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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 6f12e29f7deab6e12bf56e4bdb61eb7a6ea18ad3 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]910<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]919<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1133
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1134 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame^]1135 <dd>This attribute indicates that the function should be 'hotpatchable',
1136 meaning the function can be patched even while it is loaded into memory.
1137 On x86, the function prologue will contain a two-byte no-op sequence;
1138 this is the same sequence used in the system DLLs in Microsoft Windows
1139 XP Service Pack 2 and higher.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1140
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1141 <dt><tt><b>inlinehint</b></tt></dt>
1142 <dd>This attribute indicates that the source code contained a hint that inlining
1143 this function is desirable (such as the "inline" keyword in C/C++). It
1144 is just a hint; it imposes no requirements on the inliner.</dd>
1145
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1146 <dt><tt><b>naked</b></tt></dt>
1147 <dd>This attribute disables prologue / epilogue emission for the function.
1148 This can have very system-specific consequences.</dd>
1149
1150 <dt><tt><b>noimplicitfloat</b></tt></dt>
1151 <dd>This attributes disables implicit floating point instructions.</dd>
1152
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the inliner should never inline this
1155 function in any situation. This attribute may not be used together with
1156 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1157
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1158 <dt><tt><b>noredzone</b></tt></dt>
1159 <dd>This attribute indicates that the code generator should not use a red
1160 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1161
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1162 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1163 <dd>This function attribute indicates that the function never returns
1164 normally. This produces undefined behavior at runtime if the function
1165 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1166
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1167 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1168 <dd>This function attribute indicates that the function never returns with an
1169 unwind or exceptional control flow. If the function does unwind, its
1170 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1171
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1172 <dt><tt><b>optsize</b></tt></dt>
1173 <dd>This attribute suggests that optimization passes and code generator passes
1174 make choices that keep the code size of this function low, and otherwise
1175 do optimizations specifically to reduce code size.</dd>
1176
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1177 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1178 <dd>This attribute indicates that the function computes its result (or decides
1179 to unwind an exception) based strictly on its arguments, without
1180 dereferencing any pointer arguments or otherwise accessing any mutable
1181 state (e.g. memory, control registers, etc) visible to caller functions.
1182 It does not write through any pointer arguments
1183 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1184 changes any state visible to callers. This means that it cannot unwind
1185 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1186 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1187
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1188 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1189 <dd>This attribute indicates that the function does not write through any
1190 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1191 arguments) or otherwise modify any state (e.g. memory, control registers,
1192 etc) visible to caller functions. It may dereference pointer arguments
1193 and read state that may be set in the caller. A readonly function always
1194 returns the same value (or unwinds an exception identically) when called
1195 with the same set of arguments and global state. It cannot unwind an
1196 exception by calling the <tt>C++</tt> exception throwing methods, but may
1197 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1198
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1199 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1200 <dd>This attribute indicates that the function should emit a stack smashing
1201 protector. It is in the form of a "canary"&mdash;a random value placed on
1202 the stack before the local variables that's checked upon return from the
1203 function to see if it has been overwritten. A heuristic is used to
1204 determine if a function needs stack protectors or not.<br>
1205<br>
1206 If a function that has an <tt>ssp</tt> attribute is inlined into a
1207 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1208 function will have an <tt>ssp</tt> attribute.</dd>
1209
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1210 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1211 <dd>This attribute indicates that the function should <em>always</em> emit a
1212 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1213 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1214<br>
1215 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1216 function that doesn't have an <tt>sspreq</tt> attribute or which has
1217 an <tt>ssp</tt> attribute, then the resulting function will have
1218 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1219</dl>
1220
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1221</div>
1222
1223<!-- ======================================================================= -->
1224<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1225 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1226</div>
1227
1228<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1229
1230<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1231 the GCC "file scope inline asm" blocks. These blocks are internally
1232 concatenated by LLVM and treated as a single unit, but may be separated in
1233 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1234
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1235<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1236module asm "inline asm code goes here"
1237module asm "more can go here"
1238</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1239
1240<p>The strings can contain any character by escaping non-printable characters.
1241 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]1242 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1243
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244<p>The inline asm code is simply printed to the machine code .s file when
1245 assembly code is generated.</p>
1246
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1247</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1248
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1249<!-- ======================================================================= -->
1250<div class="doc_subsection">
1251 <a name="datalayout">Data Layout</a>
1252</div>
1253
1254<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1255
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1257 data is to be laid out in memory. The syntax for the data layout is
1258 simply:</p>
1259
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1260<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261target datalayout = "<i>layout specification</i>"
1262</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1263
1264<p>The <i>layout specification</i> consists of a list of specifications
1265 separated by the minus sign character ('-'). Each specification starts with
1266 a letter and may include other information after the letter to define some
1267 aspect of the data layout. The specifications accepted are as follows:</p>
1268
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1269<dl>
1270 <dt><tt>E</tt></dt>
1271 <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]1272 bits with the most significance have the lowest address location.</dd>
1273
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1274 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1275 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1276 the bits with the least significance have the lowest address
1277 location.</dd>
1278
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1279 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1280 <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]1281 <i>preferred</i> alignments. All sizes are in bits. Specifying
1282 the <i>pref</i> alignment is optional. If omitted, the
1283 preceding <tt>:</tt> should be omitted too.</dd>
1284
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1285 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1286 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1287 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1290 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1293 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1294 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1295 <i>size</i>. Only values of <i>size</i> that are supported by the target
1296 will work. 32 (float) and 64 (double) are supported on all targets;
1297 80 or 128 (different flavors of long double) are also supported on some
1298 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1299
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1300 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1301 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1302 <i>size</i>.</dd>
1303
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1304 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1305 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1306 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1307
1308 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1309 <dd>This specifies a set of native integer widths for the target CPU
1310 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1311 "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]1312 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1313 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1314</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1315
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1316<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1317 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1318 specifications in the <tt>datalayout</tt> keyword. The default specifications
1319 are given in this list:</p>
1320
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1321<ul>
1322 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1323 <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]1324 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1325 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1326 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1327 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1328 <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]1329 alignment of 64-bits</li>
1330 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1331 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1332 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1333 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1334 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1335 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1336</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1337
1338<p>When LLVM is determining the alignment for a given type, it uses the
1339 following rules:</p>
1340
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1341<ol>
1342 <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]1343 specification is used.</li>
1344
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1345 <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]1346 smallest integer type that is larger than the bitwidth of the sought type
1347 is used. If none of the specifications are larger than the bitwidth then
1348 the the largest integer type is used. For example, given the default
1349 specifications above, the i7 type will use the alignment of i8 (next
1350 largest) while both i65 and i256 will use the alignment of i64 (largest
1351 specified).</li>
1352
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1353 <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]1354 largest vector type that is smaller than the sought vector type will be
1355 used as a fall back. This happens because &lt;128 x double&gt; can be
1356 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1357</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1358
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1359</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1360
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1361<!-- ======================================================================= -->
1362<div class="doc_subsection">
1363 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1364</div>
1365
1366<div class="doc_text">
1367
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1368<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1369with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1370is undefined. Pointer values are associated with address ranges
1371according to the following rules:</p>
1372
1373<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1374 <li>A pointer value is associated with the addresses associated with
1375 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1376 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1377 range of the variable's storage.</li>
1378 <li>The result value of an allocation instruction is associated with
1379 the address range of the allocated storage.</li>
1380 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1381 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1382 <li>An integer constant other than zero or a pointer value returned
1383 from a function not defined within LLVM may be associated with address
1384 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1385 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1386 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1387</ul>
1388
1389<p>A pointer value is <i>based</i> on another pointer value according
1390 to the following rules:</p>
1391
1392<ul>
1393 <li>A pointer value formed from a
1394 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1395 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1396 <li>The result value of a
1397 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1398 of the <tt>bitcast</tt>.</li>
1399 <li>A pointer value formed by an
1400 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1401 pointer values that contribute (directly or indirectly) to the
1402 computation of the pointer's value.</li>
1403 <li>The "<i>based</i> on" relationship is transitive.</li>
1404</ul>
1405
1406<p>Note that this definition of <i>"based"</i> is intentionally
1407 similar to the definition of <i>"based"</i> in C99, though it is
1408 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1409
1410<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1411<tt><a href="#i_load">load</a></tt> merely indicates the size and
1412alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1413interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1414<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1415and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1416
1417<p>Consequently, type-based alias analysis, aka TBAA, aka
1418<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1419LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1420additional information which specialized optimization passes may use
1421to implement type-based alias analysis.</p>
1422
1423</div>
1424
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1425<!-- ======================================================================= -->
1426<div class="doc_subsection">
1427 <a name="volatile">Volatile Memory Accesses</a>
1428</div>
1429
1430<div class="doc_text">
1431
1432<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1433href="#i_store"><tt>store</tt></a>s, and <a
1434href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1435The optimizers must not change the number of volatile operations or change their
1436order of execution relative to other volatile operations. The optimizers
1437<i>may</i> change the order of volatile operations relative to non-volatile
1438operations. This is not Java's "volatile" and has no cross-thread
1439synchronization behavior.</p>
1440
1441</div>
1442
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1443<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1444<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1445<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1449<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1450 intermediate representation. Being typed enables a number of optimizations
1451 to be performed on the intermediate representation directly, without having
1452 to do extra analyses on the side before the transformation. A strong type
1453 system makes it easier to read the generated code and enables novel analyses
1454 and transformations that are not feasible to perform on normal three address
1455 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1456
1457</div>
1458
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1459<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1460<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1461Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1463<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1464
1465<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1466
1467<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1469 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1470 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1471 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1472 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1473 </tr>
1474 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1475 <td><a href="#t_floating">floating point</a></td>
1476 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1477 </tr>
1478 <tr>
1479 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1480 <td><a href="#t_integer">integer</a>,
1481 <a href="#t_floating">floating point</a>,
1482 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1484 <a href="#t_struct">structure</a>,
1485 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1486 <a href="#t_label">label</a>,
1487 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1488 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1489 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1490 <tr>
1491 <td><a href="#t_primitive">primitive</a></td>
1492 <td><a href="#t_label">label</a>,
1493 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1494 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1495 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1496 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497 </tr>
1498 <tr>
1499 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1500 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1501 <a href="#t_function">function</a>,
1502 <a href="#t_pointer">pointer</a>,
1503 <a href="#t_struct">structure</a>,
1504 <a href="#t_pstruct">packed structure</a>,
1505 <a href="#t_vector">vector</a>,
1506 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1507 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1508 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1509 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1510</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1511
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1512<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1513 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1514 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1515
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1516</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1518<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1520
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1521<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1522
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1523<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1524 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1525
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1526</div>
1527
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1528<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1529<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1530
1531<div class="doc_text">
1532
1533<h5>Overview:</h5>
1534<p>The integer type is a very simple type that simply specifies an arbitrary
1535 bit width for the integer type desired. Any bit width from 1 bit to
1536 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1537
1538<h5>Syntax:</h5>
1539<pre>
1540 iN
1541</pre>
1542
1543<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1544 value.</p>
1545
1546<h5>Examples:</h5>
1547<table class="layout">
1548 <tr class="layout">
1549 <td class="left"><tt>i1</tt></td>
1550 <td class="left">a single-bit integer.</td>
1551 </tr>
1552 <tr class="layout">
1553 <td class="left"><tt>i32</tt></td>
1554 <td class="left">a 32-bit integer.</td>
1555 </tr>
1556 <tr class="layout">
1557 <td class="left"><tt>i1942652</tt></td>
1558 <td class="left">a really big integer of over 1 million bits.</td>
1559 </tr>
1560</table>
1561
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1562</div>
1563
1564<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1565<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1566
1567<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1568
1569<table>
1570 <tbody>
1571 <tr><th>Type</th><th>Description</th></tr>
1572 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1573 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1574 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1575 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1576 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1577 </tbody>
1578</table>
1579
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1580</div>
1581
1582<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1583<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1584
1585<div class="doc_text">
1586
1587<h5>Overview:</h5>
1588<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>
1589
1590<h5>Syntax:</h5>
1591<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1592 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1593</pre>
1594
1595</div>
1596
1597<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1598<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1599
1600<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1601
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1602<h5>Overview:</h5>
1603<p>The void type does not represent any value and has no size.</p>
1604
1605<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1606<pre>
1607 void
1608</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1609
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1610</div>
1611
1612<!-- _______________________________________________________________________ -->
1613<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1614
1615<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1616
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1617<h5>Overview:</h5>
1618<p>The label type represents code labels.</p>
1619
1620<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1621<pre>
1622 label
1623</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1624
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1625</div>
1626
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1627<!-- _______________________________________________________________________ -->
1628<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1629
1630<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1631
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1632<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1633<p>The metadata type represents embedded metadata. No derived types may be
1634 created from metadata except for <a href="#t_function">function</a>
1635 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1636
1637<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1638<pre>
1639 metadata
1640</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1641
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1642</div>
1643
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1644
1645<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1649
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1650<p>The real power in LLVM comes from the derived types in the system. This is
1651 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1652 useful types. Each of these types contain one or more element types which
1653 may be a primitive type, or another derived type. For example, it is
1654 possible to have a two dimensional array, using an array as the element type
1655 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1656
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1657
1658</div>
1659
1660<!-- _______________________________________________________________________ -->
1661<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1662
1663<div class="doc_text">
1664
1665<p>Aggregate Types are a subset of derived types that can contain multiple
1666 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1667 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1668 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1669
1670</div>
1671
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1672<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1673<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1674
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1675<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1678<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1679 sequentially in memory. The array type requires a size (number of elements)
1680 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1681
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1682<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1683<pre>
1684 [&lt;# elements&gt; x &lt;elementtype&gt;]
1685</pre>
1686
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1687<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1688 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1689
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1690<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1691<table class="layout">
1692 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1693 <td class="left"><tt>[40 x i32]</tt></td>
1694 <td class="left">Array of 40 32-bit integer values.</td>
1695 </tr>
1696 <tr class="layout">
1697 <td class="left"><tt>[41 x i32]</tt></td>
1698 <td class="left">Array of 41 32-bit integer values.</td>
1699 </tr>
1700 <tr class="layout">
1701 <td class="left"><tt>[4 x i8]</tt></td>
1702 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1703 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1705<p>Here are some examples of multidimensional arrays:</p>
1706<table class="layout">
1707 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1708 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1709 <td class="left">3x4 array of 32-bit integer values.</td>
1710 </tr>
1711 <tr class="layout">
1712 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1713 <td class="left">12x10 array of single precision floating point values.</td>
1714 </tr>
1715 <tr class="layout">
1716 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1717 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1718 </tr>
1719</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1720
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1721<p>There is no restriction on indexing beyond the end of the array implied by
1722 a static type (though there are restrictions on indexing beyond the bounds
1723 of an allocated object in some cases). This means that single-dimension
1724 'variable sized array' addressing can be implemented in LLVM with a zero
1725 length array type. An implementation of 'pascal style arrays' in LLVM could
1726 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1727
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1728</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1729
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1730<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1731<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1732
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1733<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1734
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1736<p>The function type can be thought of as a function signature. It consists of
1737 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]1738 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1739
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1741<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1742 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1743</pre>
1744
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1745<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]1746 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1747 which indicates that the function takes a variable number of arguments.
1748 Variable argument functions can access their arguments with
1749 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1750 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1751 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1754<table class="layout">
1755 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1756 <td class="left"><tt>i32 (i32)</tt></td>
1757 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1758 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1759 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1760 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1761 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1762 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1763 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1764 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1765 </td>
1766 </tr><tr class="layout">
1767 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1768 <td class="left">A vararg function that takes at least one
1769 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1770 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1771 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1772 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1773 </tr><tr class="layout">
1774 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1775 <td class="left">A function taking an <tt>i32</tt>, returning a
1776 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1777 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1778 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1779</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1783<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1784<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1789<p>The structure type is used to represent a collection of data members together
1790 in memory. The packing of the field types is defined to match the ABI of the
1791 underlying processor. The elements of a structure may be any type that has a
1792 size.</p>
1793
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1794<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1795 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1796 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1797 Structures in registers are accessed using the
1798 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1799 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1801<pre>
1802 { &lt;type list&gt; }
1803</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1806<table class="layout">
1807 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1808 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1809 <td class="left">A triple of three <tt>i32</tt> values</td>
1810 </tr><tr class="layout">
1811 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1812 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1813 second element is a <a href="#t_pointer">pointer</a> to a
1814 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1815 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1816 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1817</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1818
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1819</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1821<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1822<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1823</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1825<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1826
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1827<h5>Overview:</h5>
1828<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1829 together in memory. There is no padding between fields. Further, the
1830 alignment of a packed structure is 1 byte. The elements of a packed
1831 structure may be any type that has a size.</p>
1832
1833<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1834 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1835 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1836
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1837<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1838<pre>
1839 &lt; { &lt;type list&gt; } &gt;
1840</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1841
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1842<h5>Examples:</h5>
1843<table class="layout">
1844 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1845 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1846 <td class="left">A triple of three <tt>i32</tt> values</td>
1847 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1848 <td class="left">
1849<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1850 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1851 second element is a <a href="#t_pointer">pointer</a> to a
1852 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1853 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1854 </tr>
1855</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1856
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1857</div>
1858
1859<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1860<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1861
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1862<div class="doc_text">
1863
1864<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1865<p>The pointer type is used to specify memory locations.
