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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ff23535df64ffdfa73540669ea642f6b84221217 / . / 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 Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]55 </ol>
56 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]83 </ol>
84 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]88 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]89 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]97 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]127 </ol>
128 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </ol>
144 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]160 </ol>
161 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]169 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]174 </ol>
175 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]176 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]190 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]200 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]205 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]211 </ol>
212 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218 </ol>
219 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]241 </ol>
242 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]244 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <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]258 <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]259 </ol>
260 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <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]265 </ol>
266 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]300 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]326<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]361</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]363<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]366<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]373<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]374<pre>
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>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]377</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]379<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
380 LLVM infrastructure provides a verification pass that may be used to verify
381 that an LLVM module is well formed. This pass is automatically run by the
382 parser after parsing input assembly and by the optimizer before it outputs
383 bitcode. The violations pointed out by the verifier pass indicate bugs in
384 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]385
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]386</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]391<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]394<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]440<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]442%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]444</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]446<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]447
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]448<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]452</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]454<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]455
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]456<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]457<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%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]460%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]462</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]464<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
465 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]467<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
471 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]472 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]474 <li>Unnamed temporaries are numbered sequentially</li>
475</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]476
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]477<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]478 demonstrating instructions, we will follow an instruction with a comment that
479 defines the type and name of value produced. Comments are shown in italic
480 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]482</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
484<!-- *********************************************************************** -->
485<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
486<!-- *********************************************************************** -->
487
488<!-- ======================================================================= -->
489<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
490</div>
491
492<div class="doc_text">
493
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]494<p>LLVM programs are composed of "Module"s, each of which is a translation unit
495 of the input programs. Each module consists of functions, global variables,
496 and symbol table entries. Modules may be combined together with the LLVM
497 linker, which merges function (and global variable) definitions, resolves
498 forward declarations, and merges symbol table entries. Here is an example of
499 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]501<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]502<pre>
503<i>; Declare the string constant as a global constant.</i>
504<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>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
506<i>; External declaration of the puts function</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]507<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508
509<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]510define i32 @main() { <i>; i32()* </i>
511 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]512 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]513
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]514 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]515 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]516 <a href="#i_ret">ret</a> i32 0<br>}
517
518<i>; Named metadata</i>
519!1 = metadata !{i32 41}
520!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]521</pre>
522</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]524<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]525 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]527 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
528 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]530<p>In general, a module is made up of a list of global values, where both
531 functions and global variables are global values. Global values are
532 represented by a pointer to a memory location (in this case, a pointer to an
533 array of char, and a pointer to a function), and have one of the
534 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]535
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="linkage">Linkage Types</a>
541</div>
542
543<div class="doc_text">
544
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]545<p>All Global Variables and Functions have one of the following types of
546 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]547
548<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
551 by objects in the current module. In particular, linking code into a
552 module with an private global value may cause the private to be renamed as
553 necessary to avoid collisions. Because the symbol is private to the
554 module, all references can be updated. This doesn't show up in any symbol
555 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]556
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]558 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
559 assembler and evaluated by the linker. Unlike normal strong symbols, they
560 are removed by the linker from the final linked image (executable or
561 dynamic library).</dd>
562
563 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
565 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
566 linker. The symbols are removed by the linker from the final linked image
567 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]573
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]596
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]613
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]614
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]626
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]636
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]641</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]642
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]646
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]654
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]661</dl>
662
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]718
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]743</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]775
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<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]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]795
796<div class="doc_code">
797<pre>
798%mytype = type { %mytype*, i32 }
799</pre>
800</div>
801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802<p>You may give a name to any <a href="#typesystem">type</a> except
803 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
804 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]805
806<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 and that you can therefore specify multiple names for the same type. This
808 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
809 uses structural typing, the name is not part of the type. When printing out
810 LLVM IR, the printer will pick <em>one name</em> to render all types of a
811 particular shape. This means that if you have code where two different
812 source types end up having the same LLVM type, that the dumper will sometimes
813 print the "wrong" or unexpected type. This is an important design point and
814 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]815
816</div>
817
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]818<!-- ======================================================================= -->
819<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]820 <a name="globalvars">Global Variables</a>
821</div>
822
823<div class="doc_text">
824
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]825<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826 instead of run-time. Global variables may optionally be initialized, may
827 have an explicit section to be placed in, and may have an optional explicit
828 alignment specified. A variable may be defined as "thread_local", which
829 means that it will not be shared by threads (each thread will have a
830 separated copy of the variable). A variable may be defined as a global
831 "constant," which indicates that the contents of the variable
832 will <b>never</b> be modified (enabling better optimization, allowing the
833 global data to be placed in the read-only section of an executable, etc).
