5252 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5253
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5254 <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]5255 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5256
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5257 <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]5258
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5259 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5260</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5261
5262<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5263<pre>
5264 &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]5265 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5266 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5267 &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]5268</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5269
5270<p>Note that the code generator does not yet support vector types with
5271 the <tt>fcmp</tt> instruction.</p>
5272
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5273</div>
5274
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5275<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5276<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5277 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5278</div>
5279
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5280<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5281
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5282<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5283<pre>
5284 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5285</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5286
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5287<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5288<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5289 SSA graph representing the function.</p>
5290
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5291<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5292<p>The type of the incoming values is specified with the first type field. After
5293 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5294 one pair for each predecessor basic block of the current block. Only values
5295 of <a href="#t_firstclass">first class</a> type may be used as the value
5296 arguments to the PHI node. Only labels may be used as the label
5297 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5298
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5299<p>There must be no non-phi instructions between the start of a basic block and
5300 the PHI instructions: i.e. PHI instructions must be first in a basic
5301 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5302
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5303<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5304 occur on the edge from the corresponding predecessor block to the current
5305 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5306 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5307
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5308<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5309<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5310 specified by the pair corresponding to the predecessor basic block that
5311 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5312
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5313<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5314<pre>
5315Loop: ; Infinite loop that counts from 0 on up...
5316 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5317 %nextindvar = add i32 %indvar, 1
5318 br label %Loop
5319</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5320
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5321</div>
5322
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5323<!-- _______________________________________________________________________ -->
5324<div class="doc_subsubsection">
5325 <a name="i_select">'<tt>select</tt>' Instruction</a>
5326</div>
5327
5328<div class="doc_text">
5329
5330<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5331<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5332 &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>
5333
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5334 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5335</pre>
5336
5337<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5338<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5339 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5340
5341
5342<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5343<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5344 values indicating the condition, and two values of the
5345 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5346 vectors and the condition is a scalar, then entire vectors are selected, not
5347 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5348
5349<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5350<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5351 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5352
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5353<p>If the condition is a vector of i1, then the value arguments must be vectors
5354 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5355
5356<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5357<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5358 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5359</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5360
5361<p>Note that the code generator does not yet support conditions
5362 with vector type.</p>
5363
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5364</div>
5365
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5366<!-- _______________________________________________________________________ -->
5367<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5368 <a name="i_call">'<tt>call</tt>' Instruction</a>
5369</div>
5370
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5371<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5373<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5374<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5375 &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]5376</pre>
5377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5378<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5379<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5380
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5381<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5382<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5383
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5384<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5385 <li>The optional "tail" marker indicates that the callee function does not
5386 access any allocas or varargs in the caller. Note that calls may be
5387 marked "tail" even if they do not occur before
5388 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5389 present, the function call is eligible for tail call optimization,
5390 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5391 optimized into a jump</a>. The code generator may optimize calls marked
5392 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5393 sibling call optimization</a> when the caller and callee have
5394 matching signatures, or 2) forced tail call optimization when the
5395 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5396 <ul>
5397 <li>Caller and callee both have the calling
5398 convention <tt>fastcc</tt>.</li>
5399 <li>The call is in tail position (ret immediately follows call and ret
5400 uses value of call or is void).</li>
5401 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5402 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5403 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5404 constraints are met.</a></li>
5405 </ul>
5406 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5407
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5408 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5409 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5410 defaults to using C calling conventions. The calling convention of the
5411 call must match the calling convention of the target function, or else the
5412 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5413
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5414 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5415 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5416 '<tt>inreg</tt>' attributes are valid here.</li>
5417
5418 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5419 type of the return value. Functions that return no value are marked
5420 <tt><a href="#t_void">void</a></tt>.</li>
5421
5422 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5423 being invoked. The argument types must match the types implied by this
5424 signature. This type can be omitted if the function is not varargs and if
5425 the function type does not return a pointer to a function.</li>
5426
5427 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5428 be invoked. In most cases, this is a direct function invocation, but
5429 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5430 to function value.</li>
5431
5432 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5433 signature argument types and parameter attributes. All arguments must be
5434 of <a href="#t_firstclass">first class</a> type. If the function
5435 signature indicates the function accepts a variable number of arguments,
5436 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5437
5438 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5439 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5440 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5441</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5443<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5444<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5445 a specified function, with its incoming arguments bound to the specified
5446 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5447 function, control flow continues with the instruction after the function
5448 call, and the return value of the function is bound to the result
5449 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5450
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5451<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5452<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5453 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5454 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5455 %X = tail call i32 @foo() <i>; yields i32</i>
5456 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5457 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5458
5459 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5460 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5461 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5462 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5463 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5464 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5465</pre>
5466
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5467<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5468standard C99 library as being the C99 library functions, and may perform
5469optimizations or generate code for them under that assumption. This is
5470something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5471freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5473</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5474
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5475<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5476<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5477 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5478</div>
5479
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5480<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5481
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5482<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5483<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5484 &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]5485</pre>
5486
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5487<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5488<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5489 the "variable argument" area of a function call. It is used to implement the
5490 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5491
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5492<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5494 argument. It returns a value of the specified argument type and increments
5495 the <tt>va_list</tt> to point to the next argument. The actual type
5496 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5497
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5498<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5500 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5501 to the next argument. For more information, see the variable argument
5502 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5503
5504<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]5505 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5506 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508<p><tt>va_arg</tt> is an LLVM instruction instead of
5509 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5510 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5511
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5512<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5513<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5514
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5515<p>Note that the code generator does not yet fully support va_arg on many
5516 targets. Also, it does not currently support va_arg with aggregate types on
5517 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5518
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5519</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5520
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5521<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5522<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5523<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5524
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5525<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5526
5527<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5528 well known names and semantics and are required to follow certain
5529 restrictions. Overall, these intrinsics represent an extension mechanism for
5530 the LLVM language that does not require changing all of the transformations
5531 in LLVM when adding to the language (or the bitcode reader/writer, the
5532 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5533
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5534<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5535 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5536 begin with this prefix. Intrinsic functions must always be external
5537 functions: you cannot define the body of intrinsic functions. Intrinsic
5538 functions may only be used in call or invoke instructions: it is illegal to
5539 take the address of an intrinsic function. Additionally, because intrinsic
5540 functions are part of the LLVM language, it is required if any are added that
5541 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5544 family of functions that perform the same operation but on different data
5545 types. Because LLVM can represent over 8 million different integer types,
5546 overloading is used commonly to allow an intrinsic function to operate on any