1866 Pointers are commonly used to reference objects in memory.</p>
1867
1868<p>Pointer types may have an optional address space attribute defining the
1869 numbered address space where the pointed-to object resides. The default
1870 address space is number zero. The semantics of non-zero address
1871 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1872
1873<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1874 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1875
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1876<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1877<pre>
1878 &lt;type&gt; *
1879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1881<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1882<table class="layout">
1883 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1884 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1885 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1886 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1887 </tr>
1888 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1889 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1890 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1891 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1892 <tt>i32</tt>.</td>
1893 </tr>
1894 <tr class="layout">
1895 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1896 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1897 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1898 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1899</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1901</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1902
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1903<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1904<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1905
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1906<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1907
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1908<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1909<p>A vector type is a simple derived type that represents a vector of elements.
1910 Vector types are used when multiple primitive data are operated in parallel
1911 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1912 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1913 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1914
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1915<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1916<pre>
1917 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1918</pre>
1919
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1920<p>The number of elements is a constant integer value larger than 0; elementtype
1921 may be any integer or floating point type. Vectors of size zero are not
1922 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1923
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1924<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1925<table class="layout">
1926 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1927 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1928 <td class="left">Vector of 4 32-bit integer values.</td>
1929 </tr>
1930 <tr class="layout">
1931 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1932 <td class="left">Vector of 8 32-bit floating-point values.</td>
1933 </tr>
1934 <tr class="layout">
1935 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1936 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1937 </tr>
1938</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1939
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1940</div>
1941
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1942<!-- _______________________________________________________________________ -->
1943<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1944<div class="doc_text">
1945
1946<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1947<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1948 corresponds (for example) to the C notion of a forward declared structure
1949 type. In LLVM, opaque types can eventually be resolved to any type (not just
1950 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1951
1952<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1953<pre>
1954 opaque
1955</pre>
1956
1957<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1958<table class="layout">
1959 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1960 <td class="left"><tt>opaque</tt></td>
1961 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1962 </tr>
1963</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1964
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1965</div>
1966
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1967<!-- ======================================================================= -->
1968<div class="doc_subsection">
1969 <a name="t_uprefs">Type Up-references</a>
1970</div>
1971
1972<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1973
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1974<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1975<p>An "up reference" allows you to refer to a lexically enclosing type without
1976 requiring it to have a name. For instance, a structure declaration may
1977 contain a pointer to any of the types it is lexically a member of. Example
1978 of up references (with their equivalent as named type declarations)
1979 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1980
1981<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1982 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1983 { \2 }* %y = type { %y }*
1984 \1* %z = type %z*
1985</pre>
1986
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1987<p>An up reference is needed by the asmprinter for printing out cyclic types
1988 when there is no declared name for a type in the cycle. Because the
1989 asmprinter does not want to print out an infinite type string, it needs a
1990 syntax to handle recursive types that have no names (all names are optional
1991 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1992
1993<h5>Syntax:</h5>
1994<pre>
1995 \&lt;level&gt;
1996</pre>
1997
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1998<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]1999
2000<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2001<table class="layout">
2002 <tr class="layout">
2003 <td class="left"><tt>\1*</tt></td>
2004 <td class="left">Self-referential pointer.</td>
2005 </tr>
2006 <tr class="layout">
2007 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2008 <td class="left">Recursive structure where the upref refers to the out-most
2009 structure.</td>
2010 </tr>
2011</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2012
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2013</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2014
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2015<!-- *********************************************************************** -->
2016<div class="doc_section"> <a name="constants">Constants</a> </div>
2017<!-- *********************************************************************** -->
2018
2019<div class="doc_text">
2020
2021<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2022 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2023
2024</div>
2025
2026<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2027<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2028
2029<div class="doc_text">
2030
2031<dl>
2032 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2033 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2034 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2035
2036 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2037 <dd>Standard integers (such as '4') are constants of
2038 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2039 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2040
2041 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2042 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2043 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2044 notation (see below). The assembler requires the exact decimal value of a
2045 floating-point constant. For example, the assembler accepts 1.25 but
2046 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2047 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2050 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2051 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2052</dl>
2053
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2054<p>The one non-intuitive notation for constants is the hexadecimal form of
2055 floating point constants. For example, the form '<tt>double
2056 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2057 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2058 constants are required (and the only time that they are generated by the
2059 disassembler) is when a floating point constant must be emitted but it cannot
2060 be represented as a decimal floating point number in a reasonable number of
2061 digits. For example, NaN's, infinities, and other special values are
2062 represented in their IEEE hexadecimal format so that assembly and disassembly
2063 do not cause any bits to change in the constants.</p>
2064
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2065<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2066 represented using the 16-digit form shown above (which matches the IEEE754
2067 representation for double); float values must, however, be exactly
2068 representable as IEE754 single precision. Hexadecimal format is always used
2069 for long double, and there are three forms of long double. The 80-bit format
2070 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2071 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2072 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2073 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2074 currently supported target uses this format. Long doubles will only work if
2075 they match the long double format on your target. All hexadecimal formats
2076 are big-endian (sign bit at the left).</p>
2077
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2078<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2079</div>
2080
2081<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2082<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2083<a name="aggregateconstants"></a> <!-- old anchor -->
2084<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2085</div>
2086
2087<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2088
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2089<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2090 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2091
2092<dl>
2093 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2094 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2095 type definitions (a comma separated list of elements, surrounded by braces
2096 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2097 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2098 Structure constants must have <a href="#t_struct">structure type</a>, and
2099 the number and types of elements must match those specified by the
2100 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2101
2102 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2103 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2104 definitions (a comma separated list of elements, surrounded by square
2105 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2106 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2107 the number and types of elements must match those specified by the
2108 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2109
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2110 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2111 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2112 definitions (a comma separated list of elements, surrounded by
2113 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2114 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2115 have <a href="#t_vector">vector type</a>, and the number and types of
2116 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2117
2118 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2119 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2120 value to zero of <em>any</em> type, including scalar and
2121 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2122 This is often used to avoid having to print large zero initializers
2123 (e.g. for large arrays) and is always exactly equivalent to using explicit
2124 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2125
2126 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2127 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2128 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2129 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2130 be interpreted as part of the instruction stream, metadata is a place to
2131 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2132</dl>
2133
2134</div>
2135
2136<!-- ======================================================================= -->
2137<div class="doc_subsection">
2138 <a name="globalconstants">Global Variable and Function Addresses</a>
2139</div>
2140
2141<div class="doc_text">
2142
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2143<p>The addresses of <a href="#globalvars">global variables</a>
2144 and <a href="#functionstructure">functions</a> are always implicitly valid
2145 (link-time) constants. These constants are explicitly referenced when
2146 the <a href="#identifiers">identifier for the global</a> is used and always
2147 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2148 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2149
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2150<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2151@X = global i32 17
2152@Y = global i32 42
2153@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2154</pre>
2155
2156</div>
2157
2158<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2159<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2160<div class="doc_text">
2161
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2162<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]2163 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2164 Undefined values may be of any type (other than label or void) and be used
2165 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2166
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2167<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2168 program is well defined no matter what value is used. This gives the
2169 compiler more freedom to optimize. Here are some examples of (potentially
2170 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2171
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2172
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2173<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2174 %A = add %X, undef
2175 %B = sub %X, undef
2176 %C = xor %X, undef
2177Safe:
2178 %A = undef
2179 %B = undef
2180 %C = undef
2181</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2182
2183<p>This is safe because all of the output bits are affected by the undef bits.
2184Any output bit can have a zero or one depending on the input bits.</p>
2185
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2186<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2187 %A = or %X, undef
2188 %B = and %X, undef
2189Safe:
2190 %A = -1
2191 %B = 0
2192Unsafe:
2193 %A = undef
2194 %B = undef
2195</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2196
2197<p>These logical operations have bits that are not always affected by the input.
2198For example, if "%X" has a zero bit, then the output of the 'and' operation will
2199always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2200such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2201However, it is safe to assume that all bits of the undef could be 0, and
2202optimize the and to 0. Likewise, it is safe to assume that all the bits of
2203the undef operand to the or could be set, allowing the or to be folded to
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2204-1.</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 = select undef, %X, %Y
2208 %B = select undef, 42, %Y
2209 %C = select %X, %Y, undef
2210Safe:
2211 %A = %X (or %Y)
2212 %B = 42 (or %Y)
2213 %C = %Y
2214Unsafe:
2215 %A = undef
2216 %B = undef
2217 %C = undef
2218</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2219
2220<p>This set of examples show that undefined select (and conditional branch)
2221conditions can go "either way" but they have to come from one of the two
2222operands. In the %A example, if %X and %Y were both known to have a clear low
2223bit, then %A would have to have a cleared low bit. However, in the %C example,
2224the optimizer is allowed to assume that the undef operand could be the same as
2225%Y, allowing the whole select to be eliminated.</p>
2226
2227
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2228<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2229 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2230
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2231 %B = undef
2232 %C = xor %B, %B
2233
2234 %D = undef
2235 %E = icmp lt %D, 4
2236 %F = icmp gte %D, 4
2237
2238Safe:
2239 %A = undef
2240 %B = undef
2241 %C = undef
2242 %D = undef
2243 %E = undef
2244 %F = undef
2245</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2246
2247<p>This example points out that two undef operands are not necessarily the same.
2248This can be surprising to people (and also matches C semantics) where they
2249assume that "X^X" is always zero, even if X is undef. This isn't true for a
2250number of reasons, but the short answer is that an undef "variable" can
2251arbitrarily change its value over its "live range". This is true because the
2252"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2253logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2254so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2255to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2256would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2257
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2258<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2259 %A = fdiv undef, %X
2260 %B = fdiv %X, undef
2261Safe:
2262 %A = undef
2263b: unreachable
2264</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2265
2266<p>These examples show the crucial difference between an <em>undefined
2267value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2268allowed to have an arbitrary bit-pattern. This means that the %A operation
2269can be constant folded to undef because the undef could be an SNaN, and fdiv is
2270not (currently) defined on SNaN's. However, in the second example, we can make
2271a more aggressive assumption: because the undef is allowed to be an arbitrary
2272value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner8e371aa2009-09-08 19:45:34 +0000[diff] [blame]2273has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2274does not execute at all. This allows us to delete the divide and all code after
2275it: since the undefined operation "can't happen", the optimizer can assume that
2276it occurs in dead code.
2277</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2278
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2279<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2280a: store undef -> %X
2281b: store %X -> undef
2282Safe:
2283a: &lt;deleted&gt;
2284b: unreachable
2285</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2286
2287<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2288can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2289overwritten with bits that happen to match what was already there. However, a
2290store "to" an undefined location could clobber arbitrary memory, therefore, it
2291has undefined behavior.</p>
2292
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2293</div>
2294
2295<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2296<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2297<div class="doc_text">
2298
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2299<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2300 instead of representing an unspecified bit pattern, they represent the
2301 fact that an instruction or constant expression which cannot evoke side
2302 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2303 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2304
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2305<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]2306 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2307 <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]2308
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2309<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2310
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2311<ul>
2312<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2313 their operands.</li>
2314
2315<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2316 to their dynamic predecessor basic block.</li>
2317
2318<li>Function arguments depend on the corresponding actual argument values in
2319 the dynamic callers of their functions.</li>
2320
2321<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2322 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2323 control back to them.</li>
2324
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2325<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2326 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2327 or exception-throwing call instructions that dynamically transfer control
2328 back to them.</li>
2329
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2330<li>Non-volatile loads and stores depend on the most recent stores to all of the
2331 referenced memory addresses, following the order in the IR
2332 (including loads and stores implied by intrinsics such as
2333 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2334
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2335<!-- TODO: In the case of multiple threads, this only applies if the store
2336 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2337
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2338<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2339
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2340<li>An instruction with externally visible side effects depends on the most
2341 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2342 the order in the IR. (This includes
2343 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2344
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2345<li>An instruction <i>control-depends</i> on a
2346 <a href="#terminators">terminator instruction</a>
2347 if the terminator instruction has multiple successors and the instruction
2348 is always executed when control transfers to one of the successors, and
2349 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2350
2351<li>Dependence is transitive.</li>
2352
2353</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2354
2355<p>Whenever a trap value is generated, all values which depend on it evaluate
2356 to trap. If they have side effects, the evoke their side effects as if each
2357 operand with a trap value were undef. If they have externally-visible side
2358 effects, the behavior is undefined.</p>
2359
2360<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2361
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2362<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2363entry:
2364 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2365 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2366 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2367 store i32 0, i32* %trap_yet_again ; undefined behavior
2368
2369 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2370 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2371
2372 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2373
2374 %narrowaddr = bitcast i32* @g to i16*
2375 %wideaddr = bitcast i32* @g to i64*
2376 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2377 %trap4 = load i64* %widaddr ; Returns a trap value.
2378
2379 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2380 %br i1 %cmp, %true, %end ; Branch to either destination.
2381
2382true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2383 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2384 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2385 br label %end
2386
2387end:
2388 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2389 ; Both edges into this PHI are
2390 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2391 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2392
2393 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2394 ; so this is defined (ignoring earlier
2395 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2396</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2397
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2398</div>
2399
2400<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2401<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2402 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2403<div class="doc_text">
2404
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2405<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2406
2407<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2408 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2409 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2410
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2411<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2412 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2413 against null. Pointer equality tests between labels addresses is undefined
2414 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2415 equal to the null pointer. This may also be passed around as an opaque
2416 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2417 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2418 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2419
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2420<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2421 using the value as the operand to an inline assembly, but that is target
2422 specific.
2423 </p>
2424
2425</div>
2426
2427
2428<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2429<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2430</div>
2431
2432<div class="doc_text">
2433
2434<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2435 to be used as constants. Constant expressions may be of
2436 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2437 operation that does not have side effects (e.g. load and call are not
2438 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2439
2440<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2441 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2442 <dd>Truncate a constant to another type. The bit size of CST must be larger
2443 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2444
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2445 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2446 <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]2447 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2448
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2449 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2450 <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]2451 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2452
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2453 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2454 <dd>Truncate a floating point constant to another floating point type. The
2455 size of CST must be larger than the size of TYPE. Both types must be
2456 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2457
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2458 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2459 <dd>Floating point extend a constant to another type. The size of CST must be
2460 smaller or equal to the size of TYPE. Both types must be floating
2461 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2462
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2463 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2464 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2465 constant. TYPE must be a scalar or vector integer type. CST must be of
2466 scalar or vector floating point type. Both CST and TYPE must be scalars,
2467 or vectors of the same number of elements. If the value won't fit in the
2468 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2469
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2470 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2471 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2472 constant. TYPE must be a scalar or vector integer type. CST must be of
2473 scalar or vector floating point type. Both CST and TYPE must be scalars,
2474 or vectors of the same number of elements. If the value won't fit in the
2475 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2476
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2477 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2478 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479 constant. TYPE must be a scalar or vector floating point type. CST must be
2480 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2481 vectors of the same number of elements. If the value won't fit in the
2482 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2483
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2484 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2485 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2486 constant. TYPE must be a scalar or vector floating point type. CST must be
2487 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2488 vectors of the same number of elements. If the value won't fit in the
2489 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2490
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2491 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2492 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2493 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2494 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2495 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2496
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2497 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2498 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2499 type. CST must be of integer type. The CST value is zero extended,
2500 truncated, or unchanged to make it fit in a pointer size. This one is
2501 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2502
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2503 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2504 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2505 are the same as those for the <a href="#i_bitcast">bitcast
2506 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2507
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2508 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2509 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2510 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2511 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2512 instruction, the index list may have zero or more indexes, which are
2513 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2514
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2515 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2516 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2517
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2519 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2520
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2521 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2522 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2523
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2525 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2526 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2527
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2528 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2529 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2530 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2531
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2532 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2533 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2534 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2535
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2536 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2537 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2538 constants. The index list is interpreted in a similar manner as indices in
2539 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2540 index value must be specified.</dd>
2541
2542 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2543 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2544 constants. The index list is interpreted in a similar manner as indices in
2545 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2546 index value must be specified.</dd>
2547
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2549 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2550 be any of the <a href="#binaryops">binary</a>
2551 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2552 on operands are the same as those for the corresponding instruction
2553 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2554</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2556</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2559<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2560<!-- *********************************************************************** -->
2561
2562<!-- ======================================================================= -->
2563<div class="doc_subsection">
2564<a name="inlineasm">Inline Assembler Expressions</a>
2565</div>
2566
2567<div class="doc_text">
2568
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2569<p>LLVM supports inline assembler expressions (as opposed
2570 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2571 a special value. This value represents the inline assembler as a string
2572 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2573 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2574 expression has side effects, and a flag indicating whether the function
2575 containing the asm needs to align its stack conservatively. An example
2576 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2577
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2578<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2579i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2580</pre>
2581
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2582<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2583 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2584 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2585
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2586<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2587%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]2588</pre>
2589
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2590<p>Inline asms with side effects not visible in the constraint list must be
2591 marked as having side effects. This is done through the use of the
2592 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2593
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2594<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2595call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2596</pre>
2597
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2598<p>In some cases inline asms will contain code that will not work unless the
2599 stack is aligned in some way, such as calls or SSE instructions on x86,
2600 yet will not contain code that does that alignment within the asm.