834 Note that variables that need runtime initialization cannot be marked
835 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
838 constant, even if the final definition of the global is not. This capability
839 can be used to enable slightly better optimization of the program, but
840 requires the language definition to guarantee that optimizations based on the
841 'constantness' are valid for the translation units that do not include the
842 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]843
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]844<p>As SSA values, global variables define pointer values that are in scope
845 (i.e. they dominate) all basic blocks in the program. Global variables
846 always define a pointer to their "content" type because they describe a
847 region of memory, and all memory objects in LLVM are accessed through
848 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]850<p>A global variable may be declared to reside in a target-specific numbered
851 address space. For targets that support them, address spaces may affect how
852 optimizations are performed and/or what target instructions are used to
853 access the variable. The default address space is zero. The address space
854 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]855
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]856<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]857 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]858
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]859<p>An explicit alignment may be specified for a global, which must be a power
860 of 2. If not present, or if the alignment is set to zero, the alignment of
861 the global is set by the target to whatever it feels convenient. If an
862 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]863 alignment. Targets and optimizers are not allowed to over-align the global
864 if the global has an assigned section. In this case, the extra alignment
865 could be observable: for example, code could assume that the globals are
866 densely packed in their section and try to iterate over them as an array,
867 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]869<p>For example, the following defines a global in a numbered address space with
870 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]871
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]872<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]873<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]875</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]876</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]877
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]878</div>
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
883 <a name="functionstructure">Functions</a>
884</div>
885
886<div class="doc_text">
887
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]888<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]889 optional <a href="#linkage">linkage type</a>, an optional
890 <a href="#visibility">visibility style</a>, an optional
891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>, a return type, an optional
903 <a href="#paramattrs">parameter attribute</a> for the return type, a function
904 name, a possibly empty list of arguments, an optional alignment, and an
905 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]906
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]907<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908 (Control Flow Graph) for the function. Each basic block may optionally start
909 with a label (giving the basic block a symbol table entry), contains a list
910 of instructions, and ends with a <a href="#terminators">terminator</a>
911 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]913<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]914 executed on entrance to the function, and it is not allowed to have
915 predecessor basic blocks (i.e. there can not be any branches to the entry
916 block of a function). Because the block can have no predecessors, it also
917 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]918
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]919<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]920 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]921
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922<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]923 the alignment is set to zero, the alignment of the function is set by the
924 target to whatever it feels convenient. If an explicit alignment is
925 specified, the function is forced to have at least that much alignment. All
926 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]927
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]928<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]929<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]930<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]931define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
933 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
934 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
935 [<a href="#gc">gc</a>] { ... }
936</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]937</div>
938
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]939</div>
940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<!-- ======================================================================= -->
942<div class="doc_subsection">
943 <a name="aliasstructure">Aliases</a>
944</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]945
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]946<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947
948<p>Aliases act as "second name" for the aliasee value (which can be either
949 function, global variable, another alias or bitcast of global value). Aliases
950 may have an optional <a href="#linkage">linkage type</a>, and an
951 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]953<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]954<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]955<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]956@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]957</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]958</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]959
960</div>
961
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]962<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]963<div class="doc_subsection">
964 <a name="namedmetadatastructure">Named Metadata</a>
965</div>
966
967<div class="doc_text">
968
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
970 nodes</a> (but not metadata strings) and null are the only valid operands for
971 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
974<div class="doc_code">
975<pre>
976!1 = metadata !{metadata !"one"}
977!name = !{null, !1}
978</pre>
979</div>
980
981</div>
982
983<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]984<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]985
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986<div class="doc_text">
987
988<p>The return type and each parameter of a function type may have a set of
989 <i>parameter attributes</i> associated with them. Parameter attributes are
990 used to communicate additional information about the result or parameters of
991 a function. Parameter attributes are considered to be part of the function,
992 not of the function type, so functions with different parameter attributes
993 can have the same function type.</p>
994
995<p>Parameter attributes are simple keywords that follow the type specified. If
996 multiple parameter attributes are needed, they are space separated. For
997 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]998
999<div class="doc_code">
1000<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1001declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1002declare i32 @atoi(i8 zeroext)
1003declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1004</pre>
1005</div>
1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1008 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1009
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1012<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be zero-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be sign-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that this parameter or return value should be treated in a
1025 special target-dependent fashion during while emitting code for a function
1026 call or return (usually, by putting it in a register as opposed to memory,
1027 though some targets use it to distinguish between two different kinds of
1028 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that the pointer parameter should really be passed by value
1032 to the function. The attribute implies that a hidden copy of the pointee
1033 is made between the caller and the callee, so the callee is unable to
1034 modify the value in the callee. This attribute is only valid on LLVM
1035 pointer arguments. It is generally used to pass structs and arrays by
1036 value, but is also valid on pointers to scalars. The copy is considered
1037 to belong to the caller not the callee (for example,
1038 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1039 <tt>byval</tt> parameters). This is not a valid attribute for return
1040 values. The byval attribute also supports specifying an alignment with
1041 the align attribute. This has a target-specific effect on the code
1042 generator that usually indicates a desired alignment for the synthesized
1043 stack slot.</dd>
1044
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame^]1045 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This indicates that the pointer parameter specifies the address of a
1047 structure that is the return value of the function in the source program.