5547 integer type. One or more of the argument types or the result type can be
5548 overloaded to accept any integer type. Argument types may also be defined as
5549 exactly matching a previous argument's type or the result type. This allows
5550 an intrinsic function which accepts multiple arguments, but needs all of them
5551 to be of the same type, to only be overloaded with respect to a single
5552 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5553
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5554<p>Overloaded intrinsics will have the names of its overloaded argument types
5555 encoded into its function name, each preceded by a period. Only those types
5556 which are overloaded result in a name suffix. Arguments whose type is matched
5557 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5558 can take an integer of any width and returns an integer of exactly the same
5559 integer width. This leads to a family of functions such as
5560 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5561 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5562 suffix is required. Because the argument's type is matched against the return
5563 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5564
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5565<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5566 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5567
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5568</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5569
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5570<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5571<div class="doc_subsection">
5572 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5573</div>
5574
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5575<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5576
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5577<p>Variable argument support is defined in LLVM with
5578 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5579 intrinsic functions. These functions are related to the similarly named
5580 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5581
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5582<p>All of these functions operate on arguments that use a target-specific value
5583 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5584 not define what this type is, so all transformations should be prepared to
5585 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5586
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5587<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]5588 instruction and the variable argument handling intrinsic functions are
5589 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5590
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5591<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5592define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5593 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5594 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5595 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5596 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5597
5598 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5599 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5600
5601 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5602 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5603 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5604 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5605 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5606
5607 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5608 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5609 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5610}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5611
5612declare void @llvm.va_start(i8*)
5613declare void @llvm.va_copy(i8*, i8*)
5614declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5615</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5616
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5617</div>
5618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5619<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5620<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5621 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5622</div>
5623
5624
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5625<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5626
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5627<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5628<pre>
5629 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5630</pre>
5631
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5632<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5633<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5634 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]5635
5636<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5637<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]5638
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5639<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5640<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]5641 macro available in C. In a target-dependent way, it initializes
5642 the <tt>va_list</tt> element to which the argument points, so that the next
5643 call to <tt>va_arg</tt> will produce the first variable argument passed to
5644 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5645 need to know the last argument of the function as the compiler can figure
5646 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5648</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5649
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5650<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5651<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5652 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5653</div>
5654
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5655<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5656
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5657<h5>Syntax:</h5>
5658<pre>
5659 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5660</pre>
5661
5662<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5663<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5664 which has been initialized previously
5665 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5666 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5667
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5668<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5669<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]5670
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5671<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5672<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]5673 macro available in C. In a target-dependent way, it destroys
5674 the <tt>va_list</tt> element to which the argument points. Calls
5675 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5676 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5677 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5678
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5679</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5680
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5681<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5682<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5683 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5684</div>
5685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5686<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5687
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5688<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5690 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5691</pre>
5692
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5693<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5694<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5695 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5696
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5697<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5698<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]5699 The second argument is a pointer to a <tt>va_list</tt> element to copy
5700 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5702<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5703<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]5704 macro available in C. In a target-dependent way, it copies the
5705 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5706 element. This intrinsic is necessary because
5707 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5708 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5710</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5711
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5712<!-- ======================================================================= -->
5713<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5714 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5715</div>
5716
5717<div class="doc_text">
5718
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5719<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5720Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5722roots on the stack</a>, as well as garbage collector implementations that
5723require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5724barriers. Front-ends for type-safe garbage collected languages should generate
5725these intrinsics to make use of the LLVM garbage collectors. For more details,
5726see <a href="GarbageCollection.html">Accurate Garbage Collection with
5727LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5728
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729<p>The garbage collection intrinsics only operate on objects in the generic
5730 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5731
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5732</div>
5733
5734<!-- _______________________________________________________________________ -->
5735<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5736 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737</div>
5738
5739<div class="doc_text">
5740
5741<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5742<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5743 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5744</pre>
5745
5746<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5747<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]5748 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5749
5750<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5751<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5752 root pointer. The second pointer (which must be either a constant or a
5753 global value address) contains the meta-data to be associated with the
5754 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755
5756<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5757<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]5758 location. At compile-time, the code generator generates information to allow
5759 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5760 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5761 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5762
5763</div>
5764
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5765<!-- _______________________________________________________________________ -->
5766<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5767 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5768</div>
5769
5770<div class="doc_text">
5771
5772<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5773<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5774 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5775</pre>
5776
5777<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5778<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5779 locations, allowing garbage collector implementations that require read
5780 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5781
5782<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5783<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]5784 allocated from the garbage collector. The first object is a pointer to the
5785 start of the referenced object, if needed by the language runtime (otherwise
5786 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5787
5788<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5789<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5790 instruction, but may be replaced with substantially more complex code by the
5791 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5792 may only be used in a function which <a href="#gc">specifies a GC
5793 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5794
5795</div>
5796
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5797<!-- _______________________________________________________________________ -->
5798<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5799 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5800</div>
5801
5802<div class="doc_text">
5803
5804<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5805<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5806 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5807</pre>
5808
5809<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5810<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5811 locations, allowing garbage collector implementations that require write
5812 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5813
5814<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5815<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]5816 object to store it to, and the third is the address of the field of Obj to
5817 store to. If the runtime does not require a pointer to the object, Obj may
5818 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5819
5820<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5821<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822 instruction, but may be replaced with substantially more complex code by the
5823 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5824 may only be used in a function which <a href="#gc">specifies a GC
5825 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5826
5827</div>
5828
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5829<!-- ======================================================================= -->
5830<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5831 <a name="int_codegen">Code Generator Intrinsics</a>
5832</div>
5833
5834<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5835
5836<p>These intrinsics are provided by LLVM to expose special features that may
5837 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5838
5839</div>
5840
5841<!-- _______________________________________________________________________ -->
5842<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5843 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5844</div>
5845
5846<div class="doc_text">
5847
5848<h5>Syntax:</h5>
5849<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5850 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5851</pre>
5852
5853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5854<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5855 target-specific value indicating the return address of the current function
5856 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5857
5858<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5859<p>The argument to this intrinsic indicates which function to return the address
5860 for. Zero indicates the calling function, one indicates its caller, etc.