2601 The compiler should make conservative assumptions about what the asm might
2602 contain and should generate its usual stack alignment code in the prologue
2603 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2604
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2605<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2606call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2607</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2608
2609<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2610 first.</p>
2611
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2612<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2613 documented here. Constraints on what can be done (e.g. duplication, moving,
2614 etc need to be documented). This is probably best done by reference to
2615 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2616</div>
2617
2618<div class="doc_subsubsection">
2619<a name="inlineasm_md">Inline Asm Metadata</a>
2620</div>
2621
2622<div class="doc_text">
2623
2624<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2625 attached to it that contains a constant integer. If present, the code
2626 generator will use the integer as the location cookie value when report
2627 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2628 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2629 source code that produced it. For example:</p>
2630
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2631<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2632call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2633...
2634!42 = !{ i32 1234567 }
2635</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2636
2637<p>It is up to the front-end to make sense of the magic numbers it places in the
2638 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2639
2640</div>
2641
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2642<!-- ======================================================================= -->
2643<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2644 Strings</a>
2645</div>
2646
2647<div class="doc_text">
2648
2649<p>LLVM IR allows metadata to be attached to instructions in the program that
2650 can convey extra information about the code to the optimizers and code
2651 generator. One example application of metadata is source-level debug
2652 information. There are two metadata primitives: strings and nodes. All
2653 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2654 preceding exclamation point ('<tt>!</tt>').</p>
2655
2656<p>A metadata string is a string surrounded by double quotes. It can contain
2657 any character by escaping non-printable characters with "\xx" where "xx" is
2658 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2659
2660<p>Metadata nodes are represented with notation similar to structure constants
2661 (a comma separated list of elements, surrounded by braces and preceded by an
2662 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2663 10}</tt>". Metadata nodes can have any values as their operand.</p>
2664
2665<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2666 metadata nodes, which can be looked up in the module symbol table. For
2667 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2668
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2669<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2670 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2671
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2672 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2673 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2674 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2675
2676<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2677 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2678
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2679 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2680 %indvar.next = add i64 %indvar, 1, !dbg !21
2681 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2682</div>
2683
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2684
2685<!-- *********************************************************************** -->
2686<div class="doc_section">
2687 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2688</div>
2689<!-- *********************************************************************** -->
2690
2691<p>LLVM has a number of "magic" global variables that contain data that affect
2692code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2693of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2694section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2695by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2696
2697<!-- ======================================================================= -->
2698<div class="doc_subsection">
2699<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2700</div>
2701
2702<div class="doc_text">
2703
2704<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2705href="#linkage_appending">appending linkage</a>. This array contains a list of
2706pointers to global variables and functions which may optionally have a pointer
2707cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2708
2709<pre>
2710 @X = global i8 4
2711 @Y = global i32 123
2712
2713 @llvm.used = appending global [2 x i8*] [
2714 i8* @X,
2715 i8* bitcast (i32* @Y to i8*)
2716 ], section "llvm.metadata"
2717</pre>
2718
2719<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2720compiler, assembler, and linker are required to treat the symbol as if there is
2721a reference to the global that it cannot see. For example, if a variable has
2722internal linkage and no references other than that from the <tt>@llvm.used</tt>
2723list, it cannot be deleted. This is commonly used to represent references from
2724inline asms and other things the compiler cannot "see", and corresponds to
2725"attribute((used))" in GNU C.</p>
2726
2727<p>On some targets, the code generator must emit a directive to the assembler or
2728object file to prevent the assembler and linker from molesting the symbol.</p>
2729
2730</div>
2731
2732<!-- ======================================================================= -->
2733<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2734<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2735</div>
2736
2737<div class="doc_text">
2738
2739<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2740<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2741touching the symbol. On targets that support it, this allows an intelligent
2742linker to optimize references to the symbol without being impeded as it would be
2743by <tt>@llvm.used</tt>.</p>
2744
2745<p>This is a rare construct that should only be used in rare circumstances, and
2746should not be exposed to source languages.</p>
2747
2748</div>
2749
2750<!-- ======================================================================= -->
2751<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2752<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2753</div>
2754
2755<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2756<pre>
2757%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2758@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2759</pre>
2760<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.
2761</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2762
2763</div>
2764
2765<!-- ======================================================================= -->
2766<div class="doc_subsection">
2767<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2768</div>
2769
2770<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2771<pre>
2772%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2773@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2774</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2775
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2776<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.
2777</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2778
2779</div>
2780
2781
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2782<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2783<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2784<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2786<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2787
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2788<p>The LLVM instruction set consists of several different classifications of
2789 instructions: <a href="#terminators">terminator
2790 instructions</a>, <a href="#binaryops">binary instructions</a>,
2791 <a href="#bitwiseops">bitwise binary instructions</a>,
2792 <a href="#memoryops">memory instructions</a>, and
2793 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2794
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2795</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2797<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2798<div class="doc_subsection"> <a name="terminators">Terminator
2799Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2801<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2803<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2804 in a program ends with a "Terminator" instruction, which indicates which
2805 block should be executed after the current block is finished. These
2806 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2807 control flow, not values (the one exception being the
2808 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2809
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2810<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2811 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2812 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2813 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2814 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2816 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2817 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2818
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2819</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2821<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2822<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2823Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2825<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2827<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2828<pre>
2829 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]2830 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2833<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2834<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2835 a value) from a function back to the caller.</p>
2836
2837<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2838 value and then causes control flow, and one that just causes control flow to
2839 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2841<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2842<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2843 return value. The type of the return value must be a
2844 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2846<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2847 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2848 value or a return value with a type that does not match its type, or if it
2849 has a void return type and contains a '<tt>ret</tt>' instruction with a
2850 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2851
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2852<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2854 the calling function's context. If the caller is a
2855 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2856 instruction after the call. If the caller was an
2857 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2858 the beginning of the "normal" destination block. If the instruction returns
2859 a value, that value shall set the call or invoke instruction's return
2860 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2863<pre>
2864 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2865 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2866 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]2867</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2868
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2869</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2870<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2871<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</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>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876<pre>
2877 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]2878</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2879
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2881<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2882 different basic block in the current function. There are two forms of this
2883 instruction, corresponding to a conditional branch and an unconditional
2884 branch.</p>
2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2888 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2889 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2890 target.</p>
2891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2892<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2893<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2895 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2896 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2898<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2899<pre>
2900Test:
2901 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2902 br i1 %cond, label %IfEqual, label %IfUnequal
2903IfEqual:
2904 <a href="#i_ret">ret</a> i32 1
2905IfUnequal:
2906 <a href="#i_ret">ret</a> i32 0
2907</pre>
2908
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2909</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2911<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2912<div class="doc_subsubsection">
2913 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2914</div>
2915
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2917
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2918<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2919<pre>
2920 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2921</pre>
2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2924<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]2925 several different places. It is a generalization of the '<tt>br</tt>'
2926 instruction, allowing a branch to occur to one of many possible
2927 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2928
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2929<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2930<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2932 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2933 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2935<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2936<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2937 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2938 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2939 transferred to the corresponding destination; otherwise, control flow is
2940 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2941
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2942<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2943<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2944 <tt>switch</tt> instruction, this instruction may be code generated in
2945 different ways. For example, it could be generated as a series of chained
2946 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2947
2948<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2949<pre>
2950 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2951 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2952 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2953
2954 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2955 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2956
2957 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2958 switch i32 %val, label %otherwise [ i32 0, label %onzero
2959 i32 1, label %onone
2960 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2961</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2963</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2964
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2965
2966<!-- _______________________________________________________________________ -->
2967<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2968 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2969</div>
2970
2971<div class="doc_text">
2972
2973<h5>Syntax:</h5>
2974<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2975 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]2976</pre>
2977
2978<h5>Overview:</h5>
2979
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2980<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2981 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2982 "<tt>address</tt>". Address must be derived from a <a
2983 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2984
2985<h5>Arguments:</h5>
2986
2987<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2988 rest of the arguments indicate the full set of possible destinations that the
2989 address may point to. Blocks are allowed to occur multiple times in the
2990 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2991
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2992<p>This destination list is required so that dataflow analysis has an accurate
2993 understanding of the CFG.</p>
2994
2995<h5>Semantics:</h5>
2996
2997<p>Control transfers to the block specified in the address argument. All
2998 possible destination blocks must be listed in the label list, otherwise this
2999 instruction has undefined behavior. This implies that jumps to labels
3000 defined in other functions have undefined behavior as well.</p>
3001
3002<h5>Implementation:</h5>
3003
3004<p>This is typically implemented with a jump through a register.</p>
3005
3006<h5>Example:</h5>
3007<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3008 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3009</pre>
3010
3011</div>
3012
3013
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3014<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3015<div class="doc_subsubsection">
3016 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3017</div>
3018
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3019<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3020
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3021<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3022<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3023 &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]3024 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3025</pre>
3026
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3027<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3028<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3029 function, with the possibility of control flow transfer to either the
3030 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3031 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3032 control flow will return to the "normal" label. If the callee (or any
3033 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3034 instruction, control is interrupted and continued at the dynamically nearest
3035 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3036
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3037<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3038<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3039
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3040<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3041 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3042 convention</a> the call should use. If none is specified, the call
3043 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3044
3045 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3046 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3047 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3048
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3049 <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]3050 function value being invoked. In most cases, this is a direct function
3051 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3052 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3053
3054 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3055 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3056
3057 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3058 signature argument types and parameter attributes. All arguments must be
3059 of <a href="#t_firstclass">first class</a> type. If the function
3060 signature indicates the function accepts a variable number of arguments,
3061 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3062
3063 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3064 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3065
3066 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3068
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3069 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3071 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3072</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3073
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075<p>This instruction is designed to operate as a standard
3076 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3077 primary difference is that it establishes an association with a label, which
3078 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3079
3080<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3081 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3082 exception. Additionally, this is important for implementation of
3083 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085<p>For the purposes of the SSA form, the definition of the value returned by the
3086 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3087 block to the "normal" label. If the callee unwinds then no return value is
3088 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3089
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3090<p>Note that the code generator does not yet completely support unwind, and
3091that the invoke/unwind semantics are likely to change in future versions.</p>
3092
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3093<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3094<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3095 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3096 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3097 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3098 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3099</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3100
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3102
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3103<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3104
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3105<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3106Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3108<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3109
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3110<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3111<pre>
3112 unwind
3113</pre>
3114
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3115<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3116<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117 at the first callee in the dynamic call stack which used
3118 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3119 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3120
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3121<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3122<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123 immediately halt. The dynamic call stack is then searched for the
3124 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3125 Once found, execution continues at the "exceptional" destination block
3126 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3127 instruction in the dynamic call chain, undefined behavior results.</p>
3128
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3129<p>Note that the code generator does not yet completely support unwind, and
3130that the invoke/unwind semantics are likely to change in future versions.</p>
3131
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3132</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3133
3134<!-- _______________________________________________________________________ -->
3135
3136<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3137Instruction</a> </div>
3138
3139<div class="doc_text">
3140
3141<h5>Syntax:</h5>
3142<pre>
3143 unreachable
3144</pre>
3145
3146<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3147<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3148 instruction is used to inform the optimizer that a particular portion of the
3149 code is not reachable. This can be used to indicate that the code after a
3150 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3151
3152<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3153<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3154
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3155</div>
3156
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3157<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3158<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3159
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3160<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161
3162<p>Binary operators are used to do most of the computation in a program. They
3163 require two operands of the same type, execute an operation on them, and
3164 produce a single value. The operands might represent multiple data, as is
3165 the case with the <a href="#t_vector">vector</a> data type. The result value
3166 has the same type as its operands.</p>
3167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3168<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3170</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3172<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3173<div class="doc_subsubsection">
3174 <a name="i_add">'<tt>add</tt>' Instruction</a>
3175</div>
3176
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3177<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3178
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3179<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3180<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3181 &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]3182 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3183 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3184 &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]3185</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3187<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3188<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3191<p>The two arguments to the '<tt>add</tt>' instruction must
3192 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3193 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3194
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3195<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3196<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3197
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3198<p>If the sum has unsigned overflow, the result returned is the mathematical
3199 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]3200
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201<p>Because LLVM integers use a two's complement representation, this instruction
3202 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3203
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3204<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3205 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3206 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3207 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3208 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3209
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3210<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3211<pre>
3212 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3213</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3215</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3217<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3218<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3219 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3220</div>
3221
3222<div class="doc_text">
3223
3224<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3225<pre>
3226 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3227</pre>
3228
3229<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3230<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3231
3232<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3233<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3234 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3235 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3236
3237<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3238<p>The value produced is the floating point sum of the two operands.</p>
3239
3240<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3241<pre>
3242 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3245</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3246
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3247<!-- _______________________________________________________________________ -->
3248<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3249 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3250</div>
3251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3252<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3253
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3254<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3255<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3256 &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]3257 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3258 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3259 &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]3260</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3262<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3263<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3265
3266<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267 '<tt>neg</tt>' instruction present in most other intermediate
3268 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3269
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3270<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3271<p>The two arguments to the '<tt>sub</tt>' instruction must
3272 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3273 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3275<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3276<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3277
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3278<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3280 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3281
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3282<p>Because LLVM integers use a two's complement representation, this instruction
3283 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3284
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3285<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3286 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3287 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3288 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3289 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3291<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3292<pre>
3293 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3294 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3296
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3297</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3299<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3300<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3301 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3302</div>
3303
3304<div class="doc_text">
3305
3306<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3307<pre>
3308 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3309</pre>
3310
3311<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3312<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3313 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3314
3315<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316 '<tt>fneg</tt>' instruction present in most other intermediate
3317 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318
3319<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3320<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3322 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3323
3324<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3325<p>The value produced is the floating point difference of the two operands.</p>
3326
3327<h5>Example:</h5>
3328<pre>
3329 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3330 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3331</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3332
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3333</div>
3334
3335<!-- _______________________________________________________________________ -->
3336<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3337 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3338</div>
3339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3340<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3341
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3342<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3343<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3344 &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]3345 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3346 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3347 &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]3348</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3350<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3351<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3353<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3354<p>The two arguments to the '<tt>mul</tt>' instruction must
3355 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3356 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3358<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3360
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3361<p>If the result of the multiplication has unsigned overflow, the result
3362 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3363 width of the result.</p>
3364
3365<p>Because LLVM integers use a two's complement representation, and the result
3366 is the same width as the operands, this instruction returns the correct
3367 result for both signed and unsigned integers. If a full product
3368 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3369 be sign-extended or zero-extended as appropriate to the width of the full
3370 product.</p>
3371
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3372<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3373 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3374 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3375 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3376 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3377
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3379<pre>
3380 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3381</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3383</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3385<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3386<div class="doc_subsubsection">
3387 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3388</div>
3389
3390<div class="doc_text">
3391
3392<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3393<pre>
3394 &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]3395</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3396
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3397<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3399
3400<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3401<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3402 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3403 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3404
3405<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3406<p>The value produced is the floating point product of the two operands.</p>
3407
3408<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409<pre>
3410 &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]3411</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3412
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3413</div>
3414
3415<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3416<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3417</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3419<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3421<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422<pre>
3423 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3424</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3425
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3426<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3427<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3428
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3429<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3430<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3431 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3432 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3433
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3434<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3435<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3437<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3439
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3440<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3442<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3445</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3447</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3448
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3449<!-- _______________________________________________________________________ -->
3450<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3451</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3455<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3456<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3457 &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]3458 &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]3459</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3460
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3461<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3463
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3464<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3465<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3466 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3467 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3468
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3469<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3470<p>The value produced is the signed integer quotient of the two operands rounded
3471 towards zero.</p>
3472
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3473<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3475
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3476<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3477 undefined behavior; this is a rare case, but can occur, for example, by doing
3478 a 32-bit division of -2147483648 by -1.</p>
3479
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3480<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3481 <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]3482 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3483
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3484<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3485<pre>
3486 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3491<!-- _______________________________________________________________________ -->
3492<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3493Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3495<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3497<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3498<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3499 &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]3500</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3501
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502<h5>Overview:</h5>
3503<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3504
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3505<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3506<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3507 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3508 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3509
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3510<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3511<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3512
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3513<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3514<pre>
3515 &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]3516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3518</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3519
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3520<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3521<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3522</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3524<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3526<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527<pre>
3528 &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]3529</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3531<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3533 division of its two arguments.</p>
3534
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3535<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3536<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3538 values. Both arguments must have identical types.</p>
3539
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3540<h5>Semantics:</h5>
3541<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3542 This instruction always performs an unsigned division to get the
3543 remainder.</p>
3544
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3545<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3546 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3547
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3548<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3550<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3551<pre>
3552 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3553</pre>
3554
3555</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3557<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3558<div class="doc_subsubsection">
3559 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3560</div>
3561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3563
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3564<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3565<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3566 &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]3567</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3568
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3569<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3570<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3571 division of its two operands. This instruction can also take
3572 <a href="#t_vector">vector</a> versions of the values in which case the
3573 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3574
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3575<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3576<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3578 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3579
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3580<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3581<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3582 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3583 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3584 a value. For more information about the difference,
3585 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3586 Math Forum</a>. For a table of how this is implemented in various languages,
3587 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3588 Wikipedia: modulo operation</a>.</p>
3589
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3590<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3592
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3593<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594 Overflow also leads to undefined behavior; this is a rare case, but can
3595 occur, for example, by taking the remainder of a 32-bit division of
3596 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3597 lets srem be implemented using instructions that return both the result of
3598 the division and the remainder.)</p>
3599
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3600<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3601<pre>
3602 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3603</pre>
3604
3605</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3607<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3608<div class="doc_subsubsection">
3609 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3613<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614<pre>
3615 &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]3616</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3618<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3619<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3620 its two operands.</p>
3621
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3622<h5>Arguments:</h5>
3623<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3624 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3625 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3626
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3627<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3628<p>This instruction returns the <i>remainder</i> of a division. The remainder
3629 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3630
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3631<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3632<pre>
3633 &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]3634</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3635
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3636</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3637
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3638<!-- ======================================================================= -->
3639<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3640Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3642<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643
3644<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3645 program. They are generally very efficient instructions and can commonly be
3646 strength reduced from other instructions. They require two operands of the
3647 same type, execute an operation on them, and produce a single value. The
3648 resulting value is the same type as its operands.</p>
3649
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3650</div>
3651
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3652<!-- _______________________________________________________________________ -->
3653<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3654Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3655
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3656<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3657
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3658<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659<pre>
3660 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3661</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3662
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3663<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3664<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3665 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3666
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3667<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3668<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3669 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3670 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3671
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3672<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3673<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3674 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3675 is (statically or dynamically) negative or equal to or larger than the number
3676 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3677 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3678 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3679
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3680<h5>Example:</h5>
3681<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3682 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3683 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3684 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3685 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3686 &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]3687</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3689</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3691<!-- _______________________________________________________________________ -->
3692<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3693Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3697<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3698<pre>
3699 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3700</pre>
3701
3702<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3703<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3704 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3705
3706<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3707<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3708 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3709 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3710
3711<h5>Semantics:</h5>
3712<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3713 significant bits of the result will be filled with zero bits after the shift.