1048 This pointer must be guaranteed by the caller to be valid: loads and
1049 stores to the structure may be assumed by the callee to not to trap. This
1050 may only be applied to the first parameter. This is not a valid attribute
1051 for return values. </dd>
1052
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame^]1053 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1054 <dd>This indicates that pointer values
1055 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
1056 value do not alias pointer values which are not <i>based</i> on it.
1057 The caller shares the responsibility with the callee for ensuring that
1058 these requirements are met.
1059 For further details, please see the discussion of the NoAlias response in
1060 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame^]1062 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1063 <dd>This indicates that the callee does not make any copies of the pointer
1064 that outlive the callee itself. This is not a valid attribute for return
1065 values.</dd>
1066
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame^]1067 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This indicates that the pointer parameter can be excised using the
1069 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1070 attribute for return values.</dd>
1071</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1072
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1073</div>
1074
1075<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1076<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1077 <a name="gc">Garbage Collector Names</a>
1078</div>
1079
1080<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1082<p>Each function may specify a garbage collector name, which is simply a
1083 string:</p>
1084
1085<div class="doc_code">
1086<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1087define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088</pre>
1089</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1090
1091<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092 collector which will cause the compiler to alter its output in order to
1093 support the named garbage collection algorithm.</p>
1094
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1095</div>
1096
1097<!-- ======================================================================= -->
1098<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1099 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1100</div>
1101
1102<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1103
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104<p>Function attributes are set to communicate additional information about a
1105 function. Function attributes are considered to be part of the function, not
1106 of the function type, so functions with different parameter attributes can
1107 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1108
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1109<p>Function attributes are simple keywords that follow the type specified. If
1110 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1111
1112<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1113<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1114define void @f() noinline { ... }
1115define void @f() alwaysinline { ... }
1116define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1117define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1118</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1119</div>
1120
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1121<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1122 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1123 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1124 the backend should forcibly align the stack pointer. Specify the
1125 desired alignment, which must be a power of two, in parentheses.
1126
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1127 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute indicates that the inliner should attempt to inline this
1129 function into callers whenever possible, ignoring any active inlining size
1130 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1131
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1132 <dt><tt><b>inlinehint</b></tt></dt>
1133 <dd>This attribute indicates that the source code contained a hint that inlining
1134 this function is desirable (such as the "inline" keyword in C/C++). It
1135 is just a hint; it imposes no requirements on the inliner.</dd>
1136
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1137 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1138 <dd>This attribute indicates that the inliner should never inline this
1139 function in any situation. This attribute may not be used together with
1140 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1141
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1142 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1143 <dd>This attribute suggests that optimization passes and code generator passes
1144 make choices that keep the code size of this function low, and otherwise
1145 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1146
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This function attribute indicates that the function never returns
1149 normally. This produces undefined behavior at runtime if the function
1150 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1151
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1152 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1153 <dd>This function attribute indicates that the function never returns with an
1154 unwind or exceptional control flow. If the function does unwind, its
1155 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1156
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1157 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1158 <dd>This attribute indicates that the function computes its result (or decides
1159 to unwind an exception) based strictly on its arguments, without
1160 dereferencing any pointer arguments or otherwise accessing any mutable
1161 state (e.g. memory, control registers, etc) visible to caller functions.
