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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0076d2057c627473ed69c227f7ead6283fdff44e / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]910<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]919<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1133
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1134 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis6f12e292010-10-25 16:29:03 +0000[diff] [blame]1135 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis0076d202010-10-25 19:07:39 +0000[diff] [blame^]1136 meaning the function can be patched and/or hooked even while it is
1137 loaded into memory. On x86, the function prologue will be preceded
1138 by six bytes of padding and will begin with a two-byte instruction.
1139 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1140 higher were compiled in this fashion.</dd>
Charles Davis970bfcc2010-10-25 15:37:09 +0000[diff] [blame]1141
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1142 <dt><tt><b>inlinehint</b></tt></dt>
1143 <dd>This attribute indicates that the source code contained a hint that inlining
1144 this function is desirable (such as the "inline" keyword in C/C++). It
1145 is just a hint; it imposes no requirements on the inliner.</dd>
1146
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1147 <dt><tt><b>naked</b></tt></dt>
1148 <dd>This attribute disables prologue / epilogue emission for the function.
1149 This can have very system-specific consequences.</dd>
1150
1151 <dt><tt><b>noimplicitfloat</b></tt></dt>
1152 <dd>This attributes disables implicit floating point instructions.</dd>
1153
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the inliner should never inline this
1156 function in any situation. This attribute may not be used together with
1157 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1158
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1159 <dt><tt><b>noredzone</b></tt></dt>
1160 <dd>This attribute indicates that the code generator should not use a red
1161 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1162
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1163 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1164 <dd>This function attribute indicates that the function never returns
1165 normally. This produces undefined behavior at runtime if the function
1166 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1167
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This function attribute indicates that the function never returns with an
1170 unwind or exceptional control flow. If the function does unwind, its
1171 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1172
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>optsize</b></tt></dt>
1174 <dd>This attribute suggests that optimization passes and code generator passes
1175 make choices that keep the code size of this function low, and otherwise
1176 do optimizations specifically to reduce code size.</dd>
1177
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1178 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1179 <dd>This attribute indicates that the function computes its result (or decides
1180 to unwind an exception) based strictly on its arguments, without
1181 dereferencing any pointer arguments or otherwise accessing any mutable
1182 state (e.g. memory, control registers, etc) visible to caller functions.
1183 It does not write through any pointer arguments
1184 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1185 changes any state visible to callers. This means that it cannot unwind
1186 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1187 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1188
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This attribute indicates that the function does not write through any
1191 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1192 arguments) or otherwise modify any state (e.g. memory, control registers,
1193 etc) visible to caller functions. It may dereference pointer arguments
1194 and read state that may be set in the caller. A readonly function always
1195 returns the same value (or unwinds an exception identically) when called
1196 with the same set of arguments and global state. It cannot unwind an
1197 exception by calling the <tt>C++</tt> exception throwing methods, but may
1198 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attribute indicates that the function should emit a stack smashing
1202 protector. It is in the form of a "canary"&mdash;a random value placed on
1203 the stack before the local variables that's checked upon return from the
1204 function to see if it has been overwritten. A heuristic is used to
1205 determine if a function needs stack protectors or not.<br>
1206<br>
1207 If a function that has an <tt>ssp</tt> attribute is inlined into a
1208 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1209 function will have an <tt>ssp</tt> attribute.</dd>
1210
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1211 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212 <dd>This attribute indicates that the function should <em>always</em> emit a
1213 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1214 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1215<br>
1216 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1217 function that doesn't have an <tt>sspreq</tt> attribute or which has
1218 an <tt>ssp</tt> attribute, then the resulting function will have
1219 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1220</dl>
1221
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1222</div>
1223
1224<!-- ======================================================================= -->
1225<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1226 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1227</div>
1228
1229<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1230
1231<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1232 the GCC "file scope inline asm" blocks. These blocks are internally
1233 concatenated by LLVM and treated as a single unit, but may be separated in
1234 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1235
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1236<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1237module asm "inline asm code goes here"
1238module asm "more can go here"
1239</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1240
1241<p>The strings can contain any character by escaping non-printable characters.
1242 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1243 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1244
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1245<p>The inline asm code is simply printed to the machine code .s file when
1246 assembly code is generated.</p>
1247
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1248</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1249
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1250<!-- ======================================================================= -->
1251<div class="doc_subsection">
1252 <a name="datalayout">Data Layout</a>
1253</div>
1254
1255<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1256
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1257<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1258 data is to be laid out in memory. The syntax for the data layout is
1259 simply:</p>
1260
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1261<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262target datalayout = "<i>layout specification</i>"
1263</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1264
1265<p>The <i>layout specification</i> consists of a list of specifications
1266 separated by the minus sign character ('-'). Each specification starts with
1267 a letter and may include other information after the letter to define some
1268 aspect of the data layout. The specifications accepted are as follows:</p>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270<dl>
1271 <dt><tt>E</tt></dt>
1272 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1273 bits with the most significance have the lowest address location.</dd>
1274
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1276 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1277 the bits with the least significance have the lowest address
1278 location.</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>preferred</i> alignments. All sizes are in bits. Specifying
1283 the <i>pref</i> alignment is optional. If omitted, the
1284 preceding <tt>:</tt> should be omitted too.</dd>
1285
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1287 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1289
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1290 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1291 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1292 <i>size</i>.</dd>
1293
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1294 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1295 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1296 <i>size</i>. Only values of <i>size</i> that are supported by the target
1297 will work. 32 (float) and 64 (double) are supported on all targets;
1298 80 or 128 (different flavors of long double) are also supported on some
1299 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1301 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1302 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1303 <i>size</i>.</dd>
1304
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1305 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1306 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1308
1309 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1310 <dd>This specifies a set of native integer widths for the target CPU
1311 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1312 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1313 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1314 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1315</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1317<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1318 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 specifications in the <tt>datalayout</tt> keyword. The default specifications
1320 are given in this list:</p>
1321
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1322<ul>
1323 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1324 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1326 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1327 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1328 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1329 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330 alignment of 64-bits</li>
1331 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1332 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1333 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1334 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1335 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1336 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1337</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1338
1339<p>When LLVM is determining the alignment for a given type, it uses the
1340 following rules:</p>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342<ol>
1343 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1344 specification is used.</li>
1345
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347 smallest integer type that is larger than the bitwidth of the sought type
1348 is used. If none of the specifications are larger than the bitwidth then
1349 the the largest integer type is used. For example, given the default
1350 specifications above, the i7 type will use the alignment of i8 (next
1351 largest) while both i65 and i256 will use the alignment of i64 (largest
1352 specified).</li>
1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355 largest vector type that is smaller than the sought vector type will be
1356 used as a fall back. This happens because &lt;128 x double&gt; can be
1357 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1358</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1359
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1360</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1361
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1365</div>
1366
1367<div class="doc_text">
1368
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1369<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1370with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1371is undefined. Pointer values are associated with address ranges
1372according to the following rules:</p>
1373
1374<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1375 <li>A pointer value is associated with the addresses associated with
1376 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1377 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1378 range of the variable's storage.</li>
1379 <li>The result value of an allocation instruction is associated with
1380 the address range of the allocated storage.</li>
1381 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1382 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1383 <li>An integer constant other than zero or a pointer value returned
1384 from a function not defined within LLVM may be associated with address
1385 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1386 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1387 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1388</ul>
1389
1390<p>A pointer value is <i>based</i> on another pointer value according
1391 to the following rules:</p>
1392
1393<ul>
1394 <li>A pointer value formed from a
1395 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1396 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1397 <li>The result value of a
1398 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1399 of the <tt>bitcast</tt>.</li>
1400 <li>A pointer value formed by an
1401 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1402 pointer values that contribute (directly or indirectly) to the
1403 computation of the pointer's value.</li>
1404 <li>The "<i>based</i> on" relationship is transitive.</li>
1405</ul>
1406
1407<p>Note that this definition of <i>"based"</i> is intentionally
1408 similar to the definition of <i>"based"</i> in C99, though it is
1409 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1410
1411<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1412<tt><a href="#i_load">load</a></tt> merely indicates the size and
1413alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1414interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1415<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1416and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>Consequently, type-based alias analysis, aka TBAA, aka
1419<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1420LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1421additional information which specialized optimization passes may use
1422to implement type-based alias analysis.</p>
1423
1424</div>
1425
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1426<!-- ======================================================================= -->
1427<div class="doc_subsection">
1428 <a name="volatile">Volatile Memory Accesses</a>
1429</div>
1430
1431<div class="doc_text">
1432
1433<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1434href="#i_store"><tt>store</tt></a>s, and <a
1435href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1436The optimizers must not change the number of volatile operations or change their
1437order of execution relative to other volatile operations. The optimizers
1438<i>may</i> change the order of volatile operations relative to non-volatile
1439operations. This is not Java's "volatile" and has no cross-thread
1440synchronization behavior.</p>
1441
1442</div>
1443
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1444<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1446<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1447
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1450<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1451 intermediate representation. Being typed enables a number of optimizations
1452 to be performed on the intermediate representation directly, without having
1453 to do extra analyses on the side before the transformation. A strong type
1454 system makes it easier to read the generated code and enables novel analyses
1455 and transformations that are not feasible to perform on normal three address
1456 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1457
1458</div>
1459
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1460<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1462Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1465
1466<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1467
1468<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1469 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1470 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1472 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1473 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
1475 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476 <td><a href="#t_floating">floating point</a></td>
1477 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1478 </tr>
1479 <tr>
1480 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1481 <td><a href="#t_integer">integer</a>,
1482 <a href="#t_floating">floating point</a>,
1483 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1484 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1485 <a href="#t_struct">structure</a>,
1486 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1487 <a href="#t_label">label</a>,
1488 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1489 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1491 <tr>
1492 <td><a href="#t_primitive">primitive</a></td>
1493 <td><a href="#t_label">label</a>,
1494 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1496 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1497 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1498 </tr>
1499 <tr>
1500 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1501 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1502 <a href="#t_function">function</a>,
1503 <a href="#t_pointer">pointer</a>,
1504 <a href="#t_struct">structure</a>,
1505 <a href="#t_pstruct">packed structure</a>,
1506 <a href="#t_vector">vector</a>,
1507 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1508 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1509 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1510 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1511</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1513<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1514 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1515 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1517</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1519<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1520<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1521
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1522<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1523
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1524<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1525 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1527</div>
1528
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1530<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1531
1532<div class="doc_text">
1533
1534<h5>Overview:</h5>
1535<p>The integer type is a very simple type that simply specifies an arbitrary
1536 bit width for the integer type desired. Any bit width from 1 bit to
1537 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1538
1539<h5>Syntax:</h5>
1540<pre>
1541 iN
1542</pre>
1543
1544<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1545 value.</p>
1546
1547<h5>Examples:</h5>
1548<table class="layout">
1549 <tr class="layout">
1550 <td class="left"><tt>i1</tt></td>
1551 <td class="left">a single-bit integer.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>i32</tt></td>
1555 <td class="left">a 32-bit integer.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>i1942652</tt></td>
1559 <td class="left">a really big integer of over 1 million bits.</td>
1560 </tr>
1561</table>
1562
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1563</div>
1564
1565<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1566<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1567
1568<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1569
1570<table>
1571 <tbody>
1572 <tr><th>Type</th><th>Description</th></tr>
1573 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1574 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1575 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1576 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1577 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1578 </tbody>
1579</table>
1580
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1581</div>
1582
1583<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1585
1586<div class="doc_text">
1587
1588<h5>Overview:</h5>
1589<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1590
1591<h5>Syntax:</h5>
1592<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1593 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1594</pre>
1595
1596</div>
1597
1598<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1599<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1600
1601<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1602
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1603<h5>Overview:</h5>
1604<p>The void type does not represent any value and has no size.</p>
1605
1606<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607<pre>
1608 void
1609</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1611</div>
1612
1613<!-- _______________________________________________________________________ -->
1614<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1615
1616<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1617
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1618<h5>Overview:</h5>
1619<p>The label type represents code labels.</p>
1620
1621<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1622<pre>
1623 label
1624</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1625
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1626</div>
1627
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1628<!-- _______________________________________________________________________ -->
1629<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1630
1631<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1632
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1633<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1634<p>The metadata type represents embedded metadata. No derived types may be
1635 created from metadata except for <a href="#t_function">function</a>
1636 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1637
1638<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1639<pre>
1640 metadata
1641</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1642
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1643</div>
1644
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1645
1646<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1647<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The real power in LLVM comes from the derived types in the system. This is
1652 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1653 useful types. Each of these types contain one or more element types which
1654 may be a primitive type, or another derived type. For example, it is
1655 possible to have a two dimensional array, using an array as the element type
1656 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1657
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1658
1659</div>
1660
1661<!-- _______________________________________________________________________ -->
1662<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1663
1664<div class="doc_text">
1665
1666<p>Aggregate Types are a subset of derived types that can contain multiple
1667 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1668 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1669 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1670
1671</div>
1672
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1673<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1674<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680 sequentially in memory. The array type requires a size (number of elements)
1681 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1682
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1684<pre>
1685 [&lt;# elements&gt; x &lt;elementtype&gt;]
1686</pre>
1687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1688<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1689 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1690
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1691<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1692<table class="layout">
1693 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1694 <td class="left"><tt>[40 x i32]</tt></td>
1695 <td class="left">Array of 40 32-bit integer values.</td>
1696 </tr>
1697 <tr class="layout">
1698 <td class="left"><tt>[41 x i32]</tt></td>
1699 <td class="left">Array of 41 32-bit integer values.</td>
1700 </tr>
1701 <tr class="layout">
1702 <td class="left"><tt>[4 x i8]</tt></td>
1703 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1704 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1705</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1706<p>Here are some examples of multidimensional arrays:</p>
1707<table class="layout">
1708 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1709 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1710 <td class="left">3x4 array of 32-bit integer values.</td>
1711 </tr>
1712 <tr class="layout">
1713 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1714 <td class="left">12x10 array of single precision floating point values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1718 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1719 </tr>
1720</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1721
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1722<p>There is no restriction on indexing beyond the end of the array implied by
1723 a static type (though there are restrictions on indexing beyond the bounds
1724 of an allocated object in some cases). This means that single-dimension
1725 'variable sized array' addressing can be implemented in LLVM with a zero
1726 length array type. An implementation of 'pascal style arrays' in LLVM could
1727 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1728
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1731<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1732<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1734<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1735
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1737<p>The function type can be thought of as a function signature. It consists of
1738 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1739 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1740
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1742<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1743 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1744</pre>
1745
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1746<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1747 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1748 which indicates that the function takes a variable number of arguments.
1749 Variable argument functions can access their arguments with
1750 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1751 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1752 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1755<table class="layout">
1756 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1757 <td class="left"><tt>i32 (i32)</tt></td>
1758 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1759 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1760 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1761 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1762 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1763 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1764 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1765 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1766 </td>
1767 </tr><tr class="layout">
1768 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1769 <td class="left">A vararg function that takes at least one
1770 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1771 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1772 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1774 </tr><tr class="layout">
1775 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1776 <td class="left">A function taking an <tt>i32</tt>, returning a
1777 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1778 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1781
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1782</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1790<p>The structure type is used to represent a collection of data members together
1791 in memory. The packing of the field types is defined to match the ABI of the
1792 underlying processor. The elements of a structure may be any type that has a
1793 size.</p>
1794
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1795<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1796 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1797 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Structures in registers are accessed using the
1799 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1800 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1802<pre>
1803 { &lt;type list&gt; }
1804</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1807<table class="layout">
1808 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1809 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1810 <td class="left">A triple of three <tt>i32</tt> values</td>
1811 </tr><tr class="layout">
1812 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1817 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1820</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1824</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1825
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1826<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1828<h5>Overview:</h5>
1829<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1830 together in memory. There is no padding between fields. Further, the
1831 alignment of a packed structure is 1 byte. The elements of a packed
1832 structure may be any type that has a size.</p>
1833
1834<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1835 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1836 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1837
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt; { &lt;type list&gt; } &gt;
1841</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1843<h5>Examples:</h5>
1844<table class="layout">
1845 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1846 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1847 <td class="left">A triple of three <tt>i32</tt> values</td>
1848 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1849 <td class="left">
1850<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1851 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1852 second element is a <a href="#t_pointer">pointer</a> to a
1853 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1854 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855 </tr>
1856</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1858</div>
1859
1860<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1863<div class="doc_text">
1864
1865<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1866<p>The pointer type is used to specify memory locations.