3714 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3715 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3716 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3717 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3718
3719<h5>Example:</h5>
3720<pre>
3721 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3722 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3723 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3724 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3725 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3726 &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]3727</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3729</div>
3730
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3731<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3732<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3733Instruction</a> </div>
3734<div class="doc_text">
3735
3736<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737<pre>
3738 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3739</pre>
3740
3741<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3743 operand shifted to the right a specified number of bits with sign
3744 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3745
3746<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3747<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3749 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3750
3751<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3752<p>This instruction always performs an arithmetic shift right operation, The
3753 most significant bits of the result will be filled with the sign bit
3754 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3755 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3756 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3757 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3758
3759<h5>Example:</h5>
3760<pre>
3761 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3762 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3763 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3764 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3765 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3766 &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]3767</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3768
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3769</div>
3770
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3771<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3772<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3773Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3774
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3775<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3777<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3778<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3779 &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]3780</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3781
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3782<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3783<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3784 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3786<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3787<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3788 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3789 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3790
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3791<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3792<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3794<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3795 <tbody>
3796 <tr>
3797 <td>In0</td>
3798 <td>In1</td>
3799 <td>Out</td>
3800 </tr>
3801 <tr>
3802 <td>0</td>
3803 <td>0</td>
3804 <td>0</td>
3805 </tr>
3806 <tr>
3807 <td>0</td>
3808 <td>1</td>
3809 <td>0</td>
3810 </tr>
3811 <tr>
3812 <td>1</td>
3813 <td>0</td>
3814 <td>0</td>
3815 </tr>
3816 <tr>
3817 <td>1</td>
3818 <td>1</td>
3819 <td>1</td>
3820 </tr>
3821 </tbody>
3822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3824<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3825<pre>
3826 &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]3827 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3828 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3829</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3830</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3831<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3832<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834<div class="doc_text">
3835
3836<h5>Syntax:</h5>
3837<pre>
3838 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3839</pre>
3840
3841<h5>Overview:</h5>
3842<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3843 two operands.</p>
3844
3845<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3846<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3848 values. Both arguments must have identical types.</p>
3849
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3850<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3851<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3852
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3853<table border="1" cellspacing="0" cellpadding="4">
3854 <tbody>
3855 <tr>
3856 <td>In0</td>
3857 <td>In1</td>
3858 <td>Out</td>
3859 </tr>
3860 <tr>
3861 <td>0</td>
3862 <td>0</td>
3863 <td>0</td>
3864 </tr>
3865 <tr>
3866 <td>0</td>
3867 <td>1</td>
3868 <td>1</td>
3869 </tr>
3870 <tr>
3871 <td>1</td>
3872 <td>0</td>
3873 <td>1</td>
3874 </tr>
3875 <tr>
3876 <td>1</td>
3877 <td>1</td>
3878 <td>1</td>
3879 </tr>
3880 </tbody>
3881</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3883<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3884<pre>
3885 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3886 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3887 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3888</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3890</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3892<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3893<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3894Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3896<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3898<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3899<pre>
3900 &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]3901</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3903<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3904<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3905 its two operands. The <tt>xor</tt> is used to implement the "one's
3906 complement" operation, which is the "~" operator in C.</p>
3907
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3908<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3909<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3910 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3911 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3914<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3915
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3916<table border="1" cellspacing="0" cellpadding="4">
3917 <tbody>
3918 <tr>
3919 <td>In0</td>
3920 <td>In1</td>
3921 <td>Out</td>
3922 </tr>
3923 <tr>
3924 <td>0</td>
3925 <td>0</td>
3926 <td>0</td>
3927 </tr>
3928 <tr>
3929 <td>0</td>
3930 <td>1</td>
3931 <td>1</td>
3932 </tr>
3933 <tr>
3934 <td>1</td>
3935 <td>0</td>
3936 <td>1</td>
3937 </tr>
3938 <tr>
3939 <td>1</td>
3940 <td>1</td>
3941 <td>0</td>
3942 </tr>
3943 </tbody>
3944</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3946<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3947<pre>
3948 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3949 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3950 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3951 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3952</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3954</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3955
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3956<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3957<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3958 <a name="vectorops">Vector Operations</a>
3959</div>
3960
3961<div class="doc_text">
3962
3963<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964 target-independent manner. These instructions cover the element-access and
3965 vector-specific operations needed to process vectors effectively. While LLVM
3966 does directly support these vector operations, many sophisticated algorithms
3967 will want to use target-specific intrinsics to take full advantage of a
3968 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3969
3970</div>
3971
3972<!-- _______________________________________________________________________ -->
3973<div class="doc_subsubsection">
3974 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3975</div>
3976
3977<div class="doc_text">
3978
3979<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3980<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3981 &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]3982</pre>
3983
3984<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3985<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3986 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3987
3988
3989<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3991 of <a href="#t_vector">vector</a> type. The second operand is an index
3992 indicating the position from which to extract the element. The index may be
3993 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3994
3995<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3996<p>The result is a scalar of the same type as the element type of
3997 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3998 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3999 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4000
4001<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4002<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4003 &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]4004</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4005
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4007
4008<!-- _______________________________________________________________________ -->
4009<div class="doc_subsubsection">
4010 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4011</div>
4012
4013<div class="doc_text">
4014
4015<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4016<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4017 &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]4018</pre>
4019
4020<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4022 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4023
4024<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4025<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4026 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4027 whose type must equal the element type of the first operand. The third
4028 operand is an index indicating the position at which to insert the value.
4029 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4030
4031<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4033 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4034 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4035 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036
4037<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4038<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4039 &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]4040</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4042</div>
4043
4044<!-- _______________________________________________________________________ -->
4045<div class="doc_subsubsection">
4046 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4047</div>
4048
4049<div class="doc_text">
4050
4051<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4052<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4053 &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]4054</pre>
4055
4056<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4058 from two input vectors, returning a vector with the same element type as the
4059 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4060
4061<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4063 with types that match each other. The third argument is a shuffle mask whose
4064 element type is always 'i32'. The result of the instruction is a vector
4065 whose length is the same as the shuffle mask and whose element type is the
4066 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4068<p>The shuffle mask operand is required to be a constant vector with either
4069 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4070
4071<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4072<p>The elements of the two input vectors are numbered from left to right across
4073 both of the vectors. The shuffle mask operand specifies, for each element of
4074 the result vector, which element of the two input vectors the result element
4075 gets. The element selector may be undef (meaning "don't care") and the
4076 second operand may be undef if performing a shuffle from only one vector.</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>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4080 &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]4081 &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]4082 &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]4083 &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]4084 &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]4085 &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]4086 &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]4087 &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]4088</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4089
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4090</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4091
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4092<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4093<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4094 <a name="aggregateops">Aggregate Operations</a>
4095</div>
4096
4097<div class="doc_text">
4098
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4099<p>LLVM supports several instructions for working with
4100 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4101
4102</div>
4103
4104<!-- _______________________________________________________________________ -->
4105<div class="doc_subsubsection">
4106 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4107</div>
4108
4109<div class="doc_text">
4110
4111<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4112<pre>
4113 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4114</pre>
4115
4116<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4117<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4118 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4119
4120<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4122 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4123 <a href="#t_array">array</a> type. The operands are constant indices to
4124 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4125 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4126
4127<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128<p>The result is the value at the position in the aggregate specified by the
4129 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4130
4131<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4132<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4133 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4134</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4136</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4141</div>
4142
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4146<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4147 &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]4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4151<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4152 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4156 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4157 <a href="#t_array">array</a> type. The second operand is a first-class
4158 value to insert. The following operands are constant indices indicating
4159 the position at which to insert the value in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4160 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4161 value to insert must have the same type as the value identified by the
4162 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4163
4164<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4166 that of <tt>val</tt> except that the value at the position specified by the
4167 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4168
4169<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4170<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4171 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4172 %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]4173</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4174
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4175</div>
4176
4177
4178<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4179<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4180 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4181</div>
4182
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4183<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4184
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185<p>A key design point of an SSA-based representation is how it represents
4186 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4187 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4189
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4190</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4191
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4192<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4193<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4194 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4195</div>
4196
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4197<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4199<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4200<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4201 &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]4202</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4204<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4205<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206 currently executing function, to be automatically released when this function
4207 returns to its caller. The object is always allocated in the generic address
4208 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4209
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4210<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>alloca</tt>' instruction
4212 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4213 runtime stack, returning a pointer of the appropriate type to the program.
4214 If "NumElements" is specified, it is the number of elements allocated,
4215 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4216 specified, the value result of the allocation is guaranteed to be aligned to
4217 at least that boundary. If not specified, or if zero, the target can choose
4218 to align the allocation on any convenient boundary compatible with the
4219 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4221<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4223<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4224<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4225 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4226 memory is automatically released when the function returns. The
4227 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4228 variables that must have an address available. When the function returns
4229 (either with the <tt><a href="#i_ret">ret</a></tt>
4230 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4231 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4233<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4234<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4235 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4236 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4237 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4238 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4239</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4240
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4241</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4242
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4243<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4244<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4245Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4249<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4251 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4252 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4253 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4254</pre>
4255
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4256<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4257<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4258
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4259<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4260<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4261 from which to load. The pointer must point to
4262 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4263 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4264 number or order of execution of this <tt>load</tt> with other <a
4265 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4267<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268 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]4269 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4270 alignment for the target. It is the responsibility of the code emitter to
4271 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4272 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4273 produce less efficient code. An alignment of 1 is always safe.</p>
4274
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4275<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4276 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4277 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4278 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4279 and code generator that this load is not expected to be reused in the cache.
