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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 852dda46251f50286b6d83425f39e20a5c7592e9 / . / 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>
1135 <dd>This attribute indicates that the prologue should contain a 'hotpatch'
1136 sequence at the beginning. This is the same sequence used in the
1137 system DLLs in Microsoft Windows XP Service Pack 2 and higher.</dd>
1138
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1139 <dt><tt><b>inlinehint</b></tt></dt>
1140 <dd>This attribute indicates that the source code contained a hint that inlining
1141 this function is desirable (such as the "inline" keyword in C/C++). It
1142 is just a hint; it imposes no requirements on the inliner.</dd>
1143
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1144 <dt><tt><b>naked</b></tt></dt>
1145 <dd>This attribute disables prologue / epilogue emission for the function.
1146 This can have very system-specific consequences.</dd>
1147
1148 <dt><tt><b>noimplicitfloat</b></tt></dt>
1149 <dd>This attributes disables implicit floating point instructions.</dd>
1150
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1151 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1152 <dd>This attribute indicates that the inliner should never inline this
1153 function in any situation. This attribute may not be used together with
1154 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1155
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1156 <dt><tt><b>noredzone</b></tt></dt>
1157 <dd>This attribute indicates that the code generator should not use a red
1158 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1159
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This function attribute indicates that the function never returns
1162 normally. This produces undefined behavior at runtime if the function
1163 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1164
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1165 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1166 <dd>This function attribute indicates that the function never returns with an
1167 unwind or exceptional control flow. If the function does unwind, its
1168 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1169
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1170 <dt><tt><b>optsize</b></tt></dt>
1171 <dd>This attribute suggests that optimization passes and code generator passes
1172 make choices that keep the code size of this function low, and otherwise
1173 do optimizations specifically to reduce code size.</dd>
1174
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function computes its result (or decides
1177 to unwind an exception) based strictly on its arguments, without
1178 dereferencing any pointer arguments or otherwise accessing any mutable
1179 state (e.g. memory, control registers, etc) visible to caller functions.
1180 It does not write through any pointer arguments
1181 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1182 changes any state visible to callers. This means that it cannot unwind
1183 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1184 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1185
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function does not write through any
1188 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1189 arguments) or otherwise modify any state (e.g. memory, control registers,
1190 etc) visible to caller functions. It may dereference pointer arguments
1191 and read state that may be set in the caller. A readonly function always
1192 returns the same value (or unwinds an exception identically) when called
1193 with the same set of arguments and global state. It cannot unwind an
1194 exception by calling the <tt>C++</tt> exception throwing methods, but may
1195 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1196
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute indicates that the function should emit a stack smashing
1199 protector. It is in the form of a "canary"&mdash;a random value placed on
1200 the stack before the local variables that's checked upon return from the
1201 function to see if it has been overwritten. A heuristic is used to
1202 determine if a function needs stack protectors or not.<br>
1203<br>
1204 If a function that has an <tt>ssp</tt> attribute is inlined into a
1205 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1206 function will have an <tt>ssp</tt> attribute.</dd>
1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute indicates that the function should <em>always</em> emit a
1210 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1211 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1212<br>
1213 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1214 function that doesn't have an <tt>sspreq</tt> attribute or which has
1215 an <tt>ssp</tt> attribute, then the resulting function will have
1216 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1217</dl>
1218
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1219</div>
1220
1221<!-- ======================================================================= -->
1222<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1223 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1224</div>
1225
1226<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1227
1228<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1229 the GCC "file scope inline asm" blocks. These blocks are internally
1230 concatenated by LLVM and treated as a single unit, but may be separated in
1231 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1233<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1234module asm "inline asm code goes here"
1235module asm "more can go here"
1236</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1237
1238<p>The strings can contain any character by escaping non-printable characters.
1239 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]1240 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1241
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1242<p>The inline asm code is simply printed to the machine code .s file when
1243 assembly code is generated.</p>
1244
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1245</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1246
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1247<!-- ======================================================================= -->
1248<div class="doc_subsection">
1249 <a name="datalayout">Data Layout</a>
1250</div>
1251
1252<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1253
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1254<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1255 data is to be laid out in memory. The syntax for the data layout is
1256 simply:</p>
1257
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1258<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1259target datalayout = "<i>layout specification</i>"
1260</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1261
1262<p>The <i>layout specification</i> consists of a list of specifications
1263 separated by the minus sign character ('-'). Each specification starts with
1264 a letter and may include other information after the letter to define some
1265 aspect of the data layout. The specifications accepted are as follows:</p>
1266
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1267<dl>
1268 <dt><tt>E</tt></dt>
1269 <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]1270 bits with the most significance have the lowest address location.</dd>
1271
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1272 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1273 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1274 the bits with the least significance have the lowest address
1275 location.</dd>
1276
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1277 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1278 <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]1279 <i>preferred</i> alignments. All sizes are in bits. Specifying
1280 the <i>pref</i> alignment is optional. If omitted, the
1281 preceding <tt>:</tt> should be omitted too.</dd>
1282
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1283 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1284 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1285 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1286
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1287 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1288 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1289 <i>size</i>.</dd>
1290
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1291 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1292 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1293 <i>size</i>. Only values of <i>size</i> that are supported by the target
1294 will work. 32 (float) and 64 (double) are supported on all targets;
1295 80 or 128 (different flavors of long double) are also supported on some
1296 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1297
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1298 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1299 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1300 <i>size</i>.</dd>
1301
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1302 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1303 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1305
1306 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1307 <dd>This specifies a set of native integer widths for the target CPU
1308 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1309 "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]1310 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1311 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1312</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1313
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1314<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1315 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1316 specifications in the <tt>datalayout</tt> keyword. The default specifications
1317 are given in this list:</p>
1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319<ul>
1320 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1321 <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]1322 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1323 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1324 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1325 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1326 <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]1327 alignment of 64-bits</li>
1328 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1329 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1330 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1331 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1332 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1333 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1335
1336<p>When LLVM is determining the alignment for a given type, it uses the
1337 following rules:</p>
1338
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1339<ol>
1340 <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]1341 specification is used.</li>
1342
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1343 <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]1344 smallest integer type that is larger than the bitwidth of the sought type
1345 is used. If none of the specifications are larger than the bitwidth then
1346 the the largest integer type is used. For example, given the default
1347 specifications above, the i7 type will use the alignment of i8 (next
1348 largest) while both i65 and i256 will use the alignment of i64 (largest
1349 specified).</li>
1350
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1351 <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]1352 largest vector type that is smaller than the sought vector type will be
1353 used as a fall back. This happens because &lt;128 x double&gt; can be
1354 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1355</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1356
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1357</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1358
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1359<!-- ======================================================================= -->
1360<div class="doc_subsection">
1361 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1362</div>
1363
1364<div class="doc_text">
1365
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1366<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1367with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1368is undefined. Pointer values are associated with address ranges
1369according to the following rules:</p>
1370
1371<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1372 <li>A pointer value is associated with the addresses associated with
1373 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1374 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1375 range of the variable's storage.</li>
1376 <li>The result value of an allocation instruction is associated with
1377 the address range of the allocated storage.</li>
1378 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1379 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1385</ul>
1386
1387<p>A pointer value is <i>based</i> on another pointer value according
1388 to the following rules:</p>
1389
1390<ul>
1391 <li>A pointer value formed from a
1392 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1393 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1394 <li>The result value of a
1395 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1396 of the <tt>bitcast</tt>.</li>
1397 <li>A pointer value formed by an
1398 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1399 pointer values that contribute (directly or indirectly) to the
1400 computation of the pointer's value.</li>
1401 <li>The "<i>based</i> on" relationship is transitive.</li>
1402</ul>
1403
1404<p>Note that this definition of <i>"based"</i> is intentionally
1405 similar to the definition of <i>"based"</i> in C99, though it is
1406 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1407
1408<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1409<tt><a href="#i_load">load</a></tt> merely indicates the size and
1410alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1411interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1412<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1413and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1414
1415<p>Consequently, type-based alias analysis, aka TBAA, aka
1416<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1417LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1418additional information which specialized optimization passes may use
1419to implement type-based alias analysis.</p>
1420
1421</div>
1422
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1423<!-- ======================================================================= -->
1424<div class="doc_subsection">
1425 <a name="volatile">Volatile Memory Accesses</a>
1426</div>
1427
1428<div class="doc_text">
1429
1430<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1431href="#i_store"><tt>store</tt></a>s, and <a
1432href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1433The optimizers must not change the number of volatile operations or change their
1434order of execution relative to other volatile operations. The optimizers
1435<i>may</i> change the order of volatile operations relative to non-volatile
1436operations. This is not Java's "volatile" and has no cross-thread
1437synchronization behavior.</p>
1438
1439</div>
1440
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1441<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1442<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1443<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1445<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1446
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1447<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1448 intermediate representation. Being typed enables a number of optimizations
1449 to be performed on the intermediate representation directly, without having
1450 to do extra analyses on the side before the transformation. A strong type
1451 system makes it easier to read the generated code and enables novel analyses
1452 and transformations that are not feasible to perform on normal three address
1453 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1454
1455</div>
1456
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1457<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1458<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1459Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1461<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1462
1463<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1464
1465<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1466 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1467 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1469 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1470 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1471 </tr>
1472 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1473 <td><a href="#t_floating">floating point</a></td>
1474 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1475 </tr>
1476 <tr>
1477 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1478 <td><a href="#t_integer">integer</a>,
1479 <a href="#t_floating">floating point</a>,
1480 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1481 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1482 <a href="#t_struct">structure</a>,
1483 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1484 <a href="#t_label">label</a>,
1485 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1486 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488 <tr>
1489 <td><a href="#t_primitive">primitive</a></td>
1490 <td><a href="#t_label">label</a>,
1491 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1492 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1493 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1494 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1495 </tr>
1496 <tr>
1497 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1498 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499 <a href="#t_function">function</a>,
1500 <a href="#t_pointer">pointer</a>,
1501 <a href="#t_struct">structure</a>,
1502 <a href="#t_pstruct">packed structure</a>,
1503 <a href="#t_vector">vector</a>,
1504 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1505 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1507 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1508</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1509
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1510<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1511 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1512 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1514</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1516<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1518
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1520
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1521<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1522 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1523
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1524</div>
1525
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1526<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1527<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1528
1529<div class="doc_text">
1530
1531<h5>Overview:</h5>
1532<p>The integer type is a very simple type that simply specifies an arbitrary
1533 bit width for the integer type desired. Any bit width from 1 bit to
1534 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1535
1536<h5>Syntax:</h5>
1537<pre>
1538 iN
1539</pre>
1540
1541<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1542 value.</p>
1543
1544<h5>Examples:</h5>
1545<table class="layout">
1546 <tr class="layout">
1547 <td class="left"><tt>i1</tt></td>
1548 <td class="left">a single-bit integer.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>i32</tt></td>
1552 <td class="left">a 32-bit integer.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>i1942652</tt></td>
1556 <td class="left">a really big integer of over 1 million bits.</td>
1557 </tr>
1558</table>
1559
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1560</div>
1561
1562<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1563<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1564
1565<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1566
1567<table>
1568 <tbody>
1569 <tr><th>Type</th><th>Description</th></tr>
1570 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1571 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1572 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1573 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1574 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1575 </tbody>
1576</table>
1577
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1578</div>
1579
1580<!-- _______________________________________________________________________ -->
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1581<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1582
1583<div class="doc_text">
1584
1585<h5>Overview:</h5>
1586<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>
1587
1588<h5>Syntax:</h5>
1589<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1590 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1591</pre>
1592
1593</div>
1594
1595<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1596<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1597
1598<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1599
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1600<h5>Overview:</h5>
1601<p>The void type does not represent any value and has no size.</p>
1602
1603<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1604<pre>
1605 void
1606</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1607
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1608</div>
1609
1610<!-- _______________________________________________________________________ -->
1611<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1612
1613<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1614
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1615<h5>Overview:</h5>
1616<p>The label type represents code labels.</p>
1617
1618<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1619<pre>
1620 label
1621</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1622
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1623</div>
1624
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1625<!-- _______________________________________________________________________ -->
1626<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1627
1628<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1629
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1630<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1631<p>The metadata type represents embedded metadata. No derived types may be
1632 created from metadata except for <a href="#t_function">function</a>
1633 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1634
1635<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1636<pre>
1637 metadata
1638</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1639
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1640</div>
1641
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1642
1643<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1645
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1646<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1648<p>The real power in LLVM comes from the derived types in the system. This is
1649 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1650 useful types. Each of these types contain one or more element types which
1651 may be a primitive type, or another derived type. For example, it is
1652 possible to have a two dimensional array, using an array as the element type
1653 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1654
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1655
1656</div>
1657
1658<!-- _______________________________________________________________________ -->
1659<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1660
1661<div class="doc_text">
1662
1663<p>Aggregate Types are a subset of derived types that can contain multiple
1664 member types. <a href="#t_array">Arrays</a>,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1665 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1666 aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1667
1668</div>
1669
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1670<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1673<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1677 sequentially in memory. The array type requires a size (number of elements)
1678 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1679
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1680<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1681<pre>
1682 [&lt;# elements&gt; x &lt;elementtype&gt;]
1683</pre>
1684
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1685<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1686 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1687
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1688<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1689<table class="layout">
1690 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1691 <td class="left"><tt>[40 x i32]</tt></td>
1692 <td class="left">Array of 40 32-bit integer values.</td>
1693 </tr>
1694 <tr class="layout">
1695 <td class="left"><tt>[41 x i32]</tt></td>
1696 <td class="left">Array of 41 32-bit integer values.</td>
1697 </tr>
1698 <tr class="layout">
1699 <td class="left"><tt>[4 x i8]</tt></td>
1700 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1701 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1702</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1703<p>Here are some examples of multidimensional arrays:</p>
1704<table class="layout">
1705 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1706 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1707 <td class="left">3x4 array of 32-bit integer values.</td>
1708 </tr>
1709 <tr class="layout">
1710 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1711 <td class="left">12x10 array of single precision floating point values.</td>
1712 </tr>
1713 <tr class="layout">
1714 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1715 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1716 </tr>
1717</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1718
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1719<p>There is no restriction on indexing beyond the end of the array implied by
1720 a static type (though there are restrictions on indexing beyond the bounds
1721 of an allocated object in some cases). This means that single-dimension
1722 'variable sized array' addressing can be implemented in LLVM with a zero
1723 length array type. An implementation of 'pascal style arrays' in LLVM could
1724 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1725
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1726</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1729<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1734<p>The function type can be thought of as a function signature. It consists of
1735 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]1736 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1739<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1740 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1741</pre>
1742
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1743<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]1744 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1745 which indicates that the function takes a variable number of arguments.
1746 Variable argument functions can access their arguments with
1747 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1748 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1749 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1750
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1751<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1752<table class="layout">
1753 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1754 <td class="left"><tt>i32 (i32)</tt></td>
1755 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1756 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1757 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1758 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1759 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1760 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1761 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1762 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1763 </td>
1764 </tr><tr class="layout">
1765 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1766 <td class="left">A vararg function that takes at least one
1767 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1768 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1769 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1770 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1771 </tr><tr class="layout">
1772 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1773 <td class="left">A function taking an <tt>i32</tt>, returning a
1774 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1775 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1776 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1777</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1779</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1782<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1784<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1787<p>The structure type is used to represent a collection of data members together
1788 in memory. The packing of the field types is defined to match the ABI of the
1789 underlying processor. The elements of a structure may be any type that has a
1790 size.</p>
1791
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1792<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1793 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1794 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1795 Structures in registers are accessed using the
1796 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1797 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1799<pre>
1800 { &lt;type list&gt; }
1801</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1804<table class="layout">
1805 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1806 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1807 <td class="left">A triple of three <tt>i32</tt> values</td>
1808 </tr><tr class="layout">
1809 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1810 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1811 second element is a <a href="#t_pointer">pointer</a> to a
1812 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1813 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1814 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1815</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1817</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1820<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1821</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1824
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1825<h5>Overview:</h5>
1826<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1827 together in memory. There is no padding between fields. Further, the
1828 alignment of a packed structure is 1 byte. The elements of a packed
1829 structure may be any type that has a size.</p>
1830
1831<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1832 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1833 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1834
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1835<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1836<pre>
1837 &lt; { &lt;type list&gt; } &gt;
1838</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1839
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1840<h5>Examples:</h5>
1841<table class="layout">
1842 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1843 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1844 <td class="left">A triple of three <tt>i32</tt> values</td>
1845 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1846 <td class="left">
1847<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1848 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1849 second element is a <a href="#t_pointer">pointer</a> to a
1850 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1851 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1852 </tr>
1853</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1854
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1855</div>
1856
1857<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1858<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1859
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1860<div class="doc_text">
1861
1862<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1863<p>The pointer type is used to specify memory locations.