5861 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5862
5863<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5864<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5865 indicating the return address of the specified call frame, or zero if it
5866 cannot be identified. The value returned by this intrinsic is likely to be
5867 incorrect or 0 for arguments other than zero, so it should only be used for
5868 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5870<p>Note that calling this intrinsic does not prevent function inlining or other
5871 aggressive transformations, so the value returned may not be that of the
5872 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5873
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5874</div>
5875
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5878 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5879</div>
5880
5881<div class="doc_text">
5882
5883<h5>Syntax:</h5>
5884<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5885 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5886</pre>
5887
5888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5890 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5891
5892<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893<p>The argument to this intrinsic indicates which function to return the frame
5894 pointer for. Zero indicates the calling function, one indicates its caller,
5895 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5896
5897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5898<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5899 indicating the frame address of the specified call frame, or zero if it
5900 cannot be identified. The value returned by this intrinsic is likely to be
5901 incorrect or 0 for arguments other than zero, so it should only be used for
5902 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904<p>Note that calling this intrinsic does not prevent function inlining or other
5905 aggressive transformations, so the value returned may not be that of the
5906 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5907
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5908</div>
5909
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5910<!-- _______________________________________________________________________ -->
5911<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5912 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5913</div>
5914
5915<div class="doc_text">
5916
5917<h5>Syntax:</h5>
5918<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5919 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5920</pre>
5921
5922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5924 of the function stack, for use
5925 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5926 useful for implementing language features like scoped automatic variable
5927 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5928
5929<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>This intrinsic returns a opaque pointer value that can be passed
5931 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5932 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5933 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5934 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5935 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5936 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5937
5938</div>
5939
5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5942 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
5948<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5949 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5950</pre>
5951
5952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5954 the function stack to the state it was in when the
5955 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5956 executed. This is useful for implementing language features like scoped
5957 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5958
5959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>See the description
5961 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5962
5963</div>
5964
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5965<!-- _______________________________________________________________________ -->
5966<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5967 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5968</div>
5969
5970<div class="doc_text">
5971
5972<h5>Syntax:</h5>
5973<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5974 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]5975</pre>
5976
5977<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5978<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5979 insert a prefetch instruction if supported; otherwise, it is a noop.
5980 Prefetches have no effect on the behavior of the program but can change its
5981 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5982
5983<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5984<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5985 specifier determining if the fetch should be for a read (0) or write (1),
5986 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5987 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5988 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991<p>This intrinsic does not modify the behavior of the program. In particular,
5992 prefetches cannot trap and do not produce a value. On targets that support
5993 this intrinsic, the prefetch can provide hints to the processor cache for
5994 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5995
5996</div>
5997
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5998<!-- _______________________________________________________________________ -->
5999<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6000 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6001</div>
6002
6003<div class="doc_text">
6004
6005<h5>Syntax:</h5>
6006<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6007 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6008</pre>
6009
6010<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6012 Counter (PC) in a region of code to simulators and other tools. The method
6013 is target specific, but it is expected that the marker will use exported
6014 symbols to transmit the PC of the marker. The marker makes no guarantees
6015 that it will remain with any specific instruction after optimizations. It is
6016 possible that the presence of a marker will inhibit optimizations. The
6017 intended use is to be inserted after optimizations to allow correlations of
6018 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6019
6020<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6021<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6022
6023<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6025 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6026
6027</div>
6028
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6031 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
6037<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6038 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6039</pre>
6040
6041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6043 counter register (or similar low latency, high accuracy clocks) on those
6044 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6045 should map to RPCC. As the backing counters overflow quickly (on the order
6046 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6047
6048<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049<p>When directly supported, reading the cycle counter should not modify any
6050 memory. Implementations are allowed to either return a application specific
6051 value or a system wide value. On backends without support, this is lowered
6052 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6053
6054</div>
6055
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6056<!-- ======================================================================= -->
6057<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6058 <a name="int_libc">Standard C Library Intrinsics</a>
6059</div>
6060
6061<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062
6063<p>LLVM provides intrinsics for a few important standard C library functions.
6064 These intrinsics allow source-language front-ends to pass information about
6065 the alignment of the pointer arguments to the code generator, providing
6066 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6067
6068</div>
6069
6070<!-- _______________________________________________________________________ -->
6071<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6072 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6073</div>
6074
6075<div class="doc_text">
6076
6077<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<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]6079 integer bit width and for different address spaces. Not all targets support
6080 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6081
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6082<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6083 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]6084 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6085 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]6086 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6087</pre>
6088
6089<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6090<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6091 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6092
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6094 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6095 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6096
6097<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6098
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099<p>The first argument is a pointer to the destination, the second is a pointer
6100 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6101 number of bytes to copy, the fourth argument is the alignment of the
6102 source and destination locations, and the fifth is a boolean indicating a
6103 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6104
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6105<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]6106 then the caller guarantees that both the source and destination pointers are
6107 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6108
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6109<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6110 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6111 The detailed access behavior is not very cleanly specified and it is unwise
6112 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6113
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6114<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6115
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6117 source location to the destination location, which are not allowed to
6118 overlap. It copies "len" bytes of memory over. If the argument is known to
6119 be aligned to some boundary, this can be specified as the fourth argument,
6120 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6121
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6122</div>
6123
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6124<!-- _______________________________________________________________________ -->
6125<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6126 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6127</div>
6128
6129<div class="doc_text">
6130
6131<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6132<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]6133 width and for different address space. Not all targets support all bit
6134 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6135
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6136<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6137 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]6138 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6139 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]6140 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6141</pre>
6142
6143<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6144<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6145 source location to the destination location. It is similar to the
6146 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6147 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6148
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6150 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6151 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6152
6153<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6154
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6155<p>The first argument is a pointer to the destination, the second is a pointer
6156 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6157 number of bytes to copy, the fourth argument is the alignment of the
6158 source and destination locations, and the fifth is a boolean indicating a
6159 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6160
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6161<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]6162 then the caller guarantees that the source and destination pointers are
6163 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6164
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6165<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6166 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6167 The detailed access behavior is not very cleanly specified and it is unwise
6168 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6169
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6170<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6171
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6172<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6173 source location to the destination location, which may overlap. It copies
6174 "len" bytes of memory over. If the argument is known to be aligned to some
6175 boundary, this can be specified as the fourth argument, otherwise it should
6176 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6177
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6178</div>
6179
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6180<!-- _______________________________________________________________________ -->
6181<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6182 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6183</div>
6184
6185<div class="doc_text">
6186
6187<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6188<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]6189 width and for different address spaces. However, not all targets support all
6190 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6191
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6192<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6193 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6194 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6195 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6196 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6197</pre>
6198
6199<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6200<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6201 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6202
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6204 intrinsic does not return a value and takes extra alignment/volatile
6205 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6206