4280 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4281 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4282
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4283<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The location of memory pointed to is loaded. If the value being loaded is of
4285 scalar type then the number of bytes read does not exceed the minimum number
4286 of bytes needed to hold all bits of the type. For example, loading an
4287 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4288 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4289 is undefined if the value was not originally written using a store of the
4290 same type.</p>
4291
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4292<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4293<pre>
4294 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4295 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4296 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4297</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4299</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4301<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4302<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4303Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4305<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4307<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4309 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>
4310 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]4311</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4313<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4314<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4316<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4317<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4318 and an address at which to store it. The type of the
4319 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4320 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4321 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4322 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4323 order of execution of this <tt>store</tt> with other <a
4324 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325
4326<p>The optional constant "align" argument specifies the alignment of the
4327 operation (that is, the alignment of the memory address). A value of 0 or an
4328 omitted "align" argument means that the operation has the preferential
4329 alignment for the target. It is the responsibility of the code emitter to
4330 ensure that the alignment information is correct. Overestimating the
4331 alignment results in an undefined behavior. Underestimating the alignment may
4332 produce less efficient code. An alignment of 1 is always safe.</p>
4333
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4334<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4335 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4336 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4337 instruction tells the optimizer and code generator that this load is
4338 not expected to be reused in the cache. The code generator may
4339 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4340 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4341
4342
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4343<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4345 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4346 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4347 does not exceed the minimum number of bytes needed to hold all bits of the
4348 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4349 writing a value of a type like <tt>i20</tt> with a size that is not an
4350 integral number of bytes, it is unspecified what happens to the extra bits
4351 that do not belong to the type, but they will typically be overwritten.</p>
4352
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4353<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4354<pre>
4355 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4356 store i32 3, i32* %ptr <i>; yields {void}</i>
4357 %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]4358</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4360</div>
4361
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4362<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4363<div class="doc_subsubsection">
4364 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4365</div>
4366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4367<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4369<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4370<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4371 &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]4372 &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]4373</pre>
4374
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4375<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4376<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4377 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4378 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4379
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4380<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4381<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4382 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383 elements of the aggregate object are indexed. The interpretation of each
4384 index is dependent on the type being indexed into. The first index always
4385 indexes the pointer value given as the first argument, the second index
4386 indexes a value of the type pointed to (not necessarily the value directly
4387 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4388 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4389 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4390 can never be pointers, since that would require loading the pointer before
4391 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4392
4393<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]4394 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4395 integer <b>constants</b> are allowed. When indexing into an array, pointer
4396 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]4397 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4398
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4399<p>For example, let's consider a C code fragment and how it gets compiled to
4400 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4401
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4402<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4403struct RT {
4404 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4405 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4406 char C;
4407};
4408struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4409 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4410 double Y;
4411 struct RT Z;
4412};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4413
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4414int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4415 return &amp;s[1].Z.B[5][13];
4416}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4417</pre>
4418
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4419<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4420
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4421<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4422%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4423%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4424
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4425define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4426entry:
4427 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4428 ret i32* %reg
4429}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4430</pre>
4431
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4432<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4433<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]4434 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4435 }</tt>' type, a structure. The second index indexes into the third element
4436 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4437 i8 }</tt>' type, another structure. The third index indexes into the second
4438 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4439 array. The two dimensions of the array are subscripted into, yielding an
4440 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4441 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4442
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443<p>Note that it is perfectly legal to index partially through a structure,
4444 returning a pointer to an inner element. Because of this, the LLVM code for
4445 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4446
4447<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4448 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4449 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4450 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4451 %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]4452 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4453 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4454 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4455 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4456</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4457
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4458<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4459 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4460 base pointer is not an <i>in bounds</i> address of an allocated object,
4461 or if any of the addresses that would be formed by successive addition of
4462 the offsets implied by the indices to the base address with infinitely
4463 precise arithmetic are not an <i>in bounds</i> address of that allocated
4464 object. The <i>in bounds</i> addresses for an allocated object are all
4465 the addresses that point into the object, plus the address one byte past
4466 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4467
4468<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4469 the base address with silently-wrapping two's complement arithmetic, and
4470 the result value of the <tt>getelementptr</tt> may be outside the object
4471 pointed to by the base pointer. The result value may not necessarily be
4472 used to access memory though, even if it happens to point into allocated
4473 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4474 section for more information.</p>
4475
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4476<p>The getelementptr instruction is often confusing. For some more insight into
4477 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4478
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4479<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4480<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4481 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4482 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4483 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4484 %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]4485 <i>; yields i8*:eptr</i>
4486 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4487 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4488 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4491</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4492
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4493<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4494<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4495</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4497<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4498
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4499<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4500 which all take a single operand and a type. They perform various bit
4501 conversions on the operand.</p>
4502
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4503</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4504
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4505<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4506<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4507 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4508</div>
4509<div class="doc_text">
4510
4511<h5>Syntax:</h5>
4512<pre>
4513 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4514</pre>
4515
4516<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4517<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4518 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4519
4520<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4521<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4522 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4523 size and type of the result, which must be
4524 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4525 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4526 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4527
4528<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4530 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4531 source size must be larger than the destination size, <tt>trunc</tt> cannot
4532 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4533
4534<h5>Example:</h5>
4535<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4536 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4537 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4538 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4539</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4541</div>
4542
4543<!-- _______________________________________________________________________ -->
4544<div class="doc_subsubsection">
4545 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4546</div>
4547<div class="doc_text">
4548
4549<h5>Syntax:</h5>
4550<pre>
4551 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4552</pre>
4553
4554<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4555<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4556 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4557
4558
4559<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4560<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4562 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4563 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4565
4566<h5>Semantics:</h5>
4567<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]4568 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4569
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4570<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]4571
4572<h5>Example:</h5>
4573<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4574 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4575 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4576</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4577
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4578</div>
4579
4580<!-- _______________________________________________________________________ -->
4581<div class="doc_subsubsection">
4582 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4583</div>
4584<div class="doc_text">
4585
4586<h5>Syntax:</h5>
4587<pre>
4588 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4589</pre>
4590
4591<h5>Overview:</h5>
4592<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4593
4594<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4595<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4597 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4598 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4600
4601<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4603 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4604 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4605
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4606<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]4607
4608<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4609<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4610 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4611 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614</div>
4615
4616<!-- _______________________________________________________________________ -->
4617<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4618 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4619</div>
4620
4621<div class="doc_text">
4622
4623<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4624<pre>
4625 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4626</pre>
4627
4628<h5>Overview:</h5>
4629<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4630 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4631
4632<h5>Arguments:</h5>
4633<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4634 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4635 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]4636 <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]4637 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4638
4639<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4641 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642 <a href="#t_floating">floating point</a> type. If the value cannot fit
4643 within the destination type, <tt>ty2</tt>, then the results are
4644 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4645
4646<h5>Example:</h5>
4647<pre>
4648 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4649 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4650</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4651
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4652</div>
4653
4654<!-- _______________________________________________________________________ -->
4655<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4656 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4657</div>
4658<div class="doc_text">
4659
4660<h5>Syntax:</h5>
4661<pre>
4662 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4663</pre>
4664
4665<h5>Overview:</h5>
4666<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]4667 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4668
4669<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4670<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4672 a <a href="#t_floating">floating point</a> type to cast it to. The source
4673 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4674
4675<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4676<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677 <a href="#t_floating">floating point</a> type to a larger
4678 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4679 used to make a <i>no-op cast</i> because it always changes bits. Use
4680 <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]4681
4682<h5>Example:</h5>
4683<pre>
4684 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4685 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4688</div>
4689
4690<!-- _______________________________________________________________________ -->
4691<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4692 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4693</div>
4694<div class="doc_text">
4695
4696<h5>Syntax:</h5>
4697<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4698 &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]4699</pre>
4700
4701<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4702<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4703 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4704
4705<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4707 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4708 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4709 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4710 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4711
4712<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4713<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4715 towards zero) unsigned integer value. If the value cannot fit
4716 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4717
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4718<h5>Example:</h5>
4719<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4720 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4721 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4722 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4723</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4724
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4725</div>
4726
4727<!-- _______________________________________________________________________ -->
4728<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4729 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4730</div>
4731<div class="doc_text">
4732
4733<h5>Syntax:</h5>
4734<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4735 &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]4736</pre>
4737
4738<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4739<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740 <a href="#t_floating">floating point</a> <tt>value</tt> to
4741 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4742
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4743<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4744<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4745 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4746 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4747 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4748 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4749
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4750<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4751<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4753 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4754 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4755
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4756<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4757<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4758 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4759 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4760 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4761</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4767 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4768</div>
4769<div class="doc_text">
4770
4771<h5>Syntax:</h5>
4772<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4773 &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]4774</pre>
4775
4776<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4777<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4779
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4780<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4781<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]4782 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4783 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4784 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4785 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4786
4787<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4788<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789 integer quantity and converts it to the corresponding floating point
4790 value. If the value cannot fit in the floating point value, the results are
4791 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4792
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4793<h5>Example:</h5>
4794<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4795 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4796 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4797</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4799</div>
4800
4801<!-- _______________________________________________________________________ -->
4802<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4803 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4804</div>
4805<div class="doc_text">
4806
4807<h5>Syntax:</h5>
4808<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4809 &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]4810</pre>
4811
4812<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4814 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4815
4816<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4817<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]4818 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4819 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4820 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4821 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4822
4823<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4824<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4825 quantity and converts it to the corresponding floating point value. If the
4826 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4827
4828<h5>Example:</h5>
4829<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4830 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4831 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4832</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4833
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4834</div>
4835
4836<!-- _______________________________________________________________________ -->
4837<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4838 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4839</div>
4840<div class="doc_text">
4841
4842<h5>Syntax:</h5>
4843<pre>
4844 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4845</pre>
4846
4847<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4849 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4850
4851<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4852<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4853 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4854 <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]4855
4856<h5>Semantics:</h5>
4857<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4858 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4859 truncating or zero extending that value to the size of the integer type. If
4860 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4861 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4862 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4863 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4864
4865<h5>Example:</h5>
4866<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4867 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4868 %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]4869</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4870
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4871</div>
4872
4873<!-- _______________________________________________________________________ -->
4874<div class="doc_subsubsection">
4875 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4876</div>
4877<div class="doc_text">
4878
4879<h5>Syntax:</h5>
4880<pre>
4881 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4882</pre>
4883
4884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4885<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4886 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4887
4888<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4889<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4890 value to cast, and a type to cast it to, which must be a
4891 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4892
4893<h5>Semantics:</h5>
4894<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4895 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4896 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4897 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4898 than the size of a pointer then a zero extension is done. If they are the
4899 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4900
4901<h5>Example:</h5>
4902<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4903 %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]4904 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4905 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4906</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4907
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4908</div>
4909
4910<!-- _______________________________________________________________________ -->
4911<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4912 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4913</div>
4914<div class="doc_text">
4915
4916<h5>Syntax:</h5>
4917<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4918 &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]4919</pre>
4920
4921<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4922<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4924
4925<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4926<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4927 non-aggregate first class value, and a type to cast it to, which must also be
4928 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4929 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4930 identical. If the source type is a pointer, the destination type must also be
4931 a pointer. This instruction supports bitwise conversion of vectors to
4932 integers and to vectors of other types (as long as they have the same
4933 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4934
4935<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4936<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4938 this conversion. The conversion is done as if the <tt>value</tt> had been
4939 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4940 be converted to other pointer types with this instruction. To convert
4941 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4942 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4943
4944<h5>Example:</h5>
4945<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4946 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4947 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4948 %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]4949</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4951</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4952
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4953<!-- ======================================================================= -->
4954<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4956<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4957
4958<p>The instructions in this category are the "miscellaneous" instructions, which
4959 defy better classification.</p>
4960
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4961</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4962
4963<!-- _______________________________________________________________________ -->
4964<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4965</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4966
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4967<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4968
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4969<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4970<pre>
4971 &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]4972</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4973
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4974<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4975<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4976 boolean values based on comparison of its two integer, integer vector, or
4977 pointer operands.</p>
4978
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4979<h5>Arguments:</h5>
4980<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4981 the condition code indicating the kind of comparison to perform. It is not a
4982 value, just a keyword. The possible condition code are:</p>
4983
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4984<ol>
4985 <li><tt>eq</tt>: equal</li>
4986 <li><tt>ne</tt>: not equal </li>
4987 <li><tt>ugt</tt>: unsigned greater than</li>
4988 <li><tt>uge</tt>: unsigned greater or equal</li>
4989 <li><tt>ult</tt>: unsigned less than</li>
4990 <li><tt>ule</tt>: unsigned less or equal</li>
4991 <li><tt>sgt</tt>: signed greater than</li>
4992 <li><tt>sge</tt>: signed greater or equal</li>
4993 <li><tt>slt</tt>: signed less than</li>
4994 <li><tt>sle</tt>: signed less or equal</li>
4995</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4997<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4998 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4999 typed. They must also be identical types.</p>
5000
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5001<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5002<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5003 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5004 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]5005 result, as follows:</p>
5006
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5007<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5008 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5009 <tt>false</tt> otherwise. No sign interpretation is necessary or
5010 performed.</li>
5011
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5012 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5013 <tt>false</tt> otherwise. No sign interpretation is necessary or
5014 performed.</li>
5015
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5016 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5017 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5018
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5019 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5020 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5021 to <tt>op2</tt>.</li>
5022
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5023 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5024 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5025
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5026 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5028
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5029 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5031
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5032 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5033 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5034 to <tt>op2</tt>.</li>
5035
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5036 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5037 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5038
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5041</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5043<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044 values are compared as if they were integers.</p>
5045
5046<p>If the operands are integer vectors, then they are compared element by
5047 element. The result is an <tt>i1</tt> vector with the same number of elements
5048 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5049
5050<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051<pre>
5052 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5053 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5054 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5055 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5056 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5057 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5058</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5059
5060<p>Note that the code generator does not yet support vector types with
5061 the <tt>icmp</tt> instruction.</p>
5062
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5063</div>
5064
5065<!-- _______________________________________________________________________ -->
5066<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5067</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5069<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5071<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5072<pre>
5073 &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]5074</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5076<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5077<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5078 values based on comparison of its operands.</p>
5079
5080<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]5081(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082
5083<p>If the operands are floating point vectors, then the result type is a vector
5084 of boolean with the same number of elements as the operands being
5085 compared.</p>
5086
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5087<h5>Arguments:</h5>
5088<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089 the condition code indicating the kind of comparison to perform. It is not a
5090 value, just a keyword. The possible condition code are:</p>
5091
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5092<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5093 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5094 <li><tt>oeq</tt>: ordered and equal</li>
5095 <li><tt>ogt</tt>: ordered and greater than </li>
5096 <li><tt>oge</tt>: ordered and greater than or equal</li>
5097 <li><tt>olt</tt>: ordered and less than </li>
5098 <li><tt>ole</tt>: ordered and less than or equal</li>
5099 <li><tt>one</tt>: ordered and not equal</li>
5100 <li><tt>ord</tt>: ordered (no nans)</li>
5101 <li><tt>ueq</tt>: unordered or equal</li>
5102 <li><tt>ugt</tt>: unordered or greater than </li>
5103 <li><tt>uge</tt>: unordered or greater than or equal</li>
5104 <li><tt>ult</tt>: unordered or less than </li>
5105 <li><tt>ule</tt>: unordered or less than or equal</li>
5106 <li><tt>une</tt>: unordered or not equal</li>
5107 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5108 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5109</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5111<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112 <i>unordered</i> means that either operand may be a QNAN.</p>
5113
5114<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5115 a <a href="#t_floating">floating point</a> type or
5116 a <a href="#t_vector">vector</a> of floating point type. They must have
5117 identical types.</p>
5118
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5119<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5120<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5121 according to the condition code given as <tt>cond</tt>. If the operands are
5122 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5123 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124 follows:</p>
5125
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5126<ol>
5127 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5128
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5129 <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]5130 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5131
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5132 <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]5133 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5135 <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]5136 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5137
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5138 <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]5139 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5140
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5141 <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]5142 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5143
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5144 <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]5145 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5146
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5147 <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]5148
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5149 <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]5150 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5151
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5152 <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]5153 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5154
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5155 <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]5156 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5157
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5160
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5161 <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]5162 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5163
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5164 <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]5165 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5166
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5167 <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]5168
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5169 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5170</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5171
5172<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5173<pre>
5174 &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]5175 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5176 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5177 &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]5178</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5179
5180<p>Note that the code generator does not yet support vector types with
5181 the <tt>fcmp</tt> instruction.</p>
5182
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5183</div>
5184
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5185<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5186<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5187 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5188</div>
5189
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5190<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5191
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5192<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5193<pre>
5194 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5195</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5196
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5197<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5198<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5199 SSA graph representing the function.</p>
5200
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5201<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202<p>The type of the incoming values is specified with the first type field. After
5203 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5204 one pair for each predecessor basic block of the current block. Only values
5205 of <a href="#t_firstclass">first class</a> type may be used as the value
5206 arguments to the PHI node. Only labels may be used as the label
5207 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5208
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209<p>There must be no non-phi instructions between the start of a basic block and
5210 the PHI instructions: i.e. PHI instructions must be first in a basic
5211 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5212
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5213<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5214 occur on the edge from the corresponding predecessor block to the current
5215 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5216 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5217
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5218<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5219<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5220 specified by the pair corresponding to the predecessor basic block that
5221 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5222
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5223<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5224<pre>
5225Loop: ; Infinite loop that counts from 0 on up...