1864 Pointers are commonly used to reference objects in memory.</p>
1865
1866<p>Pointer types may have an optional address space attribute defining the
1867 numbered address space where the pointed-to object resides. The default
1868 address space is number zero. The semantics of non-zero address
1869 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1870
1871<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1872 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1873
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1874<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1875<pre>
1876 &lt;type&gt; *
1877</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1878
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1879<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1880<table class="layout">
1881 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1882 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1883 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1884 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1885 </tr>
1886 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1887 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1888 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1889 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1890 <tt>i32</tt>.</td>
1891 </tr>
1892 <tr class="layout">
1893 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1894 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1895 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1896 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1897</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1898
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1899</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1900
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1901<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1902<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1904<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1905
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1906<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1907<p>A vector type is a simple derived type that represents a vector of elements.
1908 Vector types are used when multiple primitive data are operated in parallel
1909 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1910 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1911 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1912
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1913<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1914<pre>
1915 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1916</pre>
1917
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]1918<p>The number of elements is a constant integer value larger than 0; elementtype
1919 may be any integer or floating point type. Vectors of size zero are not
1920 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1923<table class="layout">
1924 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1925 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1926 <td class="left">Vector of 4 32-bit integer values.</td>
1927 </tr>
1928 <tr class="layout">
1929 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1930 <td class="left">Vector of 8 32-bit floating-point values.</td>
1931 </tr>
1932 <tr class="layout">
1933 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1934 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1935 </tr>
1936</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938</div>
1939
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1940<!-- _______________________________________________________________________ -->
1941<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1942<div class="doc_text">
1943
1944<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1945<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1946 corresponds (for example) to the C notion of a forward declared structure
1947 type. In LLVM, opaque types can eventually be resolved to any type (not just
1948 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1949
1950<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1951<pre>
1952 opaque
1953</pre>
1954
1955<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1956<table class="layout">
1957 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1958 <td class="left"><tt>opaque</tt></td>
1959 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960 </tr>
1961</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1962
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1963</div>
1964
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1965<!-- ======================================================================= -->
1966<div class="doc_subsection">
1967 <a name="t_uprefs">Type Up-references</a>
1968</div>
1969
1970<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1971
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1973<p>An "up reference" allows you to refer to a lexically enclosing type without
1974 requiring it to have a name. For instance, a structure declaration may
1975 contain a pointer to any of the types it is lexically a member of. Example
1976 of up references (with their equivalent as named type declarations)
1977 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1978
1979<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1980 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1981 { \2 }* %y = type { %y }*
1982 \1* %z = type %z*
1983</pre>
1984
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1985<p>An up reference is needed by the asmprinter for printing out cyclic types
1986 when there is no declared name for a type in the cycle. Because the
1987 asmprinter does not want to print out an infinite type string, it needs a
1988 syntax to handle recursive types that have no names (all names are optional
1989 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1990
1991<h5>Syntax:</h5>
1992<pre>
1993 \&lt;level&gt;
1994</pre>
1995
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1996<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]1997
1998<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1999<table class="layout">
2000 <tr class="layout">
2001 <td class="left"><tt>\1*</tt></td>
2002 <td class="left">Self-referential pointer.</td>
2003 </tr>
2004 <tr class="layout">
2005 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2006 <td class="left">Recursive structure where the upref refers to the out-most
2007 structure.</td>
2008 </tr>
2009</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2011</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2012
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2013<!-- *********************************************************************** -->
2014<div class="doc_section"> <a name="constants">Constants</a> </div>
2015<!-- *********************************************************************** -->
2016
2017<div class="doc_text">
2018
2019<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2020 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2021
2022</div>
2023
2024<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2025<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2026
2027<div class="doc_text">
2028
2029<dl>
2030 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2031 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2032 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2033
2034 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035 <dd>Standard integers (such as '4') are constants of
2036 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2037 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2038
2039 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2040 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2042 notation (see below). The assembler requires the exact decimal value of a
2043 floating-point constant. For example, the assembler accepts 1.25 but
2044 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2045 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046
2047 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2048 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2049 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2050</dl>
2051
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2052<p>The one non-intuitive notation for constants is the hexadecimal form of
2053 floating point constants. For example, the form '<tt>double
2054 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2055 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2056 constants are required (and the only time that they are generated by the
2057 disassembler) is when a floating point constant must be emitted but it cannot
2058 be represented as a decimal floating point number in a reasonable number of
2059 digits. For example, NaN's, infinities, and other special values are
2060 represented in their IEEE hexadecimal format so that assembly and disassembly
2061 do not cause any bits to change in the constants.</p>
2062
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2063<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 represented using the 16-digit form shown above (which matches the IEEE754
2065 representation for double); float values must, however, be exactly
2066 representable as IEE754 single precision. Hexadecimal format is always used
2067 for long double, and there are three forms of long double. The 80-bit format
2068 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2069 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2070 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2071 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2072 currently supported target uses this format. Long doubles will only work if
2073 they match the long double format on your target. All hexadecimal formats
2074 are big-endian (sign bit at the left).</p>
2075
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2076<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2077</div>
2078
2079<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2080<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2081<a name="aggregateconstants"></a> <!-- old anchor -->
2082<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2083</div>
2084
2085<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2086
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2087<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2088 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2089
2090<dl>
2091 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2092 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2093 type definitions (a comma separated list of elements, surrounded by braces
2094 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2095 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2096 Structure constants must have <a href="#t_struct">structure type</a>, and
2097 the number and types of elements must match those specified by the
2098 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099
2100 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2101 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102 definitions (a comma separated list of elements, surrounded by square
2103 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2104 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2105 the number and types of elements must match those specified by the
2106 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2107
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2108 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2109 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2110 definitions (a comma separated list of elements, surrounded by
2111 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2112 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2113 have <a href="#t_vector">vector type</a>, and the number and types of
2114 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2115
2116 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2117 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2118 value to zero of <em>any</em> type, including scalar and
2119 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2120 This is often used to avoid having to print large zero initializers
2121 (e.g. for large arrays) and is always exactly equivalent to using explicit
2122 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2123
2124 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2125 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2126 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2127 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2128 be interpreted as part of the instruction stream, metadata is a place to
2129 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2130</dl>
2131
2132</div>
2133
2134<!-- ======================================================================= -->
2135<div class="doc_subsection">
2136 <a name="globalconstants">Global Variable and Function Addresses</a>
2137</div>
2138
2139<div class="doc_text">
2140
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2141<p>The addresses of <a href="#globalvars">global variables</a>
2142 and <a href="#functionstructure">functions</a> are always implicitly valid
2143 (link-time) constants. These constants are explicitly referenced when
2144 the <a href="#identifiers">identifier for the global</a> is used and always
2145 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2146 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2147
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2148<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2149@X = global i32 17
2150@Y = global i32 42
2151@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2152</pre>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2157<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2158<div class="doc_text">
2159
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2160<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]2161 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2162 Undefined values may be of any type (other than label or void) and be used
2163 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2164
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2165<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2166 program is well defined no matter what value is used. This gives the
2167 compiler more freedom to optimize. Here are some examples of (potentially
2168 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2169
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2170
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2171<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2172 %A = add %X, undef
2173 %B = sub %X, undef
2174 %C = xor %X, undef
2175Safe:
2176 %A = undef
2177 %B = undef
2178 %C = undef
2179</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2180
2181<p>This is safe because all of the output bits are affected by the undef bits.
2182Any output bit can have a zero or one depending on the input bits.</p>
2183
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2184<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2185 %A = or %X, undef
2186 %B = and %X, undef
2187Safe:
2188 %A = -1
2189 %B = 0
2190Unsafe:
2191 %A = undef
2192 %B = undef
2193</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2194
2195<p>These logical operations have bits that are not always affected by the input.
2196For example, if "%X" has a zero bit, then the output of the 'and' operation will
2197always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2198such, 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]2199However, it is safe to assume that all bits of the undef could be 0, and
2200optimize the and to 0. Likewise, it is safe to assume that all the bits of
2201the 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]2202-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2203
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2204<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2205 %A = select undef, %X, %Y
2206 %B = select undef, 42, %Y
2207 %C = select %X, %Y, undef
2208Safe:
2209 %A = %X (or %Y)
2210 %B = 42 (or %Y)
2211 %C = %Y
2212Unsafe:
2213 %A = undef
2214 %B = undef
2215 %C = undef
2216</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2217
2218<p>This set of examples show that undefined select (and conditional branch)
2219conditions can go "either way" but they have to come from one of the two
2220operands. In the %A example, if %X and %Y were both known to have a clear low
2221bit, then %A would have to have a cleared low bit. However, in the %C example,
2222the optimizer is allowed to assume that the undef operand could be the same as
2223%Y, allowing the whole select to be eliminated.</p>
2224
2225
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2226<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2227 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2228
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2229 %B = undef
2230 %C = xor %B, %B
2231
2232 %D = undef
2233 %E = icmp lt %D, 4
2234 %F = icmp gte %D, 4
2235
2236Safe:
2237 %A = undef
2238 %B = undef
2239 %C = undef
2240 %D = undef
2241 %E = undef
2242 %F = undef
2243</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2244
2245<p>This example points out that two undef operands are not necessarily the same.
2246This can be surprising to people (and also matches C semantics) where they
2247assume that "X^X" is always zero, even if X is undef. This isn't true for a
2248number of reasons, but the short answer is that an undef "variable" can
2249arbitrarily change its value over its "live range". This is true because the
2250"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2251logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2252so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2253to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2254would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2255
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2256<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2257 %A = fdiv undef, %X
2258 %B = fdiv %X, undef
2259Safe:
2260 %A = undef
2261b: unreachable
2262</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2263
2264<p>These examples show the crucial difference between an <em>undefined
2265value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2266allowed to have an arbitrary bit-pattern. This means that the %A operation
2267can be constant folded to undef because the undef could be an SNaN, and fdiv is
2268not (currently) defined on SNaN's. However, in the second example, we can make
2269a more aggressive assumption: because the undef is allowed to be an arbitrary
2270value, 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]2271has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2272does not execute at all. This allows us to delete the divide and all code after
2273it: since the undefined operation "can't happen", the optimizer can assume that
2274it occurs in dead code.
2275</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2276
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2277<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2278a: store undef -> %X
2279b: store %X -> undef
2280Safe:
2281a: &lt;deleted&gt;
2282b: unreachable
2283</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2284
2285<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2286can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2287overwritten with bits that happen to match what was already there. However, a
2288store "to" an undefined location could clobber arbitrary memory, therefore, it
2289has undefined behavior.</p>
2290
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2291</div>
2292
2293<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2294<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2295<div class="doc_text">
2296
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2297<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2298 instead of representing an unspecified bit pattern, they represent the
2299 fact that an instruction or constant expression which cannot evoke side
2300 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2301 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2302
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2303<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]2304 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2305 <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]2306
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2307<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2308
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2309<ul>
2310<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2311 their operands.</li>
2312
2313<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2314 to their dynamic predecessor basic block.</li>
2315
2316<li>Function arguments depend on the corresponding actual argument values in
2317 the dynamic callers of their functions.</li>
2318
2319<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2320 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2321 control back to them.</li>
2322
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2323<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2324 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2325 or exception-throwing call instructions that dynamically transfer control
2326 back to them.</li>
2327
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2328<li>Non-volatile loads and stores depend on the most recent stores to all of the
2329 referenced memory addresses, following the order in the IR
2330 (including loads and stores implied by intrinsics such as
2331 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2332
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2333<!-- TODO: In the case of multiple threads, this only applies if the store
2334 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2335
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2336<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2337
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2338<li>An instruction with externally visible side effects depends on the most
2339 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2340 the order in the IR. (This includes
2341 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2342
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2343<li>An instruction <i>control-depends</i> on a
2344 <a href="#terminators">terminator instruction</a>
2345 if the terminator instruction has multiple successors and the instruction
2346 is always executed when control transfers to one of the successors, and
2347 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2348
2349<li>Dependence is transitive.</li>
2350
2351</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2352
2353<p>Whenever a trap value is generated, all values which depend on it evaluate
2354 to trap. If they have side effects, the evoke their side effects as if each
2355 operand with a trap value were undef. If they have externally-visible side
2356 effects, the behavior is undefined.</p>
2357
2358<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2359
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2360<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2361entry:
2362 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2363 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2364 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2365 store i32 0, i32* %trap_yet_again ; undefined behavior
2366
2367 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2368 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2369
2370 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2371
2372 %narrowaddr = bitcast i32* @g to i16*
2373 %wideaddr = bitcast i32* @g to i64*
2374 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2375 %trap4 = load i64* %widaddr ; Returns a trap value.
2376
2377 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2378 %br i1 %cmp, %true, %end ; Branch to either destination.
2379
2380true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2381 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2382 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2383 br label %end
2384
2385end:
2386 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2387 ; Both edges into this PHI are
2388 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2389 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2390
2391 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2392 ; so this is defined (ignoring earlier
2393 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2394</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2395
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2396</div>
2397
2398<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2399<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2400 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2401<div class="doc_text">
2402
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2403<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2404
2405<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2406 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2407 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2408
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2409<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2410 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2411 against null. Pointer equality tests between labels addresses is undefined
2412 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2413 equal to the null pointer. This may also be passed around as an opaque
2414 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2415 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2416 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2417
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2418<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2419 using the value as the operand to an inline assembly, but that is target
2420 specific.
2421 </p>
2422
2423</div>
2424
2425
2426<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2427<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2428</div>
2429
2430<div class="doc_text">
2431
2432<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2433 to be used as constants. Constant expressions may be of
2434 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2435 operation that does not have side effects (e.g. load and call are not
2436 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2437
2438<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2439 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2440 <dd>Truncate a constant to another type. The bit size of CST must be larger
2441 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2442
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2443 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2444 <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]2445 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2446
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2447 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2448 <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]2449 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2450
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2451 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2452 <dd>Truncate a floating point constant to another floating point type. The
2453 size of CST must be larger than the size of TYPE. Both types must be
2454 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2455
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2456 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Floating point extend a constant to another type. The size of CST must be
2458 smaller or equal to the size of TYPE. Both types must be floating
2459 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2460
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2461 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2462 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2463 constant. TYPE must be a scalar or vector integer type. CST must be of
2464 scalar or vector floating point type. Both CST and TYPE must be scalars,
2465 or vectors of the same number of elements. If the value won't fit in the
2466 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2467
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2468 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2469 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2470 constant. TYPE must be a scalar or vector integer type. CST must be of
2471 scalar or vector floating point type. Both CST and TYPE must be scalars,
2472 or vectors of the same number of elements. If the value won't fit in the
2473 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2474
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2475 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2476 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2477 constant. TYPE must be a scalar or vector floating point type. CST must be
2478 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2479 vectors of the same number of elements. If the value won't fit in the
2480 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2481
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2482 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2483 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2484 constant. TYPE must be a scalar or vector floating point type. CST must be
2485 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2486 vectors of the same number of elements. If the value won't fit in the
2487 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2488
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2489 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2490 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2491 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2492 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2493 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2494
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2495 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2497 type. CST must be of integer type. The CST value is zero extended,
2498 truncated, or unchanged to make it fit in a pointer size. This one is
2499 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2500
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2501 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2502 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2503 are the same as those for the <a href="#i_bitcast">bitcast
2504 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2505
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2506 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2507 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2508 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2509 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2510 instruction, the index list may have zero or more indexes, which are
2511 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2512
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2513 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2514 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2515
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2517 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2518
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2520 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2521
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2523 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2524 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2525
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2526 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2528 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2529
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2530 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2531 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2532 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2533
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2534 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2535 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2536 constants. The index list is interpreted in a similar manner as indices in
2537 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2538 index value must be specified.</dd>
2539
2540 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2541 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2542 constants. The index list is interpreted in a similar manner as indices in
2543 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2544 index value must be specified.</dd>
2545
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2546 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2547 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2548 be any of the <a href="#binaryops">binary</a>
2549 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2550 on operands are the same as those for the corresponding instruction
2551 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2552</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2554</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2555
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2557<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2558<!-- *********************************************************************** -->
2559
2560<!-- ======================================================================= -->
2561<div class="doc_subsection">
2562<a name="inlineasm">Inline Assembler Expressions</a>
2563</div>
2564
2565<div class="doc_text">
2566
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567<p>LLVM supports inline assembler expressions (as opposed
2568 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2569 a special value. This value represents the inline assembler as a string
2570 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2571 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2572 expression has side effects, and a flag indicating whether the function
2573 containing the asm needs to align its stack conservatively. An example
2574 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2575
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2576<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2577i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2578</pre>
2579
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2580<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2581 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2582 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2583
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2584<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2585%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]2586</pre>
2587
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2588<p>Inline asms with side effects not visible in the constraint list must be
2589 marked as having side effects. This is done through the use of the
2590 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2591
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2592<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2593call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2594</pre>
2595
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2596<p>In some cases inline asms will contain code that will not work unless the
2597 stack is aligned in some way, such as calls or SSE instructions on x86,
2598 yet will not contain code that does that alignment within the asm.