6207<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6208<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]6209 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6211 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6212
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6213<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]6214 then the caller guarantees that the destination pointer is aligned to that
6215 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6216
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6217<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6218 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6219 The detailed access behavior is not very cleanly specified and it is unwise
6220 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6221
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6222<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6223<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6224 at the destination location. If the argument is known to be aligned to some
6225 boundary, this can be specified as the fourth argument, otherwise it should
6226 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6227
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6228</div>
6229
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6230<!-- _______________________________________________________________________ -->
6231<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6232 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6233</div>
6234
6235<div class="doc_text">
6236
6237<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6239 floating point or vector of floating point type. Not all targets support all
6240 types however.</p>
6241
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6242<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6243 declare float @llvm.sqrt.f32(float %Val)
6244 declare double @llvm.sqrt.f64(double %Val)
6245 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6246 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6247 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6248</pre>
6249
6250<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6251<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6252 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6253 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6254 behavior for negative numbers other than -0.0 (which allows for better
6255 optimization, because there is no need to worry about errno being
6256 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]6257
6258<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6259<p>The argument and return value are floating point numbers of the same
6260 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6261
6262<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6263<p>This function returns the sqrt of the specified operand if it is a
6264 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6265
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6266</div>
6267
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6268<!-- _______________________________________________________________________ -->
6269<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6270 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6271</div>
6272
6273<div class="doc_text">
6274
6275<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6277 floating point or vector of floating point type. Not all targets support all
6278 types however.</p>
6279
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6280<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6281 declare float @llvm.powi.f32(float %Val, i32 %power)
6282 declare double @llvm.powi.f64(double %Val, i32 %power)
6283 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6284 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6285 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6286</pre>
6287
6288<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6289<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6290 specified (positive or negative) power. The order of evaluation of
6291 multiplications is not defined. When a vector of floating point type is
6292 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6293
6294<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6295<p>The second argument is an integer power, and the first is a value to raise to
6296 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6297
6298<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6299<p>This function returns the first value raised to the second power with an
6300 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6301
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6302</div>
6303
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6304<!-- _______________________________________________________________________ -->
6305<div class="doc_subsubsection">
6306 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6307</div>
6308
6309<div class="doc_text">
6310
6311<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6313 floating point or vector of floating point type. Not all targets support all
6314 types however.</p>
6315
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6316<pre>
6317 declare float @llvm.sin.f32(float %Val)
6318 declare double @llvm.sin.f64(double %Val)
6319 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6320 declare fp128 @llvm.sin.f128(fp128 %Val)
6321 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6322</pre>
6323
6324<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6325<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6326
6327<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6328<p>The argument and return value are floating point numbers of the same
6329 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6330
6331<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6332<p>This function returns the sine of the specified operand, returning the same
6333 values as the libm <tt>sin</tt> functions would, and handles error conditions
6334 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6335
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6336</div>
6337
6338<!-- _______________________________________________________________________ -->
6339<div class="doc_subsubsection">
6340 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6341</div>
6342
6343<div class="doc_text">
6344
6345<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6346<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6347 floating point or vector of floating point type. Not all targets support all
6348 types however.</p>
6349
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6350<pre>
6351 declare float @llvm.cos.f32(float %Val)
6352 declare double @llvm.cos.f64(double %Val)
6353 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6354 declare fp128 @llvm.cos.f128(fp128 %Val)
6355 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6356</pre>
6357
6358<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6359<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6360
6361<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6362<p>The argument and return value are floating point numbers of the same
6363 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6364
6365<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6366<p>This function returns the cosine of the specified operand, returning the same
6367 values as the libm <tt>cos</tt> functions would, and handles error conditions
6368 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6369
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6370</div>
6371
6372<!-- _______________________________________________________________________ -->
6373<div class="doc_subsubsection">
6374 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6375</div>
6376
6377<div class="doc_text">
6378
6379<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6380<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6381 floating point or vector of floating point type. Not all targets support all
6382 types however.</p>
6383
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6384<pre>
6385 declare float @llvm.pow.f32(float %Val, float %Power)
6386 declare double @llvm.pow.f64(double %Val, double %Power)
6387 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6388 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6389 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6390</pre>
6391
6392<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6393<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6394 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6395
6396<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6397<p>The second argument is a floating point power, and the first is a value to
6398 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6399
6400<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6401<p>This function returns the first value raised to the second power, returning
6402 the same values as the libm <tt>pow</tt> functions would, and handles error
6403 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6404
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6405</div>
6406
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6407<!-- ======================================================================= -->
6408<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6409 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6410</div>
6411
6412<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6413
6414<p>LLVM provides intrinsics for a few important bit manipulation operations.
6415 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6416
6417</div>
6418
6419<!-- _______________________________________________________________________ -->
6420<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6421 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6422</div>
6423
6424<div class="doc_text">
6425
6426<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6427<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6429
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6430<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6431 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6432 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6433 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6434</pre>
6435
6436<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6437<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6438 values with an even number of bytes (positive multiple of 16 bits). These
6439 are useful for performing operations on data that is not in the target's
6440 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6441
6442<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6443<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6444 and low byte of the input i16 swapped. Similarly,
6445 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6446 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6447 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6448 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6449 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6450 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6451
6452</div>
6453
6454<!-- _______________________________________________________________________ -->
6455<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6456 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6457</div>
6458
6459<div class="doc_text">
6460
6461<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6462<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]6463 width. Not all targets support all bit widths however.</p>
6464
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6465<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6466 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6467 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6468 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6469 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6470 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6471</pre>
6472
6473<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6474<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6475 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6476
6477<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6478<p>The only argument is the value to be counted. The argument may be of any
6479 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6480
6481<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482<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]6483
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6484</div>
6485
6486<!-- _______________________________________________________________________ -->
6487<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6488 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6489</div>
6490
6491<div class="doc_text">
6492
6493<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6495 integer bit width. Not all targets support all bit widths however.</p>
6496
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6497<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6498 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6499 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6500 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6501 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6502 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6503</pre>
6504
6505<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6507 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6508
6509<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510<p>The only argument is the value to be counted. The argument may be of any
6511 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6512
6513<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6514<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6515 zeros in a variable. If the src == 0 then the result is the size in bits of
6516 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6517
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6518</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6519
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6520<!-- _______________________________________________________________________ -->
6521<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6522 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6523</div>
6524
6525<div class="doc_text">
6526
6527<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6528<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6529 integer bit width. Not all targets support all bit widths however.</p>
6530
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6531<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6532 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6533 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6534 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6535 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6536 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6537</pre>
6538
6539<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6541 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6542
6543<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544<p>The only argument is the value to be counted. The argument may be of any
6545 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6546
6547<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6549 zeros in a variable. If the src == 0 then the result is the size in bits of
6550 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6551
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6552</div>
6553