5226 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5227 %nextindvar = add i32 %indvar, 1
5228 br label %Loop
5229</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5231</div>
5232
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5233<!-- _______________________________________________________________________ -->
5234<div class="doc_subsubsection">
5235 <a name="i_select">'<tt>select</tt>' Instruction</a>
5236</div>
5237
5238<div class="doc_text">
5239
5240<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5241<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5242 &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>
5243
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5244 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5245</pre>
5246
5247<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5248<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5249 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5250
5251
5252<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5253<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5254 values indicating the condition, and two values of the
5255 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5256 vectors and the condition is a scalar, then entire vectors are selected, not
5257 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5258
5259<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5260<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5261 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5262
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5263<p>If the condition is a vector of i1, then the value arguments must be vectors
5264 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5265
5266<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5267<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5268 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5269</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5270
5271<p>Note that the code generator does not yet support conditions
5272 with vector type.</p>
5273
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5274</div>
5275
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5276<!-- _______________________________________________________________________ -->
5277<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5278 <a name="i_call">'<tt>call</tt>' Instruction</a>
5279</div>
5280
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5281<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5283<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5284<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5285 &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]5286</pre>
5287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5288<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5289<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5291<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5292<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5293
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5294<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5295 <li>The optional "tail" marker indicates that the callee function does not
5296 access any allocas or varargs in the caller. Note that calls may be
5297 marked "tail" even if they do not occur before
5298 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5299 present, the function call is eligible for tail call optimization,
5300 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5301 optimized into a jump</a>. The code generator may optimize calls marked
5302 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5303 sibling call optimization</a> when the caller and callee have
5304 matching signatures, or 2) forced tail call optimization when the
5305 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5306 <ul>
5307 <li>Caller and callee both have the calling
5308 convention <tt>fastcc</tt>.</li>
5309 <li>The call is in tail position (ret immediately follows call and ret
5310 uses value of call or is void).</li>
5311 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5312 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5313 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5314 constraints are met.</a></li>
5315 </ul>
5316 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5317
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5318 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5319 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5320 defaults to using C calling conventions. The calling convention of the
5321 call must match the calling convention of the target function, or else the
5322 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5324 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5325 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5326 '<tt>inreg</tt>' attributes are valid here.</li>
5327
5328 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5329 type of the return value. Functions that return no value are marked
5330 <tt><a href="#t_void">void</a></tt>.</li>
5331
5332 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5333 being invoked. The argument types must match the types implied by this
5334 signature. This type can be omitted if the function is not varargs and if
5335 the function type does not return a pointer to a function.</li>
5336
5337 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5338 be invoked. In most cases, this is a direct function invocation, but
5339 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5340 to function value.</li>
5341
5342 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5343 signature argument types and parameter attributes. All arguments must be
5344 of <a href="#t_firstclass">first class</a> type. If the function
5345 signature indicates the function accepts a variable number of arguments,
5346 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5347
5348 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5349 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5350 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5351</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5352
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5353<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5354<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5355 a specified function, with its incoming arguments bound to the specified
5356 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5357 function, control flow continues with the instruction after the function
5358 call, and the return value of the function is bound to the result
5359 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5361<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5362<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5363 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5364 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5365 %X = tail call i32 @foo() <i>; yields i32</i>
5366 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5367 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5368
5369 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5370 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5371 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5372 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5373 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5374 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5375</pre>
5376
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5377<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5378standard C99 library as being the C99 library functions, and may perform
5379optimizations or generate code for them under that assumption. This is
5380something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5381freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5382
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5383</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5384
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5385<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5386<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5387 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5388</div>
5389
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5390<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5391
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5392<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5393<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5394 &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]5395</pre>
5396
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5397<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5398<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5399 the "variable argument" area of a function call. It is used to implement the
5400 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5401
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5402<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5403<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5404 argument. It returns a value of the specified argument type and increments
5405 the <tt>va_list</tt> to point to the next argument. The actual type
5406 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5407
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5408<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5409<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5410 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5411 to the next argument. For more information, see the variable argument
5412 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5413
5414<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]5415 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5416 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5417
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418<p><tt>va_arg</tt> is an LLVM instruction instead of
5419 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5420 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5421
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5422<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5423<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5424
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5425<p>Note that the code generator does not yet fully support va_arg on many
5426 targets. Also, it does not currently support va_arg with aggregate types on
5427 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5429</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5430
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5431<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5432<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5433<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5435<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5436
5437<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5438 well known names and semantics and are required to follow certain
5439 restrictions. Overall, these intrinsics represent an extension mechanism for
5440 the LLVM language that does not require changing all of the transformations
5441 in LLVM when adding to the language (or the bitcode reader/writer, the
5442 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5443
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5444<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5445 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5446 begin with this prefix. Intrinsic functions must always be external
5447 functions: you cannot define the body of intrinsic functions. Intrinsic
5448 functions may only be used in call or invoke instructions: it is illegal to
5449 take the address of an intrinsic function. Additionally, because intrinsic
5450 functions are part of the LLVM language, it is required if any are added that
5451 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5453<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5454 family of functions that perform the same operation but on different data
5455 types. Because LLVM can represent over 8 million different integer types,
5456 overloading is used commonly to allow an intrinsic function to operate on any
5457 integer type. One or more of the argument types or the result type can be
5458 overloaded to accept any integer type. Argument types may also be defined as
5459 exactly matching a previous argument's type or the result type. This allows
5460 an intrinsic function which accepts multiple arguments, but needs all of them
5461 to be of the same type, to only be overloaded with respect to a single
5462 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5464<p>Overloaded intrinsics will have the names of its overloaded argument types
5465 encoded into its function name, each preceded by a period. Only those types
5466 which are overloaded result in a name suffix. Arguments whose type is matched
5467 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5468 can take an integer of any width and returns an integer of exactly the same
5469 integer width. This leads to a family of functions such as
5470 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5471 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5472 suffix is required. Because the argument's type is matched against the return
5473 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5474
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5475<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5476 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5477
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5478</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5479
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5480<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5481<div class="doc_subsection">
5482 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5483</div>
5484
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5485<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5487<p>Variable argument support is defined in LLVM with
5488 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5489 intrinsic functions. These functions are related to the similarly named
5490 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5491
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5492<p>All of these functions operate on arguments that use a target-specific value
5493 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5494 not define what this type is, so all transformations should be prepared to
5495 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5496
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5497<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]5498 instruction and the variable argument handling intrinsic functions are
5499 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5500
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5501<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5502define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5503 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5504 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5505 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5506 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5507
5508 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5509 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5510
5511 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5512 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5513 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5514 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5515 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5516
5517 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5518 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5519 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5520}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5521
5522declare void @llvm.va_start(i8*)
5523declare void @llvm.va_copy(i8*, i8*)
5524declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5525</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5526
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5527</div>
5528
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5529<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5530<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5531 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5532</div>
5533
5534
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5535<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5537<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5538<pre>
5539 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5540</pre>
5541
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5542<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5544 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]5545
5546<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5547<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]5548
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5549<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5550<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]5551 macro available in C. In a target-dependent way, it initializes
5552 the <tt>va_list</tt> element to which the argument points, so that the next
5553 call to <tt>va_arg</tt> will produce the first variable argument passed to
5554 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5555 need to know the last argument of the function as the compiler can figure
5556 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5557
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5558</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5559
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5560<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5561<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5562 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5563</div>
5564
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5565<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5566
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<h5>Syntax:</h5>
5568<pre>
5569 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5570</pre>
5571
5572<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5573<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5574 which has been initialized previously
5575 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5576 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5577
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5578<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5579<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]5580
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5581<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5582<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]5583 macro available in C. In a target-dependent way, it destroys
5584 the <tt>va_list</tt> element to which the argument points. Calls
5585 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5586 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5587 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5589</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5590
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5591<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5592<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5593 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5594</div>
5595
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5596<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5597
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5598<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5599<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5600 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5601</pre>
5602
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5603<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5604<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5605 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5607<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5608<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]5609 The second argument is a pointer to a <tt>va_list</tt> element to copy
5610 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5611
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5612<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5613<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]5614 macro available in C. In a target-dependent way, it copies the
5615 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5616 element. This intrinsic is necessary because
5617 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5618 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5619
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5620</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5621
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5622<!-- ======================================================================= -->
5623<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5624 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5625</div>
5626
5627<div class="doc_text">
5628
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5630Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5632roots on the stack</a>, as well as garbage collector implementations that
5633require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5634barriers. Front-ends for type-safe garbage collected languages should generate
5635these intrinsics to make use of the LLVM garbage collectors. For more details,
5636see <a href="GarbageCollection.html">Accurate Garbage Collection with
5637LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5638
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5639<p>The garbage collection intrinsics only operate on objects in the generic
5640 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5641
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5642</div>
5643
5644<!-- _______________________________________________________________________ -->
5645<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5646 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5647</div>
5648
5649<div class="doc_text">
5650
5651<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5652<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5653 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5654</pre>
5655
5656<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5657<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]5658 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5659
5660<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5661<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5662 root pointer. The second pointer (which must be either a constant or a
5663 global value address) contains the meta-data to be associated with the
5664 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5665
5666<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5667<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]5668 location. At compile-time, the code generator generates information to allow
5669 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5670 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5671 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5672
5673</div>
5674
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5675<!-- _______________________________________________________________________ -->
5676<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5677 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5678</div>
5679
5680<div class="doc_text">
5681
5682<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5684 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5685</pre>
5686
5687<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5689 locations, allowing garbage collector implementations that require read
5690 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5691
5692<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5693<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]5694 allocated from the garbage collector. The first object is a pointer to the
5695 start of the referenced object, if needed by the language runtime (otherwise
5696 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5697
5698<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5699<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5700 instruction, but may be replaced with substantially more complex code by the
5701 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5702 may only be used in a function which <a href="#gc">specifies a GC
5703 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5704
5705</div>
5706
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707<!-- _______________________________________________________________________ -->
5708<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5709 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5710</div>
5711
5712<div class="doc_text">
5713
5714<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5716 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5717</pre>
5718
5719<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5720<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5721 locations, allowing garbage collector implementations that require write
5722 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723
5724<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5725<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]5726 object to store it to, and the third is the address of the field of Obj to
5727 store to. If the runtime does not require a pointer to the object, Obj may
5728 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5729
5730<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732 instruction, but may be replaced with substantially more complex code by the
5733 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5734 may only be used in a function which <a href="#gc">specifies a GC
5735 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5736
5737</div>
5738
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739<!-- ======================================================================= -->
5740<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5741 <a name="int_codegen">Code Generator Intrinsics</a>
5742</div>
5743
5744<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745
5746<p>These intrinsics are provided by LLVM to expose special features that may
5747 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5748
5749</div>
5750
5751<!-- _______________________________________________________________________ -->
5752<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5753 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5754</div>
5755
5756<div class="doc_text">
5757
5758<h5>Syntax:</h5>
5759<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5760 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5761</pre>
5762
5763<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5765 target-specific value indicating the return address of the current function
5766 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5767
5768<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5769<p>The argument to this intrinsic indicates which function to return the address
5770 for. Zero indicates the calling function, one indicates its caller, etc.
5771 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5772
5773<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5775 indicating the return address of the specified call frame, or zero if it
5776 cannot be identified. The value returned by this intrinsic is likely to be
5777 incorrect or 0 for arguments other than zero, so it should only be used for
5778 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5779
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5780<p>Note that calling this intrinsic does not prevent function inlining or other
5781 aggressive transformations, so the value returned may not be that of the
5782 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5783
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5784</div>
5785
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5786<!-- _______________________________________________________________________ -->
5787<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5788 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789</div>
5790
5791<div class="doc_text">
5792
5793<h5>Syntax:</h5>
5794<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5795 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796</pre>
5797
5798<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5799<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5800 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5801
5802<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803<p>The argument to this intrinsic indicates which function to return the frame
5804 pointer for. Zero indicates the calling function, one indicates its caller,
5805 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5806
5807<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5809 indicating the frame address of the specified call frame, or zero if it
5810 cannot be identified. The value returned by this intrinsic is likely to be
5811 incorrect or 0 for arguments other than zero, so it should only be used for
5812 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5813
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5814<p>Note that calling this intrinsic does not prevent function inlining or other
5815 aggressive transformations, so the value returned may not be that of the
5816 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5817
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818</div>
5819
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5820<!-- _______________________________________________________________________ -->
5821<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5822 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5823</div>
5824
5825<div class="doc_text">
5826
5827<h5>Syntax:</h5>
5828<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5829 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5830</pre>
5831
5832<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5833<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5834 of the function stack, for use
5835 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5836 useful for implementing language features like scoped automatic variable
5837 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5838
5839<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5840<p>This intrinsic returns a opaque pointer value that can be passed
5841 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5842 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5843 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5844 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5845 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5846 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5847
5848</div>
5849
5850<!-- _______________________________________________________________________ -->
5851<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5852 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5853</div>
5854
5855<div class="doc_text">
5856
5857<h5>Syntax:</h5>
5858<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5859 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5860</pre>
5861
5862<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5863<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5864 the function stack to the state it was in when the
5865 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5866 executed. This is useful for implementing language features like scoped
5867 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5868
5869<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5870<p>See the description
5871 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5872
5873</div>
5874
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5875<!-- _______________________________________________________________________ -->
5876<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5877 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5878</div>
5879
5880<div class="doc_text">
5881
5882<h5>Syntax:</h5>
5883<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5884 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]5885</pre>
5886
5887<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5888<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5889 insert a prefetch instruction if supported; otherwise, it is a noop.
5890 Prefetches have no effect on the behavior of the program but can change its
5891 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5892
5893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5894<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5895 specifier determining if the fetch should be for a read (0) or write (1),
5896 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5897 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5898 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5899
5900<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901<p>This intrinsic does not modify the behavior of the program. In particular,
5902 prefetches cannot trap and do not produce a value. On targets that support
5903 this intrinsic, the prefetch can provide hints to the processor cache for
5904 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5905
5906</div>
5907
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5908<!-- _______________________________________________________________________ -->
5909<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5910 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5911</div>
5912
5913<div class="doc_text">
5914
5915<h5>Syntax:</h5>
5916<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5917 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5918</pre>
5919
5920<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5921<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5922 Counter (PC) in a region of code to simulators and other tools. The method
5923 is target specific, but it is expected that the marker will use exported
5924 symbols to transmit the PC of the marker. The marker makes no guarantees
5925 that it will remain with any specific instruction after optimizations. It is
5926 possible that the presence of a marker will inhibit optimizations. The
5927 intended use is to be inserted after optimizations to allow correlations of
5928 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5929
5930<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5931<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5932
5933<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5935 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5936
5937</div>
5938
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5939<!-- _______________________________________________________________________ -->
5940<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5941 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5942</div>
5943
5944<div class="doc_text">
5945
5946<h5>Syntax:</h5>
5947<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5948 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5949</pre>
5950
5951<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5952<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5953 counter register (or similar low latency, high accuracy clocks) on those
5954 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5955 should map to RPCC. As the backing counters overflow quickly (on the order
5956 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5957
5958<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5959<p>When directly supported, reading the cycle counter should not modify any
5960 memory. Implementations are allowed to either return a application specific
5961 value or a system wide value. On backends without support, this is lowered
5962 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5963
5964</div>
5965
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5966<!-- ======================================================================= -->
5967<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5968 <a name="int_libc">Standard C Library Intrinsics</a>
5969</div>
5970
5971<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5972
5973<p>LLVM provides intrinsics for a few important standard C library functions.