1867 Pointers are commonly used to reference objects in memory.</p>
1868
1869<p>Pointer types may have an optional address space attribute defining the
1870 numbered address space where the pointed-to object resides. The default
1871 address space is number zero. The semantics of non-zero address
1872 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1873
1874<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1875 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1876
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1877<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1878<pre>
1879 &lt;type&gt; *
1880</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1882<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1883<table class="layout">
1884 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1885 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1886 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1887 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1888 </tr>
1889 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1890 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1891 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1892 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1893 <tt>i32</tt>.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1897 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1898 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1899 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1900</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1902</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1903
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1907<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1908
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910<p>A vector type is a simple derived type that represents a vector of elements.
1911 Vector types are used when multiple primitive data are operated in parallel
1912 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1913 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1915
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1917<pre>
1918 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1919</pre>
1920
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1921<p>The number of elements is a constant integer value larger than 0; elementtype
1922 may be any integer or floating point type. Vectors of size zero are not
1923 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1924
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1925<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1926<table class="layout">
1927 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1928 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1929 <td class="left">Vector of 4 32-bit integer values.</td>
1930 </tr>
1931 <tr class="layout">
1932 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1933 <td class="left">Vector of 8 32-bit floating-point values.</td>
1934 </tr>
1935 <tr class="layout">
1936 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1937 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938 </tr>
1939</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1940
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1941</div>
1942
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1943<!-- _______________________________________________________________________ -->
1944<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1945<div class="doc_text">
1946
1947<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1948<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1949 corresponds (for example) to the C notion of a forward declared structure
1950 type. In LLVM, opaque types can eventually be resolved to any type (not just
1951 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1952
1953<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1954<pre>
1955 opaque
1956</pre>
1957
1958<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1959<table class="layout">
1960 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>opaque</tt></td>
1962 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1963 </tr>
1964</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1965
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966</div>
1967
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1968<!-- ======================================================================= -->
1969<div class="doc_subsection">
1970 <a name="t_uprefs">Type Up-references</a>
1971</div>
1972
1973<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1974
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976<p>An "up reference" allows you to refer to a lexically enclosing type without
1977 requiring it to have a name. For instance, a structure declaration may
1978 contain a pointer to any of the types it is lexically a member of. Example
1979 of up references (with their equivalent as named type declarations)
1980 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1981
1982<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1983 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1984 { \2 }* %y = type { %y }*
1985 \1* %z = type %z*
1986</pre>
1987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An up reference is needed by the asmprinter for printing out cyclic types
1989 when there is no declared name for a type in the cycle. Because the
1990 asmprinter does not want to print out an infinite type string, it needs a
1991 syntax to handle recursive types that have no names (all names are optional
1992 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<h5>Syntax:</h5>
1995<pre>
1996 \&lt;level&gt;
1997</pre>
1998
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1999<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2000
2001<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
2004 <td class="left"><tt>\1*</tt></td>
2005 <td class="left">Self-referential pointer.</td>
2006 </tr>
2007 <tr class="layout">
2008 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2009 <td class="left">Recursive structure where the upref refers to the out-most
2010 structure.</td>
2011 </tr>
2012</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2014</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2015
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<!-- *********************************************************************** -->
2017<div class="doc_section"> <a name="constants">Constants</a> </div>
2018<!-- *********************************************************************** -->
2019
2020<div class="doc_text">
2021
2022<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2023 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2024
2025</div>
2026
2027<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2028<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2029
2030<div class="doc_text">
2031
2032<dl>
2033 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2034 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2035 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038 <dd>Standard integers (such as '4') are constants of
2039 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2040 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2043 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2045 notation (see below). The assembler requires the exact decimal value of a
2046 floating-point constant. For example, the assembler accepts 1.25 but
2047 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2048 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2049
2050 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2051 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2052 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053</dl>
2054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2055<p>The one non-intuitive notation for constants is the hexadecimal form of
2056 floating point constants. For example, the form '<tt>double
2057 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2058 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2059 constants are required (and the only time that they are generated by the
2060 disassembler) is when a floating point constant must be emitted but it cannot
2061 be represented as a decimal floating point number in a reasonable number of
2062 digits. For example, NaN's, infinities, and other special values are
2063 represented in their IEEE hexadecimal format so that assembly and disassembly
2064 do not cause any bits to change in the constants.</p>
2065
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2066<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2067 represented using the 16-digit form shown above (which matches the IEEE754
2068 representation for double); float values must, however, be exactly
2069 representable as IEE754 single precision. Hexadecimal format is always used
2070 for long double, and there are three forms of long double. The 80-bit format
2071 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2072 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2073 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2074 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2075 currently supported target uses this format. Long doubles will only work if
2076 they match the long double format on your target. All hexadecimal formats
2077 are big-endian (sign bit at the left).</p>
2078
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2079<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2080</div>
2081
2082<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2083<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2084<a name="aggregateconstants"></a> <!-- old anchor -->
2085<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2086</div>
2087
2088<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2090<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2091 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2092
2093<dl>
2094 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2095 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2096 type definitions (a comma separated list of elements, surrounded by braces
2097 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2098 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2099 Structure constants must have <a href="#t_struct">structure type</a>, and
2100 the number and types of elements must match those specified by the
2101 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2102
2103 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2104 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2105 definitions (a comma separated list of elements, surrounded by square
2106 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2107 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2108 the number and types of elements must match those specified by the
2109 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2110
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2111 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2112 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2113 definitions (a comma separated list of elements, surrounded by
2114 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2115 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2116 have <a href="#t_vector">vector type</a>, and the number and types of
2117 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2118
2119 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2121 value to zero of <em>any</em> type, including scalar and
2122 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2123 This is often used to avoid having to print large zero initializers
2124 (e.g. for large arrays) and is always exactly equivalent to using explicit
2125 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2126
2127 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2128 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2129 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2130 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2131 be interpreted as part of the instruction stream, metadata is a place to
2132 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2133</dl>
2134
2135</div>
2136
2137<!-- ======================================================================= -->
2138<div class="doc_subsection">
2139 <a name="globalconstants">Global Variable and Function Addresses</a>
2140</div>
2141
2142<div class="doc_text">
2143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2144<p>The addresses of <a href="#globalvars">global variables</a>
2145 and <a href="#functionstructure">functions</a> are always implicitly valid
2146 (link-time) constants. These constants are explicitly referenced when
2147 the <a href="#identifiers">identifier for the global</a> is used and always
2148 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2149 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2150
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2151<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2152@X = global i32 17
2153@Y = global i32 42
2154@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2155</pre>
2156
2157</div>
2158
2159<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2160<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2161<div class="doc_text">
2162
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2163<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2164 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2165 Undefined values may be of any type (other than label or void) and be used
2166 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2167
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2168<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2169 program is well defined no matter what value is used. This gives the
2170 compiler more freedom to optimize. Here are some examples of (potentially
2171 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2172
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2173
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2174<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2175 %A = add %X, undef
2176 %B = sub %X, undef
2177 %C = xor %X, undef
2178Safe:
2179 %A = undef
2180 %B = undef
2181 %C = undef
2182</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2183
2184<p>This is safe because all of the output bits are affected by the undef bits.
2185Any output bit can have a zero or one depending on the input bits.</p>
2186
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2187<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2188 %A = or %X, undef
2189 %B = and %X, undef
2190Safe:
2191 %A = -1
2192 %B = 0
2193Unsafe:
2194 %A = undef
2195 %B = undef
2196</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2197
2198<p>These logical operations have bits that are not always affected by the input.
2199For example, if "%X" has a zero bit, then the output of the 'and' operation will
2200always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2201such, 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]2202However, it is safe to assume that all bits of the undef could be 0, and
2203optimize the and to 0. Likewise, it is safe to assume that all the bits of
2204the 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]2205-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2206
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2207<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2208 %A = select undef, %X, %Y
2209 %B = select undef, 42, %Y
2210 %C = select %X, %Y, undef
2211Safe:
2212 %A = %X (or %Y)
2213 %B = 42 (or %Y)
2214 %C = %Y
2215Unsafe:
2216 %A = undef
2217 %B = undef
2218 %C = undef
2219</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2220
2221<p>This set of examples show that undefined select (and conditional branch)
2222conditions can go "either way" but they have to come from one of the two
2223operands. In the %A example, if %X and %Y were both known to have a clear low
2224bit, then %A would have to have a cleared low bit. However, in the %C example,
2225the optimizer is allowed to assume that the undef operand could be the same as
2226%Y, allowing the whole select to be eliminated.</p>
2227
2228
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2229<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2230 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2231
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2232 %B = undef
2233 %C = xor %B, %B
2234
2235 %D = undef
2236 %E = icmp lt %D, 4
2237 %F = icmp gte %D, 4
2238
2239Safe:
2240 %A = undef
2241 %B = undef
2242 %C = undef
2243 %D = undef
2244 %E = undef
2245 %F = undef
2246</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2247
2248<p>This example points out that two undef operands are not necessarily the same.
2249This can be surprising to people (and also matches C semantics) where they
2250assume that "X^X" is always zero, even if X is undef. This isn't true for a
2251number of reasons, but the short answer is that an undef "variable" can
2252arbitrarily change its value over its "live range". This is true because the
2253"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2254logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2255so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2256to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2257would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2258
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2259<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2260 %A = fdiv undef, %X
2261 %B = fdiv %X, undef
2262Safe:
2263 %A = undef
2264b: unreachable
2265</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2266
2267<p>These examples show the crucial difference between an <em>undefined
2268value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2269allowed to have an arbitrary bit-pattern. This means that the %A operation
2270can be constant folded to undef because the undef could be an SNaN, and fdiv is
2271not (currently) defined on SNaN's. However, in the second example, we can make
2272a more aggressive assumption: because the undef is allowed to be an arbitrary
2273value, 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]2274has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2275does not execute at all. This allows us to delete the divide and all code after
2276it: since the undefined operation "can't happen", the optimizer can assume that
2277it occurs in dead code.
2278</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2279
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2280<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2281a: store undef -> %X
2282b: store %X -> undef
2283Safe:
2284a: &lt;deleted&gt;
2285b: unreachable
2286</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2287
2288<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2289can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2290overwritten with bits that happen to match what was already there. However, a
2291store "to" an undefined location could clobber arbitrary memory, therefore, it
2292has undefined behavior.</p>
2293
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294</div>
2295
2296<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2297<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2298<div class="doc_text">
2299
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2300<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2301 instead of representing an unspecified bit pattern, they represent the
2302 fact that an instruction or constant expression which cannot evoke side
2303 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2304 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2305
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2306<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]2307 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2308 <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]2309
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2310<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2311
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2312<ul>
2313<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2314 their operands.</li>
2315
2316<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2317 to their dynamic predecessor basic block.</li>
2318
2319<li>Function arguments depend on the corresponding actual argument values in
2320 the dynamic callers of their functions.</li>
2321
2322<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2323 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2324 control back to them.</li>
2325
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2326<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2327 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2328 or exception-throwing call instructions that dynamically transfer control
2329 back to them.</li>
2330
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2331<li>Non-volatile loads and stores depend on the most recent stores to all of the
2332 referenced memory addresses, following the order in the IR
2333 (including loads and stores implied by intrinsics such as
2334 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2335
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2336<!-- TODO: In the case of multiple threads, this only applies if the store
2337 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2338
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2339<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2340
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2341<li>An instruction with externally visible side effects depends on the most
2342 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2343 the order in the IR. (This includes
2344 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2345
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2346<li>An instruction <i>control-depends</i> on a
2347 <a href="#terminators">terminator instruction</a>
2348 if the terminator instruction has multiple successors and the instruction
2349 is always executed when control transfers to one of the successors, and
2350 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2351
2352<li>Dependence is transitive.</li>
2353
2354</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2355
2356<p>Whenever a trap value is generated, all values which depend on it evaluate
2357 to trap. If they have side effects, the evoke their side effects as if each
2358 operand with a trap value were undef. If they have externally-visible side
2359 effects, the behavior is undefined.</p>
2360
2361<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2362
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2363<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2364entry:
2365 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2366 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2367 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2368 store i32 0, i32* %trap_yet_again ; undefined behavior
2369
2370 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2371 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2372
2373 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2374
2375 %narrowaddr = bitcast i32* @g to i16*
2376 %wideaddr = bitcast i32* @g to i64*
2377 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2378 %trap4 = load i64* %widaddr ; Returns a trap value.
2379
2380 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2381 %br i1 %cmp, %true, %end ; Branch to either destination.
2382
2383true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2384 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2385 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2386 br label %end
2387
2388end:
2389 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2390 ; Both edges into this PHI are
2391 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2392 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2393
2394 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2395 ; so this is defined (ignoring earlier
2396 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2397</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2398
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2399</div>
2400
2401<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2402<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2403 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2404<div class="doc_text">
2405
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2406<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2407
2408<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2409 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2410 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2411
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2412<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2413 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2414 against null. Pointer equality tests between labels addresses is undefined
2415 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2416 equal to the null pointer. This may also be passed around as an opaque
2417 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2418 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2419 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2420
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2421<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2422 using the value as the operand to an inline assembly, but that is target
2423 specific.
2424 </p>
2425
2426</div>
2427
2428
2429<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2430<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2431</div>
2432
2433<div class="doc_text">
2434
2435<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2436 to be used as constants. Constant expressions may be of
2437 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2438 operation that does not have side effects (e.g. load and call are not
2439 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2440
2441<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2442 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2443 <dd>Truncate a constant to another type. The bit size of CST must be larger
2444 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2445
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2446 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2447 <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]2448 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2449
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2450 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2451 <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]2452 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2453
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2454 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2455 <dd>Truncate a floating point constant to another floating point type. The
2456 size of CST must be larger than the size of TYPE. Both types must be
2457 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2458
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2459 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2460 <dd>Floating point extend a constant to another type. The size of CST must be
2461 smaller or equal to the size of TYPE. Both types must be floating
2462 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2463
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2464 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2465 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2466 constant. TYPE must be a scalar or vector integer type. CST must be of
2467 scalar or vector floating point type. Both CST and TYPE must be scalars,
2468 or vectors of the same number of elements. If the value won't fit in the
2469 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2470
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2471 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2472 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2473 constant. TYPE must be a scalar or vector integer type. CST must be of
2474 scalar or vector floating point type. Both CST and TYPE must be scalars,
2475 or vectors of the same number of elements. If the value won't fit in the
2476 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2477
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2478 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2479 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2480 constant. TYPE must be a scalar or vector floating point type. CST must be
2481 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2482 vectors of the same number of elements. If the value won't fit in the
2483 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2484
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2486 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2487 constant. TYPE must be a scalar or vector floating point type. CST must be
2488 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2489 vectors of the same number of elements. If the value won't fit in the
2490 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2491
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2493 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2494 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2495 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2496 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2497
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2498 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2500 type. CST must be of integer type. The CST value is zero extended,
2501 truncated, or unchanged to make it fit in a pointer size. This one is
2502 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2503
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2505 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2506 are the same as those for the <a href="#i_bitcast">bitcast
2507 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2508
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2509 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2510 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2511 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2512 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2513 instruction, the index list may have zero or more indexes, which are
2514 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2515
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2517 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2518
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2520 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2521
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2523 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2524
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2526 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2527 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2528
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2529 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2530 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2531 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2532
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2533 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2534 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2535 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2536
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2537 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2538 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2539 constants. The index list is interpreted in a similar manner as indices in
2540 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2541 index value must be specified.</dd>
2542
2543 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2544 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2545 constants. The index list is interpreted in a similar manner as indices in
2546 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2547 index value must be specified.</dd>
2548
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2551 be any of the <a href="#binaryops">binary</a>
2552 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2553 on operands are the same as those for the corresponding instruction
2554 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2555</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2557</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2559<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2560<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2561<!-- *********************************************************************** -->
2562
2563<!-- ======================================================================= -->
2564<div class="doc_subsection">
2565<a name="inlineasm">Inline Assembler Expressions</a>
2566</div>
2567
2568<div class="doc_text">
2569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570<p>LLVM supports inline assembler expressions (as opposed
2571 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2572 a special value. This value represents the inline assembler as a string
2573 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2574 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2575 expression has side effects, and a flag indicating whether the function
2576 containing the asm needs to align its stack conservatively. An example
2577 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2578
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2579<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2580i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2581</pre>
2582
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2583<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2584 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2585 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2586
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2587<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2588%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]2589</pre>
2590
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2591<p>Inline asms with side effects not visible in the constraint list must be
2592 marked as having side effects. This is done through the use of the
2593 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2594
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2595<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2596call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2597</pre>
2598
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2599<p>In some cases inline asms will contain code that will not work unless the
2600 stack is aligned in some way, such as calls or SSE instructions on x86,
2601 yet will not contain code that does that alignment within the asm.