2599 The compiler should make conservative assumptions about what the asm might
2600 contain and should generate its usual stack alignment code in the prologue
2601 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2602
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2603<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2604call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2605</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2606
2607<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2608 first.</p>
2609
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2610<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2611 documented here. Constraints on what can be done (e.g. duplication, moving,
2612 etc need to be documented). This is probably best done by reference to
2613 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2614</div>
2615
2616<div class="doc_subsubsection">
2617<a name="inlineasm_md">Inline Asm Metadata</a>
2618</div>
2619
2620<div class="doc_text">
2621
2622<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2623 attached to it that contains a constant integer. If present, the code
2624 generator will use the integer as the location cookie value when report
2625 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2626 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2627 source code that produced it. For example:</p>
2628
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2629<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2630call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2631...
2632!42 = !{ i32 1234567 }
2633</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2634
2635<p>It is up to the front-end to make sense of the magic numbers it places in the
2636 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2637
2638</div>
2639
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2640<!-- ======================================================================= -->
2641<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2642 Strings</a>
2643</div>
2644
2645<div class="doc_text">
2646
2647<p>LLVM IR allows metadata to be attached to instructions in the program that
2648 can convey extra information about the code to the optimizers and code
2649 generator. One example application of metadata is source-level debug
2650 information. There are two metadata primitives: strings and nodes. All
2651 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2652 preceding exclamation point ('<tt>!</tt>').</p>
2653
2654<p>A metadata string is a string surrounded by double quotes. It can contain
2655 any character by escaping non-printable characters with "\xx" where "xx" is
2656 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2657
2658<p>Metadata nodes are represented with notation similar to structure constants
2659 (a comma separated list of elements, surrounded by braces and preceded by an
2660 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2661 10}</tt>". Metadata nodes can have any values as their operand.</p>
2662
2663<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2664 metadata nodes, which can be looked up in the module symbol table. For
2665 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2666
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2667<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2668 function is using two metadata arguments.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2669
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2670 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2671 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2672 </pre>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2673
2674<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2675 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2676
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2677 <pre class="doc_code">
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2678 %indvar.next = add i64 %indvar, 1, !dbg !21
2679 </pre>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2680</div>
2681
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2682
2683<!-- *********************************************************************** -->
2684<div class="doc_section">
2685 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2686</div>
2687<!-- *********************************************************************** -->
2688
2689<p>LLVM has a number of "magic" global variables that contain data that affect
2690code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2691of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2692section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2693by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2694
2695<!-- ======================================================================= -->
2696<div class="doc_subsection">
2697<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2698</div>
2699
2700<div class="doc_text">
2701
2702<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2703href="#linkage_appending">appending linkage</a>. This array contains a list of
2704pointers to global variables and functions which may optionally have a pointer
2705cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2706
2707<pre>
2708 @X = global i8 4
2709 @Y = global i32 123
2710
2711 @llvm.used = appending global [2 x i8*] [
2712 i8* @X,
2713 i8* bitcast (i32* @Y to i8*)
2714 ], section "llvm.metadata"
2715</pre>
2716
2717<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2718compiler, assembler, and linker are required to treat the symbol as if there is
2719a reference to the global that it cannot see. For example, if a variable has
2720internal linkage and no references other than that from the <tt>@llvm.used</tt>
2721list, it cannot be deleted. This is commonly used to represent references from
2722inline asms and other things the compiler cannot "see", and corresponds to
2723"attribute((used))" in GNU C.</p>
2724
2725<p>On some targets, the code generator must emit a directive to the assembler or
2726object file to prevent the assembler and linker from molesting the symbol.</p>
2727
2728</div>
2729
2730<!-- ======================================================================= -->
2731<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2732<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2733</div>
2734
2735<div class="doc_text">
2736
2737<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2738<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2739touching the symbol. On targets that support it, this allows an intelligent
2740linker to optimize references to the symbol without being impeded as it would be
2741by <tt>@llvm.used</tt>.</p>
2742
2743<p>This is a rare construct that should only be used in rare circumstances, and
2744should not be exposed to source languages.</p>
2745
2746</div>
2747
2748<!-- ======================================================================= -->
2749<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2750<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2751</div>
2752
2753<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2754<pre>
2755%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2756@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2757</pre>
2758<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.
2759</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2760
2761</div>
2762
2763<!-- ======================================================================= -->
2764<div class="doc_subsection">
2765<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2766</div>
2767
2768<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2769<pre>
2770%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2771@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2772</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2773
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2774<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.
2775</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2776
2777</div>
2778
2779
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2780<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2781<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2782<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2784<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786<p>The LLVM instruction set consists of several different classifications of
2787 instructions: <a href="#terminators">terminator
2788 instructions</a>, <a href="#binaryops">binary instructions</a>,
2789 <a href="#bitwiseops">bitwise binary instructions</a>,
2790 <a href="#memoryops">memory instructions</a>, and
2791 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2792
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2793</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2795<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2796<div class="doc_subsection"> <a name="terminators">Terminator
2797Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2799<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2800
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2801<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2802 in a program ends with a "Terminator" instruction, which indicates which
2803 block should be executed after the current block is finished. These
2804 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2805 control flow, not values (the one exception being the
2806 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2807
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2808<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2810 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2811 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2812 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2813 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2814 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2815 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2817</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2819<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2820<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2821Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2826<pre>
2827 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]2828 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2829</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2833 a value) from a function back to the caller.</p>
2834
2835<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2836 value and then causes control flow, and one that just causes control flow to
2837 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2840<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2841 return value. The type of the return value must be a
2842 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2843
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2844<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2845 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2846 value or a return value with a type that does not match its type, or if it
2847 has a void return type and contains a '<tt>ret</tt>' instruction with a
2848 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2849
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2850<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2851<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2852 the calling function's context. If the caller is a
2853 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2854 instruction after the call. If the caller was an
2855 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2856 the beginning of the "normal" destination block. If the instruction returns
2857 a value, that value shall set the call or invoke instruction's return
2858 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2860<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2861<pre>
2862 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2863 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2864 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]2865</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2868<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2869<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2871<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2872
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2873<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<pre>
2875 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]2876</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2879<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2880 different basic block in the current function. There are two forms of this
2881 instruction, corresponding to a conditional branch and an unconditional
2882 branch.</p>
2883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2885<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2886 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2887 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2888 target.</p>
2889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2891<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2892 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2893 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2894 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2897<pre>
2898Test:
2899 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2900 br i1 %cond, label %IfEqual, label %IfUnequal
2901IfEqual:
2902 <a href="#i_ret">ret</a> i32 1
2903IfUnequal:
2904 <a href="#i_ret">ret</a> i32 0
2905</pre>
2906
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2907</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2909<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2910<div class="doc_subsubsection">
2911 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2912</div>
2913
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2914<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2915
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2916<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2917<pre>
2918 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2919</pre>
2920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2921<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2922<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]2923 several different places. It is a generalization of the '<tt>br</tt>'
2924 instruction, allowing a branch to occur to one of many possible
2925 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2926
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2927<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2928<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2929 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2930 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2931 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2933<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2934<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2935 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2936 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2937 transferred to the corresponding destination; otherwise, control flow is
2938 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2939
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2940<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2941<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2942 <tt>switch</tt> instruction, this instruction may be code generated in
2943 different ways. For example, it could be generated as a series of chained
2944 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2945
2946<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2947<pre>
2948 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2949 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2950 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2951
2952 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2953 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2954
2955 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2956 switch i32 %val, label %otherwise [ i32 0, label %onzero
2957 i32 1, label %onone
2958 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2959</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2960
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2961</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2962
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2963
2964<!-- _______________________________________________________________________ -->
2965<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2966 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2967</div>
2968
2969<div class="doc_text">
2970
2971<h5>Syntax:</h5>
2972<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2973 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]2974</pre>
2975
2976<h5>Overview:</h5>
2977
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2978<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2979 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2980 "<tt>address</tt>". Address must be derived from a <a
2981 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2982
2983<h5>Arguments:</h5>
2984
2985<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2986 rest of the arguments indicate the full set of possible destinations that the
2987 address may point to. Blocks are allowed to occur multiple times in the
2988 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2989
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2990<p>This destination list is required so that dataflow analysis has an accurate
2991 understanding of the CFG.</p>
2992
2993<h5>Semantics:</h5>
2994
2995<p>Control transfers to the block specified in the address argument. All
2996 possible destination blocks must be listed in the label list, otherwise this
2997 instruction has undefined behavior. This implies that jumps to labels
2998 defined in other functions have undefined behavior as well.</p>
2999
3000<h5>Implementation:</h5>
3001
3002<p>This is typically implemented with a jump through a register.</p>
3003
3004<h5>Example:</h5>
3005<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3006 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3007</pre>
3008
3009</div>
3010
3011
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3012<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3013<div class="doc_subsubsection">
3014 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3015</div>
3016
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3017<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3018
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3019<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3020<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3021 &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]3022 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3023</pre>
3024
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3025<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3026<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3027 function, with the possibility of control flow transfer to either the
3028 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3029 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3030 control flow will return to the "normal" label. If the callee (or any
3031 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3032 instruction, control is interrupted and continued at the dynamically nearest
3033 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3035<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3036<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3038<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3039 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3040 convention</a> the call should use. If none is specified, the call
3041 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3042
3043 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3045 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3046
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3047 <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]3048 function value being invoked. In most cases, this is a direct function
3049 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3050 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3051
3052 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3053 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3054
3055 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3056 signature argument types and parameter attributes. All arguments must be
3057 of <a href="#t_firstclass">first class</a> type. If the function
3058 signature indicates the function accepts a variable number of arguments,
3059 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3060
3061 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3063
3064 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3066
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3067 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3069 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3070</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3071
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073<p>This instruction is designed to operate as a standard
3074 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3075 primary difference is that it establishes an association with a label, which
3076 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3077
3078<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3079 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3080 exception. Additionally, this is important for implementation of
3081 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3082
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083<p>For the purposes of the SSA form, the definition of the value returned by the
3084 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3085 block to the "normal" label. If the callee unwinds then no return value is
3086 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3087
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3088<p>Note that the code generator does not yet completely support unwind, and
3089that the invoke/unwind semantics are likely to change in future versions.</p>
3090
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3091<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3092<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3093 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3094 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3095 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3096 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3097</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3098
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3099</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3100
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3101<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3102
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3103<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3104Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3105
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3106<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3107
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3108<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3109<pre>
3110 unwind
3111</pre>
3112
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3113<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3114<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115 at the first callee in the dynamic call stack which used
3116 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3117 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3118
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3119<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3120<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3121 immediately halt. The dynamic call stack is then searched for the
3122 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3123 Once found, execution continues at the "exceptional" destination block
3124 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3125 instruction in the dynamic call chain, undefined behavior results.</p>
3126
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3127<p>Note that the code generator does not yet completely support unwind, and
3128that the invoke/unwind semantics are likely to change in future versions.</p>
3129
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3130</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3131
3132<!-- _______________________________________________________________________ -->
3133
3134<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3135Instruction</a> </div>
3136
3137<div class="doc_text">
3138
3139<h5>Syntax:</h5>
3140<pre>
3141 unreachable
3142</pre>
3143
3144<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3145<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146 instruction is used to inform the optimizer that a particular portion of the
3147 code is not reachable. This can be used to indicate that the code after a
3148 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3149
3150<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3151<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3153</div>
3154
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3155<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3156<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3158<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3159
3160<p>Binary operators are used to do most of the computation in a program. They
3161 require two operands of the same type, execute an operation on them, and
3162 produce a single value. The operands might represent multiple data, as is
3163 the case with the <a href="#t_vector">vector</a> data type. The result value
3164 has the same type as its operands.</p>
3165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3166<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3168</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3170<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3171<div class="doc_subsubsection">
3172 <a name="i_add">'<tt>add</tt>' Instruction</a>
3173</div>
3174
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3175<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3176
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3177<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3178<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3179 &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]3180 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3181 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3182 &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]3183</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3185<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3186<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3187
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3188<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189<p>The two arguments to the '<tt>add</tt>' instruction must
3190 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3191 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3192
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3193<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3194<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3195
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196<p>If the sum has unsigned overflow, the result returned is the mathematical
3197 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]3198
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199<p>Because LLVM integers use a two's complement representation, this instruction
3200 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3202<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3203 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3204 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3205 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3206 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3208<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3209<pre>
3210 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3211</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3212
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3213</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3216<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3217 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3218</div>
3219
3220<div class="doc_text">
3221
3222<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3223<pre>
3224 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3225</pre>
3226
3227<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3228<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3229
3230<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3231<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3233 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3234
3235<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3236<p>The value produced is the floating point sum of the two operands.</p>
3237
3238<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3239<pre>
3240 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3241</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3243</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3245<!-- _______________________________________________________________________ -->
3246<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3247 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3248</div>
3249
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3250<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3253<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3254 &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]3255 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3256 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3257 &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]3258</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3259
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3260<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3261<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3263
3264<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265 '<tt>neg</tt>' instruction present in most other intermediate
3266 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3267
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3268<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3269<p>The two arguments to the '<tt>sub</tt>' instruction must
3270 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3271 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3272
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3273<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3274<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3275
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3276<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3277 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3278 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3279
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280<p>Because LLVM integers use a two's complement representation, this instruction
3281 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3283<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3284 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3285 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3286 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3287 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3289<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3290<pre>
3291 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3292 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3293</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3295</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3297<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3299 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3300</div>
3301
3302<div class="doc_text">
3303
3304<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3305<pre>
3306 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3307</pre>
3308
3309<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3310<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3311 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3312
3313<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314 '<tt>fneg</tt>' instruction present in most other intermediate
3315 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3316
3317<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3318<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3320 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3321
3322<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3323<p>The value produced is the floating point difference of the two operands.</p>
3324
3325<h5>Example:</h5>
3326<pre>
3327 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3328 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3329</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3331</div>
3332
3333<!-- _______________________________________________________________________ -->
3334<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3335 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3336</div>
3337
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3338<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3340<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3341<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3342 &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]3343 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3344 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3345 &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]3346</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3348<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352<p>The two arguments to the '<tt>mul</tt>' instruction must
3353 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3354 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3356<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3357<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3358
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359<p>If the result of the multiplication has unsigned overflow, the result
3360 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3361 width of the result.</p>
3362
3363<p>Because LLVM integers use a two's complement representation, and the result
3364 is the same width as the operands, this instruction returns the correct
3365 result for both signed and unsigned integers. If a full product
3366 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3367 be sign-extended or zero-extended as appropriate to the width of the full
3368 product.</p>
3369
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3370<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3371 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3372 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3373 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3374 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3375
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3376<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
3378 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3379</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3381</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3382
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3383<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3384<div class="doc_subsubsection">
3385 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3386</div>
3387
3388<div class="doc_text">
3389
3390<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3391<pre>
3392 &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]3393</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3395<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3396<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3397
3398<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3399<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3400 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3401 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3402
3403<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3404<p>The value produced is the floating point product of the two operands.</p>
3405
3406<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3407<pre>
3408 &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]3409</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3411</div>
3412
3413<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3414<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3415</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3416
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3417<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3419<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420<pre>
3421 &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]3422</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3424<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3425<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3426
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3427<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3428<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3430 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3431
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3432<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3433<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3434
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3435<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3436 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3437
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3438<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3439
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3440<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441<pre>
3442 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3443</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3445</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3446
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3447<!-- _______________________________________________________________________ -->
3448<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3449</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3451<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3453<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3454<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3455 &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]3456 &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]3457</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3458
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3459<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3461
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3462<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3463<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3464 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3465 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3466
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3467<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3468<p>The value produced is the signed integer quotient of the two operands rounded
3469 towards zero.</p>
3470
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3471<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3473
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3474<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3475 undefined behavior; this is a rare case, but can occur, for example, by doing
3476 a 32-bit division of -2147483648 by -1.</p>
3477
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3478<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3479 <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]3480 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3481
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3482<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483<pre>
3484 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3485</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489<!-- _______________________________________________________________________ -->
3490<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3491Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3492
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3493<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3495<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3496<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3497 &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]3498</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3500<h5>Overview:</h5>
3501<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3503<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3504<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3506 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3507
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3508<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3509<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3511<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3512<pre>
3513 &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]3514</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3515
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3516</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3517
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3518<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3519<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3520</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3522<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3524<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525<pre>
3526 &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]3527</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3529<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3531 division of its two arguments.</p>
3532
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3533<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3534<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3535 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3536 values. Both arguments must have identical types.</p>
3537
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3538<h5>Semantics:</h5>
3539<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3540 This instruction always performs an unsigned division to get the
3541 remainder.</p>
3542
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3543<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3545
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3546<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3547
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3548<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549<pre>
3550 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3551</pre>
3552
3553</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3554
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3555<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3556<div class="doc_subsubsection">
3557 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3558</div>
3559
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3560<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3563<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3564 &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]3565</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3566
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3567<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3568<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3569 division of its two operands. This instruction can also take
3570 <a href="#t_vector">vector</a> versions of the values in which case the
3571 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3572
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3573<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3574<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3576 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3577
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3578<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3579<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3580 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3581 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3582 a value. For more information about the difference,
3583 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3584 Math Forum</a>. For a table of how this is implemented in various languages,
3585 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3586 Wikipedia: modulo operation</a>.</p>
3587
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3588<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3589 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3590
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3591<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592 Overflow also leads to undefined behavior; this is a rare case, but can
3593 occur, for example, by taking the remainder of a 32-bit division of
3594 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3595 lets srem be implemented using instructions that return both the result of
3596 the division and the remainder.)</p>
3597
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3598<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3599<pre>
3600 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3601</pre>
3602
3603</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3604
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3605<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3606<div class="doc_subsubsection">
3607 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3608
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3609<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612<pre>
3613 &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]3614</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3615
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3616<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3618 its two operands.</p>
3619
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3620<h5>Arguments:</h5>
3621<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3623 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3624
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3625<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3626<p>This instruction returns the <i>remainder</i> of a division. The remainder
3627 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3628
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3629<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3630<pre>
3631 &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]3632</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3633
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3634</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3635
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3636<!-- ======================================================================= -->
3637<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3638Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3639
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3640<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641
3642<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3643 program. They are generally very efficient instructions and can commonly be
3644 strength reduced from other instructions. They require two operands of the
3645 same type, execute an operation on them, and produce a single value. The
3646 resulting value is the same type as its operands.</p>
3647
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3648</div>
3649
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3650<!-- _______________________________________________________________________ -->
3651<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3652Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3654<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3655
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3656<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3657<pre>
3658 &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]3659</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3660
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3661<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3663 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3664
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3665<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3666<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3667 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3668 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3669
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3670<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3671<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3672 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3673 is (statically or dynamically) negative or equal to or larger than the number
3674 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3675 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3676 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678<h5>Example:</h5>
3679<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3680 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3681 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3682 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3683 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3684 &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]3685</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3687</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3689<!-- _______________________________________________________________________ -->
3690<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3691Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3693<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3695<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696<pre>
3697 &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]3698</pre>
3699
3700<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3702 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3703
3704<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3705<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3707 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3708
3709<h5>Semantics:</h5>
3710<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711 significant bits of the result will be filled with zero bits after the shift.