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6554<!-- ======================================================================= -->
6555<div class="doc_subsection">
6556 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6557</div>
6558
6559<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560
6561<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6562
6563</div>
6564
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6565<!-- _______________________________________________________________________ -->
6566<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6567 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6568</div>
6569
6570<div class="doc_text">
6571
6572<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573<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]6574 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6575
6576<pre>
6577 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6578 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6579 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6580</pre>
6581
6582<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6583<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6584 a signed addition of the two arguments, and indicate whether an overflow
6585 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6586
6587<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6588<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]6589 be of integer types of any bit width, but they must have the same bit
6590 width. The second element of the result structure must be of
6591 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6592 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6593
6594<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6595<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6596 a signed addition of the two variables. They return a structure &mdash; the
6597 first element of which is the signed summation, and the second element of
6598 which is a bit specifying if the signed summation resulted in an
6599 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6600
6601<h5>Examples:</h5>
6602<pre>
6603 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6604 %sum = extractvalue {i32, i1} %res, 0
6605 %obit = extractvalue {i32, i1} %res, 1
6606 br i1 %obit, label %overflow, label %normal
6607</pre>
6608
6609</div>
6610
6611<!-- _______________________________________________________________________ -->
6612<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6613 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6614</div>
6615
6616<div class="doc_text">
6617
6618<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6619<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]6620 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621
6622<pre>
6623 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6624 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6625 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6626</pre>
6627
6628<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6629<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630 an unsigned addition of the two arguments, and indicate whether a carry
6631 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6632
6633<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6634<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]6635 be of integer types of any bit width, but they must have the same bit
6636 width. The second element of the result structure must be of
6637 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6638 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6639
6640<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6641<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6642 an unsigned addition of the two arguments. They return a structure &mdash;
6643 the first element of which is the sum, and the second element of which is a
6644 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6645
6646<h5>Examples:</h5>
6647<pre>
6648 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6649 %sum = extractvalue {i32, i1} %res, 0
6650 %obit = extractvalue {i32, i1} %res, 1
6651 br i1 %obit, label %carry, label %normal
6652</pre>
6653
6654</div>
6655
6656<!-- _______________________________________________________________________ -->
6657<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6658 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659</div>
6660
6661<div class="doc_text">
6662
6663<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664<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]6665 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666
6667<pre>
6668 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6669 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6670 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6671</pre>
6672
6673<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6674<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6675 a signed subtraction of the two arguments, and indicate whether an overflow
6676 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6677
6678<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6679<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]6680 be of integer types of any bit width, but they must have the same bit
6681 width. The second element of the result structure must be of
6682 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6683 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6684
6685<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6686<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687 a signed subtraction of the two arguments. They return a structure &mdash;
6688 the first element of which is the subtraction, and the second element of
6689 which is a bit specifying if the signed subtraction resulted in an
6690 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6691
6692<h5>Examples:</h5>
6693<pre>
6694 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6695 %sum = extractvalue {i32, i1} %res, 0
6696 %obit = extractvalue {i32, i1} %res, 1
6697 br i1 %obit, label %overflow, label %normal
6698</pre>
6699
6700</div>
6701
6702<!-- _______________________________________________________________________ -->
6703<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6704 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6705</div>
6706
6707<div class="doc_text">
6708
6709<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6710<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]6711 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6712
6713<pre>
6714 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6715 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6716 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6717</pre>
6718
6719<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6720<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6721 an unsigned subtraction of the two arguments, and indicate whether an
6722 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6723
6724<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6725<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]6726 be of integer types of any bit width, but they must have the same bit
6727 width. The second element of the result structure must be of
6728 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6729 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6730
6731<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6732<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6733 an unsigned subtraction of the two arguments. They return a structure &mdash;
6734 the first element of which is the subtraction, and the second element of
6735 which is a bit specifying if the unsigned subtraction resulted in an
6736 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6737
6738<h5>Examples:</h5>
6739<pre>
6740 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6741 %sum = extractvalue {i32, i1} %res, 0
6742 %obit = extractvalue {i32, i1} %res, 1
6743 br i1 %obit, label %overflow, label %normal
6744</pre>
6745
6746</div>
6747
6748<!-- _______________________________________________________________________ -->
6749<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6750 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6751</div>
6752
6753<div class="doc_text">
6754
6755<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6756<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]6757 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6758
6759<pre>
6760 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6761 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6762 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6763</pre>
6764
6765<h5>Overview:</h5>
6766
6767<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6768 a signed multiplication of the two arguments, and indicate whether an
6769 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6770
6771<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6772<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]6773 be of integer types of any bit width, but they must have the same bit
6774 width. The second element of the result structure must be of
6775 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6776 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6777
6778<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6779<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6780 a signed multiplication of the two arguments. They return a structure &mdash;
6781 the first element of which is the multiplication, and the second element of
6782 which is a bit specifying if the signed multiplication resulted in an
6783 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6784
6785<h5>Examples:</h5>
6786<pre>
6787 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6788 %sum = extractvalue {i32, i1} %res, 0
6789 %obit = extractvalue {i32, i1} %res, 1
6790 br i1 %obit, label %overflow, label %normal
6791</pre>
6792
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6793</div>
6794
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6795<!-- _______________________________________________________________________ -->
6796<div class="doc_subsubsection">
6797 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6798</div>
6799
6800<div class="doc_text">
6801
6802<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6803<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]6804 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6805
6806<pre>
6807 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6808 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6809 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6810</pre>
6811
6812<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6813<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6814 a unsigned multiplication of the two arguments, and indicate whether an
6815 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6816
6817<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6818<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]6819 be of integer types of any bit width, but they must have the same bit
6820 width. The second element of the result structure must be of
6821 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6822 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6823
6824<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6825<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6826 an unsigned multiplication of the two arguments. They return a structure
6827 &mdash; the first element of which is the multiplication, and the second
6828 element of which is a bit specifying if the unsigned multiplication resulted
6829 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6830
6831<h5>Examples:</h5>
6832<pre>
6833 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6834 %sum = extractvalue {i32, i1} %res, 0
6835 %obit = extractvalue {i32, i1} %res, 1
6836 br i1 %obit, label %overflow, label %normal
6837</pre>
6838
6839</div>
6840
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6841<!-- ======================================================================= -->
6842<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6843 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6844</div>
6845
6846<div class="doc_text">
6847
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6848<p>Half precision floating point is a storage-only format. This means that it is
6849 a dense encoding (in memory) but does not support computation in the
6850 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6851
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6852<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6853 value as an i16, then convert it to float with <a
6854 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6855 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6856 double etc). To store the value back to memory, it is first converted to
6857 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6858 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6859 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6860</div>
6861
6862<!-- _______________________________________________________________________ -->
6863<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6864 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6865</div>
6866
6867<div class="doc_text">
6868
6869<h5>Syntax:</h5>
6870<pre>
6871 declare i16 @llvm.convert.to.fp16(f32 %a)
6872</pre>
6873
6874<h5>Overview:</h5>
6875<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6876 a conversion from single precision floating point format to half precision
6877 floating point format.</p>
6878
6879<h5>Arguments:</h5>
6880<p>The intrinsic function contains single argument - the value to be
6881 converted.</p>
6882
6883<h5>Semantics:</h5>
6884<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6885 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6886 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6887 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6888
6889<h5>Examples:</h5>
6890<pre>
6891 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6892 store i16 %res, i16* @x, align 2
6893</pre>
6894
6895</div>
6896
6897<!-- _______________________________________________________________________ -->
6898<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6899 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6900</div>
6901
6902<div class="doc_text">
6903
6904<h5>Syntax:</h5>
6905<pre>
6906 declare f32 @llvm.convert.from.fp16(i16 %a)
6907</pre>
6908
6909<h5>Overview:</h5>
6910<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6911 a conversion from half precision floating point format to single precision
6912 floating point format.</p>
6913
6914<h5>Arguments:</h5>
6915<p>The intrinsic function contains single argument - the value to be
6916 converted.</p>
6917
6918<h5>Semantics:</h5>
6919<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6920 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6921 precision floating point format. The input half-float value is represented by
6922 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6923
6924<h5>Examples:</h5>
6925<pre>
6926 %a = load i16* @x, align 2
6927 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6928</pre>
6929
6930</div>
6931
6932<!-- ======================================================================= -->
6933<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6934 <a name="int_debugger">Debugger Intrinsics</a>
6935</div>
6936
6937<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6938
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6940 prefix), are described in