2602 The compiler should make conservative assumptions about what the asm might
2603 contain and should generate its usual stack alignment code in the prologue
2604 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2605
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2606<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2607call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2608</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2609
2610<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2611 first.</p>
2612
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2613<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2614 documented here. Constraints on what can be done (e.g. duplication, moving,
2615 etc need to be documented). This is probably best done by reference to
2616 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2617</div>
2618
2619<div class="doc_subsubsection">
2620<a name="inlineasm_md">Inline Asm Metadata</a>
2621</div>
2622
2623<div class="doc_text">
2624
2625<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2626 attached to it that contains a constant integer. If present, the code
2627 generator will use the integer as the location cookie value when report
2628 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2629 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2630 source code that produced it. For example:</p>
2631
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2632<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2633call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2634...
2635!42 = !{ i32 1234567 }
2636</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2637
2638<p>It is up to the front-end to make sense of the magic numbers it places in the
2639 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2640
2641</div>
2642
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2643<!-- ======================================================================= -->
2644<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2645 Strings</a>
2646</div>
2647
2648<div class="doc_text">
2649
2650<p>LLVM IR allows metadata to be attached to instructions in the program that
2651 can convey extra information about the code to the optimizers and code
2652 generator. One example application of metadata is source-level debug
2653 information. There are two metadata primitives: strings and nodes. All
2654 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2655 preceding exclamation point ('<tt>!</tt>').</p>
2656
2657<p>A metadata string is a string surrounded by double quotes. It can contain
2658 any character by escaping non-printable characters with "\xx" where "xx" is
2659 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2660
2661<p>Metadata nodes are represented with notation similar to structure constants
2662 (a comma separated list of elements, surrounded by braces and preceded by an
2663 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2664 10}</tt>". Metadata nodes can have any values as their operand.</p>
2665
2666<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2667 metadata nodes, which can be looked up in the module symbol table. For
2668 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2669
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2670<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2671 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2672
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2673 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2674 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2675 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2676
2677<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2678 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2679
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2680 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2681 %indvar.next = add i64 %indvar, 1, !dbg !21
2682 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2683</div>
2684
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2685
2686<!-- *********************************************************************** -->
2687<div class="doc_section">
2688 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2689</div>
2690<!-- *********************************************************************** -->
2691
2692<p>LLVM has a number of "magic" global variables that contain data that affect
2693code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2694of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2695section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2696by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2697
2698<!-- ======================================================================= -->
2699<div class="doc_subsection">
2700<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2706href="#linkage_appending">appending linkage</a>. This array contains a list of
2707pointers to global variables and functions which may optionally have a pointer
2708cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2709
2710<pre>
2711 @X = global i8 4
2712 @Y = global i32 123
2713
2714 @llvm.used = appending global [2 x i8*] [
2715 i8* @X,
2716 i8* bitcast (i32* @Y to i8*)
2717 ], section "llvm.metadata"
2718</pre>
2719
2720<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2721compiler, assembler, and linker are required to treat the symbol as if there is
2722a reference to the global that it cannot see. For example, if a variable has
2723internal linkage and no references other than that from the <tt>@llvm.used</tt>
2724list, it cannot be deleted. This is commonly used to represent references from
2725inline asms and other things the compiler cannot "see", and corresponds to
2726"attribute((used))" in GNU C.</p>
2727
2728<p>On some targets, the code generator must emit a directive to the assembler or
2729object file to prevent the assembler and linker from molesting the symbol.</p>
2730
2731</div>
2732
2733<!-- ======================================================================= -->
2734<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2735<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2736</div>
2737
2738<div class="doc_text">
2739
2740<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2741<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2742touching the symbol. On targets that support it, this allows an intelligent
2743linker to optimize references to the symbol without being impeded as it would be
2744by <tt>@llvm.used</tt>.</p>
2745
2746<p>This is a rare construct that should only be used in rare circumstances, and
2747should not be exposed to source languages.</p>
2748
2749</div>
2750
2751<!-- ======================================================================= -->
2752<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2753<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2754</div>
2755
2756<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2757<pre>
2758%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2759@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2760</pre>
2761<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.
2762</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2763
2764</div>
2765
2766<!-- ======================================================================= -->
2767<div class="doc_subsection">
2768<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2769</div>
2770
2771<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2772<pre>
2773%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2774@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2775</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2776
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2777<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.
2778</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2779
2780</div>
2781
2782
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2783<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2784<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2785<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2787<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2788
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2789<p>The LLVM instruction set consists of several different classifications of
2790 instructions: <a href="#terminators">terminator
2791 instructions</a>, <a href="#binaryops">binary instructions</a>,
2792 <a href="#bitwiseops">bitwise binary instructions</a>,
2793 <a href="#memoryops">memory instructions</a>, and
2794 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2796</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2798<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2799<div class="doc_subsection"> <a name="terminators">Terminator
2800Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2803
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2804<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2805 in a program ends with a "Terminator" instruction, which indicates which
2806 block should be executed after the current block is finished. These
2807 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2808 control flow, not values (the one exception being the
2809 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2810
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2811<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2812 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2813 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2814 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2815 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2817 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2818 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2820</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2822<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2823<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2824Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2825
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2826<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2828<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2829<pre>
2830 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]2831 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2832</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2835<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2836 a value) from a function back to the caller.</p>
2837
2838<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2839 value and then causes control flow, and one that just causes control flow to
2840 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2843<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2844 return value. The type of the return value must be a
2845 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2846
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2847<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2848 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2849 value or a return value with a type that does not match its type, or if it
2850 has a void return type and contains a '<tt>ret</tt>' instruction with a
2851 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2853<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2855 the calling function's context. If the caller is a
2856 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2857 instruction after the call. If the caller was an
2858 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2859 the beginning of the "normal" destination block. If the instruction returns
2860 a value, that value shall set the call or invoke instruction's return
2861 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2863<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2864<pre>
2865 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2866 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2867 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]2868</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2869
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2870</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2872<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2873
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2874<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877<pre>
2878 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]2879</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2881<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2883 different basic block in the current function. There are two forms of this
2884 instruction, corresponding to a conditional branch and an unconditional
2885 branch.</p>
2886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2887<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2888<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2889 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2890 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2891 target.</p>
2892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2894<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2896 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2897 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2900<pre>
2901Test:
2902 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2903 br i1 %cond, label %IfEqual, label %IfUnequal
2904IfEqual:
2905 <a href="#i_ret">ret</a> i32 1
2906IfUnequal:
2907 <a href="#i_ret">ret</a> i32 0
2908</pre>
2909
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2910</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2913<div class="doc_subsubsection">
2914 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2915</div>
2916
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2917<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2920<pre>
2921 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2922</pre>
2923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2924<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2925<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]2926 several different places. It is a generalization of the '<tt>br</tt>'
2927 instruction, allowing a branch to occur to one of many possible
2928 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2929
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2930<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2931<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2932 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2933 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2934 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2936<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2937<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2939 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2940 transferred to the corresponding destination; otherwise, control flow is
2941 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2942
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2943<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2944<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2945 <tt>switch</tt> instruction, this instruction may be code generated in
2946 different ways. For example, it could be generated as a series of chained
2947 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2948
2949<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2950<pre>
2951 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2952 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2953 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2954
2955 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2956 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2957
2958 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2959 switch i32 %val, label %otherwise [ i32 0, label %onzero
2960 i32 1, label %onone
2961 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2962</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2963
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2964</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2965
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2966
2967<!-- _______________________________________________________________________ -->
2968<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2969 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2970</div>
2971
2972<div class="doc_text">
2973
2974<h5>Syntax:</h5>
2975<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2976 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]2977</pre>
2978
2979<h5>Overview:</h5>
2980
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2981<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2982 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2983 "<tt>address</tt>". Address must be derived from a <a
2984 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2985
2986<h5>Arguments:</h5>
2987
2988<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2989 rest of the arguments indicate the full set of possible destinations that the
2990 address may point to. Blocks are allowed to occur multiple times in the
2991 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2992
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2993<p>This destination list is required so that dataflow analysis has an accurate
2994 understanding of the CFG.</p>
2995
2996<h5>Semantics:</h5>
2997
2998<p>Control transfers to the block specified in the address argument. All
2999 possible destination blocks must be listed in the label list, otherwise this
3000 instruction has undefined behavior. This implies that jumps to labels
3001 defined in other functions have undefined behavior as well.</p>
3002
3003<h5>Implementation:</h5>
3004
3005<p>This is typically implemented with a jump through a register.</p>
3006
3007<h5>Example:</h5>
3008<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3009 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3010</pre>
3011
3012</div>
3013
3014
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3015<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3016<div class="doc_subsubsection">
3017 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3018</div>
3019
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3020<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3021
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3022<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3023<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3024 &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]3025 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3026</pre>
3027
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3028<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3029<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3030 function, with the possibility of control flow transfer to either the
3031 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3032 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3033 control flow will return to the "normal" label. If the callee (or any
3034 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3035 instruction, control is interrupted and continued at the dynamically nearest
3036 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3038<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3039<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3040
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3041<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3043 convention</a> the call should use. If none is specified, the call
3044 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3045
3046 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3048 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3049
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3050 <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]3051 function value being invoked. In most cases, this is a direct function
3052 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3053 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3054
3055 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3056 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3057
3058 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3059 signature argument types and parameter attributes. All arguments must be
3060 of <a href="#t_firstclass">first class</a> type. If the function
3061 signature indicates the function accepts a variable number of arguments,
3062 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3063
3064 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3066
3067 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3069
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3070 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3071 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3072 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3073</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3074
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3076<p>This instruction is designed to operate as a standard
3077 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3078 primary difference is that it establishes an association with a label, which
3079 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3080
3081<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3083 exception. Additionally, this is important for implementation of
3084 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3085
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3086<p>For the purposes of the SSA form, the definition of the value returned by the
3087 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3088 block to the "normal" label. If the callee unwinds then no return value is
3089 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3090
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3091<p>Note that the code generator does not yet completely support unwind, and
3092that the invoke/unwind semantics are likely to change in future versions.</p>
3093
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3094<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3095<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3096 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3097 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3098 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3099 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3100</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3101
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3102</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3103
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3104<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3105
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3106<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3107Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3108
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3109<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3110
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3111<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3112<pre>
3113 unwind
3114</pre>
3115
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3116<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3117<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118 at the first callee in the dynamic call stack which used
3119 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3120 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3121
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3122<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3123<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124 immediately halt. The dynamic call stack is then searched for the
3125 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3126 Once found, execution continues at the "exceptional" destination block
3127 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3128 instruction in the dynamic call chain, undefined behavior results.</p>
3129
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3130<p>Note that the code generator does not yet completely support unwind, and
3131that the invoke/unwind semantics are likely to change in future versions.</p>
3132
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3133</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3134
3135<!-- _______________________________________________________________________ -->
3136
3137<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3138Instruction</a> </div>
3139
3140<div class="doc_text">
3141
3142<h5>Syntax:</h5>
3143<pre>
3144 unreachable
3145</pre>
3146
3147<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3148<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149 instruction is used to inform the optimizer that a particular portion of the
3150 code is not reachable. This can be used to indicate that the code after a
3151 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3152
3153<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3154<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3155
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3156</div>
3157
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3158<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3159<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3160
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3161<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3162
3163<p>Binary operators are used to do most of the computation in a program. They
3164 require two operands of the same type, execute an operation on them, and
3165 produce a single value. The operands might represent multiple data, as is
3166 the case with the <a href="#t_vector">vector</a> data type. The result value
3167 has the same type as its operands.</p>
3168
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3169<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3171</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3173<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3174<div class="doc_subsubsection">
3175 <a name="i_add">'<tt>add</tt>' Instruction</a>
3176</div>
3177
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3178<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3179
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3180<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3181<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3182 &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]3183 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3184 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3185 &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]3186</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3187
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3188<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3189<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3190
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3191<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192<p>The two arguments to the '<tt>add</tt>' instruction must
3193 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3194 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3197<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3198
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199<p>If the sum has unsigned overflow, the result returned is the mathematical
3200 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]3201
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3202<p>Because LLVM integers use a two's complement representation, this instruction
3203 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3204
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3205<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3206 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3207 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3208 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3209 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3212<pre>
3213 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3214</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3216</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3217
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3218<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3219<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3220 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3221</div>
3222
3223<div class="doc_text">
3224
3225<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3226<pre>
3227 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3228</pre>
3229
3230<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3231<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3232
3233<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3234<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3236 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3237
3238<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3239<p>The value produced is the floating point sum of the two operands.</p>
3240
3241<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3242<pre>
3243 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3246</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3248<!-- _______________________________________________________________________ -->
3249<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3250 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3251</div>
3252
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3253<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3255<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3256<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3257 &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]3258 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3259 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3260 &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]3261</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3263<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3264<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3266
3267<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3268 '<tt>neg</tt>' instruction present in most other intermediate
3269 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3270
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3271<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272<p>The two arguments to the '<tt>sub</tt>' instruction must
3273 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3274 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3276<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3277<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3278
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3279<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3281 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3283<p>Because LLVM integers use a two's complement representation, this instruction
3284 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3285
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3286<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3287 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3288 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3289 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3290 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3291
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3292<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3293<pre>
3294 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3295 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3298</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3299
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3300<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3301<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3302 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3303</div>
3304
3305<div class="doc_text">
3306
3307<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3308<pre>
3309 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3310</pre>
3311
3312<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3313<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3315
3316<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317 '<tt>fneg</tt>' instruction present in most other intermediate
3318 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3319
3320<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3321<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3323 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3324
3325<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3326<p>The value produced is the floating point difference of the two operands.</p>
3327
3328<h5>Example:</h5>
3329<pre>
3330 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3331 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3332</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3333
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3334</div>
3335
3336<!-- _______________________________________________________________________ -->
3337<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3338 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3339</div>
3340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3341<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3342
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3343<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3345 &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]3346 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3347 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3348 &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]3349</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3354<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355<p>The two arguments to the '<tt>mul</tt>' instruction must
3356 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3357 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3360<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3362<p>If the result of the multiplication has unsigned overflow, the result
3363 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3364 width of the result.</p>
3365
3366<p>Because LLVM integers use a two's complement representation, and the result
3367 is the same width as the operands, this instruction returns the correct
3368 result for both signed and unsigned integers. If a full product
3369 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3370 be sign-extended or zero-extended as appropriate to the width of the full
3371 product.</p>
3372
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3373<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3374 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3375 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3376 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3377 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3378
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380<pre>
3381 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3384</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3385
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3387<div class="doc_subsubsection">
3388 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3389</div>
3390
3391<div class="doc_text">
3392
3393<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394<pre>
3395 &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]3396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3398<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3399<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3400
3401<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3402<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3404 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3405
3406<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3407<p>The value produced is the floating point product of the two operands.</p>
3408
3409<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410<pre>
3411 &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]3412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3413
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3414</div>
3415
3416<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3417<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3418</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3419
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3420<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3422<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &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]3425</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3427<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3429
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3430<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3431<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3433 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3434
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3435<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3436<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3437
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3438<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3440
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3441<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3442
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3443<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444<pre>
3445 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3446</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3448</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3449
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3450<!-- _______________________________________________________________________ -->
3451<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3452</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3453
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3454<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3456<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3457<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3458 &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]3459 &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]3460</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3461
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3462<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3463<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3464
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3465<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3466<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3468 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3469
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3470<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3471<p>The value produced is the signed integer quotient of the two operands rounded
3472 towards zero.</p>
3473
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3474<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3476
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3477<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478 undefined behavior; this is a rare case, but can occur, for example, by doing
3479 a 32-bit division of -2147483648 by -1.</p>
3480
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3481<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3482 <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]3483 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3484
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
3487 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3488</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3492<!-- _______________________________________________________________________ -->
3493<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3494Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3496<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3498<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3500 &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]3501</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503<h5>Overview:</h5>
3504<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3505
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3506<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3507<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3509 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3511<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3512<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3513
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3514<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3515<pre>
3516 &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]3517</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3519</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3521<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3522<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3523</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3525<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3527<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528<pre>
3529 &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]3530</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3534 division of its two arguments.</p>
3535
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3536<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3537<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3539 values. Both arguments must have identical types.</p>
3540
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3541<h5>Semantics:</h5>
3542<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3543 This instruction always performs an unsigned division to get the
3544 remainder.</p>
3545
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3546<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3548
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3549<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3551<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3552<pre>
3553 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3554</pre>
3555
3556</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3558<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3559<div class="doc_subsubsection">
3560 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3561</div>
3562
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3563<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3564
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3565<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3567 &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]3568</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3570<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3572 division of its two operands. This instruction can also take
3573 <a href="#t_vector">vector</a> versions of the values in which case the
3574 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3575
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3576<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3577<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3578 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3579 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3580
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3581<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3582<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3583 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3584 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3585 a value. For more information about the difference,
3586 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3587 Math Forum</a>. For a table of how this is implemented in various languages,
3588 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3589 Wikipedia: modulo operation</a>.</p>
3590
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3591<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3593
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3594<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3595 Overflow also leads to undefined behavior; this is a rare case, but can
3596 occur, for example, by taking the remainder of a 32-bit division of
3597 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3598 lets srem be implemented using instructions that return both the result of
3599 the division and the remainder.)</p>
3600
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3601<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602<pre>
3603 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3604</pre>
3605
3606</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3608<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3609<div class="doc_subsubsection">
3610 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3611
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3612<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3613
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3614<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615<pre>
3616 &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]3617</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3619<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3621 its two operands.</p>
3622
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3623<h5>Arguments:</h5>
3624<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3626 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3627
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3628<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629<p>This instruction returns the <i>remainder</i> of a division. The remainder
3630 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3631
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3632<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3633<pre>
3634 &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]3635</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3637</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3638
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3639<!-- ======================================================================= -->
3640<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3641Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3643<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3644
3645<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3646 program. They are generally very efficient instructions and can commonly be
3647 strength reduced from other instructions. They require two operands of the
3648 same type, execute an operation on them, and produce a single value. The
3649 resulting value is the same type as its operands.</p>
3650
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3651</div>
3652
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3653<!-- _______________________________________________________________________ -->
3654<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3655Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3657<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3658
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3659<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660<pre>
3661 &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]3662</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3663
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3666 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3667
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3668<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3669<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3670 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3671 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3672
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3673<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3674<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3675 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3676 is (statically or dynamically) negative or equal to or larger than the number
3677 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3678 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3679 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3680
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681<h5>Example:</h5>
3682<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3683 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3684 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3685 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3686 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3687 &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]3688</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3690</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3692<!-- _______________________________________________________________________ -->
3693<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3694Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3695
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3696<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3698<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699<pre>
3700 &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]3701</pre>
3702
3703<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3704<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3705 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3706
3707<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3708<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3710 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3711
3712<h5>Semantics:</h5>
3713<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714 significant bits of the result will be filled with zero bits after the shift.