3712 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3713 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3714 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3715 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3716
3717<h5>Example:</h5>
3718<pre>
3719 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3720 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3721 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3722 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3723 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3724 &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]3725</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3727</div>
3728
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3729<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3730<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3731Instruction</a> </div>
3732<div class="doc_text">
3733
3734<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3735<pre>
3736 &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]3737</pre>
3738
3739<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3741 operand shifted to the right a specified number of bits with sign
3742 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3743
3744<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3745<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3747 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3748
3749<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750<p>This instruction always performs an arithmetic shift right operation, The
3751 most significant bits of the result will be filled with the sign bit
3752 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3753 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3754 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3755 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3756
3757<h5>Example:</h5>
3758<pre>
3759 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3760 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3761 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3762 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3763 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3764 &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]3765</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3767</div>
3768
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3769<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3770<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3771Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3772
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3773<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3775<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3776<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3777 &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]3778</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3780<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3781<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3782 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3784<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3785<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3787 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3789<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3790<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3792<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3793 <tbody>
3794 <tr>
3795 <td>In0</td>
3796 <td>In1</td>
3797 <td>Out</td>
3798 </tr>
3799 <tr>
3800 <td>0</td>
3801 <td>0</td>
3802 <td>0</td>
3803 </tr>
3804 <tr>
3805 <td>0</td>
3806 <td>1</td>
3807 <td>0</td>
3808 </tr>
3809 <tr>
3810 <td>1</td>
3811 <td>0</td>
3812 <td>0</td>
3813 </tr>
3814 <tr>
3815 <td>1</td>
3816 <td>1</td>
3817 <td>1</td>
3818 </tr>
3819 </tbody>
3820</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3822<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3823<pre>
3824 &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]3825 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3826 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3827</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3828</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3829<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3830<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3831
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3832<div class="doc_text">
3833
3834<h5>Syntax:</h5>
3835<pre>
3836 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3837</pre>
3838
3839<h5>Overview:</h5>
3840<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3841 two operands.</p>
3842
3843<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3844<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3846 values. Both arguments must have identical types.</p>
3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3849<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3851<table border="1" cellspacing="0" cellpadding="4">
3852 <tbody>
3853 <tr>
3854 <td>In0</td>
3855 <td>In1</td>
3856 <td>Out</td>
3857 </tr>
3858 <tr>
3859 <td>0</td>
3860 <td>0</td>
3861 <td>0</td>
3862 </tr>
3863 <tr>
3864 <td>0</td>
3865 <td>1</td>
3866 <td>1</td>
3867 </tr>
3868 <tr>
3869 <td>1</td>
3870 <td>0</td>
3871 <td>1</td>
3872 </tr>
3873 <tr>
3874 <td>1</td>
3875 <td>1</td>
3876 <td>1</td>
3877 </tr>
3878 </tbody>
3879</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3881<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882<pre>
3883 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3884 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3885 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3886</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3888</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3890<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3891<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3892Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3894<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3896<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897<pre>
3898 &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]3899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3902<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3903 its two operands. The <tt>xor</tt> is used to implement the "one's
3904 complement" operation, which is the "~" operator in C.</p>
3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3907<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3909 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3911<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3912<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3914<table border="1" cellspacing="0" cellpadding="4">
3915 <tbody>
3916 <tr>
3917 <td>In0</td>
3918 <td>In1</td>
3919 <td>Out</td>
3920 </tr>
3921 <tr>
3922 <td>0</td>
3923 <td>0</td>
3924 <td>0</td>
3925 </tr>
3926 <tr>
3927 <td>0</td>
3928 <td>1</td>
3929 <td>1</td>
3930 </tr>
3931 <tr>
3932 <td>1</td>
3933 <td>0</td>
3934 <td>1</td>
3935 </tr>
3936 <tr>
3937 <td>1</td>
3938 <td>1</td>
3939 <td>0</td>
3940 </tr>
3941 </tbody>
3942</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3943
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3944<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945<pre>
3946 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3947 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3948 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3949 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3950</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3952</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3954<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3955<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3956 <a name="vectorops">Vector Operations</a>
3957</div>
3958
3959<div class="doc_text">
3960
3961<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962 target-independent manner. These instructions cover the element-access and
3963 vector-specific operations needed to process vectors effectively. While LLVM
3964 does directly support these vector operations, many sophisticated algorithms
3965 will want to use target-specific intrinsics to take full advantage of a
3966 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3967
3968</div>
3969
3970<!-- _______________________________________________________________________ -->
3971<div class="doc_subsubsection">
3972 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3973</div>
3974
3975<div class="doc_text">
3976
3977<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3978<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3979 &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]3980</pre>
3981
3982<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3983<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3984 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3985
3986
3987<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3989 of <a href="#t_vector">vector</a> type. The second operand is an index
3990 indicating the position from which to extract the element. The index may be
3991 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3992
3993<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3994<p>The result is a scalar of the same type as the element type of
3995 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3996 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3997 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3998
3999<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4000<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4001 &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]4002</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4003
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4004</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4005
4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection">
4008 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4009</div>
4010
4011<div class="doc_text">
4012
4013<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4014<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4015 &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]4016</pre>
4017
4018<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4020 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4021
4022<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4023<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4024 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4025 whose type must equal the element type of the first operand. The third
4026 operand is an index indicating the position at which to insert the value.
4027 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4031 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4032 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4033 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4034
4035<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4037 &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]4038</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4039
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4040</div>
4041
4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
4044 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4050<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4051 &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]4052</pre>
4053
4054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4056 from two input vectors, returning a vector with the same element type as the
4057 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4058
4059<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4060<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4061 with types that match each other. The third argument is a shuffle mask whose
4062 element type is always 'i32'. The result of the instruction is a vector
4063 whose length is the same as the shuffle mask and whose element type is the
4064 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4066<p>The shuffle mask operand is required to be a constant vector with either
4067 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4068
4069<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070<p>The elements of the two input vectors are numbered from left to right across
4071 both of the vectors. The shuffle mask operand specifies, for each element of
4072 the result vector, which element of the two input vectors the result element
4073 gets. The element selector may be undef (meaning "don't care") and the
4074 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4075
4076<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4077<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4078 &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]4079 &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]4080 &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]4081 &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]4082 &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]4083 &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]4084 &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]4085 &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]4086</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4088</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4089
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4090<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4091<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4092 <a name="aggregateops">Aggregate Operations</a>
4093</div>
4094
4095<div class="doc_text">
4096
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4097<p>LLVM supports several instructions for working with
4098 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4099
4100</div>
4101
4102<!-- _______________________________________________________________________ -->
4103<div class="doc_subsubsection">
4104 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4105</div>
4106
4107<div class="doc_text">
4108
4109<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4110<pre>
4111 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4112</pre>
4113
4114<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4115<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4116 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4117
4118<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4119<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4120 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4121 <a href="#t_array">array</a> type. The operands are constant indices to
4122 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4123 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4124
4125<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4126<p>The result is the value at the position in the aggregate specified by the
4127 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4128
4129<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4130<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4131 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4132</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4135
4136<!-- _______________________________________________________________________ -->
4137<div class="doc_subsubsection">
4138 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4139</div>
4140
4141<div class="doc_text">
4142
4143<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4144<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4145 &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]4146</pre>
4147
4148<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4149<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4150 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4151
4152<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4153<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4154 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4155 <a href="#t_array">array</a> type. The second operand is a first-class
4156 value to insert. The following operands are constant indices indicating
4157 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]4158 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4159 value to insert must have the same type as the value identified by the
4160 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161
4162<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4164 that of <tt>val</tt> except that the value at the position specified by the
4165 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4166
4167<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4168<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4169 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4170 %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]4171</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4172
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4173</div>
4174
4175
4176<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4177<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4178 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4179</div>
4180
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4181<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4182
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4183<p>A key design point of an SSA-based representation is how it represents
4184 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4185 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4187
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4188</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4190<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4191<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4192 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4193</div>
4194
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4195<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4196
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4197<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4198<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4199 &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]4200</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4201
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4202<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4203<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4204 currently executing function, to be automatically released when this function
4205 returns to its caller. The object is always allocated in the generic address
4206 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4208<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209<p>The '<tt>alloca</tt>' instruction
4210 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4211 runtime stack, returning a pointer of the appropriate type to the program.
4212 If "NumElements" is specified, it is the number of elements allocated,
4213 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4214 specified, the value result of the allocation is guaranteed to be aligned to
4215 at least that boundary. If not specified, or if zero, the target can choose
4216 to align the allocation on any convenient boundary compatible with the
4217 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4219<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4221<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4222<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4223 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4224 memory is automatically released when the function returns. The
4225 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4226 variables that must have an address available. When the function returns
4227 (either with the <tt><a href="#i_ret">ret</a></tt>
4228 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4229 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4230
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4231<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4232<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4233 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4234 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4235 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4236 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4239</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4242<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4243Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4245<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4247<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4249 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4250 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4251 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4252</pre>
4253
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4254<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4255<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4257<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4258<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4259 from which to load. The pointer must point to
4260 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4261 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4262 number or order of execution of this <tt>load</tt> with other <a
4263 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4264
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4265<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266 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]4267 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268 alignment for the target. It is the responsibility of the code emitter to
4269 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4270 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4271 produce less efficient code. An alignment of 1 is always safe.</p>
4272
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4273<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4274 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4275 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4276 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4277 and code generator that this load is not expected to be reused in the cache.