6941 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6942 Level Debugging</a> document.</p>
6943
6944</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6945
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6946<!-- ======================================================================= -->
6947<div class="doc_subsection">
6948 <a name="int_eh">Exception Handling Intrinsics</a>
6949</div>
6950
6951<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952
6953<p>The LLVM exception handling intrinsics (which all start with
6954 <tt>llvm.eh.</tt> prefix), are described in
6955 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6956 Handling</a> document.</p>
6957
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6958</div>
6959
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6960<!-- ======================================================================= -->
6961<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6962 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6963</div>
6964
6965<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6966
6967<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6968 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6969 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6970 function pointer lacking the nest parameter - the caller does not need to
6971 provide a value for it. Instead, the value to use is stored in advance in a
6972 "trampoline", a block of memory usually allocated on the stack, which also
6973 contains code to splice the nest value into the argument list. This is used
6974 to implement the GCC nested function address extension.</p>
6975
6976<p>For example, if the function is
6977 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6978 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6979 follows:</p>
6980
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6981<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6982 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6983 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6984 %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]6985 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6986</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6988<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6989 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6991</div>
6992
6993<!-- _______________________________________________________________________ -->
6994<div class="doc_subsubsection">
6995 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6996</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6997
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6998<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6999
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7000<h5>Syntax:</h5>
7001<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002 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]7003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7004
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7006<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
7007 function pointer suitable for executing it.</p>
7008
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7009<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7010<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7011 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7012 sufficiently aligned block of memory; this memory is written to by the
7013 intrinsic. Note that the size and the alignment are target-specific - LLVM
7014 currently provides no portable way of determining them, so a front-end that
7015 generates this intrinsic needs to have some target-specific knowledge.
7016 The <tt>func</tt> argument must hold a function bitcast to
7017 an <tt>i8*</tt>.</p>
7018
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7019<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7020<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7021 dependent code, turning it into a function. A pointer to this function is
7022 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7023 function pointer type</a> before being called. The new function's signature
7024 is the same as that of <tt>func</tt> with any arguments marked with
7025 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7026 is allowed, and it must be of pointer type. Calling the new function is
7027 equivalent to calling <tt>func</tt> with the same argument list, but
7028 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7029 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7030 by <tt>tramp</tt> is modified, then the effect of any later call to the
7031 returned function pointer is undefined.</p>
7032
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7033</div>
7034
7035<!-- ======================================================================= -->
7036<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7037 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7038</div>
7039
7040<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7042<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7043 hardware constructs for atomic operations and memory synchronization. This
7044 provides an interface to the hardware, not an interface to the programmer. It
7045 is aimed at a low enough level to allow any programming models or APIs
7046 (Application Programming Interfaces) which need atomic behaviors to map
7047 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7048 hardware provides a "universal IR" for source languages, it also provides a
7049 starting point for developing a "universal" atomic operation and
7050 synchronization IR.</p>
7051
7052<p>These do <em>not</em> form an API such as high-level threading libraries,
7053 software transaction memory systems, atomic primitives, and intrinsic
7054 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7055 application libraries. The hardware interface provided by LLVM should allow
7056 a clean implementation of all of these APIs and parallel programming models.
7057 No one model or paradigm should be selected above others unless the hardware
7058 itself ubiquitously does so.</p>
7059
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7060</div>
7061
7062<!-- _______________________________________________________________________ -->
7063<div class="doc_subsubsection">
7064 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7065</div>
7066<div class="doc_text">
7067<h5>Syntax:</h5>
7068<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7069 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]7070</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7072<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7073<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7074 specific pairs of memory access types.</p>
7075
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7076<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7077<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7078 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7079 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7082<ul>
7083 <li><tt>ll</tt>: load-load barrier</li>
7084 <li><tt>ls</tt>: load-store barrier</li>
7085 <li><tt>sl</tt>: store-load barrier</li>
7086 <li><tt>ss</tt>: store-store barrier</li>
7087 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7088</ul>
7089
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7090<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7091<p>This intrinsic causes the system to enforce some ordering constraints upon
7092 the loads and stores of the program. This barrier does not
7093 indicate <em>when</em> any events will occur, it only enforces
7094 an <em>order</em> in which they occur. For any of the specified pairs of load
7095 and store operations (f.ex. load-load, or store-load), all of the first
7096 operations preceding the barrier will complete before any of the second
7097 operations succeeding the barrier begin. Specifically the semantics for each
7098 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7100<ul>
7101 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7102 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7103 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7104 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7105 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7106 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7107 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108 load after the barrier begins.</li>
7109</ul>
7110
7111<p>These semantics are applied with a logical "and" behavior when more than one
7112 is enabled in a single memory barrier intrinsic.</p>
7113
7114<p>Backends may implement stronger barriers than those requested when they do
7115 not support as fine grained a barrier as requested. Some architectures do
7116 not need all types of barriers and on such architectures, these become
7117 noops.</p>
7118
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7119<h5>Example:</h5>
7120<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7121%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7122%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7123 store i32 4, %ptr
7124
7125%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7126 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7127 <i>; guarantee the above finishes</i>
7128 store i32 8, %ptr <i>; before this begins</i>
7129</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7131</div>
7132
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133<!-- _______________________________________________________________________ -->
7134<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7135 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7137
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7138<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7139
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7140<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7141<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7142 any integer bit width and for different address spaces. Not all targets
7143 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144
7145<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7146 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7147 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7148 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7149 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]7150</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7151
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7152<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7153<p>This loads a value in memory and compares it to a given value. If they are
7154 equal, it stores a new value into the memory.</p>
7155
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7156<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7157<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7158 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7159 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7160 this integer type. While any bit width integer may be used, targets may only
7161 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7162
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7163<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164<p>This entire intrinsic must be executed atomically. It first loads the value
7165 in memory pointed to by <tt>ptr</tt> and compares it with the
7166 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7167 memory. The loaded value is yielded in all cases. This provides the
7168 equivalent of an atomic compare-and-swap operation within the SSA
7169 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7170
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7171<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7172<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7173%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7174%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175 store i32 4, %ptr
7176
7177%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7178%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7179 <i>; yields {i32}:result1 = 4</i>
7180%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7181%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7182
7183%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7184%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7185 <i>; yields {i32}:result2 = 8</i>
7186%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7187
7188%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7189</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7191</div>
7192
7193<!-- _______________________________________________________________________ -->
7194<div class="doc_subsubsection">
7195 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7196</div>
7197<div class="doc_text">
7198<h5>Syntax:</h5>
7199
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7200<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7201 integer bit width. Not all targets support all bit widths however.</p>
7202
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7204 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7205 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7206 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7207 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]7208</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7209
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7210<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7211<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7212 the value from memory. It then stores the value in <tt>val</tt> in the memory
7213 at <tt>ptr</tt>.</p>
7214
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7215<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7216<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7217 the <tt>val</tt> argument and the result must be integers of the same bit
7218 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7219 integer type. The targets may only lower integer representations they
7220 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7221
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7222<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7223<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7224 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7225 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7226
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7227<h5>Examples:</h5>
7228<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7229%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7230%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7231 store i32 4, %ptr
7232
7233%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7234%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7235 <i>; yields {i32}:result1 = 4</i>
7236%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7237%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7238
7239%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7240%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7241 <i>; yields {i32}:result2 = 8</i>
7242
7243%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7244%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7245</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7247</div>
7248
7249<!-- _______________________________________________________________________ -->
7250<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7251 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7252
7253</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7254