3715 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3716 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3717 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3718 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3719
3720<h5>Example:</h5>
3721<pre>
3722 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3723 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3724 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3725 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3726 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3727 &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]3728</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3729
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3730</div>
3731
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3732<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3733<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3734Instruction</a> </div>
3735<div class="doc_text">
3736
3737<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738<pre>
3739 &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]3740</pre>
3741
3742<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3743<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3744 operand shifted to the right a specified number of bits with sign
3745 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3746
3747<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3748<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3750 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3751
3752<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3753<p>This instruction always performs an arithmetic shift right operation, The
3754 most significant bits of the result will be filled with the sign bit
3755 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3756 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3757 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3758 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3759
3760<h5>Example:</h5>
3761<pre>
3762 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3763 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3764 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3765 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3766 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3767 &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]3768</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3770</div>
3771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3772<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3773<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3774Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3775
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3776<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3777
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3778<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3779<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3780 &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]3781</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3785 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3787<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3788<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3790 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3791
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3792<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3793<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3795<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3796 <tbody>
3797 <tr>
3798 <td>In0</td>
3799 <td>In1</td>
3800 <td>Out</td>
3801 </tr>
3802 <tr>
3803 <td>0</td>
3804 <td>0</td>
3805 <td>0</td>
3806 </tr>
3807 <tr>
3808 <td>0</td>
3809 <td>1</td>
3810 <td>0</td>
3811 </tr>
3812 <tr>
3813 <td>1</td>
3814 <td>0</td>
3815 <td>0</td>
3816 </tr>
3817 <tr>
3818 <td>1</td>
3819 <td>1</td>
3820 <td>1</td>
3821 </tr>
3822 </tbody>
3823</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3826<pre>
3827 &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]3828 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3829 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3830</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3831</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3832<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3833<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3834
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3835<div class="doc_text">
3836
3837<h5>Syntax:</h5>
3838<pre>
3839 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3840</pre>
3841
3842<h5>Overview:</h5>
3843<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3844 two operands.</p>
3845
3846<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
3850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3851<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3852<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3854<table border="1" cellspacing="0" cellpadding="4">
3855 <tbody>
3856 <tr>
3857 <td>In0</td>
3858 <td>In1</td>
3859 <td>Out</td>
3860 </tr>
3861 <tr>
3862 <td>0</td>
3863 <td>0</td>
3864 <td>0</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>1</td>
3869 <td>1</td>
3870 </tr>
3871 <tr>
3872 <td>1</td>
3873 <td>0</td>
3874 <td>1</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>1</td>
3879 <td>1</td>
3880 </tr>
3881 </tbody>
3882</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<pre>
3886 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3887 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3888 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3889</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3891</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3893<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3894<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3895Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3896
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3897<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3899<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &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]3902</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3906 its two operands. The <tt>xor</tt> is used to implement the "one's
3907 complement" operation, which is the "~" operator in C.</p>
3908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3910<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3912 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3915<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3917<table border="1" cellspacing="0" cellpadding="4">
3918 <tbody>
3919 <tr>
3920 <td>In0</td>
3921 <td>In1</td>
3922 <td>Out</td>
3923 </tr>
3924 <tr>
3925 <td>0</td>
3926 <td>0</td>
3927 <td>0</td>
3928 </tr>
3929 <tr>
3930 <td>0</td>
3931 <td>1</td>
3932 <td>1</td>
3933 </tr>
3934 <tr>
3935 <td>1</td>
3936 <td>0</td>
3937 <td>1</td>
3938 </tr>
3939 <tr>
3940 <td>1</td>
3941 <td>1</td>
3942 <td>0</td>
3943 </tr>
3944 </tbody>
3945</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948<pre>
3949 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3950 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3951 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3952 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3955</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3957<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3958<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3959 <a name="vectorops">Vector Operations</a>
3960</div>
3961
3962<div class="doc_text">
3963
3964<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3965 target-independent manner. These instructions cover the element-access and
3966 vector-specific operations needed to process vectors effectively. While LLVM
3967 does directly support these vector operations, many sophisticated algorithms
3968 will want to use target-specific intrinsics to take full advantage of a
3969 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3970
3971</div>
3972
3973<!-- _______________________________________________________________________ -->
3974<div class="doc_subsubsection">
3975 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3976</div>
3977
3978<div class="doc_text">
3979
3980<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3981<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3982 &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]3983</pre>
3984
3985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3986<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3987 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3988
3989
3990<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3992 of <a href="#t_vector">vector</a> type. The second operand is an index
3993 indicating the position from which to extract the element. The index may be
3994 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3995
3996<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3997<p>The result is a scalar of the same type as the element type of
3998 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3999 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4000 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4001
4002<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4003<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4004 &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]4005</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4008
4009<!-- _______________________________________________________________________ -->
4010<div class="doc_subsubsection">
4011 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4012</div>
4013
4014<div class="doc_text">
4015
4016<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4017<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4018 &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]4019</pre>
4020
4021<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4022<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4023 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4024
4025<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4026<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4027 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4028 whose type must equal the element type of the first operand. The third
4029 operand is an index indicating the position at which to insert the value.
4030 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4031
4032<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4034 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4035 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4036 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4037
4038<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4039<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4040 &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]4041</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4043</div>
4044
4045<!-- _______________________________________________________________________ -->
4046<div class="doc_subsubsection">
4047 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4048</div>
4049
4050<div class="doc_text">
4051
4052<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4053<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4054 &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]4055</pre>
4056
4057<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4058<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4059 from two input vectors, returning a vector with the same element type as the
4060 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4061
4062<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4064 with types that match each other. The third argument is a shuffle mask whose
4065 element type is always 'i32'. The result of the instruction is a vector
4066 whose length is the same as the shuffle mask and whose element type is the
4067 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4068
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069<p>The shuffle mask operand is required to be a constant vector with either
4070 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The elements of the two input vectors are numbered from left to right across
4074 both of the vectors. The shuffle mask operand specifies, for each element of
4075 the result vector, which element of the two input vectors the result element
4076 gets. The element selector may be undef (meaning "don't care") and the
4077 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4080<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4081 &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]4082 &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]4083 &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]4084 &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]4085 &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]4086 &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]4087 &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]4088 &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]4089</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4090
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4091</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4092
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4093<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4094<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4095 <a name="aggregateops">Aggregate Operations</a>
4096</div>
4097
4098<div class="doc_text">
4099
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4100<p>LLVM supports several instructions for working with
4101 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4102
4103</div>
4104
4105<!-- _______________________________________________________________________ -->
4106<div class="doc_subsubsection">
4107 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4108</div>
4109
4110<div class="doc_text">
4111
4112<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4113<pre>
4114 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4115</pre>
4116
4117<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4118<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4119 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4120
4121<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4122<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4123 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4124 <a href="#t_array">array</a> type. The operands are constant indices to
4125 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4127
4128<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4129<p>The result is the value at the position in the aggregate specified by the
4130 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4131
4132<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4133<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4134 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4137</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4138
4139<!-- _______________________________________________________________________ -->
4140<div class="doc_subsubsection">
4141 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4142</div>
4143
4144<div class="doc_text">
4145
4146<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4147<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4148 &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]4149</pre>
4150
4151<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4152<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4153 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4154
4155<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4156<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4157 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4158 <a href="#t_array">array</a> type. The second operand is a first-class
4159 value to insert. The following operands are constant indices indicating
4160 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]4161 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4162 value to insert must have the same type as the value identified by the
4163 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4166<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4167 that of <tt>val</tt> except that the value at the position specified by the
4168 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4169
4170<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4171<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4172 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4173 %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]4174</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4176</div>
4177
4178
4179<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4180<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4181 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4182</div>
4183
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4184<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4185
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186<p>A key design point of an SSA-based representation is how it represents
4187 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4188 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4190
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4191</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4193<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4194<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4195 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4196</div>
4197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4198<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4200<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4201<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4202 &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]4203</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4204
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4205<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4206<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207 currently executing function, to be automatically released when this function
4208 returns to its caller. The object is always allocated in the generic address
4209 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4210
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4211<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212<p>The '<tt>alloca</tt>' instruction
4213 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4214 runtime stack, returning a pointer of the appropriate type to the program.
4215 If "NumElements" is specified, it is the number of elements allocated,
4216 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4217 specified, the value result of the allocation is guaranteed to be aligned to
4218 at least that boundary. If not specified, or if zero, the target can choose
4219 to align the allocation on any convenient boundary compatible with the
4220 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4221
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4222<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4224<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4225<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4226 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4227 memory is automatically released when the function returns. The
4228 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4229 variables that must have an address available. When the function returns
4230 (either with the <tt><a href="#i_ret">ret</a></tt>
4231 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4232 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4235<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4236 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4237 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4238 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4239 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4240</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4241
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4242</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4244<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4245<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4246Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4248<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4249
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4250<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4251<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4252 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4253 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4254 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4255</pre>
4256
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4257<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4258<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4260<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4261<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4262 from which to load. The pointer must point to
4263 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4264 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4265 number or order of execution of this <tt>load</tt> with other <a
4266 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4268<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4269 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]4270 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 alignment for the target. It is the responsibility of the code emitter to
4272 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4273 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4274 produce less efficient code. An alignment of 1 is always safe.</p>
4275
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4276<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4277 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4278 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4279 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4280 and code generator that this load is not expected to be reused in the cache.