4278 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4279 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4280
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4281<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282<p>The location of memory pointed to is loaded. If the value being loaded is of
4283 scalar type then the number of bytes read does not exceed the minimum number
4284 of bytes needed to hold all bits of the type. For example, loading an
4285 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4286 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4287 is undefined if the value was not originally written using a store of the
4288 same type.</p>
4289
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4290<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291<pre>
4292 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4293 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4294 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4297</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4298
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4299<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4300<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4301Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4303<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4305<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306<pre>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4307 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>
4308 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]4309</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4311<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4312<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4316 and an address at which to store it. The type of the
4317 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4318 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4319 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4320 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4321 order of execution of this <tt>store</tt> with other <a
4322 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323
4324<p>The optional constant "align" argument specifies the alignment of the
4325 operation (that is, the alignment of the memory address). A value of 0 or an
4326 omitted "align" argument means that the operation has the preferential
4327 alignment for the target. It is the responsibility of the code emitter to
4328 ensure that the alignment information is correct. Overestimating the
4329 alignment results in an undefined behavior. Underestimating the alignment may
4330 produce less efficient code. An alignment of 1 is always safe.</p>
4331
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4332<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4333 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4334 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4335 instruction tells the optimizer and code generator that this load is
4336 not expected to be reused in the cache. The code generator may
4337 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4338 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4339
4340
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4341<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4343 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4344 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4345 does not exceed the minimum number of bytes needed to hold all bits of the
4346 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4347 writing a value of a type like <tt>i20</tt> with a size that is not an
4348 integral number of bytes, it is unspecified what happens to the extra bits
4349 that do not belong to the type, but they will typically be overwritten.</p>
4350
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4351<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4352<pre>
4353 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4354 store i32 3, i32* %ptr <i>; yields {void}</i>
4355 %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]4356</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4358</div>
4359
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4360<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4361<div class="doc_subsubsection">
4362 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4363</div>
4364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4365<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4367<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4368<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4369 &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]4370 &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]4371</pre>
4372
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4373<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4374<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4375 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4376 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4377
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4378<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4379<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4380 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4381 elements of the aggregate object are indexed. The interpretation of each
4382 index is dependent on the type being indexed into. The first index always
4383 indexes the pointer value given as the first argument, the second index
4384 indexes a value of the type pointed to (not necessarily the value directly
4385 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4386 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4387 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4388 can never be pointers, since that would require loading the pointer before
4389 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4390
4391<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]4392 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4393 integer <b>constants</b> are allowed. When indexing into an array, pointer
4394 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]4395 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4396
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4397<p>For example, let's consider a C code fragment and how it gets compiled to
4398 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4399
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4400<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4401struct RT {
4402 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4403 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4404 char C;
4405};
4406struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4407 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4408 double Y;
4409 struct RT Z;
4410};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4411
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4412int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4413 return &amp;s[1].Z.B[5][13];
4414}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4415</pre>
4416
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4417<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4418
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4419<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4420%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4421%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4422
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4423define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4424entry:
4425 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4426 ret i32* %reg
4427}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4428</pre>
4429
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4430<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4431<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]4432 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4433 }</tt>' type, a structure. The second index indexes into the third element
4434 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4435 i8 }</tt>' type, another structure. The third index indexes into the second
4436 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4437 array. The two dimensions of the array are subscripted into, yielding an
4438 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4439 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4440
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441<p>Note that it is perfectly legal to index partially through a structure,
4442 returning a pointer to an inner element. Because of this, the LLVM code for
4443 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4444
4445<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4446 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4447 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4448 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4449 %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]4450 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4451 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4452 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4453 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4454</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4455
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4456<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4457 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4458 base pointer is not an <i>in bounds</i> address of an allocated object,
4459 or if any of the addresses that would be formed by successive addition of
4460 the offsets implied by the indices to the base address with infinitely
4461 precise arithmetic are not an <i>in bounds</i> address of that allocated
4462 object. The <i>in bounds</i> addresses for an allocated object are all
4463 the addresses that point into the object, plus the address one byte past
4464 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4465
4466<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4467 the base address with silently-wrapping two's complement arithmetic, and
4468 the result value of the <tt>getelementptr</tt> may be outside the object
4469 pointed to by the base pointer. The result value may not necessarily be
4470 used to access memory though, even if it happens to point into allocated
4471 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4472 section for more information.</p>
4473
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4474<p>The getelementptr instruction is often confusing. For some more insight into
4475 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4476
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4477<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4478<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4479 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4480 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4481 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4482 %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]4483 <i>; yields i8*:eptr</i>
4484 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4485 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4486 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4488
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4490
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4491<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4492<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4493</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4495<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4496
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4497<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4498 which all take a single operand and a type. They perform various bit
4499 conversions on the operand.</p>
4500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4501</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4502
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4503<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4504<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4505 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4506</div>
4507<div class="doc_text">
4508
4509<h5>Syntax:</h5>
4510<pre>
4511 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4512</pre>
4513
4514<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4515<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4516 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4517
4518<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4519<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4520 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4521 size and type of the result, which must be
4522 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4523 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4524 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4525
4526<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4527<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4528 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4529 source size must be larger than the destination size, <tt>trunc</tt> cannot
4530 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4531
4532<h5>Example:</h5>
4533<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4534 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4535 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4536 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4537</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4538
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4539</div>
4540
4541<!-- _______________________________________________________________________ -->
4542<div class="doc_subsubsection">
4543 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4544</div>
4545<div class="doc_text">
4546
4547<h5>Syntax:</h5>
4548<pre>
4549 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4550</pre>
4551
4552<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4553<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4554 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4555
4556
4557<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4558<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]4559 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4560 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]4561 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4562 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4563
4564<h5>Semantics:</h5>
4565<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]4566 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4567
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4568<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]4569
4570<h5>Example:</h5>
4571<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4572 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4573 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4574</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4576</div>
4577
4578<!-- _______________________________________________________________________ -->
4579<div class="doc_subsubsection">
4580 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4581</div>
4582<div class="doc_text">
4583
4584<h5>Syntax:</h5>
4585<pre>
4586 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4587</pre>
4588
4589<h5>Overview:</h5>
4590<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4591
4592<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4593<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]4594 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4595 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]4596 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4598
4599<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4600<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4601 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4602 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4604<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]4605
4606<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4607<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4608 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4609 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4610</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4612</div>
4613
4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4616 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4617</div>
4618
4619<div class="doc_text">
4620
4621<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4622<pre>
4623 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4624</pre>
4625
4626<h5>Overview:</h5>
4627<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4629
4630<h5>Arguments:</h5>
4631<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4632 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4633 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]4634 <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]4635 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4636
4637<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4638<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4639 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640 <a href="#t_floating">floating point</a> type. If the value cannot fit
4641 within the destination type, <tt>ty2</tt>, then the results are
4642 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4643
4644<h5>Example:</h5>
4645<pre>
4646 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4647 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4648</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4649
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4650</div>
4651
4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4654 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4655</div>
4656<div class="doc_text">
4657
4658<h5>Syntax:</h5>
4659<pre>
4660 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4661</pre>
4662
4663<h5>Overview:</h5>
4664<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]4665 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4666
4667<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4668<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4669 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4670 a <a href="#t_floating">floating point</a> type to cast it to. The source
4671 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4672
4673<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4674<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4675 <a href="#t_floating">floating point</a> type to a larger
4676 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4677 used to make a <i>no-op cast</i> because it always changes bits. Use
4678 <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]4679
4680<h5>Example:</h5>
4681<pre>
4682 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4683 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4684</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4685
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4686</div>
4687
4688<!-- _______________________________________________________________________ -->
4689<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4690 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4691</div>
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4696 &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]4697</pre>
4698
4699<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4700<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4701 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4702
4703<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4704<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4705 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4706 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4707 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4708 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4709
4710<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4711<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4713 towards zero) unsigned integer value. If the value cannot fit
4714 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4715
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4716<h5>Example:</h5>
4717<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4718 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4719 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4720 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4721</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4722
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4723</div>
4724
4725<!-- _______________________________________________________________________ -->
4726<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4727 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4728</div>
4729<div class="doc_text">
4730
4731<h5>Syntax:</h5>
4732<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4733 &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]4734</pre>
4735
4736<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4737<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4738 <a href="#t_floating">floating point</a> <tt>value</tt> to
4739 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4740
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4741<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4742<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4743 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4744 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4745 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4746 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4747
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4748<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4749<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4751 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4752 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4753
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4754<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4755<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4756 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4757 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4758 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4759</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4761</div>
4762
4763<!-- _______________________________________________________________________ -->
4764<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4765 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4766</div>
4767<div class="doc_text">
4768
4769<h5>Syntax:</h5>
4770<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4771 &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]4772</pre>
4773
4774<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4775<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4776 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4777
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4778<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4779<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]4780 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4781 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4782 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4783 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4784
4785<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4786<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4787 integer quantity and converts it to the corresponding floating point
4788 value. If the value cannot fit in the floating point value, the results are
4789 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4790
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4791<h5>Example:</h5>
4792<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4793 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4794 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4795</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4797</div>
4798
4799<!-- _______________________________________________________________________ -->
4800<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4801 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4802</div>
4803<div class="doc_text">
4804
4805<h5>Syntax:</h5>
4806<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4807 &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]4808</pre>
4809
4810<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4811<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4812 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4813
4814<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4815<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]4816 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4817 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4818 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4819 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4820
4821<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4822<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4823 quantity and converts it to the corresponding floating point value. If the
4824 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4825
4826<h5>Example:</h5>
4827<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4828 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4829 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4830</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4831
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4832</div>
4833
4834<!-- _______________________________________________________________________ -->
4835<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4836 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4837</div>
4838<div class="doc_text">
4839
4840<h5>Syntax:</h5>
4841<pre>
4842 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4843</pre>
4844
4845<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4846<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4847 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4848
4849<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4850<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4851 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4852 <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]4853
4854<h5>Semantics:</h5>
4855<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4856 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4857 truncating or zero extending that value to the size of the integer type. If
4858 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4859 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4860 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4861 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4862
4863<h5>Example:</h5>
4864<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4865 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4866 %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]4867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4868
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4869</div>
4870
4871<!-- _______________________________________________________________________ -->
4872<div class="doc_subsubsection">
4873 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4874</div>
4875<div class="doc_text">
4876
4877<h5>Syntax:</h5>
4878<pre>
4879 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4880</pre>
4881
4882<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4884 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4885
4886<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4887<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888 value to cast, and a type to cast it to, which must be a
4889 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4890
4891<h5>Semantics:</h5>
4892<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4893 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4894 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4895 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4896 than the size of a pointer then a zero extension is done. If they are the
4897 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4898
4899<h5>Example:</h5>
4900<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4901 %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]4902 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4903 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4904</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4905
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4906</div>
4907
4908<!-- _______________________________________________________________________ -->
4909<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4910 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4911</div>
4912<div class="doc_text">
4913
4914<h5>Syntax:</h5>
4915<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4916 &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]4917</pre>
4918
4919<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4920<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4921 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4922
4923<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4924<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4925 non-aggregate first class value, and a type to cast it to, which must also be
4926 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4927 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4928 identical. If the source type is a pointer, the destination type must also be
4929 a pointer. This instruction supports bitwise conversion of vectors to
4930 integers and to vectors of other types (as long as they have the same
4931 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4932
4933<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4934<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4935 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4936 this conversion. The conversion is done as if the <tt>value</tt> had been
4937 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4938 be converted to other pointer types with this instruction. To convert
4939 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4940 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4941
4942<h5>Example:</h5>
4943<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4944 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4945 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4946 %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]4947</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4948
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4949</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4950
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4951<!-- ======================================================================= -->
4952<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4954<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955
4956<p>The instructions in this category are the "miscellaneous" instructions, which
4957 defy better classification.</p>
4958
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4959</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4960
4961<!-- _______________________________________________________________________ -->
4962<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4963</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4965<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4966
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4967<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4968<pre>
4969 &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]4970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4971
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4973<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4974 boolean values based on comparison of its two integer, integer vector, or
4975 pointer operands.</p>
4976
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4977<h5>Arguments:</h5>
4978<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979 the condition code indicating the kind of comparison to perform. It is not a
4980 value, just a keyword. The possible condition code are:</p>
4981
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4982<ol>
4983 <li><tt>eq</tt>: equal</li>
4984 <li><tt>ne</tt>: not equal </li>
4985 <li><tt>ugt</tt>: unsigned greater than</li>
4986 <li><tt>uge</tt>: unsigned greater or equal</li>
4987 <li><tt>ult</tt>: unsigned less than</li>
4988 <li><tt>ule</tt>: unsigned less or equal</li>
4989 <li><tt>sgt</tt>: signed greater than</li>
4990 <li><tt>sge</tt>: signed greater or equal</li>
4991 <li><tt>slt</tt>: signed less than</li>
4992 <li><tt>sle</tt>: signed less or equal</li>
4993</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4994
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4995<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4997 typed. They must also be identical types.</p>
4998
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4999<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5000<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5001 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5002 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]5003 result, as follows:</p>
5004
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5005<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5006 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5007 <tt>false</tt> otherwise. No sign interpretation is necessary or
5008 performed.</li>
5009
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5010 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5011 <tt>false</tt> otherwise. No sign interpretation is necessary or
5012 performed.</li>
5013
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5014 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5015 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5016
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5017 <li><tt>uge</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 or equal
5019 to <tt>op2</tt>.</li>
5020
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5021 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5022 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5023
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5024 <li><tt>ule</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 or equal to <tt>op2</tt>.</li>
5026
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5027 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5028 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5030 <li><tt>sge</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 or equal
5032 to <tt>op2</tt>.</li>
5033
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5034 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5035 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5036
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5037 <li><tt>sle</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 or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5039</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5040
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5041<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042 values are compared as if they were integers.</p>
5043
5044<p>If the operands are integer vectors, then they are compared element by
5045 element. The result is an <tt>i1</tt> vector with the same number of elements
5046 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5047
5048<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5049<pre>
5050 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5051 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5052 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5053 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5054 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5055 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5056</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5057
5058<p>Note that the code generator does not yet support vector types with
5059 the <tt>icmp</tt> instruction.</p>
5060
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5061</div>
5062
5063<!-- _______________________________________________________________________ -->
5064<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5065</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5067<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5068
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5069<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070<pre>
5071 &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]5072</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5074<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5075<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5076 values based on comparison of its operands.</p>
5077
5078<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]5079(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080
5081<p>If the operands are floating point vectors, then the result type is a vector
5082 of boolean with the same number of elements as the operands being
5083 compared.</p>
5084
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5085<h5>Arguments:</h5>
5086<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5087 the condition code indicating the kind of comparison to perform. It is not a
5088 value, just a keyword. The possible condition code are:</p>
5089
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5090<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5091 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5092 <li><tt>oeq</tt>: ordered and equal</li>
5093 <li><tt>ogt</tt>: ordered and greater than </li>
5094 <li><tt>oge</tt>: ordered and greater than or equal</li>
5095 <li><tt>olt</tt>: ordered and less than </li>
5096 <li><tt>ole</tt>: ordered and less than or equal</li>
5097 <li><tt>one</tt>: ordered and not equal</li>
5098 <li><tt>ord</tt>: ordered (no nans)</li>
5099 <li><tt>ueq</tt>: unordered or equal</li>
5100 <li><tt>ugt</tt>: unordered or greater than </li>
5101 <li><tt>uge</tt>: unordered or greater than or equal</li>
5102 <li><tt>ult</tt>: unordered or less than </li>
5103 <li><tt>ule</tt>: unordered or less than or equal</li>
5104 <li><tt>une</tt>: unordered or not equal</li>
5105 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5106 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5107</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5109<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5110 <i>unordered</i> means that either operand may be a QNAN.</p>
5111
5112<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5113 a <a href="#t_floating">floating point</a> type or
5114 a <a href="#t_vector">vector</a> of floating point type. They must have
5115 identical types.</p>
5116
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5117<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5118<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5119 according to the condition code given as <tt>cond</tt>. If the operands are
5120 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5121 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122 follows:</p>
5123
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5124<ol>
5125 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5126
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5127 <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]5128 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5129
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5130 <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]5131 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5132
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5133 <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]5134 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5135
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5136 <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]5137 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5138
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5139 <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]5140 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5141
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5142 <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]5143 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5144
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5145 <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]5146
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5147 <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]5148 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5149
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5150 <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]5151 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5152
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5153 <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]5154 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5155
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5156 <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]5157 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5158
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5161
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5162 <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]5163 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5164
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5165 <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]5166
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5167 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5168</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5169
5170<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5171<pre>
5172 &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]5173 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5174 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5175 &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]5176</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5177
5178<p>Note that the code generator does not yet support vector types with
5179 the <tt>fcmp</tt> instruction.</p>
5180
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5181</div>
5182
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5183<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5184<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5185 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5186</div>
5187
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5188<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5189
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5190<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5191<pre>
5192 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5193</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5194
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5195<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5196<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5197 SSA graph representing the function.</p>
5198
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5199<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200<p>The type of the incoming values is specified with the first type field. After
5201 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5202 one pair for each predecessor basic block of the current block. Only values
5203 of <a href="#t_firstclass">first class</a> type may be used as the value
5204 arguments to the PHI node. Only labels may be used as the label
5205 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5206
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5207<p>There must be no non-phi instructions between the start of a basic block and
5208 the PHI instructions: i.e. PHI instructions must be first in a basic
5209 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5210
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5212 occur on the edge from the corresponding predecessor block to the current
5213 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5214 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5215
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5216<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5217<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5218 specified by the pair corresponding to the predecessor basic block that
5219 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5220
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5221<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5222<pre>
5223Loop: ; Infinite loop that counts from 0 on up...