5974 These intrinsics allow source-language front-ends to pass information about
5975 the alignment of the pointer arguments to the code generator, providing
5976 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5977
5978</div>
5979
5980<!-- _______________________________________________________________________ -->
5981<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5982 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5983</div>
5984
5985<div class="doc_text">
5986
5987<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5988<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]5989 integer bit width and for different address spaces. Not all targets support
5990 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5992<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5993 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]5994 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5995 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]5996 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5997</pre>
5998
5999<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6001 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6003<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6004 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6005 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6006
6007<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6008
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6009<p>The first argument is a pointer to the destination, the second is a pointer
6010 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6011 number of bytes to copy, the fourth argument is the alignment of the
6012 source and destination locations, and the fifth is a boolean indicating a
6013 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6014
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6015<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]6016 then the caller guarantees that both the source and destination pointers are
6017 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6018
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6019<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6020 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6021 The detailed access behavior is not very cleanly specified and it is unwise
6022 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6023
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6024<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6026<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6027 source location to the destination location, which are not allowed to
6028 overlap. It copies "len" bytes of memory over. If the argument is known to
6029 be aligned to some boundary, this can be specified as the fourth argument,
6030 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6031
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6032</div>
6033
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6034<!-- _______________________________________________________________________ -->
6035<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6036 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6037</div>
6038
6039<div class="doc_text">
6040
6041<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6042<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]6043 width and for different address space. Not all targets support all bit
6044 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6045
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6046<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6047 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]6048 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6049 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]6050 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6051</pre>
6052
6053<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6054<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6055 source location to the destination location. It is similar to the
6056 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6057 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6059<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6060 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6061 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6062
6063<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6064
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6065<p>The first argument is a pointer to the destination, the second is a pointer
6066 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6067 number of bytes to copy, the fourth argument is the alignment of the
6068 source and destination locations, and the fifth is a boolean indicating a
6069 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6070
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6071<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]6072 then the caller guarantees that the source and destination pointers are
6073 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6074
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6075<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6076 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6077 The detailed access behavior is not very cleanly specified and it is unwise
6078 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6079
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6080<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6082<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6083 source location to the destination location, which may overlap. It copies
6084 "len" bytes of memory over. If the argument is known to be aligned to some
6085 boundary, this can be specified as the fourth argument, otherwise it should
6086 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6087
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6088</div>
6089
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6090<!-- _______________________________________________________________________ -->
6091<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6092 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6093</div>
6094
6095<div class="doc_text">
6096
6097<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6098<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]6099 width and for different address spaces. However, not all targets support all
6100 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6101
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6102<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6103 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6104 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6105 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6106 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6107</pre>
6108
6109<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6111 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6113<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6114 intrinsic does not return a value and takes extra alignment/volatile
6115 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6116
6117<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6118<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]6119 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6120 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6121 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6122
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6123<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]6124 then the caller guarantees that the destination pointer is aligned to that
6125 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6126
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6127<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6128 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6129 The detailed access behavior is not very cleanly specified and it is unwise
6130 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6131
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6132<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6133<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6134 at the destination location. If the argument is known to be aligned to some
6135 boundary, this can be specified as the fourth argument, otherwise it should
6136 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6137
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6138</div>
6139
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6140<!-- _______________________________________________________________________ -->
6141<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6142 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6143</div>
6144
6145<div class="doc_text">
6146
6147<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6148<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6149 floating point or vector of floating point type. Not all targets support all
6150 types however.</p>
6151
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6152<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6153 declare float @llvm.sqrt.f32(float %Val)
6154 declare double @llvm.sqrt.f64(double %Val)
6155 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6156 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6157 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6158</pre>
6159
6160<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6161<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6162 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6163 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6164 behavior for negative numbers other than -0.0 (which allows for better
6165 optimization, because there is no need to worry about errno being
6166 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]6167
6168<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6169<p>The argument and return value are floating point numbers of the same
6170 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6171
6172<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6173<p>This function returns the sqrt of the specified operand if it is a
6174 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6175
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6176</div>
6177
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6178<!-- _______________________________________________________________________ -->
6179<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6180 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6181</div>
6182
6183<div class="doc_text">
6184
6185<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6186<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6187 floating point or vector of floating point type. Not all targets support all
6188 types however.</p>
6189
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6190<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6191 declare float @llvm.powi.f32(float %Val, i32 %power)
6192 declare double @llvm.powi.f64(double %Val, i32 %power)
6193 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6194 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6195 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6200 specified (positive or negative) power. The order of evaluation of
6201 multiplications is not defined. When a vector of floating point type is
6202 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6203
6204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6205<p>The second argument is an integer power, and the first is a value to raise to
6206 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6207
6208<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209<p>This function returns the first value raised to the second power with an
6210 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6211
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6212</div>
6213
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6214<!-- _______________________________________________________________________ -->
6215<div class="doc_subsubsection">
6216 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6217</div>
6218
6219<div class="doc_text">
6220
6221<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6222<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6223 floating point or vector of floating point type. Not all targets support all
6224 types however.</p>
6225
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6226<pre>
6227 declare float @llvm.sin.f32(float %Val)
6228 declare double @llvm.sin.f64(double %Val)
6229 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6230 declare fp128 @llvm.sin.f128(fp128 %Val)
6231 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6232</pre>
6233
6234<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6235<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6236
6237<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238<p>The argument and return value are floating point numbers of the same
6239 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6240
6241<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6242<p>This function returns the sine of the specified operand, returning the same
6243 values as the libm <tt>sin</tt> functions would, and handles error conditions
6244 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6245
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6246</div>
6247
6248<!-- _______________________________________________________________________ -->
6249<div class="doc_subsubsection">
6250 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6251</div>
6252
6253<div class="doc_text">
6254
6255<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6256<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6257 floating point or vector of floating point type. Not all targets support all
6258 types however.</p>
6259
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6260<pre>
6261 declare float @llvm.cos.f32(float %Val)
6262 declare double @llvm.cos.f64(double %Val)
6263 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6264 declare fp128 @llvm.cos.f128(fp128 %Val)
6265 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6266</pre>
6267
6268<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6269<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6270
6271<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272<p>The argument and return value are floating point numbers of the same
6273 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6274
6275<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276<p>This function returns the cosine of the specified operand, returning the same
6277 values as the libm <tt>cos</tt> functions would, and handles error conditions
6278 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6279
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6280</div>
6281
6282<!-- _______________________________________________________________________ -->
6283<div class="doc_subsubsection">
6284 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6285</div>
6286
6287<div class="doc_text">
6288
6289<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6290<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6291 floating point or vector of floating point type. Not all targets support all
6292 types however.</p>
6293
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6294<pre>
6295 declare float @llvm.pow.f32(float %Val, float %Power)
6296 declare double @llvm.pow.f64(double %Val, double %Power)
6297 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6298 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6299 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6300</pre>
6301
6302<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6304 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6305
6306<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6307<p>The second argument is a floating point power, and the first is a value to
6308 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6309
6310<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6311<p>This function returns the first value raised to the second power, returning
6312 the same values as the libm <tt>pow</tt> functions would, and handles error
6313 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6314
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6315</div>
6316
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6317<!-- ======================================================================= -->
6318<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6319 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6320</div>
6321
6322<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323
6324<p>LLVM provides intrinsics for a few important bit manipulation operations.
6325 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6326
6327</div>
6328
6329<!-- _______________________________________________________________________ -->
6330<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6331 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6332</div>
6333
6334<div class="doc_text">
6335
6336<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6337<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6338 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6339
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6340<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6341 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6342 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6343 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6344</pre>
6345
6346<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6348 values with an even number of bytes (positive multiple of 16 bits). These
6349 are useful for performing operations on data that is not in the target's
6350 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6351
6352<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6353<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6354 and low byte of the input i16 swapped. Similarly,
6355 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6356 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6357 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6358 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6359 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6360 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6361
6362</div>
6363
6364<!-- _______________________________________________________________________ -->
6365<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6366 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6367</div>
6368
6369<div class="doc_text">
6370
6371<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6372<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]6373 width. Not all targets support all bit widths however.</p>
6374
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6375<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6376 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6377 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6378 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6379 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6380 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6381</pre>
6382
6383<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6384<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6385 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6386
6387<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6388<p>The only argument is the value to be counted. The argument may be of any
6389 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6390
6391<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6392<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]6393
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6394</div>
6395
6396<!-- _______________________________________________________________________ -->
6397<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6398 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6399</div>
6400
6401<div class="doc_text">
6402
6403<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6404<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6405 integer bit width. Not all targets support all bit widths however.</p>
6406
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6407<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6408 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6409 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6410 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6411 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6412 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6413</pre>
6414
6415<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6417 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6418
6419<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6420<p>The only argument is the value to be counted. The argument may be of any
6421 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6422
6423<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6425 zeros in a variable. If the src == 0 then the result is the size in bits of
6426 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6427
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6428</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6429
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6432 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6438<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6439 integer bit width. Not all targets support all bit widths however.</p>
6440
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6441<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6442 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6443 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6444 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6445 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6446 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6447</pre>
6448
6449<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6450<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6451 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>The only argument is the value to be counted. The argument may be of any
6455 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6456
6457<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6458<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6459 zeros in a variable. If the src == 0 then the result is the size in bits of
6460 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6461
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6462</div>
6463
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6464<!-- ======================================================================= -->
6465<div class="doc_subsection">
6466 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6467</div>
6468
6469<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470
6471<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6472
6473</div>
6474
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6475<!-- _______________________________________________________________________ -->
6476<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6477 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6478</div>
6479
6480<div class="doc_text">
6481
6482<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6483<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]6484 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6485
6486<pre>
6487 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6488 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6489 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6490</pre>
6491
6492<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6493<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6494 a signed addition of the two arguments, and indicate whether an overflow
6495 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6496
6497<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6498<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]6499 be of integer types of any bit width, but they must have the same bit
6500 width. The second element of the result structure must be of
6501 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6502 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6503
6504<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6505<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506 a signed addition of the two variables. They return a structure &mdash; the
6507 first element of which is the signed summation, and the second element of
6508 which is a bit specifying if the signed summation resulted in an
6509 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6510
6511<h5>Examples:</h5>
6512<pre>
6513 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6514 %sum = extractvalue {i32, i1} %res, 0
6515 %obit = extractvalue {i32, i1} %res, 1
6516 br i1 %obit, label %overflow, label %normal
6517</pre>
6518
6519</div>
6520
6521<!-- _______________________________________________________________________ -->
6522<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6523 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6524</div>
6525
6526<div class="doc_text">
6527
6528<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6529<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]6530 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6531
6532<pre>
6533 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6534 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6535 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6536</pre>
6537
6538<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6539<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540 an unsigned addition of the two arguments, and indicate whether a carry
6541 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6542
6543<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6544<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]6545 be of integer types of any bit width, but they must have the same bit
6546 width. The second element of the result structure must be of
6547 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6548 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6549
6550<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6551<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6552 an unsigned addition of the two arguments. They return a structure &mdash;
6553 the first element of which is the sum, and the second element of which is a
6554 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6555
6556<h5>Examples:</h5>
6557<pre>
6558 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6559 %sum = extractvalue {i32, i1} %res, 0
6560 %obit = extractvalue {i32, i1} %res, 1
6561 br i1 %obit, label %carry, label %normal
6562</pre>
6563
6564</div>
6565
6566<!-- _______________________________________________________________________ -->
6567<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6568 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6569</div>
6570
6571<div class="doc_text">
6572
6573<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6574<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]6575 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6576
6577<pre>
6578 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6579 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6580 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6581</pre>
6582
6583<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6584<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585 a signed subtraction of the two arguments, and indicate whether an overflow
6586 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587
6588<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6589<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]6590 be of integer types of any bit width, but they must have the same bit
6591 width. The second element of the result structure must be of
6592 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6593 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6594
6595<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6596<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6597 a signed subtraction of the two arguments. They return a structure &mdash;
6598 the first element of which is the subtraction, and the second element of
6599 which is a bit specifying if the signed subtraction resulted in an
6600 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6601
6602<h5>Examples:</h5>
6603<pre>
6604 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6605 %sum = extractvalue {i32, i1} %res, 0
6606 %obit = extractvalue {i32, i1} %res, 1
6607 br i1 %obit, label %overflow, label %normal
6608</pre>
6609
6610</div>
6611
6612<!-- _______________________________________________________________________ -->
6613<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6614 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6615</div>
6616
6617<div class="doc_text">
6618
6619<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6620<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]6621 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6622
6623<pre>
6624 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6625 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6626 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6627</pre>
6628
6629<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6630<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631 an unsigned subtraction of the two arguments, and indicate whether an
6632 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6633
6634<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6635<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]6636 be of integer types of any bit width, but they must have the same bit
6637 width. The second element of the result structure must be of
6638 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6639 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6640
6641<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6642<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643 an unsigned subtraction of the two arguments. They return a structure &mdash;
6644 the first element of which is the subtraction, and the second element of
6645 which is a bit specifying if the unsigned subtraction resulted in an
6646 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6647
6648<h5>Examples:</h5>
6649<pre>
6650 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6651 %sum = extractvalue {i32, i1} %res, 0
6652 %obit = extractvalue {i32, i1} %res, 1
6653 br i1 %obit, label %overflow, label %normal
6654</pre>
6655
6656</div>
6657
6658<!-- _______________________________________________________________________ -->
6659<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6660 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6661</div>
6662
6663<div class="doc_text">
6664
6665<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666<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]6667 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6668
6669<pre>
6670 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6671 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6672 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6673</pre>
6674
6675<h5>Overview:</h5>
6676
6677<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678 a signed multiplication of the two arguments, and indicate whether an
6679 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6680
6681<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6682<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]6683 be of integer types of any bit width, but they must have the same bit
6684 width. The second element of the result structure must be of
6685 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6686 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6687
6688<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6689<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6690 a signed multiplication of the two arguments. They return a structure &mdash;
6691 the first element of which is the multiplication, and the second element of
6692 which is a bit specifying if the signed multiplication resulted in an
6693 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6694
6695<h5>Examples:</h5>
6696<pre>
6697 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6698 %sum = extractvalue {i32, i1} %res, 0
6699 %obit = extractvalue {i32, i1} %res, 1
6700 br i1 %obit, label %overflow, label %normal
6701</pre>
6702
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6703</div>
6704
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6705<!-- _______________________________________________________________________ -->
6706<div class="doc_subsubsection">
6707 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6708</div>
6709
6710<div class="doc_text">
6711
6712<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6713<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]6714 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6715
6716<pre>
6717 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6718 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6719 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6720</pre>
6721
6722<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6723<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724 a unsigned multiplication of the two arguments, and indicate whether an
6725 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6726
6727<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6728<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]6729 be of integer types of any bit width, but they must have the same bit
6730 width. The second element of the result structure must be of
6731 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6732 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6733
6734<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6735<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736 an unsigned multiplication of the two arguments. They return a structure
6737 &mdash; the first element of which is the multiplication, and the second
6738 element of which is a bit specifying if the unsigned multiplication resulted
6739 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6740
6741<h5>Examples:</h5>
6742<pre>
6743 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6744 %sum = extractvalue {i32, i1} %res, 0
6745 %obit = extractvalue {i32, i1} %res, 1
6746 br i1 %obit, label %overflow, label %normal
6747</pre>
6748
6749</div>
6750
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6751<!-- ======================================================================= -->
6752<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6753 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6754</div>
6755
6756<div class="doc_text">
6757
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6758<p>Half precision floating point is a storage-only format. This means that it is
6759 a dense encoding (in memory) but does not support computation in the
6760 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6761
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6762<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6763 value as an i16, then convert it to float with <a
6764 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6765 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6766 double etc). To store the value back to memory, it is first converted to
6767 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6768 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6769 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6770</div>
6771
6772<!-- _______________________________________________________________________ -->
6773<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6774 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6775</div>
6776
6777<div class="doc_text">
6778
6779<h5>Syntax:</h5>
6780<pre>
6781 declare i16 @llvm.convert.to.fp16(f32 %a)
6782</pre>
6783
6784<h5>Overview:</h5>
6785<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6786 a conversion from single precision floating point format to half precision
6787 floating point format.</p>
6788
6789<h5>Arguments:</h5>
6790<p>The intrinsic function contains single argument - the value to be
6791 converted.</p>
6792
6793<h5>Semantics:</h5>
6794<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6795 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6796 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6797 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6798
6799<h5>Examples:</h5>
6800<pre>
6801 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6802 store i16 %res, i16* @x, align 2
6803</pre>
6804
6805</div>
6806
6807<!-- _______________________________________________________________________ -->
6808<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6809 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6810</div>
6811
6812<div class="doc_text">
6813
6814<h5>Syntax:</h5>
6815<pre>
6816 declare f32 @llvm.convert.from.fp16(i16 %a)
6817</pre>
6818
6819<h5>Overview:</h5>
6820<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6821 a conversion from half precision floating point format to single precision
6822 floating point format.</p>
6823
6824<h5>Arguments:</h5>
6825<p>The intrinsic function contains single argument - the value to be
6826 converted.</p>
6827
6828<h5>Semantics:</h5>
6829<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6830 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6831 precision floating point format. The input half-float value is represented by
6832 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6833
6834<h5>Examples:</h5>
6835<pre>
6836 %a = load i16* @x, align 2
6837 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6838</pre>
6839
6840</div>
6841
6842<!-- ======================================================================= -->
6843<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6844 <a name="int_debugger">Debugger Intrinsics</a>
6845</div>
6846
6847<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6849<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6850 prefix), are described in
6851 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6852 Level Debugging</a> document.</p>
6853
6854</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6855
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6856<!-- ======================================================================= -->
6857<div class="doc_subsection">
6858 <a name="int_eh">Exception Handling Intrinsics</a>
6859</div>
6860
6861<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6862
6863<p>The LLVM exception handling intrinsics (which all start with
6864 <tt>llvm.eh.</tt> prefix), are described in
6865 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6866 Handling</a> document.</p>
6867
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6868</div>
6869
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6870<!-- ======================================================================= -->
6871<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6872 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6873</div>
6874
6875<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6876
6877<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6878 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6879 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6880 function pointer lacking the nest parameter - the caller does not need to
6881 provide a value for it. Instead, the value to use is stored in advance in a
6882 "trampoline", a block of memory usually allocated on the stack, which also
6883 contains code to splice the nest value into the argument list. This is used
6884 to implement the GCC nested function address extension.</p>
6885
6886<p>For example, if the function is
6887 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6888 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6889 follows:</p>
6890
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6891<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6892 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6893 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6894 %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]6895 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6896</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6897
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6898<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6899 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6900
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6901</div>
6902
6903<!-- _______________________________________________________________________ -->
6904<div class="doc_subsubsection">
6905 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6906</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6908<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6909
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6910<h5>Syntax:</h5>
6911<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912 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]6913</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6914
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6915<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6917 function pointer suitable for executing it.</p>
6918
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6919<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6921 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6922 sufficiently aligned block of memory; this memory is written to by the
6923 intrinsic. Note that the size and the alignment are target-specific - LLVM
6924 currently provides no portable way of determining them, so a front-end that
6925 generates this intrinsic needs to have some target-specific knowledge.