4281 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4282 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4283
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4284<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4285<p>The location of memory pointed to is loaded. If the value being loaded is of
4286 scalar type then the number of bytes read does not exceed the minimum number
4287 of bytes needed to hold all bits of the type. For example, loading an
4288 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4289 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4290 is undefined if the value was not originally written using a store of the
4291 same type.</p>
4292
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294<pre>
4295 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4296 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4297 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4298</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4299
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4300</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4301
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4302<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4303<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4304Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4305
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4306<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4307
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4308<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4310 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>
4311 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]4312</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4315<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4316
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4319 and an address at which to store it. The type of the
4320 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4321 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4322 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4323 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4324 order of execution of this <tt>store</tt> with other <a
4325 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4326
4327<p>The optional constant "align" argument specifies the alignment of the
4328 operation (that is, the alignment of the memory address). A value of 0 or an
4329 omitted "align" argument means that the operation has the preferential
4330 alignment for the target. It is the responsibility of the code emitter to
4331 ensure that the alignment information is correct. Overestimating the
4332 alignment results in an undefined behavior. Underestimating the alignment may
4333 produce less efficient code. An alignment of 1 is always safe.</p>
4334
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4335<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4336 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4337 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4338 instruction tells the optimizer and code generator that this load is
4339 not expected to be reused in the cache. The code generator may
4340 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4341 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4342
4343
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4344<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4345<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4346 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4347 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4348 does not exceed the minimum number of bytes needed to hold all bits of the
4349 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4350 writing a value of a type like <tt>i20</tt> with a size that is not an
4351 integral number of bytes, it is unspecified what happens to the extra bits
4352 that do not belong to the type, but they will typically be overwritten.</p>
4353
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4354<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355<pre>
4356 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4357 store i32 3, i32* %ptr <i>; yields {void}</i>
4358 %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]4359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4361</div>
4362
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4363<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4364<div class="doc_subsubsection">
4365 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4366</div>
4367
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4368<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4370<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4371<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4372 &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]4373 &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]4374</pre>
4375
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4376<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4378 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4379 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4380
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4381<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4382<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4383 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4384 elements of the aggregate object are indexed. The interpretation of each
4385 index is dependent on the type being indexed into. The first index always
4386 indexes the pointer value given as the first argument, the second index
4387 indexes a value of the type pointed to (not necessarily the value directly
4388 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4389 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4390 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4391 can never be pointers, since that would require loading the pointer before
4392 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4393
4394<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]4395 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4396 integer <b>constants</b> are allowed. When indexing into an array, pointer
4397 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]4398 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4399
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4400<p>For example, let's consider a C code fragment and how it gets compiled to
4401 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4402
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4403<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4404struct RT {
4405 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4406 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4407 char C;
4408};
4409struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4410 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4411 double Y;
4412 struct RT Z;
4413};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4414
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4415int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4416 return &amp;s[1].Z.B[5][13];
4417}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4418</pre>
4419
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4420<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4421
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4422<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4423%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4424%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4425
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4426define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4427entry:
4428 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4429 ret i32* %reg
4430}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4431</pre>
4432
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4433<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4434<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]4435 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4436 }</tt>' type, a structure. The second index indexes into the third element
4437 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4438 i8 }</tt>' type, another structure. The third index indexes into the second
4439 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4440 array. The two dimensions of the array are subscripted into, yielding an
4441 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4442 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4443
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4444<p>Note that it is perfectly legal to index partially through a structure,
4445 returning a pointer to an inner element. Because of this, the LLVM code for
4446 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4447
4448<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4449 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4450 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4451 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4452 %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]4453 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4454 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4455 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4456 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4457</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4458
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4459<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4460 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4461 base pointer is not an <i>in bounds</i> address of an allocated object,
4462 or if any of the addresses that would be formed by successive addition of
4463 the offsets implied by the indices to the base address with infinitely
4464 precise arithmetic are not an <i>in bounds</i> address of that allocated
4465 object. The <i>in bounds</i> addresses for an allocated object are all
4466 the addresses that point into the object, plus the address one byte past
4467 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4468
4469<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4470 the base address with silently-wrapping two's complement arithmetic, and
4471 the result value of the <tt>getelementptr</tt> may be outside the object
4472 pointed to by the base pointer. The result value may not necessarily be
4473 used to access memory though, even if it happens to point into allocated
4474 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4475 section for more information.</p>
4476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4477<p>The getelementptr instruction is often confusing. For some more insight into
4478 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4479
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4480<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4481<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4482 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4483 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4484 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4485 %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]4486 <i>; yields i8*:eptr</i>
4487 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4488 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4489 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4490</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4491
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4492</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4494<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4495<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4496</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4498<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4500<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4501 which all take a single operand and a type. They perform various bit
4502 conversions on the operand.</p>
4503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4504</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4505
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4506<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4507<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4508 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4509</div>
4510<div class="doc_text">
4511
4512<h5>Syntax:</h5>
4513<pre>
4514 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4515</pre>
4516
4517<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4518<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4519 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4520
4521<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4522<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4523 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4524 size and type of the result, which must be
4525 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4526 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4527 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4528
4529<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4530<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4531 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4532 source size must be larger than the destination size, <tt>trunc</tt> cannot
4533 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4534
4535<h5>Example:</h5>
4536<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4537 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4538 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4539 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4540</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4541
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4542</div>
4543
4544<!-- _______________________________________________________________________ -->
4545<div class="doc_subsubsection">
4546 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4547</div>
4548<div class="doc_text">
4549
4550<h5>Syntax:</h5>
4551<pre>
4552 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4553</pre>
4554
4555<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4556<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4557 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4558
4559
4560<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4561<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]4562 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4563 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]4564 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4565 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4566
4567<h5>Semantics:</h5>
4568<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]4569 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4570
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4571<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]4572
4573<h5>Example:</h5>
4574<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4575 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4576 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4577</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4578
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4579</div>
4580
4581<!-- _______________________________________________________________________ -->
4582<div class="doc_subsubsection">
4583 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4584</div>
4585<div class="doc_text">
4586
4587<h5>Syntax:</h5>
4588<pre>
4589 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4590</pre>
4591
4592<h5>Overview:</h5>
4593<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4594
4595<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4596<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]4597 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4598 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]4599 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4600 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4601
4602<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4603<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4604 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4605 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4606
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4607<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]4608
4609<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4610<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4611 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4612 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4613</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4614
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4615</div>
4616
4617<!-- _______________________________________________________________________ -->
4618<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4619 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4620</div>
4621
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4625<pre>
4626 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4627</pre>
4628
4629<h5>Overview:</h5>
4630<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4632
4633<h5>Arguments:</h5>
4634<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4635 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4636 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]4637 <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]4638 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4639
4640<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4641<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4642 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4643 <a href="#t_floating">floating point</a> type. If the value cannot fit
4644 within the destination type, <tt>ty2</tt>, then the results are
4645 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4646
4647<h5>Example:</h5>
4648<pre>
4649 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4650 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4651</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4657 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4658</div>
4659<div class="doc_text">
4660
4661<h5>Syntax:</h5>
4662<pre>
4663 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4664</pre>
4665
4666<h5>Overview:</h5>
4667<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]4668 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4671<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4673 a <a href="#t_floating">floating point</a> type to cast it to. The source
4674 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4675
4676<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4677<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4678 <a href="#t_floating">floating point</a> type to a larger
4679 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4680 used to make a <i>no-op cast</i> because it always changes bits. Use
4681 <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]4682
4683<h5>Example:</h5>
4684<pre>
4685 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4686 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4687</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4689</div>
4690
4691<!-- _______________________________________________________________________ -->
4692<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4693 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4694</div>
4695<div class="doc_text">
4696
4697<h5>Syntax:</h5>
4698<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4699 &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]4700</pre>
4701
4702<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4703<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4704 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4705
4706<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4708 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4709 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4710 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4711 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4712
4713<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4714<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4716 towards zero) unsigned integer value. If the value cannot fit
4717 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4718
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4719<h5>Example:</h5>
4720<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4721 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4722 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4723 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4724</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4726</div>
4727
4728<!-- _______________________________________________________________________ -->
4729<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4730 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4731</div>
4732<div class="doc_text">
4733
4734<h5>Syntax:</h5>
4735<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4736 &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]4737</pre>
4738
4739<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4740<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> <tt>value</tt> to
4742 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4743
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4744<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4745<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4746 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4747 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4748 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4749 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4750
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4751<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4752<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4754 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4755 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4756
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4757<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4758<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4759 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4760 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4761 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4762</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4763
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764</div>
4765
4766<!-- _______________________________________________________________________ -->
4767<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4768 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4769</div>
4770<div class="doc_text">
4771
4772<h5>Syntax:</h5>
4773<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4774 &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]4775</pre>
4776
4777<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4778<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4779 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4780
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4781<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4782<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]4783 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4784 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4785 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4786 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4787
4788<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4789<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790 integer quantity and converts it to the corresponding floating point
4791 value. If the value cannot fit in the floating point value, the results are
4792 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4793
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4794<h5>Example:</h5>
4795<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4796 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4797 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4798</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800</div>
4801
4802<!-- _______________________________________________________________________ -->
4803<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4804 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4805</div>
4806<div class="doc_text">
4807
4808<h5>Syntax:</h5>
4809<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4810 &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]4811</pre>
4812
4813<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4814<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4815 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4816
4817<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4818<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]4819 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4820 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4821 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4822 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4823
4824<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4825<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4826 quantity and converts it to the corresponding floating point value. If the
4827 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4828
4829<h5>Example:</h5>
4830<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4831 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4832 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4833</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4835</div>
4836
4837<!-- _______________________________________________________________________ -->
4838<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4839 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4840</div>
4841<div class="doc_text">
4842
4843<h5>Syntax:</h5>
4844<pre>
4845 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4846</pre>
4847
4848<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4849<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4850 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4851
4852<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4854 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4855 <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]4856
4857<h5>Semantics:</h5>
4858<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4859 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4860 truncating or zero extending that value to the size of the integer type. If
4861 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4862 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4863 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4864 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4865
4866<h5>Example:</h5>
4867<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4868 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4869 %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]4870</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4871
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4872</div>
4873
4874<!-- _______________________________________________________________________ -->
4875<div class="doc_subsubsection">
4876 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4877</div>
4878<div class="doc_text">
4879
4880<h5>Syntax:</h5>
4881<pre>
4882 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4883</pre>
4884
4885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4887 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4888
4889<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4890<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4891 value to cast, and a type to cast it to, which must be a
4892 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4893
4894<h5>Semantics:</h5>
4895<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4896 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4897 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4898 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4899 than the size of a pointer then a zero extension is done. If they are the
4900 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4901
4902<h5>Example:</h5>
4903<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4904 %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]4905 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4906 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4908
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4909</div>
4910
4911<!-- _______________________________________________________________________ -->
4912<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4913 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4914</div>
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4919 &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]4920</pre>
4921
4922<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4923<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4925
4926<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4928 non-aggregate first class value, and a type to cast it to, which must also be
4929 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4930 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4931 identical. If the source type is a pointer, the destination type must also be
4932 a pointer. This instruction supports bitwise conversion of vectors to
4933 integers and to vectors of other types (as long as they have the same
4934 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4935
4936<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4937<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4939 this conversion. The conversion is done as if the <tt>value</tt> had been
4940 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4941 be converted to other pointer types with this instruction. To convert
4942 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4943 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4944
4945<h5>Example:</h5>
4946<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4947 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4948 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4949 %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]4950</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4952</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4953
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4954<!-- ======================================================================= -->
4955<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4956
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4957<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4958
4959<p>The instructions in this category are the "miscellaneous" instructions, which
4960 defy better classification.</p>
4961
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4962</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4963
4964<!-- _______________________________________________________________________ -->
4965<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4966</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4967
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4968<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4969
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4970<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971<pre>
4972 &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]4973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4974
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4977 boolean values based on comparison of its two integer, integer vector, or
4978 pointer operands.</p>
4979
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4980<h5>Arguments:</h5>
4981<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4982 the condition code indicating the kind of comparison to perform. It is not a
4983 value, just a keyword. The possible condition code are:</p>
4984
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4985<ol>
4986 <li><tt>eq</tt>: equal</li>
4987 <li><tt>ne</tt>: not equal </li>
4988 <li><tt>ugt</tt>: unsigned greater than</li>
4989 <li><tt>uge</tt>: unsigned greater or equal</li>
4990 <li><tt>ult</tt>: unsigned less than</li>
4991 <li><tt>ule</tt>: unsigned less or equal</li>
4992 <li><tt>sgt</tt>: signed greater than</li>
4993 <li><tt>sge</tt>: signed greater or equal</li>
4994 <li><tt>slt</tt>: signed less than</li>
4995 <li><tt>sle</tt>: signed less or equal</li>
4996</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4998<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4999 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5000 typed. They must also be identical types.</p>
5001
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5002<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5003<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5004 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5005 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]5006 result, as follows:</p>
5007
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5008<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5009 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5010 <tt>false</tt> otherwise. No sign interpretation is necessary or
5011 performed.</li>
5012
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5013 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5014 <tt>false</tt> otherwise. No sign interpretation is necessary or
5015 performed.</li>
5016
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5017 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5018 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5019
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5020 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5022 to <tt>op2</tt>.</li>
5023
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5024 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5027 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5030 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5031 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5032
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5033 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5035 to <tt>op2</tt>.</li>
5036
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5037 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5039
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041 <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]5042</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5044<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045 values are compared as if they were integers.</p>
5046
5047<p>If the operands are integer vectors, then they are compared element by
5048 element. The result is an <tt>i1</tt> vector with the same number of elements
5049 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5050
5051<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5052<pre>
5053 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5054 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5055 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5056 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5057 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5058 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5059</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5060
5061<p>Note that the code generator does not yet support vector types with
5062 the <tt>icmp</tt> instruction.</p>
5063
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5064</div>
5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5068</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5069
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5070<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5072<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073<pre>
5074 &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]5075</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5077<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5078<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5079 values based on comparison of its operands.</p>
5080
5081<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]5082(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5083
5084<p>If the operands are floating point vectors, then the result type is a vector
5085 of boolean with the same number of elements as the operands being
5086 compared.</p>
5087
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5088<h5>Arguments:</h5>
5089<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5090 the condition code indicating the kind of comparison to perform. It is not a
5091 value, just a keyword. The possible condition code are:</p>
5092
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5093<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5094 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5095 <li><tt>oeq</tt>: ordered and equal</li>
5096 <li><tt>ogt</tt>: ordered and greater than </li>
5097 <li><tt>oge</tt>: ordered and greater than or equal</li>
5098 <li><tt>olt</tt>: ordered and less than </li>
5099 <li><tt>ole</tt>: ordered and less than or equal</li>
5100 <li><tt>one</tt>: ordered and not equal</li>
5101 <li><tt>ord</tt>: ordered (no nans)</li>
5102 <li><tt>ueq</tt>: unordered or equal</li>
5103 <li><tt>ugt</tt>: unordered or greater than </li>
5104 <li><tt>uge</tt>: unordered or greater than or equal</li>
5105 <li><tt>ult</tt>: unordered or less than </li>
5106 <li><tt>ule</tt>: unordered or less than or equal</li>
5107 <li><tt>une</tt>: unordered or not equal</li>
5108 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5109 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5110</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5111
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5112<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5113 <i>unordered</i> means that either operand may be a QNAN.</p>
5114
5115<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5116 a <a href="#t_floating">floating point</a> type or
5117 a <a href="#t_vector">vector</a> of floating point type. They must have
5118 identical types.</p>
5119
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5120<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5121<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122 according to the condition code given as <tt>cond</tt>. If the operands are
5123 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5124 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5125 follows:</p>
5126
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5127<ol>
5128 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5129
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5130 <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]5131 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5132
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5133 <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]5134 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5136 <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]5137 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5138
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5139 <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]5140 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5141
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5142 <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]5143 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5144
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5145 <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]5146 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5147
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5148 <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]5149
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5150 <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]5151 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5152
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5153 <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]5154 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5155
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5156 <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]5157 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5162 <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]5163 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5164
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5165 <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]5166 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5167
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5168 <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]5169
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5170 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5171</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5172
5173<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5174<pre>
5175 &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]5176 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5177 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5178 &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]5179</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5180
5181<p>Note that the code generator does not yet support vector types with
5182 the <tt>fcmp</tt> instruction.</p>
5183
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5184</div>
5185
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5186<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5187<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5188 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5189</div>
5190
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5191<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5192
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5193<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5194<pre>
5195 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5196</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5197
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5198<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5199<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5200 SSA graph representing the function.</p>
5201
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5202<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5203<p>The type of the incoming values is specified with the first type field. After
5204 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5205 one pair for each predecessor basic block of the current block. Only values
5206 of <a href="#t_firstclass">first class</a> type may be used as the value
5207 arguments to the PHI node. Only labels may be used as the label
5208 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5209
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5210<p>There must be no non-phi instructions between the start of a basic block and
5211 the PHI instructions: i.e. PHI instructions must be first in a basic
5212 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5213
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5214<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5215 occur on the edge from the corresponding predecessor block to the current
5216 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5217 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5218
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5219<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5220<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5221 specified by the pair corresponding to the predecessor basic block that
5222 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5223
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5224<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5225<pre>
5226Loop: ; Infinite loop that counts from 0 on up...