5224 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5225 %nextindvar = add i32 %indvar, 1
5226 br label %Loop
5227</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5228
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5229</div>
5230
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5231<!-- _______________________________________________________________________ -->
5232<div class="doc_subsubsection">
5233 <a name="i_select">'<tt>select</tt>' Instruction</a>
5234</div>
5235
5236<div class="doc_text">
5237
5238<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5239<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5240 &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>
5241
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5242 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5243</pre>
5244
5245<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5246<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5247 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5248
5249
5250<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5251<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5252 values indicating the condition, and two values of the
5253 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5254 vectors and the condition is a scalar, then entire vectors are selected, not
5255 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5256
5257<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5258<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5259 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5260
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5261<p>If the condition is a vector of i1, then the value arguments must be vectors
5262 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5263
5264<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5265<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5266 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5267</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5268
5269<p>Note that the code generator does not yet support conditions
5270 with vector type.</p>
5271
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5272</div>
5273
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5274<!-- _______________________________________________________________________ -->
5275<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5276 <a name="i_call">'<tt>call</tt>' Instruction</a>
5277</div>
5278
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5279<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5280
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5281<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5282<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5283 &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]5284</pre>
5285
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5286<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5287<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5289<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5290<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5291
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5292<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5293 <li>The optional "tail" marker indicates that the callee function does not
5294 access any allocas or varargs in the caller. Note that calls may be
5295 marked "tail" even if they do not occur before
5296 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5297 present, the function call is eligible for tail call optimization,
5298 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5299 optimized into a jump</a>. The code generator may optimize calls marked
5300 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5301 sibling call optimization</a> when the caller and callee have
5302 matching signatures, or 2) forced tail call optimization when the
5303 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5304 <ul>
5305 <li>Caller and callee both have the calling
5306 convention <tt>fastcc</tt>.</li>
5307 <li>The call is in tail position (ret immediately follows call and ret
5308 uses value of call or is void).</li>
5309 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5310 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5311 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5312 constraints are met.</a></li>
5313 </ul>
5314 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5315
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5316 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5317 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5318 defaults to using C calling conventions. The calling convention of the
5319 call must match the calling convention of the target function, or else the
5320 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5321
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5322 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5323 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5324 '<tt>inreg</tt>' attributes are valid here.</li>
5325
5326 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5327 type of the return value. Functions that return no value are marked
5328 <tt><a href="#t_void">void</a></tt>.</li>
5329
5330 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5331 being invoked. The argument types must match the types implied by this
5332 signature. This type can be omitted if the function is not varargs and if
5333 the function type does not return a pointer to a function.</li>
5334
5335 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5336 be invoked. In most cases, this is a direct function invocation, but
5337 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5338 to function value.</li>
5339
5340 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5341 signature argument types and parameter attributes. All arguments must be
5342 of <a href="#t_firstclass">first class</a> type. If the function
5343 signature indicates the function accepts a variable number of arguments,
5344 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5345
5346 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5347 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5348 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5349</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5350
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5351<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5352<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5353 a specified function, with its incoming arguments bound to the specified
5354 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5355 function, control flow continues with the instruction after the function
5356 call, and the return value of the function is bound to the result
5357 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5359<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5360<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5361 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5362 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5363 %X = tail call i32 @foo() <i>; yields i32</i>
5364 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5365 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5366
5367 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5368 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5369 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5370 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5371 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5372 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5373</pre>
5374
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5375<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5376standard C99 library as being the C99 library functions, and may perform
5377optimizations or generate code for them under that assumption. This is
5378something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5379freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5381</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5382
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5383<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5384<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5385 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5386</div>
5387
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5388<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5389
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5390<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5391<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5392 &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]5393</pre>
5394
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5395<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5396<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5397 the "variable argument" area of a function call. It is used to implement the
5398 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5399
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5400<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5401<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5402 argument. It returns a value of the specified argument type and increments
5403 the <tt>va_list</tt> to point to the next argument. The actual type
5404 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5405
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5406<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5407<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5408 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5409 to the next argument. For more information, see the variable argument
5410 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5411
5412<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]5413 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5414 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5415
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5416<p><tt>va_arg</tt> is an LLVM instruction instead of
5417 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5418 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5419
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5420<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5421<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5422
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5423<p>Note that the code generator does not yet fully support va_arg on many
5424 targets. Also, it does not currently support va_arg with aggregate types on
5425 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5426
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5427</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5428
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5429<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5430<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5431<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5432
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5433<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5434
5435<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436 well known names and semantics and are required to follow certain
5437 restrictions. Overall, these intrinsics represent an extension mechanism for
5438 the LLVM language that does not require changing all of the transformations
5439 in LLVM when adding to the language (or the bitcode reader/writer, the
5440 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5441
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5442<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5443 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5444 begin with this prefix. Intrinsic functions must always be external
5445 functions: you cannot define the body of intrinsic functions. Intrinsic
5446 functions may only be used in call or invoke instructions: it is illegal to
5447 take the address of an intrinsic function. Additionally, because intrinsic
5448 functions are part of the LLVM language, it is required if any are added that
5449 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5450
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5451<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5452 family of functions that perform the same operation but on different data
5453 types. Because LLVM can represent over 8 million different integer types,
5454 overloading is used commonly to allow an intrinsic function to operate on any
5455 integer type. One or more of the argument types or the result type can be
5456 overloaded to accept any integer type. Argument types may also be defined as
5457 exactly matching a previous argument's type or the result type. This allows
5458 an intrinsic function which accepts multiple arguments, but needs all of them
5459 to be of the same type, to only be overloaded with respect to a single
5460 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5461
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5462<p>Overloaded intrinsics will have the names of its overloaded argument types
5463 encoded into its function name, each preceded by a period. Only those types
5464 which are overloaded result in a name suffix. Arguments whose type is matched
5465 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5466 can take an integer of any width and returns an integer of exactly the same
5467 integer width. This leads to a family of functions such as
5468 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5469 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5470 suffix is required. Because the argument's type is matched against the return
5471 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5472
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5473<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5476</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5477
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5478<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5479<div class="doc_subsection">
5480 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5481</div>
5482
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5483<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5484
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5485<p>Variable argument support is defined in LLVM with
5486 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5487 intrinsic functions. These functions are related to the similarly named
5488 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5490<p>All of these functions operate on arguments that use a target-specific value
5491 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5492 not define what this type is, so all transformations should be prepared to
5493 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5494
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5495<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]5496 instruction and the variable argument handling intrinsic functions are
5497 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5498
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5499<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5500define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5501 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5502 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5503 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5504 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5505
5506 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5507 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5508
5509 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5510 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5511 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5512 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5513 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5514
5515 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5516 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5517 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5518}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5519
5520declare void @llvm.va_start(i8*)
5521declare void @llvm.va_copy(i8*, i8*)
5522declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5523</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5524
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5525</div>
5526
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5527<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5528<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5529 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5530</div>
5531
5532
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5533<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5534
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5535<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536<pre>
5537 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5538</pre>
5539
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5540<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5541<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5542 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]5543
5544<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5545<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]5546
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5547<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5548<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]5549 macro available in C. In a target-dependent way, it initializes
5550 the <tt>va_list</tt> element to which the argument points, so that the next
5551 call to <tt>va_arg</tt> will produce the first variable argument passed to
5552 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5553 need to know the last argument of the function as the compiler can figure
5554 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5555
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5556</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5557
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5558<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5559<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5560 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5561</div>
5562
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5563<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5564
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5565<h5>Syntax:</h5>
5566<pre>
5567 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5568</pre>
5569
5570<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5571<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572 which has been initialized previously
5573 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5574 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5575
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5576<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5577<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]5578
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5579<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5580<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]5581 macro available in C. In a target-dependent way, it destroys
5582 the <tt>va_list</tt> element to which the argument points. Calls
5583 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5584 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5585 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5587</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5588
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5589<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5590<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5591 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5592</div>
5593
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5594<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5595
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5596<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5597<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5598 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5599</pre>
5600
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5601<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5602<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5603 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5604
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5605<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5606<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]5607 The second argument is a pointer to a <tt>va_list</tt> element to copy
5608 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5610<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5611<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]5612 macro available in C. In a target-dependent way, it copies the
5613 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5614 element. This intrinsic is necessary because
5615 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5616 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5617
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5618</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5619
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5620<!-- ======================================================================= -->
5621<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5622 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5623</div>
5624
5625<div class="doc_text">
5626
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5628Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5630roots on the stack</a>, as well as garbage collector implementations that
5631require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5632barriers. Front-ends for type-safe garbage collected languages should generate
5633these intrinsics to make use of the LLVM garbage collectors. For more details,
5634see <a href="GarbageCollection.html">Accurate Garbage Collection with
5635LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5636
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5637<p>The garbage collection intrinsics only operate on objects in the generic
5638 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5639
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5640</div>
5641
5642<!-- _______________________________________________________________________ -->
5643<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5644 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5645</div>
5646
5647<div class="doc_text">
5648
5649<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5650<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5651 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5652</pre>
5653
5654<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5655<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]5656 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5657
5658<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5659<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5660 root pointer. The second pointer (which must be either a constant or a
5661 global value address) contains the meta-data to be associated with the
5662 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5663
5664<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5665<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]5666 location. At compile-time, the code generator generates information to allow
5667 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5668 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5669 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5670
5671</div>
5672
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5673<!-- _______________________________________________________________________ -->
5674<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5675 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676</div>
5677
5678<div class="doc_text">
5679
5680<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5681<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5682 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683</pre>
5684
5685<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5686<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687 locations, allowing garbage collector implementations that require read
5688 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5689
5690<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5691<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]5692 allocated from the garbage collector. The first object is a pointer to the
5693 start of the referenced object, if needed by the language runtime (otherwise
5694 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5695
5696<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5697<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5698 instruction, but may be replaced with substantially more complex code by the
5699 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5700 may only be used in a function which <a href="#gc">specifies a GC
5701 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5702
5703</div>
5704
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5707 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5713<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5714 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5715</pre>
5716
5717<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5718<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5719 locations, allowing garbage collector implementations that require write
5720 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5721
5722<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5723<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]5724 object to store it to, and the third is the address of the field of Obj to
5725 store to. If the runtime does not require a pointer to the object, Obj may
5726 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5727
5728<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5729<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5730 instruction, but may be replaced with substantially more complex code by the
5731 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5732 may only be used in a function which <a href="#gc">specifies a GC
5733 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5734
5735</div>
5736
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5737<!-- ======================================================================= -->
5738<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5739 <a name="int_codegen">Code Generator Intrinsics</a>
5740</div>
5741
5742<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5743
5744<p>These intrinsics are provided by LLVM to expose special features that may
5745 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5746
5747</div>
5748
5749<!-- _______________________________________________________________________ -->
5750<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5751 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5752</div>
5753
5754<div class="doc_text">
5755
5756<h5>Syntax:</h5>
5757<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5758 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5759</pre>
5760
5761<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5762<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5763 target-specific value indicating the return address of the current function
5764 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5765
5766<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The argument to this intrinsic indicates which function to return the address
5768 for. Zero indicates the calling function, one indicates its caller, etc.
5769 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5770
5771<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5772<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5773 indicating the return address of the specified call frame, or zero if it
5774 cannot be identified. The value returned by this intrinsic is likely to be
5775 incorrect or 0 for arguments other than zero, so it should only be used for
5776 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5777
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5778<p>Note that calling this intrinsic does not prevent function inlining or other
5779 aggressive transformations, so the value returned may not be that of the
5780 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5781
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5782</div>
5783
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5786 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787</div>
5788
5789<div class="doc_text">
5790
5791<h5>Syntax:</h5>
5792<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5793 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5794</pre>
5795
5796<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5797<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5798 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5799
5800<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5801<p>The argument to this intrinsic indicates which function to return the frame
5802 pointer for. Zero indicates the calling function, one indicates its caller,
5803 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5804
5805<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5806<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5807 indicating the frame address of the specified call frame, or zero if it
5808 cannot be identified. The value returned by this intrinsic is likely to be
5809 incorrect or 0 for arguments other than zero, so it should only be used for
5810 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>Note that calling this intrinsic does not prevent function inlining or other
5813 aggressive transformations, so the value returned may not be that of the
5814 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5815
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5816</div>
5817
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5818<!-- _______________________________________________________________________ -->
5819<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5820 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5821</div>
5822
5823<div class="doc_text">
5824
5825<h5>Syntax:</h5>
5826<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5827 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5828</pre>
5829
5830<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5831<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5832 of the function stack, for use
5833 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5834 useful for implementing language features like scoped automatic variable
5835 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5836
5837<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5838<p>This intrinsic returns a opaque pointer value that can be passed
5839 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5840 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5841 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5842 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5843 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5844 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5845
5846</div>
5847
5848<!-- _______________________________________________________________________ -->
5849<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5850 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5851</div>
5852
5853<div class="doc_text">
5854
5855<h5>Syntax:</h5>
5856<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5857 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5858</pre>
5859
5860<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5861<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5862 the function stack to the state it was in when the
5863 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5864 executed. This is useful for implementing language features like scoped
5865 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5866
5867<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5868<p>See the description
5869 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5870
5871</div>
5872
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5873<!-- _______________________________________________________________________ -->
5874<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5875 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5876</div>
5877
5878<div class="doc_text">
5879
5880<h5>Syntax:</h5>
5881<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5882 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]5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5887 insert a prefetch instruction if supported; otherwise, it is a noop.
5888 Prefetches have no effect on the behavior of the program but can change its
5889 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5890
5891<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5892<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5893 specifier determining if the fetch should be for a read (0) or write (1),
5894 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5895 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5896 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899<p>This intrinsic does not modify the behavior of the program. In particular,
5900 prefetches cannot trap and do not produce a value. On targets that support
5901 this intrinsic, the prefetch can provide hints to the processor cache for
5902 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5903
5904</div>
5905
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5906<!-- _______________________________________________________________________ -->
5907<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5908 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5909</div>
5910
5911<div class="doc_text">
5912
5913<h5>Syntax:</h5>
5914<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5915 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5916</pre>
5917
5918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5919<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5920 Counter (PC) in a region of code to simulators and other tools. The method
5921 is target specific, but it is expected that the marker will use exported
5922 symbols to transmit the PC of the marker. The marker makes no guarantees
5923 that it will remain with any specific instruction after optimizations. It is
5924 possible that the presence of a marker will inhibit optimizations. The
5925 intended use is to be inserted after optimizations to allow correlations of
5926 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5927
5928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5930
5931<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5932<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5933 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5934
5935</div>
5936
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5937<!-- _______________________________________________________________________ -->
5938<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5939 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5940</div>
5941
5942<div class="doc_text">
5943
5944<h5>Syntax:</h5>
5945<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]5946 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5947</pre>
5948
5949<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5950<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5951 counter register (or similar low latency, high accuracy clocks) on those
5952 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5953 should map to RPCC. As the backing counters overflow quickly (on the order
5954 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5955
5956<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5957<p>When directly supported, reading the cycle counter should not modify any
5958 memory. Implementations are allowed to either return a application specific
5959 value or a system wide value. On backends without support, this is lowered
5960 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5961
5962</div>
5963
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5964<!-- ======================================================================= -->
5965<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5966 <a name="int_libc">Standard C Library Intrinsics</a>
5967</div>
5968
5969<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5970
5971<p>LLVM provides intrinsics for a few important standard C library functions.
5972 These intrinsics allow source-language front-ends to pass information about
5973 the alignment of the pointer arguments to the code generator, providing
5974 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5975
5976</div>
5977
5978<!-- _______________________________________________________________________ -->
5979<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5980 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5981</div>
5982
5983<div class="doc_text">
5984
5985<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5986<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]5987 integer bit width and for different address spaces. Not all targets support
5988 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5990<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5991 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]5992 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5993 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]5994 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5995</pre>
5996
5997<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5998<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5999 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6000
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6001<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6002 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6003 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6004
6005<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>The first argument is a pointer to the destination, the second is a pointer
6008 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6009 number of bytes to copy, the fourth argument is the alignment of the
6010 source and destination locations, and the fifth is a boolean indicating a
6011 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6012
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6013<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]6014 then the caller guarantees that both the source and destination pointers are
6015 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6016
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6017<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6018 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6019 The detailed access behavior is not very cleanly specified and it is unwise
6020 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6021
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6022<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6023
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6024<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6025 source location to the destination location, which are not allowed to
6026 overlap. It copies "len" bytes of memory over. If the argument is known to
6027 be aligned to some boundary, this can be specified as the fourth argument,
6028 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6029
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6030</div>
6031
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6032<!-- _______________________________________________________________________ -->
6033<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6034 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6035</div>
6036
6037<div class="doc_text">
6038
6039<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6040<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]6041 width and for different address space. Not all targets support all bit
6042 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6044<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6045 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]6046 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6047 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]6048 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6049</pre>
6050
6051<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6052<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6053 source location to the destination location. It is similar to the
6054 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6055 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6056
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6058 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6059 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6060
6061<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6063<p>The first argument is a pointer to the destination, the second is a pointer
6064 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6065 number of bytes to copy, the fourth argument is the alignment of the
6066 source and destination locations, and the fifth is a boolean indicating a
6067 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6068
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6069<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]6070 then the caller guarantees that the source and destination pointers are
6071 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6072
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6073<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6074 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6075 The detailed access behavior is not very cleanly specified and it is unwise
6076 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6077
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6078<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6079
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6081 source location to the destination location, which may overlap. It copies
6082 "len" bytes of memory over. If the argument is known to be aligned to some
6083 boundary, this can be specified as the fourth argument, otherwise it should
6084 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6085
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6086</div>
6087
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6088<!-- _______________________________________________________________________ -->
6089<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6090 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6096<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]6097 width and for different address spaces. However, not all targets support all
6098 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6099
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6100<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6101 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6102 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6103 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6104 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6105</pre>
6106
6107<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6109 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6110
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6112 intrinsic does not return a value and takes extra alignment/volatile
6113 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6114
6115<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<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]6117 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6118 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6119 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6120
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6121<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]6122 then the caller guarantees that the destination pointer is aligned to that
6123 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6124
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6125<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6126 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6127 The detailed access behavior is not very cleanly specified and it is unwise
6128 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6129
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6130<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6132 at the destination location. If the argument is known to be aligned to some
6133 boundary, this can be specified as the fourth argument, otherwise it should
6134 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6135
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6136</div>
6137
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6138<!-- _______________________________________________________________________ -->
6139<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6140 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6141</div>
6142
6143<div class="doc_text">
6144
6145<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6146<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6147 floating point or vector of floating point type. Not all targets support all
6148 types however.</p>
6149
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6150<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6151 declare float @llvm.sqrt.f32(float %Val)
6152 declare double @llvm.sqrt.f64(double %Val)
6153 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6154 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6155 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6156</pre>
6157
6158<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6159<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6160 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6161 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6162 behavior for negative numbers other than -0.0 (which allows for better
6163 optimization, because there is no need to worry about errno being
6164 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]6165
6166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167<p>The argument and return value are floating point numbers of the same
6168 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6169
6170<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6171<p>This function returns the sqrt of the specified operand if it is a
6172 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6173
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6174</div>
6175
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6176<!-- _______________________________________________________________________ -->
6177<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6178 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6179</div>
6180
6181<div class="doc_text">
6182
6183<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6184<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6185 floating point or vector of floating point type. Not all targets support all
6186 types however.</p>
6187
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6188<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6189 declare float @llvm.powi.f32(float %Val, i32 %power)
6190 declare double @llvm.powi.f64(double %Val, i32 %power)
6191 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6192 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6193 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6194</pre>
6195
6196<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6197<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6198 specified (positive or negative) power. The order of evaluation of
6199 multiplications is not defined. When a vector of floating point type is
6200 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6201
6202<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The second argument is an integer power, and the first is a value to raise to
6204 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6207<p>This function returns the first value raised to the second power with an
6208 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6209
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6210</div>
6211
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6212<!-- _______________________________________________________________________ -->
6213<div class="doc_subsubsection">
6214 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6215</div>
6216
6217<div class="doc_text">
6218
6219<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6220<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6221 floating point or vector of floating point type. Not all targets support all
6222 types however.</p>
6223
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6224<pre>
6225 declare float @llvm.sin.f32(float %Val)
6226 declare double @llvm.sin.f64(double %Val)
6227 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6228 declare fp128 @llvm.sin.f128(fp128 %Val)
6229 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6230</pre>
6231
6232<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6233<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6234
6235<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6236<p>The argument and return value are floating point numbers of the same
6237 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6238
6239<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6240<p>This function returns the sine of the specified operand, returning the same
6241 values as the libm <tt>sin</tt> functions would, and handles error conditions
6242 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6243
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6244</div>
6245
6246<!-- _______________________________________________________________________ -->
6247<div class="doc_subsubsection">
6248 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6249</div>
6250
6251<div class="doc_text">
6252
6253<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6255 floating point or vector of floating point type. Not all targets support all
6256 types however.</p>
6257
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6258<pre>
6259 declare float @llvm.cos.f32(float %Val)
6260 declare double @llvm.cos.f64(double %Val)
6261 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6262 declare fp128 @llvm.cos.f128(fp128 %Val)
6263 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6264</pre>
6265
6266<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6267<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6268
6269<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270<p>The argument and return value are floating point numbers of the same
6271 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6272
6273<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6274<p>This function returns the cosine of the specified operand, returning the same
6275 values as the libm <tt>cos</tt> functions would, and handles error conditions
6276 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6277
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6278</div>
6279
6280<!-- _______________________________________________________________________ -->
6281<div class="doc_subsubsection">
6282 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6283</div>
6284
6285<div class="doc_text">
6286
6287<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6288<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6289 floating point or vector of floating point type. Not all targets support all
6290 types however.</p>
6291
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6292<pre>
6293 declare float @llvm.pow.f32(float %Val, float %Power)
6294 declare double @llvm.pow.f64(double %Val, double %Power)
6295 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6296 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6297 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6298</pre>
6299
6300<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6302 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6303
6304<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6305<p>The second argument is a floating point power, and the first is a value to
6306 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6307
6308<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6309<p>This function returns the first value raised to the second power, returning
6310 the same values as the libm <tt>pow</tt> functions would, and handles error
6311 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6312
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6313</div>
6314
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6315<!-- ======================================================================= -->
6316<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6317 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6318</div>
6319
6320<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6321
6322<p>LLVM provides intrinsics for a few important bit manipulation operations.