6926 The <tt>func</tt> argument must hold a function bitcast to
6927 an <tt>i8*</tt>.</p>
6928
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6929<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6930<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6931 dependent code, turning it into a function. A pointer to this function is
6932 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6933 function pointer type</a> before being called. The new function's signature
6934 is the same as that of <tt>func</tt> with any arguments marked with
6935 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6936 is allowed, and it must be of pointer type. Calling the new function is
6937 equivalent to calling <tt>func</tt> with the same argument list, but
6938 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6939 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6940 by <tt>tramp</tt> is modified, then the effect of any later call to the
6941 returned function pointer is undefined.</p>
6942
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6943</div>
6944
6945<!-- ======================================================================= -->
6946<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6947 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6948</div>
6949
6950<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6953 hardware constructs for atomic operations and memory synchronization. This
6954 provides an interface to the hardware, not an interface to the programmer. It
6955 is aimed at a low enough level to allow any programming models or APIs
6956 (Application Programming Interfaces) which need atomic behaviors to map
6957 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6958 hardware provides a "universal IR" for source languages, it also provides a
6959 starting point for developing a "universal" atomic operation and
6960 synchronization IR.</p>
6961
6962<p>These do <em>not</em> form an API such as high-level threading libraries,
6963 software transaction memory systems, atomic primitives, and intrinsic
6964 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6965 application libraries. The hardware interface provided by LLVM should allow
6966 a clean implementation of all of these APIs and parallel programming models.
6967 No one model or paradigm should be selected above others unless the hardware
6968 itself ubiquitously does so.</p>
6969
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6970</div>
6971
6972<!-- _______________________________________________________________________ -->
6973<div class="doc_subsubsection">
6974 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6975</div>
6976<div class="doc_text">
6977<h5>Syntax:</h5>
6978<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6979 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]6980</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6981
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6983<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6984 specific pairs of memory access types.</p>
6985
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6986<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6988 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6989 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6991
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6992<ul>
6993 <li><tt>ll</tt>: load-load barrier</li>
6994 <li><tt>ls</tt>: load-store barrier</li>
6995 <li><tt>sl</tt>: store-load barrier</li>
6996 <li><tt>ss</tt>: store-store barrier</li>
6997 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6998</ul>
6999
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7000<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7001<p>This intrinsic causes the system to enforce some ordering constraints upon
7002 the loads and stores of the program. This barrier does not
7003 indicate <em>when</em> any events will occur, it only enforces
7004 an <em>order</em> in which they occur. For any of the specified pairs of load
7005 and store operations (f.ex. load-load, or store-load), all of the first
7006 operations preceding the barrier will complete before any of the second
7007 operations succeeding the barrier begin. Specifically the semantics for each
7008 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7010<ul>
7011 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7012 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7013 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7015 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7016 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7017 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7018 load after the barrier begins.</li>
7019</ul>
7020
7021<p>These semantics are applied with a logical "and" behavior when more than one
7022 is enabled in a single memory barrier intrinsic.</p>
7023
7024<p>Backends may implement stronger barriers than those requested when they do
7025 not support as fine grained a barrier as requested. Some architectures do
7026 not need all types of barriers and on such architectures, these become
7027 noops.</p>
7028
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7029<h5>Example:</h5>
7030<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7031%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7032%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7033 store i32 4, %ptr
7034
7035%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7036 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7037 <i>; guarantee the above finishes</i>
7038 store i32 8, %ptr <i>; before this begins</i>
7039</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7040
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7041</div>
7042
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7043<!-- _______________________________________________________________________ -->
7044<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7045 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7046</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7047
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7048<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7050<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7051<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7052 any integer bit width and for different address spaces. Not all targets
7053 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7054
7055<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7056 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7057 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7058 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7059 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]7060</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7061
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7063<p>This loads a value in memory and compares it to a given value. If they are
7064 equal, it stores a new value into the memory.</p>
7065
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7067<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7068 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7069 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7070 this integer type. While any bit width integer may be used, targets may only
7071 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7072
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7073<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7074<p>This entire intrinsic must be executed atomically. It first loads the value
7075 in memory pointed to by <tt>ptr</tt> and compares it with the
7076 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7077 memory. The loaded value is yielded in all cases. This provides the
7078 equivalent of an atomic compare-and-swap operation within the SSA
7079 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7080
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7082<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7083%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7084%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7085 store i32 4, %ptr
7086
7087%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7088%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7089 <i>; yields {i32}:result1 = 4</i>
7090%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7091%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7092
7093%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7094%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7095 <i>; yields {i32}:result2 = 8</i>
7096%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7097
7098%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7099</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7100
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7101</div>
7102
7103<!-- _______________________________________________________________________ -->
7104<div class="doc_subsubsection">
7105 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7106</div>
7107<div class="doc_text">
7108<h5>Syntax:</h5>
7109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7110<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7111 integer bit width. Not all targets support all bit widths however.</p>
7112
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7113<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7114 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7115 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7116 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7117 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]7118</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7120<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7121<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7122 the value from memory. It then stores the value in <tt>val</tt> in the memory
7123 at <tt>ptr</tt>.</p>
7124
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7125<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7126<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7127 the <tt>val</tt> argument and the result must be integers of the same bit
7128 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7129 integer type. The targets may only lower integer representations they
7130 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7131
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7132<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7133<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7134 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7135 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7136
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7137<h5>Examples:</h5>
7138<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7139%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7140%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7141 store i32 4, %ptr
7142
7143%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7144%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145 <i>; yields {i32}:result1 = 4</i>
7146%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7147%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7148
7149%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7150%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7151 <i>; yields {i32}:result2 = 8</i>
7152
7153%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7154%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7155</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7156
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7157</div>
7158
7159<!-- _______________________________________________________________________ -->
7160<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7161 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7162
7163</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7166
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7167<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7168<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7169 any integer bit width. Not all targets support all bit widths however.</p>
7170
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7171<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7172 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7173 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7174 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7175 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]7176</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7177
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7178<h5>Overview:</h5>
7179<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7180 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7181
7182<h5>Arguments:</h5>
7183<p>The intrinsic takes two arguments, the first a pointer to an integer value
7184 and the second an integer value. The result is also an integer value. These
7185 integer types can have any bit width, but they must all have the same bit
7186 width. The targets may only lower integer representations they support.</p>
7187
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7188<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7189<p>This intrinsic does a series of operations atomically. It first loads the
7190 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7191 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]7192
7193<h5>Examples:</h5>
7194<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7195%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7196%ptr = bitcast i8* %mallocP to i32*
7197 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7198%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7199 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7200%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7202%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7204%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7205</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7207</div>
7208
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7209<!-- _______________________________________________________________________ -->
7210<div class="doc_subsubsection">
7211 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7212
7213</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7214
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7216
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7217<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7218<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7219 any integer bit width and for different address spaces. Not all targets
7220 support all bit widths however.</p>
7221
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7222<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7223 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7224 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7225 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7226 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]7227</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7228
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7229<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7230<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7231 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7232
7233<h5>Arguments:</h5>
7234<p>The intrinsic takes two arguments, the first a pointer to an integer value
7235 and the second an integer value. The result is also an integer value. These
7236 integer types can have any bit width, but they must all have the same bit
7237 width. The targets may only lower integer representations they support.</p>
7238
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7239<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7240<p>This intrinsic does a series of operations atomically. It first loads the
7241 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7242 result to <tt>ptr</tt>. It yields the original value stored
7243 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7244
7245<h5>Examples:</h5>
7246<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7247%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7248%ptr = bitcast i8* %mallocP to i32*
7249 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7250%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7251 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7252%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7253 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7254%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7255 <i>; yields {i32}:result3 = 2</i>
7256%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7257</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7258
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7259</div>
7260
7261<!-- _______________________________________________________________________ -->
7262<div class="doc_subsubsection">
7263 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7264 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7265 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7266 <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]7267</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7269<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7270
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7271<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7272<p>These are overloaded intrinsics. You can
7273 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7274 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7275 bit width and for different address spaces. Not all targets support all bit
7276 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7277
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7279 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7280 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7281 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7282 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]7283</pre>
7284
7285<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7286 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7287 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7288 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7289 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]7290</pre>
7291
7292<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7293 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7294 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7295 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7296 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]7297</pre>
7298
7299<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7300 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7301 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7302 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7303 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]7304</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7305
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7306<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7308 the value stored in memory at <tt>ptr</tt>. It yields the original value
7309 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7310
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311<h5>Arguments:</h5>
7312<p>These intrinsics take two arguments, the first a pointer to an integer value
7313 and the second an integer value. The result is also an integer value. These
7314 integer types can have any bit width, but they must all have the same bit
7315 width. The targets may only lower integer representations they support.</p>
7316
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7317<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7318<p>These intrinsics does a series of operations atomically. They first load the
7319 value stored at <tt>ptr</tt>. They then do the bitwise
7320 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7321 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7322
7323<h5>Examples:</h5>
7324<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7325%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7326%ptr = bitcast i8* %mallocP to i32*
7327 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7328%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7329 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7330%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7331 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7332%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7333 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7334%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7335 <i>; yields {i32}:result3 = FF</i>
7336%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7337</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7339</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7340
7341<!-- _______________________________________________________________________ -->
7342<div class="doc_subsubsection">
7343 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7344 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7345 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7346 <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]7347</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7349<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7350
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7351<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7352<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7353 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7354 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7355 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7356
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7357<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7358 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7359 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7360 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7361 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]7362</pre>
7363
7364<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7365 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7366 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7367 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7368 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]7369</pre>
7370
7371<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7372 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7373 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7374 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7375 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]7376</pre>
7377
7378<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7379 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7380 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7381 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7382 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]7383</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7384
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7385<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7386<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7387 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7388 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7389
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7390<h5>Arguments:</h5>
7391<p>These intrinsics take two arguments, the first a pointer to an integer value
7392 and the second an integer value. The result is also an integer value. These
7393 integer types can have any bit width, but they must all have the same bit
7394 width. The targets may only lower integer representations they support.</p>
7395
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7396<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7397<p>These intrinsics does a series of operations atomically. They first load the
7398 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7399 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7400 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7401
7402<h5>Examples:</h5>
7403<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7404%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7405%ptr = bitcast i8* %mallocP to i32*
7406 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7407%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7408 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7409%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7411%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7413%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7414 <i>; yields {i32}:result3 = 8</i>
7415%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7416</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7417
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7418</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7419
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7420
7421<!-- ======================================================================= -->
7422<div class="doc_subsection">
7423 <a name="int_memorymarkers">Memory Use Markers</a>
7424</div>
7425
7426<div class="doc_text">
7427
7428<p>This class of intrinsics exists to information about the lifetime of memory
7429 objects and ranges where variables are immutable.</p>
7430
7431</div>
7432
7433<!-- _______________________________________________________________________ -->
7434<div class="doc_subsubsection">
7435 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7436</div>
7437
7438<div class="doc_text">
7439
7440<h5>Syntax:</h5>
7441<pre>
7442 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7443</pre>
7444
7445<h5>Overview:</h5>
7446<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7447 object's lifetime.</p>
7448
7449<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7450<p>The first argument is a constant integer representing the size of the
7451 object, or -1 if it is variable sized. The second argument is a pointer to
7452 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7453
7454<h5>Semantics:</h5>
7455<p>This intrinsic indicates that before this point in the code, the value of the
7456 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]7457 never be used and has an undefined value. A load from the pointer that
7458 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7459 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7460
7461</div>
7462
7463<!-- _______________________________________________________________________ -->
7464<div class="doc_subsubsection">
7465 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7466</div>
7467
7468<div class="doc_text">
7469
7470<h5>Syntax:</h5>
7471<pre>
7472 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7473</pre>
7474
7475<h5>Overview:</h5>
7476<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7477 object's lifetime.</p>
7478
7479<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7480<p>The first argument is a constant integer representing the size of the
7481 object, or -1 if it is variable sized. The second argument is a pointer to
7482 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7483
7484<h5>Semantics:</h5>
7485<p>This intrinsic indicates that after this point in the code, the value of the
7486 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7487 never be used and has an undefined value. Any stores into the memory object
7488 following this intrinsic may be removed as dead.
7489
7490</div>
7491
7492<!-- _______________________________________________________________________ -->
7493<div class="doc_subsubsection">
7494 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7495</div>
7496
7497<div class="doc_text">
7498
7499<h5>Syntax:</h5>
7500<pre>
7501 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7502</pre>
7503
7504<h5>Overview:</h5>
7505<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7506 a memory object will not change.</p>
7507
7508<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7509<p>The first argument is a constant integer representing the size of the
7510 object, or -1 if it is variable sized. The second argument is a pointer to
7511 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7512
7513<h5>Semantics:</h5>
7514<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7515 the return value, the referenced memory location is constant and
7516 unchanging.</p>
7517
7518</div>
7519
7520<!-- _______________________________________________________________________ -->
7521<div class="doc_subsubsection">
7522 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7523</div>
7524
7525<div class="doc_text">
7526
7527<h5>Syntax:</h5>
7528<pre>
7529 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7530</pre>
7531
7532<h5>Overview:</h5>
7533<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7534 a memory object are mutable.</p>
7535
7536<h5>Arguments:</h5>
7537<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7538 The second argument is a constant integer representing the size of the
7539 object, or -1 if it is variable sized and the third argument is a pointer
7540 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7541
7542<h5>Semantics:</h5>
7543<p>This intrinsic indicates that the memory is mutable again.</p>
7544
7545</div>
7546
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7547<!-- ======================================================================= -->
7548<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7549 <a name="int_general">General Intrinsics</a>
7550</div>
7551
7552<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7553
7554<p>This class of intrinsics is designed to be generic and has no specific
7555 purpose.</p>
7556
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7557</div>
7558
7559<!-- _______________________________________________________________________ -->
7560<div class="doc_subsubsection">
7561 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7562</div>
7563
7564<div class="doc_text">
7565
7566<h5>Syntax:</h5>
7567<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7568 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]7569</pre>
7570
7571<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7572<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7573
7574<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7575<p>The first argument is a pointer to a value, the second is a pointer to a
7576 global string, the third is a pointer to a global string which is the source
7577 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7578
7579<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7580<p>This intrinsic allows annotation of local variables with arbitrary strings.
7581 This can be useful for special purpose optimizations that want to look for
7582 these annotations. These have no other defined use, they are ignored by code
7583 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7584
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7585</div>
7586
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7587<!-- _______________________________________________________________________ -->
7588<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7589 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7590</div>
7591
7592<div class="doc_text">
7593
7594<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7595<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7596 any integer bit width.</p>
7597
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7598<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7599 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7600 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7601 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7602 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7603 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]7604</pre>
7605
7606<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7607<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7608
7609<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7610<p>The first argument is an integer value (result of some expression), the
7611 second is a pointer to a global string, the third is a pointer to a global
7612 string which is the source file name, and the last argument is the line
7613 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7614
7615<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7616<p>This intrinsic allows annotations to be put on arbitrary expressions with
7617 arbitrary strings. This can be useful for special purpose optimizations that
7618 want to look for these annotations. These have no other defined use, they
7619 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7620
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7621</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7622
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7623<!-- _______________________________________________________________________ -->
7624<div class="doc_subsubsection">
7625 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7626</div>
7627
7628<div class="doc_text">
7629
7630<h5>Syntax:</h5>
7631<pre>
7632 declare void @llvm.trap()
7633</pre>
7634
7635<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7636<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7637
7638<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7640
7641<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7642<p>This intrinsics is lowered to the target dependent trap instruction. If the
7643 target does not have a trap instruction, this intrinsic will be lowered to
7644 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7645
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7646</div>
7647
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7648<!-- _______________________________________________________________________ -->
7649<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7650 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7651</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7652
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7653<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7654
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7655<h5>Syntax:</h5>
7656<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7657 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7659
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7660<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7661<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7662 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7663 ensure that it is placed on the stack before local variables.</p>
7664
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7665<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7666<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7667 arguments. The first argument is the value loaded from the stack
7668 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7669 that has enough space to hold the value of the guard.</p>
7670
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7671<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7672<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7673 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7674 stack. This is to ensure that if a local variable on the stack is
7675 overwritten, it will destroy the value of the guard. When the function exits,
7676 the guard on the stack is checked against the original guard. If they're
7677 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7678 function.</p>
7679
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7680</div>
7681
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7682<!-- _______________________________________________________________________ -->
7683<div class="doc_subsubsection">
7684 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7685</div>
7686
7687<div class="doc_text">
7688
7689<h5>Syntax:</h5>
7690<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7691 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7692 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7693</pre>
7694
7695<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7696<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7697 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7698 operation like memcpy will either overflow a buffer that corresponds to
7699 an object, or b) to determine that a runtime check for overflow isn't
7700 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7701 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7702
7703<h5>Arguments:</h5>
7704<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7705 argument is a pointer to or into the <tt>object</tt>. The second argument
7706 is a boolean 0 or 1. This argument determines whether you want the
7707 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7708 1, variables are not allowed.</p>
7709
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7710<h5>Semantics:</h5>
7711<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7712 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7713 (depending on the <tt>type</tt> argument if the size cannot be determined
7714 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7715
7716</div>
7717
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7718<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7719<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7720<address>
7721 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7725
7726 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7727 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7728 Last modified: $Date$
7729</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7731</body>
7732</html>