5227 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5228 %nextindvar = add i32 %indvar, 1
5229 br label %Loop
5230</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5231
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5232</div>
5233
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5234<!-- _______________________________________________________________________ -->
5235<div class="doc_subsubsection">
5236 <a name="i_select">'<tt>select</tt>' Instruction</a>
5237</div>
5238
5239<div class="doc_text">
5240
5241<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5242<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5243 &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>
5244
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5245 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5246</pre>
5247
5248<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5249<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5250 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5251
5252
5253<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5254<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5255 values indicating the condition, and two values of the
5256 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5257 vectors and the condition is a scalar, then entire vectors are selected, not
5258 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5259
5260<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5261<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5262 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5263
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5264<p>If the condition is a vector of i1, then the value arguments must be vectors
5265 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5266
5267<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5268<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5269 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5270</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5271
5272<p>Note that the code generator does not yet support conditions
5273 with vector type.</p>
5274
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5275</div>
5276
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5277<!-- _______________________________________________________________________ -->
5278<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5279 <a name="i_call">'<tt>call</tt>' Instruction</a>
5280</div>
5281
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5282<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5283
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5284<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5285<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5286 &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]5287</pre>
5288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5289<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5290<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5291
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5292<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5293<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5294
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5295<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5296 <li>The optional "tail" marker indicates that the callee function does not
5297 access any allocas or varargs in the caller. Note that calls may be
5298 marked "tail" even if they do not occur before
5299 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5300 present, the function call is eligible for tail call optimization,
5301 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5302 optimized into a jump</a>. The code generator may optimize calls marked
5303 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5304 sibling call optimization</a> when the caller and callee have
5305 matching signatures, or 2) forced tail call optimization when the
5306 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5307 <ul>
5308 <li>Caller and callee both have the calling
5309 convention <tt>fastcc</tt>.</li>
5310 <li>The call is in tail position (ret immediately follows call and ret
5311 uses value of call or is void).</li>
5312 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5313 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5314 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5315 constraints are met.</a></li>
5316 </ul>
5317 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5318
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5319 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5320 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5321 defaults to using C calling conventions. The calling convention of the
5322 call must match the calling convention of the target function, or else the
5323 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5325 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5326 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5327 '<tt>inreg</tt>' attributes are valid here.</li>
5328
5329 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5330 type of the return value. Functions that return no value are marked
5331 <tt><a href="#t_void">void</a></tt>.</li>
5332
5333 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5334 being invoked. The argument types must match the types implied by this
5335 signature. This type can be omitted if the function is not varargs and if
5336 the function type does not return a pointer to a function.</li>
5337
5338 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5339 be invoked. In most cases, this is a direct function invocation, but
5340 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5341 to function value.</li>
5342
5343 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5344 signature argument types and parameter attributes. All arguments must be
5345 of <a href="#t_firstclass">first class</a> type. If the function
5346 signature indicates the function accepts a variable number of arguments,
5347 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5348
5349 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5350 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5351 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5352</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5354<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5356 a specified function, with its incoming arguments bound to the specified
5357 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5358 function, control flow continues with the instruction after the function
5359 call, and the return value of the function is bound to the result
5360 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5362<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5363<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5364 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5365 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5366 %X = tail call i32 @foo() <i>; yields i32</i>
5367 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5368 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5369
5370 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5371 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5372 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5373 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5374 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5375 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5376</pre>
5377
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5378<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5379standard C99 library as being the C99 library functions, and may perform
5380optimizations or generate code for them under that assumption. This is
5381something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5382freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5383
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5384</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5385
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5386<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5387<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5388 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5389</div>
5390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5391<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5392
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5393<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5394<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5395 &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]5396</pre>
5397
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5398<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5399<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5400 the "variable argument" area of a function call. It is used to implement the
5401 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5402
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5403<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5404<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5405 argument. It returns a value of the specified argument type and increments
5406 the <tt>va_list</tt> to point to the next argument. The actual type
5407 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5408
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5409<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5410<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5411 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5412 to the next argument. For more information, see the variable argument
5413 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5414
5415<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]5416 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5417 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5418
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5419<p><tt>va_arg</tt> is an LLVM instruction instead of
5420 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5421 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5422
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5423<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5424<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5425
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5426<p>Note that the code generator does not yet fully support va_arg on many
5427 targets. Also, it does not currently support va_arg with aggregate types on
5428 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5430</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5431
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5432<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5433<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5434<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5436<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5437
5438<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5439 well known names and semantics and are required to follow certain
5440 restrictions. Overall, these intrinsics represent an extension mechanism for
5441 the LLVM language that does not require changing all of the transformations
5442 in LLVM when adding to the language (or the bitcode reader/writer, the
5443 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5444
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5445<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5447 begin with this prefix. Intrinsic functions must always be external
5448 functions: you cannot define the body of intrinsic functions. Intrinsic
5449 functions may only be used in call or invoke instructions: it is illegal to
5450 take the address of an intrinsic function. Additionally, because intrinsic
5451 functions are part of the LLVM language, it is required if any are added that
5452 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5453
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5454<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5455 family of functions that perform the same operation but on different data
5456 types. Because LLVM can represent over 8 million different integer types,
5457 overloading is used commonly to allow an intrinsic function to operate on any
5458 integer type. One or more of the argument types or the result type can be
5459 overloaded to accept any integer type. Argument types may also be defined as
5460 exactly matching a previous argument's type or the result type. This allows
5461 an intrinsic function which accepts multiple arguments, but needs all of them
5462 to be of the same type, to only be overloaded with respect to a single
5463 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5464
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5465<p>Overloaded intrinsics will have the names of its overloaded argument types
5466 encoded into its function name, each preceded by a period. Only those types
5467 which are overloaded result in a name suffix. Arguments whose type is matched
5468 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5469 can take an integer of any width and returns an integer of exactly the same
5470 integer width. This leads to a family of functions such as
5471 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5472 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5473 suffix is required. Because the argument's type is matched against the return
5474 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5475
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5476<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5477 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5478
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5479</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5480
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5481<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5482<div class="doc_subsection">
5483 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5484</div>
5485
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5486<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5487
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5488<p>Variable argument support is defined in LLVM with
5489 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5490 intrinsic functions. These functions are related to the similarly named
5491 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5492
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493<p>All of these functions operate on arguments that use a target-specific value
5494 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5495 not define what this type is, so all transformations should be prepared to
5496 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5497
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5498<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]5499 instruction and the variable argument handling intrinsic functions are
5500 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5501
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5502<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5503define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5504 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5505 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5506 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5507 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5508
5509 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5510 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5511
5512 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5513 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5514 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5515 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5516 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5517
5518 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5519 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5520 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5521}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5522
5523declare void @llvm.va_start(i8*)
5524declare void @llvm.va_copy(i8*, i8*)
5525declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5526</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5527
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5528</div>
5529
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5530<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5531<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5532 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5533</div>
5534
5535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5536<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5537
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5538<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5539<pre>
5540 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5541</pre>
5542
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5543<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5544<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5545 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]5546
5547<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5548<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]5549
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5550<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5551<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]5552 macro available in C. In a target-dependent way, it initializes
5553 the <tt>va_list</tt> element to which the argument points, so that the next
5554 call to <tt>va_arg</tt> will produce the first variable argument passed to
5555 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5556 need to know the last argument of the function as the compiler can figure
5557 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5558
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5559</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5560
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5561<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5562<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5563 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5564</div>
5565
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5566<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5567
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5568<h5>Syntax:</h5>
5569<pre>
5570 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5571</pre>
5572
5573<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5574<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5575 which has been initialized previously
5576 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5577 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5578
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5579<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5580<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]5581
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5582<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5583<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]5584 macro available in C. In a target-dependent way, it destroys
5585 the <tt>va_list</tt> element to which the argument points. Calls
5586 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5587 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5588 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5590</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5591
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5592<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5593<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5594 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5595</div>
5596
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5597<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5598
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5599<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5600<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5601 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5602</pre>
5603
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5604<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5605<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5606 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5607
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5608<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5609<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]5610 The second argument is a pointer to a <tt>va_list</tt> element to copy
5611 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5612
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5613<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5614<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]5615 macro available in C. In a target-dependent way, it copies the
5616 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5617 element. This intrinsic is necessary because
5618 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5619 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5621</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5622
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5623<!-- ======================================================================= -->
5624<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5625 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5626</div>
5627
5628<div class="doc_text">
5629
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5630<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5631Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5633roots on the stack</a>, as well as garbage collector implementations that
5634require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5635barriers. Front-ends for type-safe garbage collected languages should generate
5636these intrinsics to make use of the LLVM garbage collectors. For more details,
5637see <a href="GarbageCollection.html">Accurate Garbage Collection with
5638LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5639
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5640<p>The garbage collection intrinsics only operate on objects in the generic
5641 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5642
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5643</div>
5644
5645<!-- _______________________________________________________________________ -->
5646<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5647 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5648</div>
5649
5650<div class="doc_text">
5651
5652<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5653<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5654 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5655</pre>
5656
5657<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5658<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]5659 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5660
5661<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5662<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663 root pointer. The second pointer (which must be either a constant or a
5664 global value address) contains the meta-data to be associated with the
5665 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5666
5667<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5668<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]5669 location. At compile-time, the code generator generates information to allow
5670 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5671 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5672 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5673
5674</div>
5675
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676<!-- _______________________________________________________________________ -->
5677<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5678 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5679</div>
5680
5681<div class="doc_text">
5682
5683<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5684<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5685 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5686</pre>
5687
5688<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5690 locations, allowing garbage collector implementations that require read
5691 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5692
5693<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5694<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]5695 allocated from the garbage collector. The first object is a pointer to the
5696 start of the referenced object, if needed by the language runtime (otherwise
5697 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5698
5699<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5700<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5701 instruction, but may be replaced with substantially more complex code by the
5702 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5703 may only be used in a function which <a href="#gc">specifies a GC
5704 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5705
5706</div>
5707
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5708<!-- _______________________________________________________________________ -->
5709<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5710 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5711</div>
5712
5713<div class="doc_text">
5714
5715<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5716<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5717 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718</pre>
5719
5720<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5721<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722 locations, allowing garbage collector implementations that require write
5723 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5726<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]5727 object to store it to, and the third is the address of the field of Obj to
5728 store to. If the runtime does not require a pointer to the object, Obj may
5729 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5730
5731<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5732<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733 instruction, but may be replaced with substantially more complex code by the
5734 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5735 may only be used in a function which <a href="#gc">specifies a GC
5736 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737
5738</div>
5739
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5740<!-- ======================================================================= -->
5741<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5742 <a name="int_codegen">Code Generator Intrinsics</a>
5743</div>
5744
5745<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5746
5747<p>These intrinsics are provided by LLVM to expose special features that may
5748 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5749
5750</div>
5751
5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5754 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
5760<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5761 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5762</pre>
5763
5764<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5765<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5766 target-specific value indicating the return address of the current function
5767 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5768
5769<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770<p>The argument to this intrinsic indicates which function to return the address
5771 for. Zero indicates the calling function, one indicates its caller, etc.
5772 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5776 indicating the return address of the specified call frame, or zero if it
5777 cannot be identified. The value returned by this intrinsic is likely to be
5778 incorrect or 0 for arguments other than zero, so it should only be used for
5779 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5780
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781<p>Note that calling this intrinsic does not prevent function inlining or other
5782 aggressive transformations, so the value returned may not be that of the
5783 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5784
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5785</div>
5786
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787<!-- _______________________________________________________________________ -->
5788<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5789 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5790</div>
5791
5792<div class="doc_text">
5793
5794<h5>Syntax:</h5>
5795<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5796 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797</pre>
5798
5799<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5801 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5802
5803<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5804<p>The argument to this intrinsic indicates which function to return the frame
5805 pointer for. Zero indicates the calling function, one indicates its caller,
5806 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5810 indicating the frame address of the specified call frame, or zero if it
5811 cannot be identified. The value returned by this intrinsic is likely to be
5812 incorrect or 0 for arguments other than zero, so it should only be used for
5813 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815<p>Note that calling this intrinsic does not prevent function inlining or other
5816 aggressive transformations, so the value returned may not be that of the
5817 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5819</div>
5820
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5821<!-- _______________________________________________________________________ -->
5822<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5823 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5824</div>
5825
5826<div class="doc_text">
5827
5828<h5>Syntax:</h5>
5829<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5830 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5831</pre>
5832
5833<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5834<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5835 of the function stack, for use
5836 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5837 useful for implementing language features like scoped automatic variable
5838 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5839
5840<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5841<p>This intrinsic returns a opaque pointer value that can be passed
5842 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5843 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5844 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5845 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5846 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5847 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5848
5849</div>
5850
5851<!-- _______________________________________________________________________ -->
5852<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5853 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5854</div>
5855
5856<div class="doc_text">
5857
5858<h5>Syntax:</h5>
5859<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5860 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5861</pre>
5862
5863<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5864<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5865 the function stack to the state it was in when the
5866 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5867 executed. This is useful for implementing language features like scoped
5868 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5871<p>See the description
5872 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5873
5874</div>
5875
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5878 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5879</div>
5880
5881<div class="doc_text">
5882
5883<h5>Syntax:</h5>
5884<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5885 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]5886</pre>
5887
5888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5890 insert a prefetch instruction if supported; otherwise, it is a noop.
5891 Prefetches have no effect on the behavior of the program but can change its
5892 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5893
5894<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5896 specifier determining if the fetch should be for a read (0) or write (1),
5897 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5898 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5899 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5900
5901<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5902<p>This intrinsic does not modify the behavior of the program. In particular,
5903 prefetches cannot trap and do not produce a value. On targets that support
5904 this intrinsic, the prefetch can provide hints to the processor cache for
5905 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5906
5907</div>
5908
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5909<!-- _______________________________________________________________________ -->
5910<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5911 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5912</div>
5913
5914<div class="doc_text">
5915
5916<h5>Syntax:</h5>
5917<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5918 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5923 Counter (PC) in a region of code to simulators and other tools. The method
5924 is target specific, but it is expected that the marker will use exported
5925 symbols to transmit the PC of the marker. The marker makes no guarantees
5926 that it will remain with any specific instruction after optimizations. It is
5927 possible that the presence of a marker will inhibit optimizations. The
5928 intended use is to be inserted after optimizations to allow correlations of
5929 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5930
5931<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5932<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5933
5934<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5935<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5936 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5937
5938</div>
5939
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5942 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
5948<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5949 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5950</pre>
5951
5952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5954 counter register (or similar low latency, high accuracy clocks) on those
5955 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5956 should map to RPCC. As the backing counters overflow quickly (on the order
5957 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5958
5959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>When directly supported, reading the cycle counter should not modify any
5961 memory. Implementations are allowed to either return a application specific
5962 value or a system wide value. On backends without support, this is lowered
5963 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5964
5965</div>
5966
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5967<!-- ======================================================================= -->
5968<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5969 <a name="int_libc">Standard C Library Intrinsics</a>
5970</div>
5971
5972<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5973
5974<p>LLVM provides intrinsics for a few important standard C library functions.
5975 These intrinsics allow source-language front-ends to pass information about
5976 the alignment of the pointer arguments to the code generator, providing
5977 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5978
5979</div>
5980
5981<!-- _______________________________________________________________________ -->
5982<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5983 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5984</div>
5985
5986<div class="doc_text">
5987
5988<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989<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]5990 integer bit width and for different address spaces. Not all targets support
5991 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5992
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5993<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5994 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]5995 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5996 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]5997 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5998</pre>
5999
6000<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6002 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6003
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6005 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6006 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6007
6008<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6010<p>The first argument is a pointer to the destination, the second is a pointer
6011 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6012 number of bytes to copy, the fourth argument is the alignment of the
6013 source and destination locations, and the fifth is a boolean indicating a
6014 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6015
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6016<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]6017 then the caller guarantees that both the source and destination pointers are
6018 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6019
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6020<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6021 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6022 The detailed access behavior is not very cleanly specified and it is unwise
6023 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6024
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6025<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6027<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6028 source location to the destination location, which are not allowed to
6029 overlap. It copies "len" bytes of memory over. If the argument is known to
6030 be aligned to some boundary, this can be specified as the fourth argument,
6031 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6032
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6033</div>
6034
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6035<!-- _______________________________________________________________________ -->
6036<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6037 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6038</div>
6039
6040<div class="doc_text">
6041
6042<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6043<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]6044 width and for different address space. Not all targets support all bit
6045 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6046
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6047<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6048 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]6049 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6050 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]6051 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6052</pre>
6053
6054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6055<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6056 source location to the destination location. It is similar to the
6057 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6058 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6060<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6061 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6062 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6063
6064<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The first argument is a pointer to the destination, the second is a pointer
6067 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6068 number of bytes to copy, the fourth argument is the alignment of the
6069 source and destination locations, and the fifth is a boolean indicating a
6070 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6071
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6072<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]6073 then the caller guarantees that the source and destination pointers are
6074 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6075
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6076<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6077 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6078 The detailed access behavior is not very cleanly specified and it is unwise
6079 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6080
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6081<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6083<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6084 source location to the destination location, which may overlap. It copies
6085 "len" bytes of memory over. If the argument is known to be aligned to some
6086 boundary, this can be specified as the fourth argument, otherwise it should
6087 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6088
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6089</div>
6090
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6091<!-- _______________________________________________________________________ -->
6092<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6093 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6094</div>
6095
6096<div class="doc_text">
6097
6098<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6099<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]6100 width and for different address spaces. However, not all targets support all
6101 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6103<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6104 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6105 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6106 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6107 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6108</pre>
6109
6110<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6112 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6113
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6114<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6115 intrinsic does not return a value and takes extra alignment/volatile
6116 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6117
6118<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6119<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]6120 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6122 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6123
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6124<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]6125 then the caller guarantees that the destination pointer is aligned to that
6126 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6127
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6128<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6129 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6130 The detailed access behavior is not very cleanly specified and it is unwise
6131 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6132
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6133<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6134<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6135 at the destination location. If the argument is known to be aligned to some
6136 boundary, this can be specified as the fourth argument, otherwise it should
6137 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6138
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6139</div>
6140
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6141<!-- _______________________________________________________________________ -->
6142<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6143 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6144</div>
6145
6146<div class="doc_text">
6147
6148<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6150 floating point or vector of floating point type. Not all targets support all
6151 types however.</p>
6152
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6153<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6154 declare float @llvm.sqrt.f32(float %Val)
6155 declare double @llvm.sqrt.f64(double %Val)
6156 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6157 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6158 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6159</pre>
6160
6161<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6163 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6164 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6165 behavior for negative numbers other than -0.0 (which allows for better
6166 optimization, because there is no need to worry about errno being
6167 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]6168
6169<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6170<p>The argument and return value are floating point numbers of the same
6171 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6172
6173<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6174<p>This function returns the sqrt of the specified operand if it is a
6175 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6176
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6177</div>
6178
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6181 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6187<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6188 floating point or vector of floating point type. Not all targets support all
6189 types however.</p>
6190
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6191<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6192 declare float @llvm.powi.f32(float %Val, i32 %power)
6193 declare double @llvm.powi.f64(double %Val, i32 %power)
6194 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6195 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6196 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6197</pre>
6198
6199<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6200<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6201 specified (positive or negative) power. The order of evaluation of
6202 multiplications is not defined. When a vector of floating point type is
6203 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6204
6205<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6206<p>The second argument is an integer power, and the first is a value to raise to
6207 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6208
6209<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210<p>This function returns the first value raised to the second power with an
6211 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6212
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6213</div>
6214
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6215<!-- _______________________________________________________________________ -->
6216<div class="doc_subsubsection">
6217 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6218</div>
6219
6220<div class="doc_text">
6221
6222<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6223<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6224 floating point or vector of floating point type. Not all targets support all
6225 types however.</p>
6226
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6227<pre>
6228 declare float @llvm.sin.f32(float %Val)
6229 declare double @llvm.sin.f64(double %Val)
6230 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6231 declare fp128 @llvm.sin.f128(fp128 %Val)
6232 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6233</pre>
6234
6235<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6236<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6237
6238<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The argument and return value are floating point numbers of the same
6240 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the sine of the specified operand, returning the same
6244 values as the libm <tt>sin</tt> functions would, and handles error conditions
6245 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6246
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6247</div>
6248
6249<!-- _______________________________________________________________________ -->
6250<div class="doc_subsubsection">
6251 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6252</div>
6253
6254<div class="doc_text">
6255
6256<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6258 floating point or vector of floating point type. Not all targets support all
6259 types however.</p>
6260
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6261<pre>
6262 declare float @llvm.cos.f32(float %Val)
6263 declare double @llvm.cos.f64(double %Val)
6264 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6265 declare fp128 @llvm.cos.f128(fp128 %Val)
6266 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6267</pre>
6268
6269<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6271
6272<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6273<p>The argument and return value are floating point numbers of the same
6274 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6275
6276<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6277<p>This function returns the cosine of the specified operand, returning the same
6278 values as the libm <tt>cos</tt> functions would, and handles error conditions
6279 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6280
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6281</div>
6282
6283<!-- _______________________________________________________________________ -->
6284<div class="doc_subsubsection">
6285 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6286</div>
6287
6288<div class="doc_text">
6289
6290<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6292 floating point or vector of floating point type. Not all targets support all
6293 types however.</p>
6294
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6295<pre>
6296 declare float @llvm.pow.f32(float %Val, float %Power)
6297 declare double @llvm.pow.f64(double %Val, double %Power)
6298 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6299 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6300 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6301</pre>
6302
6303<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6304<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6305 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6308<p>The second argument is a floating point power, and the first is a value to
6309 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>This function returns the first value raised to the second power, returning
6313 the same values as the libm <tt>pow</tt> functions would, and handles error
6314 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6315
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6316</div>
6317
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6318<!-- ======================================================================= -->
6319<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6320 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6321</div>
6322
6323<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6324
6325<p>LLVM provides intrinsics for a few important bit manipulation operations.