6323 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6324
6325</div>
6326
6327<!-- _______________________________________________________________________ -->
6328<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6329 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6330</div>
6331
6332<div class="doc_text">
6333
6334<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6335<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6336 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6337
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6338<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6339 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6340 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6341 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6342</pre>
6343
6344<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6345<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6346 values with an even number of bytes (positive multiple of 16 bits). These
6347 are useful for performing operations on data that is not in the target's
6348 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6349
6350<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6351<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6352 and low byte of the input i16 swapped. Similarly,
6353 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6354 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6355 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6356 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6357 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6358 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6359
6360</div>
6361
6362<!-- _______________________________________________________________________ -->
6363<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6364 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6365</div>
6366
6367<div class="doc_text">
6368
6369<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6370<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]6371 width. Not all targets support all bit widths however.</p>
6372
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6373<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6374 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6375 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6376 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6377 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6378 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6379</pre>
6380
6381<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6383 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6384
6385<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6386<p>The only argument is the value to be counted. The argument may be of any
6387 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6388
6389<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6390<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]6391
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6392</div>
6393
6394<!-- _______________________________________________________________________ -->
6395<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6396 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6397</div>
6398
6399<div class="doc_text">
6400
6401<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6402<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6403 integer bit width. Not all targets support all bit widths however.</p>
6404
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6405<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6406 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6407 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6408 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6409 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6410 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6411</pre>
6412
6413<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6414<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6415 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6416
6417<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6418<p>The only argument is the value to be counted. The argument may be of any
6419 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6420
6421<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6422<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6423 zeros in a variable. If the src == 0 then the result is the size in bits of
6424 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6425
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6426</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6427
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6428<!-- _______________________________________________________________________ -->
6429<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6430 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6431</div>
6432
6433<div class="doc_text">
6434
6435<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6436<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6437 integer bit width. Not all targets support all bit widths however.</p>
6438
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6439<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6440 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6441 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6442 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6443 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6444 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6445</pre>
6446
6447<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6448<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6449 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6450
6451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6452<p>The only argument is the value to be counted. The argument may be of any
6453 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6454
6455<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6457 zeros in a variable. If the src == 0 then the result is the size in bits of
6458 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6459
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6460</div>
6461
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6462<!-- ======================================================================= -->
6463<div class="doc_subsection">
6464 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6465</div>
6466
6467<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6468
6469<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6470
6471</div>
6472
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6475 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6476</div>
6477
6478<div class="doc_text">
6479
6480<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6481<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]6482 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6483
6484<pre>
6485 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6486 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6487 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6488</pre>
6489
6490<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6491<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6492 a signed addition of the two arguments, and indicate whether an overflow
6493 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6494
6495<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6496<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]6497 be of integer types of any bit width, but they must have the same bit
6498 width. The second element of the result structure must be of
6499 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6500 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6501
6502<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6503<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6504 a signed addition of the two variables. They return a structure &mdash; the
6505 first element of which is the signed summation, and the second element of
6506 which is a bit specifying if the signed summation resulted in an
6507 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6508
6509<h5>Examples:</h5>
6510<pre>
6511 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6512 %sum = extractvalue {i32, i1} %res, 0
6513 %obit = extractvalue {i32, i1} %res, 1
6514 br i1 %obit, label %overflow, label %normal
6515</pre>
6516
6517</div>
6518
6519<!-- _______________________________________________________________________ -->
6520<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6521 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6522</div>
6523
6524<div class="doc_text">
6525
6526<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6527<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]6528 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6529
6530<pre>
6531 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6532 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6533 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6534</pre>
6535
6536<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6537<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6538 an unsigned addition of the two arguments, and indicate whether a carry
6539 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6540
6541<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6542<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]6543 be of integer types of any bit width, but they must have the same bit
6544 width. The second element of the result structure must be of
6545 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6546 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6547
6548<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6549<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6550 an unsigned addition of the two arguments. They return a structure &mdash;
6551 the first element of which is the sum, and the second element of which is a
6552 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553
6554<h5>Examples:</h5>
6555<pre>
6556 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6557 %sum = extractvalue {i32, i1} %res, 0
6558 %obit = extractvalue {i32, i1} %res, 1
6559 br i1 %obit, label %carry, label %normal
6560</pre>
6561
6562</div>
6563
6564<!-- _______________________________________________________________________ -->
6565<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6566 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6567</div>
6568
6569<div class="doc_text">
6570
6571<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6572<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]6573 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6574
6575<pre>
6576 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6577 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6578 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6579</pre>
6580
6581<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6582<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6583 a signed subtraction of the two arguments, and indicate whether an overflow
6584 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6585
6586<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587<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]6588 be of integer types of any bit width, but they must have the same bit
6589 width. The second element of the result structure must be of
6590 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6591 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6592
6593<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6594<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6595 a signed subtraction of the two arguments. They return a structure &mdash;
6596 the first element of which is the subtraction, and the second element of
6597 which is a bit specifying if the signed subtraction resulted in an
6598 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<h5>Examples:</h5>
6601<pre>
6602 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6603 %sum = extractvalue {i32, i1} %res, 0
6604 %obit = extractvalue {i32, i1} %res, 1
6605 br i1 %obit, label %overflow, label %normal
6606</pre>
6607
6608</div>
6609
6610<!-- _______________________________________________________________________ -->
6611<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6612 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6613</div>
6614
6615<div class="doc_text">
6616
6617<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6618<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]6619 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6620
6621<pre>
6622 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6623 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6624 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6625</pre>
6626
6627<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6628<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629 an unsigned subtraction of the two arguments, and indicate whether an
6630 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6631
6632<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6633<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]6634 be of integer types of any bit width, but they must have the same bit
6635 width. The second element of the result structure must be of
6636 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6637 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6638
6639<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6640<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641 an unsigned subtraction of the two arguments. They return a structure &mdash;
6642 the first element of which is the subtraction, and the second element of
6643 which is a bit specifying if the unsigned subtraction resulted in an
6644 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6645
6646<h5>Examples:</h5>
6647<pre>
6648 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6649 %sum = extractvalue {i32, i1} %res, 0
6650 %obit = extractvalue {i32, i1} %res, 1
6651 br i1 %obit, label %overflow, label %normal
6652</pre>
6653
6654</div>
6655
6656<!-- _______________________________________________________________________ -->
6657<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6658 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6659</div>
6660
6661<div class="doc_text">
6662
6663<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6665 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666
6667<pre>
6668 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6669 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6670 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6671</pre>
6672
6673<h5>Overview:</h5>
6674
6675<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6676 a signed multiplication of the two arguments, and indicate whether an
6677 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6678
6679<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6680<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]6681 be of integer types of any bit width, but they must have the same bit
6682 width. The second element of the result structure must be of
6683 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6684 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6685
6686<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6687<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6688 a signed multiplication of the two arguments. They return a structure &mdash;
6689 the first element of which is the multiplication, and the second element of
6690 which is a bit specifying if the signed multiplication resulted in an
6691 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<h5>Examples:</h5>
6694<pre>
6695 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6696 %sum = extractvalue {i32, i1} %res, 0
6697 %obit = extractvalue {i32, i1} %res, 1
6698 br i1 %obit, label %overflow, label %normal
6699</pre>
6700
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6701</div>
6702
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6703<!-- _______________________________________________________________________ -->
6704<div class="doc_subsubsection">
6705 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6706</div>
6707
6708<div class="doc_text">
6709
6710<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6711<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]6712 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6713
6714<pre>
6715 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6716 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6717 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6718</pre>
6719
6720<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6721<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722 a unsigned multiplication of the two arguments, and indicate whether an
6723 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6724
6725<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6726<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]6727 be of integer types of any bit width, but they must have the same bit
6728 width. The second element of the result structure must be of
6729 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6730 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6731
6732<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6733<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6734 an unsigned multiplication of the two arguments. They return a structure
6735 &mdash; the first element of which is the multiplication, and the second
6736 element of which is a bit specifying if the unsigned multiplication resulted
6737 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6738
6739<h5>Examples:</h5>
6740<pre>
6741 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6742 %sum = extractvalue {i32, i1} %res, 0
6743 %obit = extractvalue {i32, i1} %res, 1
6744 br i1 %obit, label %overflow, label %normal
6745</pre>
6746
6747</div>
6748
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6749<!-- ======================================================================= -->
6750<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6751 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6752</div>
6753
6754<div class="doc_text">
6755
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6756<p>Half precision floating point is a storage-only format. This means that it is
6757 a dense encoding (in memory) but does not support computation in the
6758 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6759
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6760<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6761 value as an i16, then convert it to float with <a
6762 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6763 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6764 double etc). To store the value back to memory, it is first converted to
6765 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6766 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6767 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6768</div>
6769
6770<!-- _______________________________________________________________________ -->
6771<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6772 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6773</div>
6774
6775<div class="doc_text">
6776
6777<h5>Syntax:</h5>
6778<pre>
6779 declare i16 @llvm.convert.to.fp16(f32 %a)
6780</pre>
6781
6782<h5>Overview:</h5>
6783<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6784 a conversion from single precision floating point format to half precision
6785 floating point format.</p>
6786
6787<h5>Arguments:</h5>
6788<p>The intrinsic function contains single argument - the value to be
6789 converted.</p>
6790
6791<h5>Semantics:</h5>
6792<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6793 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6794 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6795 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6796
6797<h5>Examples:</h5>
6798<pre>
6799 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6800 store i16 %res, i16* @x, align 2
6801</pre>
6802
6803</div>
6804
6805<!-- _______________________________________________________________________ -->
6806<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6807 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6808</div>
6809
6810<div class="doc_text">
6811
6812<h5>Syntax:</h5>
6813<pre>
6814 declare f32 @llvm.convert.from.fp16(i16 %a)
6815</pre>
6816
6817<h5>Overview:</h5>
6818<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6819 a conversion from half precision floating point format to single precision
6820 floating point format.</p>
6821
6822<h5>Arguments:</h5>
6823<p>The intrinsic function contains single argument - the value to be
6824 converted.</p>
6825
6826<h5>Semantics:</h5>
6827<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6828 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6829 precision floating point format. The input half-float value is represented by
6830 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6831
6832<h5>Examples:</h5>
6833<pre>
6834 %a = load i16* @x, align 2
6835 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6836</pre>
6837
6838</div>
6839
6840<!-- ======================================================================= -->
6841<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6842 <a name="int_debugger">Debugger Intrinsics</a>
6843</div>
6844
6845<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6846
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6847<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6848 prefix), are described in
6849 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6850 Level Debugging</a> document.</p>
6851
6852</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6853
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6854<!-- ======================================================================= -->
6855<div class="doc_subsection">
6856 <a name="int_eh">Exception Handling Intrinsics</a>
6857</div>
6858
6859<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6860
6861<p>The LLVM exception handling intrinsics (which all start with
6862 <tt>llvm.eh.</tt> prefix), are described in
6863 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6864 Handling</a> document.</p>
6865
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6866</div>
6867
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6868<!-- ======================================================================= -->
6869<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6870 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6871</div>
6872
6873<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6874
6875<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]6876 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6877 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6878 function pointer lacking the nest parameter - the caller does not need to
6879 provide a value for it. Instead, the value to use is stored in advance in a
6880 "trampoline", a block of memory usually allocated on the stack, which also
6881 contains code to splice the nest value into the argument list. This is used
6882 to implement the GCC nested function address extension.</p>
6883
6884<p>For example, if the function is
6885 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6886 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6887 follows:</p>
6888
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6889<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6890 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6891 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6892 %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]6893 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6894</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6895
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6896<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6897 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6899</div>
6900
6901<!-- _______________________________________________________________________ -->
6902<div class="doc_subsubsection">
6903 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6904</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6906<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6908<h5>Syntax:</h5>
6909<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910 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]6911</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6914<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6915 function pointer suitable for executing it.</p>
6916
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6917<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6918<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6919 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6920 sufficiently aligned block of memory; this memory is written to by the
6921 intrinsic. Note that the size and the alignment are target-specific - LLVM
6922 currently provides no portable way of determining them, so a front-end that
6923 generates this intrinsic needs to have some target-specific knowledge.
6924 The <tt>func</tt> argument must hold a function bitcast to
6925 an <tt>i8*</tt>.</p>
6926
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6927<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6928<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6929 dependent code, turning it into a function. A pointer to this function is
6930 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6931 function pointer type</a> before being called. The new function's signature
6932 is the same as that of <tt>func</tt> with any arguments marked with
6933 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6934 is allowed, and it must be of pointer type. Calling the new function is
6935 equivalent to calling <tt>func</tt> with the same argument list, but
6936 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6937 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6938 by <tt>tramp</tt> is modified, then the effect of any later call to the
6939 returned function pointer is undefined.</p>
6940
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6941</div>
6942
6943<!-- ======================================================================= -->
6944<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6945 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6946</div>
6947
6948<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6949
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6951 hardware constructs for atomic operations and memory synchronization. This
6952 provides an interface to the hardware, not an interface to the programmer. It
6953 is aimed at a low enough level to allow any programming models or APIs
6954 (Application Programming Interfaces) which need atomic behaviors to map
6955 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6956 hardware provides a "universal IR" for source languages, it also provides a
6957 starting point for developing a "universal" atomic operation and
6958 synchronization IR.</p>
6959
6960<p>These do <em>not</em> form an API such as high-level threading libraries,
6961 software transaction memory systems, atomic primitives, and intrinsic
6962 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6963 application libraries. The hardware interface provided by LLVM should allow
6964 a clean implementation of all of these APIs and parallel programming models.