1162 It does not write through any pointer arguments
1163 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1164 changes any state visible to callers. This means that it cannot unwind
1165 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1166 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1167
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attribute indicates that the function does not write through any
1170 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1171 arguments) or otherwise modify any state (e.g. memory, control registers,
1172 etc) visible to caller functions. It may dereference pointer arguments
1173 and read state that may be set in the caller. A readonly function always
1174 returns the same value (or unwinds an exception identically) when called
1175 with the same set of arguments and global state. It cannot unwind an
1176 exception by calling the <tt>C++</tt> exception throwing methods, but may
1177 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1178
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1179 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1180 <dd>This attribute indicates that the function should emit a stack smashing
1181 protector. It is in the form of a "canary"&mdash;a random value placed on
1182 the stack before the local variables that's checked upon return from the
1183 function to see if it has been overwritten. A heuristic is used to
1184 determine if a function needs stack protectors or not.<br>
1185<br>
1186 If a function that has an <tt>ssp</tt> attribute is inlined into a
1187 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1188 function will have an <tt>ssp</tt> attribute.</dd>
1189
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1190 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1191 <dd>This attribute indicates that the function should <em>always</em> emit a
1192 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1193 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1194<br>
1195 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1196 function that doesn't have an <tt>sspreq</tt> attribute or which has
1197 an <tt>ssp</tt> attribute, then the resulting function will have
1198 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attribute indicates that the code generator should not use a red
1202 zone, even if the target-specific ABI normally permits it.</dd>
1203
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1204 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1205 <dd>This attributes disables implicit floating point instructions.</dd>
1206
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute disables prologue / epilogue emission for the function.
1209 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1210</dl>
1211
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1212</div>
1213
1214<!-- ======================================================================= -->
1215<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1216 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1217</div>
1218
1219<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1220
1221<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1222 the GCC "file scope inline asm" blocks. These blocks are internally
1223 concatenated by LLVM and treated as a single unit, but may be separated in
1224 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1225
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1226<div class="doc_code">
1227<pre>
1228module asm "inline asm code goes here"
1229module asm "more can go here"
1230</pre>
1231</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
1233<p>The strings can contain any character by escaping non-printable characters.
1234 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]1235 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1236
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1237<p>The inline asm code is simply printed to the machine code .s file when
1238 assembly code is generated.</p>
1239
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1240</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1241
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1242<!-- ======================================================================= -->
1243<div class="doc_subsection">
1244 <a name="datalayout">Data Layout</a>
1245</div>
1246
1247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1249<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1250 data is to be laid out in memory. The syntax for the data layout is
1251 simply:</p>
1252
1253<div class="doc_code">
1254<pre>
1255target datalayout = "<i>layout specification</i>"
1256</pre>
1257</div>
1258
1259<p>The <i>layout specification</i> consists of a list of specifications
1260 separated by the minus sign character ('-'). Each specification starts with
1261 a letter and may include other information after the letter to define some
1262 aspect of the data layout. The specifications accepted are as follows:</p>
1263
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264<dl>
1265 <dt><tt>E</tt></dt>
1266 <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]1267 bits with the most significance have the lowest address location.</dd>
1268
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1269 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1270 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1271 the bits with the least significance have the lowest address
1272 location.</dd>
1273
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1274 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1275 <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]1276 <i>preferred</i> alignments. All sizes are in bits. Specifying
1277 the <i>pref</i> alignment is optional. If omitted, the
1278 preceding <tt>:</tt> should be omitted too.</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1281 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1283
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1285 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>.</dd>
1287
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1288 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1289 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1290 <i>size</i>. Only values of <i>size</i> that are supported by the target
1291 will work. 32 (float) and 64 (double) are supported on all targets;
1292 80 or 128 (different flavors of long double) are also supported on some
1293 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1295 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1296 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1297 <i>size</i>.</dd>
1298
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1299 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1300 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1301 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1302
1303 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1304 <dd>This specifies a set of native integer widths for the target CPU
1305 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1306 "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]1307 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1308 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1309</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1310
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1311<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1312 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1313 specifications in the <tt>datalayout</tt> keyword. The default specifications
1314 are given in this list:</p>
1315
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1316<ul>
1317 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1318 <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]1319 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1320 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1321 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1322 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1323 <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]1324 alignment of 64-bits</li>
1325 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1326 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1327 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1328 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1329 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1330 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1331</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1332