6326 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6327
6328</div>
6329
6330<!-- _______________________________________________________________________ -->
6331<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6332 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6333</div>
6334
6335<div class="doc_text">
6336
6337<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6338<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6339 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6340
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6341<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6342 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6343 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6344 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6345</pre>
6346
6347<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6348<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6349 values with an even number of bytes (positive multiple of 16 bits). These
6350 are useful for performing operations on data that is not in the target's
6351 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6352
6353<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6354<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6355 and low byte of the input i16 swapped. Similarly,
6356 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6357 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6358 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6359 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6360 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6361 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6362
6363</div>
6364
6365<!-- _______________________________________________________________________ -->
6366<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6367 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6368</div>
6369
6370<div class="doc_text">
6371
6372<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6373<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]6374 width. Not all targets support all bit widths however.</p>
6375
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6376<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6377 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6378 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6379 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6380 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6381 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6382</pre>
6383
6384<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6385<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6386 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6387
6388<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6389<p>The only argument is the value to be counted. The argument may be of any
6390 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6393<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]6394
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6395</div>
6396
6397<!-- _______________________________________________________________________ -->
6398<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6399 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6400</div>
6401
6402<div class="doc_text">
6403
6404<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6405<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6406 integer bit width. Not all targets support all bit widths however.</p>
6407
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6408<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6409 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6410 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6411 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6412 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6413 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6414</pre>
6415
6416<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6417<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6418 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6419
6420<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6421<p>The only argument is the value to be counted. The argument may be of any
6422 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6423
6424<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6425<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6426 zeros in a variable. If the src == 0 then the result is the size in bits of
6427 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6428
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6429</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6430
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6431<!-- _______________________________________________________________________ -->
6432<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6433 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6434</div>
6435
6436<div class="doc_text">
6437
6438<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6439<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6440 integer bit width. Not all targets support all bit widths however.</p>
6441
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6442<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6443 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6444 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6445 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6446 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6447 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6448</pre>
6449
6450<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6451<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6452 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6453
6454<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6455<p>The only argument is the value to be counted. The argument may be of any
6456 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6457
6458<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6459<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6460 zeros in a variable. If the src == 0 then the result is the size in bits of
6461 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6462
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6463</div>
6464
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6465<!-- ======================================================================= -->
6466<div class="doc_subsection">
6467 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6468</div>
6469
6470<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6471
6472<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6473
6474</div>
6475
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6476<!-- _______________________________________________________________________ -->
6477<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6478 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6479</div>
6480
6481<div class="doc_text">
6482
6483<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6484<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]6485 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6486
6487<pre>
6488 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6489 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6490 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6491</pre>
6492
6493<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6494<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6495 a signed addition of the two arguments, and indicate whether an overflow
6496 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6497
6498<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6499<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]6500 be of integer types of any bit width, but they must have the same bit
6501 width. The second element of the result structure must be of
6502 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6503 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6504
6505<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6506<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6507 a signed addition of the two variables. They return a structure &mdash; the
6508 first element of which is the signed summation, and the second element of
6509 which is a bit specifying if the signed summation resulted in an
6510 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6511
6512<h5>Examples:</h5>
6513<pre>
6514 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6515 %sum = extractvalue {i32, i1} %res, 0
6516 %obit = extractvalue {i32, i1} %res, 1
6517 br i1 %obit, label %overflow, label %normal
6518</pre>
6519
6520</div>
6521
6522<!-- _______________________________________________________________________ -->
6523<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6524 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6525</div>
6526
6527<div class="doc_text">
6528
6529<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6530<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]6531 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6532
6533<pre>
6534 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6535 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6536 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6537</pre>
6538
6539<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6540<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6541 an unsigned addition of the two arguments, and indicate whether a carry
6542 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6543
6544<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6545<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]6546 be of integer types of any bit width, but they must have the same bit
6547 width. The second element of the result structure must be of
6548 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6549 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6552<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6553 an unsigned addition of the two arguments. They return a structure &mdash;
6554 the first element of which is the sum, and the second element of which is a
6555 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6556
6557<h5>Examples:</h5>
6558<pre>
6559 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6560 %sum = extractvalue {i32, i1} %res, 0
6561 %obit = extractvalue {i32, i1} %res, 1
6562 br i1 %obit, label %carry, label %normal
6563</pre>
6564
6565</div>
6566
6567<!-- _______________________________________________________________________ -->
6568<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6569 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6570</div>
6571
6572<div class="doc_text">
6573
6574<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6575<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]6576 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6577
6578<pre>
6579 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6580 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6581 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6582</pre>
6583
6584<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6585<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6586 a signed subtraction of the two arguments, and indicate whether an overflow
6587 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6588
6589<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6590<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]6591 be of integer types of any bit width, but they must have the same bit
6592 width. The second element of the result structure must be of
6593 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6594 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6595
6596<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6597<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6598 a signed subtraction of the two arguments. They return a structure &mdash;
6599 the first element of which is the subtraction, and the second element of
6600 which is a bit specifying if the signed subtraction resulted in an
6601 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6602
6603<h5>Examples:</h5>
6604<pre>
6605 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6606 %sum = extractvalue {i32, i1} %res, 0
6607 %obit = extractvalue {i32, i1} %res, 1
6608 br i1 %obit, label %overflow, label %normal
6609</pre>
6610
6611</div>
6612
6613<!-- _______________________________________________________________________ -->
6614<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6615 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6616</div>
6617
6618<div class="doc_text">
6619
6620<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621<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]6622 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6623
6624<pre>
6625 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6626 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6627 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6628</pre>
6629
6630<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6631<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6632 an unsigned subtraction of the two arguments, and indicate whether an
6633 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6634
6635<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6636<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]6637 be of integer types of any bit width, but they must have the same bit
6638 width. The second element of the result structure must be of
6639 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6640 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6643<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6644 an unsigned subtraction of the two arguments. They return a structure &mdash;
6645 the first element of which is the subtraction, and the second element of
6646 which is a bit specifying if the unsigned subtraction resulted in an
6647 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6648
6649<h5>Examples:</h5>
6650<pre>
6651 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6652 %sum = extractvalue {i32, i1} %res, 0
6653 %obit = extractvalue {i32, i1} %res, 1
6654 br i1 %obit, label %overflow, label %normal
6655</pre>
6656
6657</div>
6658
6659<!-- _______________________________________________________________________ -->
6660<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6661 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6662</div>
6663
6664<div class="doc_text">
6665
6666<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6667<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]6668 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6669
6670<pre>
6671 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6672 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6673 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6674</pre>
6675
6676<h5>Overview:</h5>
6677
6678<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6679 a signed multiplication of the two arguments, and indicate whether an
6680 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6681
6682<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6683<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]6684 be of integer types of any bit width, but they must have the same bit
6685 width. The second element of the result structure must be of
6686 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6687 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6688
6689<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6691 a signed multiplication of the two arguments. They return a structure &mdash;
6692 the first element of which is the multiplication, and the second element of
6693 which is a bit specifying if the signed multiplication resulted in an
6694 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6695
6696<h5>Examples:</h5>
6697<pre>
6698 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6699 %sum = extractvalue {i32, i1} %res, 0
6700 %obit = extractvalue {i32, i1} %res, 1
6701 br i1 %obit, label %overflow, label %normal
6702</pre>
6703
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6704</div>
6705
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6706<!-- _______________________________________________________________________ -->
6707<div class="doc_subsubsection">
6708 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6709</div>
6710
6711<div class="doc_text">
6712
6713<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6714<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]6715 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6716
6717<pre>
6718 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6719 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6720 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6721</pre>
6722
6723<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6724<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6725 a unsigned multiplication of the two arguments, and indicate whether an
6726 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6727
6728<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6729<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]6730 be of integer types of any bit width, but they must have the same bit
6731 width. The second element of the result structure must be of
6732 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6733 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6734
6735<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6736<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6737 an unsigned multiplication of the two arguments. They return a structure
6738 &mdash; the first element of which is the multiplication, and the second
6739 element of which is a bit specifying if the unsigned multiplication resulted
6740 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6741
6742<h5>Examples:</h5>
6743<pre>
6744 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6745 %sum = extractvalue {i32, i1} %res, 0
6746 %obit = extractvalue {i32, i1} %res, 1
6747 br i1 %obit, label %overflow, label %normal
6748</pre>
6749
6750</div>
6751
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6752<!-- ======================================================================= -->
6753<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6754 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6755</div>
6756
6757<div class="doc_text">
6758
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6759<p>Half precision floating point is a storage-only format. This means that it is
6760 a dense encoding (in memory) but does not support computation in the
6761 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6762
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6763<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6764 value as an i16, then convert it to float with <a
6765 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6766 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6767 double etc). To store the value back to memory, it is first converted to
6768 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6769 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6770 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6771</div>
6772
6773<!-- _______________________________________________________________________ -->
6774<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6775 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6776</div>
6777
6778<div class="doc_text">
6779
6780<h5>Syntax:</h5>
6781<pre>
6782 declare i16 @llvm.convert.to.fp16(f32 %a)
6783</pre>
6784
6785<h5>Overview:</h5>
6786<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6787 a conversion from single precision floating point format to half precision
6788 floating point format.</p>
6789
6790<h5>Arguments:</h5>
6791<p>The intrinsic function contains single argument - the value to be
6792 converted.</p>
6793
6794<h5>Semantics:</h5>
6795<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6796 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6797 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6798 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6799
6800<h5>Examples:</h5>
6801<pre>
6802 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6803 store i16 %res, i16* @x, align 2
6804</pre>
6805
6806</div>
6807
6808<!-- _______________________________________________________________________ -->
6809<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6810 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6811</div>
6812
6813<div class="doc_text">
6814
6815<h5>Syntax:</h5>
6816<pre>
6817 declare f32 @llvm.convert.from.fp16(i16 %a)
6818</pre>
6819
6820<h5>Overview:</h5>
6821<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6822 a conversion from half precision floating point format to single precision
6823 floating point format.</p>
6824
6825<h5>Arguments:</h5>
6826<p>The intrinsic function contains single argument - the value to be
6827 converted.</p>
6828
6829<h5>Semantics:</h5>
6830<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6831 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6832 precision floating point format. The input half-float value is represented by
6833 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6834
6835<h5>Examples:</h5>
6836<pre>
6837 %a = load i16* @x, align 2
6838 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6839</pre>
6840
6841</div>
6842
6843<!-- ======================================================================= -->
6844<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6845 <a name="int_debugger">Debugger Intrinsics</a>
6846</div>
6847
6848<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6850<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6851 prefix), are described in
6852 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6853 Level Debugging</a> document.</p>
6854
6855</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6856
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6857<!-- ======================================================================= -->
6858<div class="doc_subsection">
6859 <a name="int_eh">Exception Handling Intrinsics</a>
6860</div>
6861
6862<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863
6864<p>The LLVM exception handling intrinsics (which all start with
6865 <tt>llvm.eh.</tt> prefix), are described in
6866 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6867 Handling</a> document.</p>
6868
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6869</div>
6870
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6871<!-- ======================================================================= -->
6872<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6873 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6874</div>
6875
6876<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6877
6878<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6879 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6880 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881 function pointer lacking the nest parameter - the caller does not need to
6882 provide a value for it. Instead, the value to use is stored in advance in a
6883 "trampoline", a block of memory usually allocated on the stack, which also
6884 contains code to splice the nest value into the argument list. This is used
6885 to implement the GCC nested function address extension.</p>
6886
6887<p>For example, if the function is
6888 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6889 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6890 follows:</p>
6891
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6892<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6893 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6894 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6895 %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]6896 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6897</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6899<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6900 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6901
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6902</div>
6903
6904<!-- _______________________________________________________________________ -->
6905<div class="doc_subsubsection">
6906 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6907</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6908
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6909<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6911<h5>Syntax:</h5>
6912<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6913 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]6914</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6915
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6916<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6918 function pointer suitable for executing it.</p>
6919
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6920<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6921<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6922 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6923 sufficiently aligned block of memory; this memory is written to by the
6924 intrinsic. Note that the size and the alignment are target-specific - LLVM
6925 currently provides no portable way of determining them, so a front-end that
6926 generates this intrinsic needs to have some target-specific knowledge.
6927 The <tt>func</tt> argument must hold a function bitcast to
6928 an <tt>i8*</tt>.</p>
6929
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6930<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6931<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6932 dependent code, turning it into a function. A pointer to this function is
6933 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6934 function pointer type</a> before being called. The new function's signature
6935 is the same as that of <tt>func</tt> with any arguments marked with
6936 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6937 is allowed, and it must be of pointer type. Calling the new function is
6938 equivalent to calling <tt>func</tt> with the same argument list, but
6939 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6940 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6941 by <tt>tramp</tt> is modified, then the effect of any later call to the
6942 returned function pointer is undefined.</p>
6943
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6944</div>
6945
6946<!-- ======================================================================= -->
6947<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6948 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6949</div>
6950
6951<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6952
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6954 hardware constructs for atomic operations and memory synchronization. This
6955 provides an interface to the hardware, not an interface to the programmer. It
6956 is aimed at a low enough level to allow any programming models or APIs
6957 (Application Programming Interfaces) which need atomic behaviors to map
6958 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6959 hardware provides a "universal IR" for source languages, it also provides a
6960 starting point for developing a "universal" atomic operation and
6961 synchronization IR.</p>
6962
6963<p>These do <em>not</em> form an API such as high-level threading libraries,
6964 software transaction memory systems, atomic primitives, and intrinsic
6965 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6966 application libraries. The hardware interface provided by LLVM should allow
6967 a clean implementation of all of these APIs and parallel programming models.