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7255<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7257<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7259 any integer bit width. Not all targets support all bit widths however.</p>
7260
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7261<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7262 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7263 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7264 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7265 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]7266</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7267
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268<h5>Overview:</h5>
7269<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7270 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7271
7272<h5>Arguments:</h5>
7273<p>The intrinsic takes two arguments, the first a pointer to an integer value
7274 and the second an integer value. The result is also an integer value. These
7275 integer types can have any bit width, but they must all have the same bit
7276 width. The targets may only lower integer representations they support.</p>
7277
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7278<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7279<p>This intrinsic does a series of operations atomically. It first loads the
7280 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7281 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]7282
7283<h5>Examples:</h5>
7284<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7285%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7286%ptr = bitcast i8* %mallocP to i32*
7287 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7288%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7289 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7290%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7291 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7292%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7293 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7294%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7296
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7297</div>
7298
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7299<!-- _______________________________________________________________________ -->
7300<div class="doc_subsubsection">
7301 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7302
7303</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7304
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7305<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7306
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7307<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7309 any integer bit width and for different address spaces. Not all targets
7310 support all bit widths however.</p>
7311
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7312<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7313 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7314 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7315 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7316 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]7317</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7320<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7321 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7322
7323<h5>Arguments:</h5>
7324<p>The intrinsic takes two arguments, the first a pointer to an integer value
7325 and the second an integer value. The result is also an integer value. These
7326 integer types can have any bit width, but they must all have the same bit
7327 width. The targets may only lower integer representations they support.</p>
7328
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7329<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7330<p>This intrinsic does a series of operations atomically. It first loads the
7331 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7332 result to <tt>ptr</tt>. It yields the original value stored
7333 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7334
7335<h5>Examples:</h5>
7336<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7337%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7338%ptr = bitcast i8* %mallocP to i32*
7339 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7340%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7342%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7343 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7344%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7345 <i>; yields {i32}:result3 = 2</i>
7346%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7347</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7349</div>
7350
7351<!-- _______________________________________________________________________ -->
7352<div class="doc_subsubsection">
7353 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7354 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7355 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7356 <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]7357</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7358
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7359<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7360
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7361<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7362<p>These are overloaded intrinsics. You can
7363 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7364 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7365 bit width and for different address spaces. Not all targets support all bit
7366 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7368<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7369 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7370 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7371 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7372 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]7373</pre>
7374
7375<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7376 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7377 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7378 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7379 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]7380</pre>
7381
7382<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7383 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7384 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7385 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7386 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]7387</pre>
7388
7389<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7390 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7391 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7392 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7393 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]7394</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7395
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7396<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7397<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7398 the value stored in memory at <tt>ptr</tt>. It yields the original value
7399 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7400
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7401<h5>Arguments:</h5>
7402<p>These intrinsics take two arguments, the first a pointer to an integer value
7403 and the second an integer value. The result is also an integer value. These
7404 integer types can have any bit width, but they must all have the same bit
7405 width. The targets may only lower integer representations they support.</p>
7406
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7407<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7408<p>These intrinsics does a series of operations atomically. They first load the
7409 value stored at <tt>ptr</tt>. They then do the bitwise
7410 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7411 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412
7413<h5>Examples:</h5>
7414<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7415%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7416%ptr = bitcast i8* %mallocP to i32*
7417 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7418%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7420%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7421 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7422%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7423 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7424%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7425 <i>; yields {i32}:result3 = FF</i>
7426%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7427</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7428
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7429</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7430
7431<!-- _______________________________________________________________________ -->
7432<div class="doc_subsubsection">
7433 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7434 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7435 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7436 <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]7437</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7438
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7439<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7440
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7441<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7442<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7443 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7444 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7445 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7447<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7448 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7449 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7450 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7451 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]7452</pre>
7453
7454<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7455 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7456 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7457 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7458 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]7459</pre>
7460
7461<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7462 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7463 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7464 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7465 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]7466</pre>
7467
7468<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7469 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7470 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7471 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7472 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]7473</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7474
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7475<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7476<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7477 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7478 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7479
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7480<h5>Arguments:</h5>
7481<p>These intrinsics take two arguments, the first a pointer to an integer value
7482 and the second an integer value. The result is also an integer value. These
7483 integer types can have any bit width, but they must all have the same bit
7484 width. The targets may only lower integer representations they support.</p>
7485
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7486<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7487<p>These intrinsics does a series of operations atomically. They first load the
7488 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7489 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7490 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7491
7492<h5>Examples:</h5>
7493<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7494%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7495%ptr = bitcast i8* %mallocP to i32*
7496 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7497%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7498 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7499%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7500 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7501%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7502 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7503%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7504 <i>; yields {i32}:result3 = 8</i>
7505%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7506</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7507
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7508</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7509
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7510
7511<!-- ======================================================================= -->
7512<div class="doc_subsection">
7513 <a name="int_memorymarkers">Memory Use Markers</a>
7514</div>
7515
7516<div class="doc_text">
7517
7518<p>This class of intrinsics exists to information about the lifetime of memory
7519 objects and ranges where variables are immutable.</p>
7520
7521</div>
7522
7523<!-- _______________________________________________________________________ -->
7524<div class="doc_subsubsection">
7525 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7526</div>
7527
7528<div class="doc_text">
7529
7530<h5>Syntax:</h5>
7531<pre>
7532 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7533</pre>
7534
7535<h5>Overview:</h5>
7536<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7537 object's lifetime.</p>
7538
7539<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7540<p>The first argument is a constant integer representing the size of the
7541 object, or -1 if it is variable sized. The second argument is a pointer to
7542 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7543
7544<h5>Semantics:</h5>
7545<p>This intrinsic indicates that before this point in the code, the value of the
7546 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]7547 never be used and has an undefined value. A load from the pointer that
7548 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7549 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7550
7551</div>
7552
7553<!-- _______________________________________________________________________ -->
7554<div class="doc_subsubsection">
7555 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7556</div>
7557
7558<div class="doc_text">
7559
7560<h5>Syntax:</h5>
7561<pre>
7562 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7563</pre>
7564
7565<h5>Overview:</h5>
7566<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7567 object's lifetime.</p>
7568
7569<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7570<p>The first argument is a constant integer representing the size of the
7571 object, or -1 if it is variable sized. The second argument is a pointer to
7572 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7573
7574<h5>Semantics:</h5>
7575<p>This intrinsic indicates that after this point in the code, the value of the
7576 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7577 never be used and has an undefined value. Any stores into the memory object
7578 following this intrinsic may be removed as dead.