1333<p>When LLVM is determining the alignment for a given type, it uses the
1334 following rules:</p>
1335
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1336<ol>
1337 <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]1338 specification is used.</li>
1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340 <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]1341 smallest integer type that is larger than the bitwidth of the sought type
1342 is used. If none of the specifications are larger than the bitwidth then
1343 the the largest integer type is used. For example, given the default
1344 specifications above, the i7 type will use the alignment of i8 (next
1345 largest) while both i65 and i256 will use the alignment of i64 (largest
1346 specified).</li>
1347
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1348 <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]1349 largest vector type that is smaller than the sought vector type will be
1350 used as a fall back. This happens because &lt;128 x double&gt; can be
1351 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1352</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1353
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1355
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1356<!-- ======================================================================= -->
1357<div class="doc_subsection">
1358 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1359</div>
1360
1361<div class="doc_text">
1362
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1363<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1364with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1365is undefined. Pointer values are associated with address ranges
1366according to the following rules:</p>
1367
1368<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1369 <li>A pointer value is associated with the addresses associated with
1370 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1371 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1372 range of the variable's storage.</li>
1373 <li>The result value of an allocation instruction is associated with
1374 the address range of the allocated storage.</li>
1375 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1376 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1377 <li>An integer constant other than zero or a pointer value returned
1378 from a function not defined within LLVM may be associated with address
1379 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1380 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1381 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1382</ul>
1383
1384<p>A pointer value is <i>based</i> on another pointer value according
1385 to the following rules:</p>
1386
1387<ul>
1388 <li>A pointer value formed from a
1389 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1390 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1391 <li>The result value of a
1392 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1393 of the <tt>bitcast</tt>.</li>
1394 <li>A pointer value formed by an
1395 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1396 pointer values that contribute (directly or indirectly) to the
1397 computation of the pointer's value.</li>
1398 <li>The "<i>based</i> on" relationship is transitive.</li>
1399</ul>
1400
1401<p>Note that this definition of <i>"based"</i> is intentionally
1402 similar to the definition of <i>"based"</i> in C99, though it is
1403 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1404
1405<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1406<tt><a href="#i_load">load</a></tt> merely indicates the size and
1407alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1408interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1409<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1410and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1411
1412<p>Consequently, type-based alias analysis, aka TBAA, aka
1413<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1414LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1415additional information which specialized optimization passes may use
1416to implement type-based alias analysis.</p>
1417
1418</div>
1419
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1420<!-- ======================================================================= -->
1421<div class="doc_subsection">
1422 <a name="volatile">Volatile Memory Accesses</a>
1423</div>
1424
1425<div class="doc_text">
1426
1427<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1428href="#i_store"><tt>store</tt></a>s, and <a
1429href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1430The optimizers must not change the number of volatile operations or change their
1431order of execution relative to other volatile operations. The optimizers
1432<i>may</i> change the order of volatile operations relative to non-volatile
1433operations. This is not Java's "volatile" and has no cross-thread
1434synchronization behavior.</p>
1435
1436</div>
1437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1438<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1439<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1440<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1441
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1442<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1444<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1445 intermediate representation. Being typed enables a number of optimizations
1446 to be performed on the intermediate representation directly, without having
1447 to do extra analyses on the side before the transformation. A strong type
1448 system makes it easier to read the generated code and enables novel analyses
1449 and transformations that are not feasible to perform on normal three address
1450 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1451
1452</div>
1453
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1454<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1455<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1456Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1457
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1458<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1459
1460<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1461
1462<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1463 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1464 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1465 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1466 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1467 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1468 </tr>
1469 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1470 <td><a href="#t_floating">floating point</a></td>
1471 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1472 </tr>
1473 <tr>
1474 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1475 <td><a href="#t_integer">integer</a>,
1476 <a href="#t_floating">floating point</a>,
1477 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1478 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1479 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1480 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1481 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1482 <a href="#t_label">label</a>,
1483 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1484 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1485 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1486 <tr>
1487 <td><a href="#t_primitive">primitive</a></td>
1488 <td><a href="#t_label">label</a>,
1489 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1490 <a href="#t_floating">floating point</a>,
1491 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492 </tr>
1493 <tr>
1494 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1495 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1496 <a href="#t_function">function</a>,
1497 <a href="#t_pointer">pointer</a>,
1498 <a href="#t_struct">structure</a>,
1499 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1500 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1501 <a href="#t_vector">vector</a>,