6968 No one model or paradigm should be selected above others unless the hardware
6969 itself ubiquitously does so.</p>
6970
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6971</div>
6972
6973<!-- _______________________________________________________________________ -->
6974<div class="doc_subsubsection">
6975 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6976</div>
6977<div class="doc_text">
6978<h5>Syntax:</h5>
6979<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6980 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]6981</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6982
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6983<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6985 specific pairs of memory access types.</p>
6986
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6987<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6988<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6989 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6990 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993<ul>
6994 <li><tt>ll</tt>: load-load barrier</li>
6995 <li><tt>ls</tt>: load-store barrier</li>
6996 <li><tt>sl</tt>: store-load barrier</li>
6997 <li><tt>ss</tt>: store-store barrier</li>
6998 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6999</ul>
7000
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7001<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002<p>This intrinsic causes the system to enforce some ordering constraints upon
7003 the loads and stores of the program. This barrier does not
7004 indicate <em>when</em> any events will occur, it only enforces
7005 an <em>order</em> in which they occur. For any of the specified pairs of load
7006 and store operations (f.ex. load-load, or store-load), all of the first
7007 operations preceding the barrier will complete before any of the second
7008 operations succeeding the barrier begin. Specifically the semantics for each
7009 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<ul>
7012 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7013 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7014 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7015 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7016 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7017 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7018 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7019 load after the barrier begins.</li>
7020</ul>
7021
7022<p>These semantics are applied with a logical "and" behavior when more than one
7023 is enabled in a single memory barrier intrinsic.</p>
7024
7025<p>Backends may implement stronger barriers than those requested when they do
7026 not support as fine grained a barrier as requested. Some architectures do
7027 not need all types of barriers and on such architectures, these become
7028 noops.</p>
7029
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7030<h5>Example:</h5>
7031<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7032%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7033%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7034 store i32 4, %ptr
7035
7036%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7037 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7038 <i>; guarantee the above finishes</i>
7039 store i32 8, %ptr <i>; before this begins</i>
7040</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7041
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7042</div>
7043
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7044<!-- _______________________________________________________________________ -->
7045<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7046 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7047</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7048
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7049<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7051<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7053 any integer bit width and for different address spaces. Not all targets
7054 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7055
7056<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7057 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7058 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7059 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7060 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]7061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7064<p>This loads a value in memory and compares it to a given value. If they are
7065 equal, it stores a new value into the memory.</p>
7066
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7067<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7068<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7069 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7070 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7071 this integer type. While any bit width integer may be used, targets may only
7072 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7073
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>This entire intrinsic must be executed atomically. It first loads the value
7076 in memory pointed to by <tt>ptr</tt> and compares it with the
7077 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7078 memory. The loaded value is yielded in all cases. This provides the
7079 equivalent of an atomic compare-and-swap operation within the SSA
7080 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7082<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7083<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7084%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7085%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7086 store i32 4, %ptr
7087
7088%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7089%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7090 <i>; yields {i32}:result1 = 4</i>
7091%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7092%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7093
7094%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7095%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7096 <i>; yields {i32}:result2 = 8</i>
7097%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7098
7099%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7100</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7101
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7102</div>
7103
7104<!-- _______________________________________________________________________ -->
7105<div class="doc_subsubsection">
7106 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7107</div>
7108<div class="doc_text">
7109<h5>Syntax:</h5>
7110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7111<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7112 integer bit width. Not all targets support all bit widths however.</p>
7113
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7114<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7115 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7116 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7117 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7118 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]7119</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7120
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7121<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7122<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7123 the value from memory. It then stores the value in <tt>val</tt> in the memory
7124 at <tt>ptr</tt>.</p>
7125
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7126<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7127<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7128 the <tt>val</tt> argument and the result must be integers of the same bit
7129 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7130 integer type. The targets may only lower integer representations they
7131 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7132
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7134<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7135 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7136 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7137
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7138<h5>Examples:</h5>
7139<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7140%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7141%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7142 store i32 4, %ptr
7143
7144%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7145%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7146 <i>; yields {i32}:result1 = 4</i>
7147%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7148%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7149
7150%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7151%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7152 <i>; yields {i32}:result2 = 8</i>
7153
7154%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7155%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7156</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7157
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7158</div>
7159
7160<!-- _______________________________________________________________________ -->
7161<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7162 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7163
7164</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7165
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7166<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7168<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7170 any integer bit width. Not all targets support all bit widths however.</p>
7171
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7172<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7173 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7174 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7175 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7176 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]7177</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7178
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7179<h5>Overview:</h5>
7180<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7181 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7182
7183<h5>Arguments:</h5>
7184<p>The intrinsic takes two arguments, the first a pointer to an integer value
7185 and the second an integer value. The result is also an integer value. These
7186 integer types can have any bit width, but they must all have the same bit
7187 width. The targets may only lower integer representations they support.</p>
7188
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7189<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7190<p>This intrinsic does a series of operations atomically. It first loads the
7191 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7192 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]7193
7194<h5>Examples:</h5>
7195<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7196%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7197%ptr = bitcast i8* %mallocP to i32*
7198 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7199%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7200 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7201%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7202 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7203%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7204 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7205%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7207
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7208</div>
7209
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7210<!-- _______________________________________________________________________ -->
7211<div class="doc_subsubsection">
7212 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7213
7214</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7215
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7216<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7217
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7218<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7220 any integer bit width and for different address spaces. Not all targets
7221 support all bit widths however.</p>
7222
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7223<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7224 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7225 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7226 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7227 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]7228</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7229
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7231<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7232 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7233
7234<h5>Arguments:</h5>
7235<p>The intrinsic takes two arguments, the first a pointer to an integer value
7236 and the second an integer value. The result is also an integer value. These
7237 integer types can have any bit width, but they must all have the same bit
7238 width. The targets may only lower integer representations they support.</p>
7239
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7240<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7241<p>This intrinsic does a series of operations atomically. It first loads the
7242 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7243 result to <tt>ptr</tt>. It yields the original value stored
7244 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7245
7246<h5>Examples:</h5>
7247<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7248%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7249%ptr = bitcast i8* %mallocP to i32*
7250 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7251%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7252 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7253%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7254 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7255%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7256 <i>; yields {i32}:result3 = 2</i>
7257%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7259
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7260</div>
7261
7262<!-- _______________________________________________________________________ -->
7263<div class="doc_subsubsection">
7264 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7265 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7266 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7267 <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]7268</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7269
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7270<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7271
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7272<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7273<p>These are overloaded intrinsics. You can
7274 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7275 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7276 bit width and for different address spaces. Not all targets support all bit
7277 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7278
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7279<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7280 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7281 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7282 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7283 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]7284</pre>
7285
7286<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7287 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7288 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7289 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7290 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]7291</pre>
7292
7293<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7294 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7295 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7296 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7297 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]7298</pre>
7299
7300<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7301 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7302 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7303 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7304 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]7305</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7306
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7307<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7309 the value stored in memory at <tt>ptr</tt>. It yields the original value
7310 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7312<h5>Arguments:</h5>
7313<p>These intrinsics take two arguments, the first a pointer to an integer value
7314 and the second an integer value. The result is also an integer value. These
7315 integer types can have any bit width, but they must all have the same bit
7316 width. The targets may only lower integer representations they support.</p>
7317
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319<p>These intrinsics does a series of operations atomically. They first load the
7320 value stored at <tt>ptr</tt>. They then do the bitwise
7321 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7322 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7323
7324<h5>Examples:</h5>
7325<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7326%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7327%ptr = bitcast i8* %mallocP to i32*
7328 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7329%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7330 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7331%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7332 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7333%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7334 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7335%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7336 <i>; yields {i32}:result3 = FF</i>
7337%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7338</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7340</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7341
7342<!-- _______________________________________________________________________ -->
7343<div class="doc_subsubsection">
7344 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7345 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7346 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7347 <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]7348</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7350<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7351
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7352<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7353<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7354 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7355 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7356 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7357
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7358<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7359 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7360 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7361 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7362 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]7363</pre>
7364
7365<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7366 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7367 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7368 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7369 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]7370</pre>
7371
7372<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7373 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7374 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7375 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7376 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]7377</pre>
7378
7379<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7380 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7381 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7382 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7383 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]7384</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7385
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7386<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7387<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7389 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7390
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7391<h5>Arguments:</h5>
7392<p>These intrinsics take two arguments, the first a pointer to an integer value
7393 and the second an integer value. The result is also an integer value. These
7394 integer types can have any bit width, but they must all have the same bit
7395 width. The targets may only lower integer representations they support.</p>
7396
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7397<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7398<p>These intrinsics does a series of operations atomically. They first load the
7399 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7400 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7401 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7402
7403<h5>Examples:</h5>
7404<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7405%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7406%ptr = bitcast i8* %mallocP to i32*
7407 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7408%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7409 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7410%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7411 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7412%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7413 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7414%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7415 <i>; yields {i32}:result3 = 8</i>
7416%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7417</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7420
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7421
7422<!-- ======================================================================= -->
7423<div class="doc_subsection">
7424 <a name="int_memorymarkers">Memory Use Markers</a>
7425</div>
7426
7427<div class="doc_text">
7428
7429<p>This class of intrinsics exists to information about the lifetime of memory
7430 objects and ranges where variables are immutable.</p>
7431
7432</div>
7433
7434<!-- _______________________________________________________________________ -->
7435<div class="doc_subsubsection">
7436 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7437</div>
7438
7439<div class="doc_text">
7440
7441<h5>Syntax:</h5>
7442<pre>
7443 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7444</pre>
7445
7446<h5>Overview:</h5>
7447<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7448 object's lifetime.</p>
7449
7450<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7451<p>The first argument is a constant integer representing the size of the
7452 object, or -1 if it is variable sized. The second argument is a pointer to
7453 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7454
7455<h5>Semantics:</h5>
7456<p>This intrinsic indicates that before this point in the code, the value of the
7457 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]7458 never be used and has an undefined value. A load from the pointer that
7459 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7460 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7461
7462</div>
7463
7464<!-- _______________________________________________________________________ -->
7465<div class="doc_subsubsection">
7466 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7467</div>
7468
7469<div class="doc_text">
7470
7471<h5>Syntax:</h5>
7472<pre>
7473 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7474</pre>
7475
7476<h5>Overview:</h5>
7477<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7478 object's lifetime.</p>
7479
7480<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7481<p>The first argument is a constant integer representing the size of the
7482 object, or -1 if it is variable sized. The second argument is a pointer to
7483 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7484
7485<h5>Semantics:</h5>
7486<p>This intrinsic indicates that after this point in the code, the value of the
7487 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7488 never be used and has an undefined value. Any stores into the memory object
7489 following this intrinsic may be removed as dead.
7490
7491</div>
7492
7493<!-- _______________________________________________________________________ -->
7494<div class="doc_subsubsection">
7495 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7496</div>
7497
7498<div class="doc_text">
7499
7500<h5>Syntax:</h5>
7501<pre>
7502 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7503</pre>
7504
7505<h5>Overview:</h5>
7506<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7507 a memory object will not change.</p>
7508
7509<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7510<p>The first argument is a constant integer representing the size of the
7511 object, or -1 if it is variable sized. The second argument is a pointer to
7512 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7513
7514<h5>Semantics:</h5>
7515<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7516 the return value, the referenced memory location is constant and
7517 unchanging.</p>
7518
7519</div>
7520
7521<!-- _______________________________________________________________________ -->
7522<div class="doc_subsubsection">
7523 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7524</div>
7525
7526<div class="doc_text">
7527
7528<h5>Syntax:</h5>
7529<pre>
7530 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7531</pre>
7532
7533<h5>Overview:</h5>
7534<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7535 a memory object are mutable.</p>
7536
7537<h5>Arguments:</h5>
7538<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7539 The second argument is a constant integer representing the size of the
7540 object, or -1 if it is variable sized and the third argument is a pointer
7541 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7542
7543<h5>Semantics:</h5>
7544<p>This intrinsic indicates that the memory is mutable again.</p>
7545
7546</div>
7547
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7548<!-- ======================================================================= -->
7549<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7550 <a name="int_general">General Intrinsics</a>
7551</div>
7552
7553<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7554
7555<p>This class of intrinsics is designed to be generic and has no specific
7556 purpose.</p>
7557
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7558</div>
7559
7560<!-- _______________________________________________________________________ -->
7561<div class="doc_subsubsection">
7562 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7563</div>
7564
7565<div class="doc_text">
7566
7567<h5>Syntax:</h5>
7568<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7569 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]7570</pre>
7571
7572<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7573<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7574
7575<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7576<p>The first argument is a pointer to a value, the second is a pointer to a
7577 global string, the third is a pointer to a global string which is the source
7578 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7579
7580<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7581<p>This intrinsic allows annotation of local variables with arbitrary strings.
7582 This can be useful for special purpose optimizations that want to look for
7583 these annotations. These have no other defined use, they are ignored by code
7584 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7585
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7586</div>
7587
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7588<!-- _______________________________________________________________________ -->
7589<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7590 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7591</div>
7592
7593<div class="doc_text">
7594
7595<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7596<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7597 any integer bit width.</p>
7598
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7599<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7600 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7601 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7602 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7603 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7604 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]7605</pre>
7606
7607<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7608<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7609
7610<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7611<p>The first argument is an integer value (result of some expression), the
7612 second is a pointer to a global string, the third is a pointer to a global
7613 string which is the source file name, and the last argument is the line
7614 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7615
7616<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7617<p>This intrinsic allows annotations to be put on arbitrary expressions with
7618 arbitrary strings. This can be useful for special purpose optimizations that
7619 want to look for these annotations. These have no other defined use, they
7620 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7621
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7622</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7623
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7624<!-- _______________________________________________________________________ -->
7625<div class="doc_subsubsection">
7626 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7627</div>
7628
7629<div class="doc_text">
7630
7631<h5>Syntax:</h5>
7632<pre>
7633 declare void @llvm.trap()
7634</pre>
7635
7636<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7637<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7638
7639<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7640<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7641
7642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7643<p>This intrinsics is lowered to the target dependent trap instruction. If the
7644 target does not have a trap instruction, this intrinsic will be lowered to
7645 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7646
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7647</div>
7648
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7649<!-- _______________________________________________________________________ -->
7650<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7651 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7652</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7653
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7654<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7655
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7656<h5>Syntax:</h5>
7657<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7658 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7659</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7660
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7661<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7662<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7663 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7664 ensure that it is placed on the stack before local variables.</p>
7665
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7666<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7667<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7668 arguments. The first argument is the value loaded from the stack
7669 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7670 that has enough space to hold the value of the guard.</p>
7671
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7672<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7673<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7674 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7675 stack. This is to ensure that if a local variable on the stack is
7676 overwritten, it will destroy the value of the guard. When the function exits,
7677 the guard on the stack is checked against the original guard. If they're
7678 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7679 function.</p>
7680
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7681</div>
7682
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7683<!-- _______________________________________________________________________ -->
7684<div class="doc_subsubsection">
7685 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7686</div>
7687
7688<div class="doc_text">
7689
7690<h5>Syntax:</h5>
7691<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7692 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7693 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7694</pre>
7695
7696<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7697<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7698 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7699 operation like memcpy will either overflow a buffer that corresponds to
7700 an object, or b) to determine that a runtime check for overflow isn't
7701 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7702 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7703
7704<h5>Arguments:</h5>
7705<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7706 argument is a pointer to or into the <tt>object</tt>. The second argument
7707 is a boolean 0 or 1. This argument determines whether you want the
7708 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7709 1, variables are not allowed.</p>
7710
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7711<h5>Semantics:</h5>
7712<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7713 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7714 (depending on the <tt>type</tt> argument if the size cannot be determined
7715 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7716
7717</div>
7718
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7719<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7720<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7721<address>
7722 <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]7724 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7726
7727 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7728 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7729 Last modified: $Date$
7730</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7731
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7732</body>
7733</html>