6965 No one model or paradigm should be selected above others unless the hardware
6966 itself ubiquitously does so.</p>
6967
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6968</div>
6969
6970<!-- _______________________________________________________________________ -->
6971<div class="doc_subsubsection">
6972 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6973</div>
6974<div class="doc_text">
6975<h5>Syntax:</h5>
6976<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6977 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]6978</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6980<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6981<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6982 specific pairs of memory access types.</p>
6983
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6984<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6985<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6986 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6987 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6988 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6989
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6990<ul>
6991 <li><tt>ll</tt>: load-load barrier</li>
6992 <li><tt>ls</tt>: load-store barrier</li>
6993 <li><tt>sl</tt>: store-load barrier</li>
6994 <li><tt>ss</tt>: store-store barrier</li>
6995 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6996</ul>
6997
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6998<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6999<p>This intrinsic causes the system to enforce some ordering constraints upon
7000 the loads and stores of the program. This barrier does not
7001 indicate <em>when</em> any events will occur, it only enforces
7002 an <em>order</em> in which they occur. For any of the specified pairs of load
7003 and store operations (f.ex. load-load, or store-load), all of the first
7004 operations preceding the barrier will complete before any of the second
7005 operations succeeding the barrier begin. Specifically the semantics for each
7006 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7008<ul>
7009 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7010 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7011 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7012 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7013 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7015 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7016 load after the barrier begins.</li>
7017</ul>
7018
7019<p>These semantics are applied with a logical "and" behavior when more than one
7020 is enabled in a single memory barrier intrinsic.</p>
7021
7022<p>Backends may implement stronger barriers than those requested when they do
7023 not support as fine grained a barrier as requested. Some architectures do
7024 not need all types of barriers and on such architectures, these become
7025 noops.</p>
7026
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7027<h5>Example:</h5>
7028<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7029%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7030%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7031 store i32 4, %ptr
7032
7033%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7034 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7035 <i>; guarantee the above finishes</i>
7036 store i32 8, %ptr <i>; before this begins</i>
7037</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7038
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7039</div>
7040
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7041<!-- _______________________________________________________________________ -->
7042<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7043 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7044</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7045
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7046<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7047
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7048<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7049<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7050 any integer bit width and for different address spaces. Not all targets
7051 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7052
7053<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7054 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7055 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7056 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7057 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]7058</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7059
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7060<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7061<p>This loads a value in memory and compares it to a given value. If they are
7062 equal, it stores a new value into the memory.</p>
7063
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7064<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7065<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7066 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7067 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7068 this integer type. While any bit width integer may be used, targets may only
7069 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7070
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7071<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7072<p>This entire intrinsic must be executed atomically. It first loads the value
7073 in memory pointed to by <tt>ptr</tt> and compares it with the
7074 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7075 memory. The loaded value is yielded in all cases. This provides the
7076 equivalent of an atomic compare-and-swap operation within the SSA
7077 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7078
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7079<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7080<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7081%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7082%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7083 store i32 4, %ptr
7084
7085%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7086%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7087 <i>; yields {i32}:result1 = 4</i>
7088%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7089%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7090
7091%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7092%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7093 <i>; yields {i32}:result2 = 8</i>
7094%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7095
7096%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7097</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7098
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7099</div>
7100
7101<!-- _______________________________________________________________________ -->
7102<div class="doc_subsubsection">
7103 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7104</div>
7105<div class="doc_text">
7106<h5>Syntax:</h5>
7107
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7109 integer bit width. Not all targets support all bit widths however.</p>
7110
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7111<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7112 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7113 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7114 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7115 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]7116</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7117
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7118<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7120 the value from memory. It then stores the value in <tt>val</tt> in the memory
7121 at <tt>ptr</tt>.</p>
7122
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7123<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7124<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7125 the <tt>val</tt> argument and the result must be integers of the same bit
7126 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7127 integer type. The targets may only lower integer representations they
7128 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7130<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7131<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7132 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7133 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7134
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7135<h5>Examples:</h5>
7136<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7137%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7138%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7139 store i32 4, %ptr
7140
7141%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7142%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7143 <i>; yields {i32}:result1 = 4</i>
7144%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7145%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7146
7147%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7148%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7149 <i>; yields {i32}:result2 = 8</i>
7150
7151%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7152%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7153</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7154
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7155</div>
7156
7157<!-- _______________________________________________________________________ -->
7158<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7159 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7160
7161</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7163<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7164
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7165<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7166<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7167 any integer bit width. Not all targets support all bit widths however.</p>
7168
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7169<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7170 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7171 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7172 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7173 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]7174</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7175
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7176<h5>Overview:</h5>
7177<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7178 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7179
7180<h5>Arguments:</h5>
7181<p>The intrinsic takes two arguments, the first a pointer to an integer value
7182 and the second an integer value. The result is also an integer value. These
7183 integer types can have any bit width, but they must all have the same bit
7184 width. The targets may only lower integer representations they support.</p>
7185
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7187<p>This intrinsic does a series of operations atomically. It first loads the
7188 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7189 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]7190
7191<h5>Examples:</h5>
7192<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7193%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7194%ptr = bitcast i8* %mallocP to i32*
7195 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7196%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7197 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7198%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7199 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7200%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7201 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7202%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7203</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7204
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7205</div>
7206
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7207<!-- _______________________________________________________________________ -->
7208<div class="doc_subsubsection">
7209 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7210
7211</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7213<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7214
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7215<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7216<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7217 any integer bit width and for different address spaces. Not all targets
7218 support all bit widths however.</p>
7219
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7220<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7221 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7222 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7223 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7224 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]7225</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7228<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7229 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7230
7231<h5>Arguments:</h5>
7232<p>The intrinsic takes two arguments, the first a pointer to an integer value
7233 and the second an integer value. The result is also an integer value. These
7234 integer types can have any bit width, but they must all have the same bit
7235 width. The targets may only lower integer representations they support.</p>
7236
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7237<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7238<p>This intrinsic does a series of operations atomically. It first loads the
7239 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7240 result to <tt>ptr</tt>. It yields the original value stored
7241 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7242
7243<h5>Examples:</h5>
7244<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7245%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7246%ptr = bitcast i8* %mallocP to i32*
7247 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7248%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7249 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7250%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7251 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7252%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7253 <i>; yields {i32}:result3 = 2</i>
7254%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7256
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7257</div>
7258
7259<!-- _______________________________________________________________________ -->
7260<div class="doc_subsubsection">
7261 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7262 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7263 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7264 <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]7265</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7267<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7269<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7270<p>These are overloaded intrinsics. You can
7271 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7272 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7273 bit width and for different address spaces. Not all targets support all bit
7274 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7275
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7276<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7277 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7278 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7279 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7280 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]7281</pre>
7282
7283<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7284 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7285 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7286 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7287 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]7288</pre>
7289
7290<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7291 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7292 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7293 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7294 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]7295</pre>
7296
7297<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7298 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7299 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7300 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7301 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]7302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7303
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7304<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7305<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7306 the value stored in memory at <tt>ptr</tt>. It yields the original value
7307 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7308
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7309<h5>Arguments:</h5>
7310<p>These intrinsics take two arguments, the first a pointer to an integer value
7311 and the second an integer value. The result is also an integer value. These
7312 integer types can have any bit width, but they must all have the same bit
7313 width. The targets may only lower integer representations they support.</p>
7314
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7315<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7316<p>These intrinsics does a series of operations atomically. They first load the
7317 value stored at <tt>ptr</tt>. They then do the bitwise
7318 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7319 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7320
7321<h5>Examples:</h5>
7322<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7323%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7324%ptr = bitcast i8* %mallocP to i32*
7325 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7326%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7327 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7328%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7329 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7330%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7331 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7332%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7333 <i>; yields {i32}:result3 = FF</i>
7334%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7335</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7336
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338
7339<!-- _______________________________________________________________________ -->
7340<div class="doc_subsubsection">
7341 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7342 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7343 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7344 <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]7345</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7346
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7347<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7348
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7349<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7350<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7351 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7352 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7353 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7354
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7355<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7356 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7357 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7358 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7359 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]7360</pre>
7361
7362<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7363 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7364 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7365 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7366 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]7367</pre>
7368
7369<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7370 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7371 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7372 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7373 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]7374</pre>
7375
7376<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7377 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7378 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7379 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7380 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]7381</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7382
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7383<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7384<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7385 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7386 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7387
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388<h5>Arguments:</h5>
7389<p>These intrinsics take two arguments, the first a pointer to an integer value
7390 and the second an integer value. The result is also an integer value. These
7391 integer types can have any bit width, but they must all have the same bit
7392 width. The targets may only lower integer representations they support.</p>
7393
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7394<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7395<p>These intrinsics does a series of operations atomically. They first load the
7396 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7397 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7398 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7399
7400<h5>Examples:</h5>
7401<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7402%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7403%ptr = bitcast i8* %mallocP to i32*
7404 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7405%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7406 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7407%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7408 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7409%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7411%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412 <i>; yields {i32}:result3 = 8</i>
7413%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7414</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7415
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7416</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7417
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7418
7419<!-- ======================================================================= -->
7420<div class="doc_subsection">
7421 <a name="int_memorymarkers">Memory Use Markers</a>
7422</div>
7423
7424<div class="doc_text">
7425
7426<p>This class of intrinsics exists to information about the lifetime of memory
7427 objects and ranges where variables are immutable.</p>
7428
7429</div>
7430
7431<!-- _______________________________________________________________________ -->
7432<div class="doc_subsubsection">
7433 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7434</div>
7435
7436<div class="doc_text">
7437
7438<h5>Syntax:</h5>
7439<pre>
7440 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7441</pre>
7442
7443<h5>Overview:</h5>
7444<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7445 object's lifetime.</p>
7446
7447<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7448<p>The first argument is a constant integer representing the size of the
7449 object, or -1 if it is variable sized. The second argument is a pointer to
7450 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7451
7452<h5>Semantics:</h5>
7453<p>This intrinsic indicates that before this point in the code, the value of the
7454 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]7455 never be used and has an undefined value. A load from the pointer that
7456 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7457 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7458
7459</div>
7460
7461<!-- _______________________________________________________________________ -->
7462<div class="doc_subsubsection">
7463 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7464</div>
7465
7466<div class="doc_text">
7467
7468<h5>Syntax:</h5>
7469<pre>
7470 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7471</pre>
7472
7473<h5>Overview:</h5>
7474<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7475 object's lifetime.</p>
7476
7477<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7478<p>The first argument is a constant integer representing the size of the
7479 object, or -1 if it is variable sized. The second argument is a pointer to
7480 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7481
7482<h5>Semantics:</h5>
7483<p>This intrinsic indicates that after this point in the code, the value of the
7484 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7485 never be used and has an undefined value. Any stores into the memory object
7486 following this intrinsic may be removed as dead.
7487
7488</div>
7489
7490<!-- _______________________________________________________________________ -->
7491<div class="doc_subsubsection">
7492 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7493</div>
7494
7495<div class="doc_text">
7496
7497<h5>Syntax:</h5>
7498<pre>
7499 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7500</pre>
7501
7502<h5>Overview:</h5>
7503<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7504 a memory object will not change.</p>
7505
7506<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7507<p>The first argument is a constant integer representing the size of the
7508 object, or -1 if it is variable sized. The second argument is a pointer to
7509 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7510
7511<h5>Semantics:</h5>
7512<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7513 the return value, the referenced memory location is constant and
7514 unchanging.</p>
7515
7516</div>
7517
7518<!-- _______________________________________________________________________ -->
7519<div class="doc_subsubsection">
7520 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7521</div>
7522
7523<div class="doc_text">
7524
7525<h5>Syntax:</h5>
7526<pre>
7527 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7528</pre>
7529
7530<h5>Overview:</h5>
7531<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7532 a memory object are mutable.</p>
7533
7534<h5>Arguments:</h5>
7535<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7536 The second argument is a constant integer representing the size of the
7537 object, or -1 if it is variable sized and the third argument is a pointer
7538 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7539
7540<h5>Semantics:</h5>
7541<p>This intrinsic indicates that the memory is mutable again.</p>
7542
7543</div>
7544
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7545<!-- ======================================================================= -->
7546<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7547 <a name="int_general">General Intrinsics</a>
7548</div>
7549
7550<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7551
7552<p>This class of intrinsics is designed to be generic and has no specific
7553 purpose.</p>
7554
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7555</div>
7556
7557<!-- _______________________________________________________________________ -->
7558<div class="doc_subsubsection">
7559 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7560</div>
7561
7562<div class="doc_text">
7563
7564<h5>Syntax:</h5>
7565<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7566 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]7567</pre>
7568
7569<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7570<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7571
7572<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7573<p>The first argument is a pointer to a value, the second is a pointer to a
7574 global string, the third is a pointer to a global string which is the source
7575 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7576
7577<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7578<p>This intrinsic allows annotation of local variables with arbitrary strings.
7579 This can be useful for special purpose optimizations that want to look for
7580 these annotations. These have no other defined use, they are ignored by code
7581 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7582
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7583</div>
7584
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7585<!-- _______________________________________________________________________ -->
7586<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7587 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7588</div>
7589
7590<div class="doc_text">
7591
7592<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7593<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7594 any integer bit width.</p>
7595
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7596<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7597 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7598 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7599 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7600 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7601 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]7602</pre>
7603
7604<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7605<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7606
7607<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7608<p>The first argument is an integer value (result of some expression), the
7609 second is a pointer to a global string, the third is a pointer to a global
7610 string which is the source file name, and the last argument is the line
7611 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7612
7613<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7614<p>This intrinsic allows annotations to be put on arbitrary expressions with
7615 arbitrary strings. This can be useful for special purpose optimizations that
7616 want to look for these annotations. These have no other defined use, they
7617 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7618
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7619</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7620
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7621<!-- _______________________________________________________________________ -->
7622<div class="doc_subsubsection">
7623 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7624</div>
7625
7626<div class="doc_text">
7627
7628<h5>Syntax:</h5>
7629<pre>
7630 declare void @llvm.trap()
7631</pre>
7632
7633<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7634<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7635
7636<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7637<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7638
7639<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7640<p>This intrinsics is lowered to the target dependent trap instruction. If the
7641 target does not have a trap instruction, this intrinsic will be lowered to
7642 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7643
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7644</div>
7645
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7646<!-- _______________________________________________________________________ -->
7647<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7648 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7649</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7650
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7651<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7652
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7653<h5>Syntax:</h5>
7654<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7655 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7656</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7657
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7658<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7659<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7660 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7661 ensure that it is placed on the stack before local variables.</p>
7662
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7663<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7664<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7665 arguments. The first argument is the value loaded from the stack
7666 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7667 that has enough space to hold the value of the guard.</p>
7668
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7669<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7670<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7671 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7672 stack. This is to ensure that if a local variable on the stack is
7673 overwritten, it will destroy the value of the guard. When the function exits,
7674 the guard on the stack is checked against the original guard. If they're
7675 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7676 function.</p>
7677
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7678</div>
7679
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7680<!-- _______________________________________________________________________ -->
7681<div class="doc_subsubsection">
7682 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7683</div>
7684
7685<div class="doc_text">
7686
7687<h5>Syntax:</h5>
7688<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7689 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7690 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7691</pre>
7692
7693<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7694<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7695 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7696 operation like memcpy will either overflow a buffer that corresponds to
7697 an object, or b) to determine that a runtime check for overflow isn't
7698 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7699 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7700
7701<h5>Arguments:</h5>
7702<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7703 argument is a pointer to or into the <tt>object</tt>. The second argument
7704 is a boolean 0 or 1. This argument determines whether you want the
7705 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7706 1, variables are not allowed.</p>
7707
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7708<h5>Semantics:</h5>
7709<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7710 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7711 (depending on the <tt>type</tt> argument if the size cannot be determined
7712 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7713
7714</div>
7715
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7716<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7717<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7718<address>
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7723
7724 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7725 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7726 Last modified: $Date$
7727</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7728
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7729</body>
7730</html>