7579
7580</div>
7581
7582<!-- _______________________________________________________________________ -->
7583<div class="doc_subsubsection">
7584 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7585</div>
7586
7587<div class="doc_text">
7588
7589<h5>Syntax:</h5>
7590<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]7591 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7592</pre>
7593
7594<h5>Overview:</h5>
7595<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7596 a memory object will not change.</p>
7597
7598<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7599<p>The first argument is a constant integer representing the size of the
7600 object, or -1 if it is variable sized. The second argument is a pointer to
7601 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7602
7603<h5>Semantics:</h5>
7604<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7605 the return value, the referenced memory location is constant and
7606 unchanging.</p>
7607
7608</div>
7609
7610<!-- _______________________________________________________________________ -->
7611<div class="doc_subsubsection">
7612 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7613</div>
7614
7615<div class="doc_text">
7616
7617<h5>Syntax:</h5>
7618<pre>
7619 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7620</pre>
7621
7622<h5>Overview:</h5>
7623<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7624 a memory object are mutable.</p>
7625
7626<h5>Arguments:</h5>
7627<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7628 The second argument is a constant integer representing the size of the
7629 object, or -1 if it is variable sized and the third argument is a pointer
7630 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7631
7632<h5>Semantics:</h5>
7633<p>This intrinsic indicates that the memory is mutable again.</p>
7634
7635</div>
7636
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7637<!-- ======================================================================= -->
7638<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7639 <a name="int_general">General Intrinsics</a>
7640</div>
7641
7642<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7643
7644<p>This class of intrinsics is designed to be generic and has no specific
7645 purpose.</p>
7646
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7647</div>
7648
7649<!-- _______________________________________________________________________ -->
7650<div class="doc_subsubsection">
7651 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7652</div>
7653
7654<div class="doc_text">
7655
7656<h5>Syntax:</h5>
7657<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7658 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]7659</pre>
7660
7661<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7662<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7663
7664<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>The first argument is a pointer to a value, the second is a pointer to a
7666 global string, the third is a pointer to a global string which is the source
7667 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7668
7669<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7670<p>This intrinsic allows annotation of local variables with arbitrary strings.
7671 This can be useful for special purpose optimizations that want to look for
7672 these annotations. These have no other defined use, they are ignored by code
7673 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7674
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7675</div>
7676
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7677<!-- _______________________________________________________________________ -->
7678<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7679 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7680</div>
7681
7682<div class="doc_text">
7683
7684<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7685<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7686 any integer bit width.</p>
7687
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7688<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7689 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7690 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7691 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7692 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7693 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]7694</pre>
7695
7696<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7697<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7698
7699<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7700<p>The first argument is an integer value (result of some expression), the
7701 second is a pointer to a global string, the third is a pointer to a global
7702 string which is the source file name, and the last argument is the line
7703 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7704
7705<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706<p>This intrinsic allows annotations to be put on arbitrary expressions with
7707 arbitrary strings. This can be useful for special purpose optimizations that
7708 want to look for these annotations. These have no other defined use, they
7709 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7710
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7711</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7712
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7713<!-- _______________________________________________________________________ -->
7714<div class="doc_subsubsection">
7715 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7716</div>
7717
7718<div class="doc_text">
7719
7720<h5>Syntax:</h5>
7721<pre>
7722 declare void @llvm.trap()
7723</pre>
7724
7725<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7726<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7727
7728<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7729<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7730
7731<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7732<p>This intrinsics is lowered to the target dependent trap instruction. If the
7733 target does not have a trap instruction, this intrinsic will be lowered to
7734 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7735
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7736</div>
7737
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7738<!-- _______________________________________________________________________ -->
7739<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7740 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7741</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7742
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7743<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7744
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7745<h5>Syntax:</h5>
7746<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7747 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7748</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7749
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7750<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7751<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7752 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7753 ensure that it is placed on the stack before local variables.</p>
7754
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7755<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7756<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7757 arguments. The first argument is the value loaded from the stack
7758 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7759 that has enough space to hold the value of the guard.</p>
7760
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7761<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7762<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7763 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7764 stack. This is to ensure that if a local variable on the stack is
7765 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7766 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7767 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7768 function.</p>
7769
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7770</div>
7771
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7772<!-- _______________________________________________________________________ -->
7773<div class="doc_subsubsection">
7774 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7775</div>
7776
7777<div class="doc_text">
7778
7779<h5>Syntax:</h5>
7780<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7781 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7782 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7783</pre>
7784
7785<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7786<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
7787 the optimizers to determine at compile time whether a) an operation (like
7788 memcpy) will overflow a buffer that corresponds to an object, or b) that a
7789 runtime check for overflow isn't necessary. An object in this context means
7790 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7791
7792<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7793<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7794 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7795 is a boolean 0 or 1. This argument determines whether you want the
7796 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]7797 1, variables are not allowed.</p>
7798
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7799<h5>Semantics:</h5>
7800<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]7801 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
7802 depending on the <tt>type</tt> argument, if the size cannot be determined at
7803 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7804
7805</div>
7806
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7807<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7808<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7809<address>
7810 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7811 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7812 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7813 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7814
7815 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]7816 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7817 Last modified: $Date$
7818</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7820</body>
7821</html>