1502 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1503 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1504 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1505 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1506</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1508<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1509 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1510 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1511
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1512</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1514<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1515<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1516
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1517<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1518
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1519<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1520 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1521
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1522</div>
1523
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1524<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1525<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1526
1527<div class="doc_text">
1528
1529<h5>Overview:</h5>
1530<p>The integer type is a very simple type that simply specifies an arbitrary
1531 bit width for the integer type desired. Any bit width from 1 bit to
1532 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1533
1534<h5>Syntax:</h5>
1535<pre>
1536 iN
1537</pre>
1538
1539<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1540 value.</p>
1541
1542<h5>Examples:</h5>
1543<table class="layout">
1544 <tr class="layout">
1545 <td class="left"><tt>i1</tt></td>
1546 <td class="left">a single-bit integer.</td>
1547 </tr>
1548 <tr class="layout">
1549 <td class="left"><tt>i32</tt></td>
1550 <td class="left">a 32-bit integer.</td>
1551 </tr>
1552 <tr class="layout">
1553 <td class="left"><tt>i1942652</tt></td>
1554 <td class="left">a really big integer of over 1 million bits.</td>
1555 </tr>
1556</table>
1557
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1561<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1562
1563<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1564
1565<table>
1566 <tbody>
1567 <tr><th>Type</th><th>Description</th></tr>
1568 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1569 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1570 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1571 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1572 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1573 </tbody>
1574</table>
1575
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1576</div>
1577
1578<!-- _______________________________________________________________________ -->
1579<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1580
1581<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1582
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1583<h5>Overview:</h5>
1584<p>The void type does not represent any value and has no size.</p>
1585
1586<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1587<pre>
1588 void
1589</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1590
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1591</div>
1592
1593<!-- _______________________________________________________________________ -->
1594<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1595
1596<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1597
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1598<h5>Overview:</h5>
1599<p>The label type represents code labels.</p>
1600
1601<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1602<pre>
1603 label
1604</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1605
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1606</div>
1607
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1608<!-- _______________________________________________________________________ -->
1609<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1610
1611<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1612
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1613<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1614<p>The metadata type represents embedded metadata. No derived types may be
1615 created from metadata except for <a href="#t_function">function</a>
1616 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1617
1618<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1619<pre>
1620 metadata
1621</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1622
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1623</div>
1624
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1625
1626<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1627<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1628
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1629<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1630
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1631<p>The real power in LLVM comes from the derived types in the system. This is
1632 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1633 useful types. Each of these types contain one or more element types which
1634 may be a primitive type, or another derived type. For example, it is
1635 possible to have a two dimensional array, using an array as the element type
1636 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1637
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1638
1639</div>
1640
1641<!-- _______________________________________________________________________ -->
1642<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1643
1644<div class="doc_text">
1645
1646<p>Aggregate Types are a subset of derived types that can contain multiple
1647 member types. <a href="#t_array">Arrays</a>,
1648 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1649 <a href="#t_union">unions</a> are aggregate types.</p>
1650
1651</div>
1652
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1653</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1654
1655<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1656<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1657
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1658<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1661<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1662 sequentially in memory. The array type requires a size (number of elements)
1663 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1664
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1665<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1666<pre>
1667 [&lt;# elements&gt; x &lt;elementtype&gt;]
1668</pre>
1669
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1670<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1671 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1672
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1673<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1674<table class="layout">
1675 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1676 <td class="left"><tt>[40 x i32]</tt></td>
1677 <td class="left">Array of 40 32-bit integer values.</td>
1678 </tr>
1679 <tr class="layout">
1680 <td class="left"><tt>[41 x i32]</tt></td>
1681 <td class="left">Array of 41 32-bit integer values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>[4 x i8]</tt></td>
1685 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1686 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1687</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1688<p>Here are some examples of multidimensional arrays:</p>
1689<table class="layout">
1690 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1691 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1692 <td class="left">3x4 array of 32-bit integer values.</td>
1693 </tr>
1694 <tr class="layout">
1695 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1696 <td class="left">12x10 array of single precision floating point values.</td>
1697 </tr>
1698 <tr class="layout">
1699 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1700 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1701 </tr>
1702</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1703
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1704<p>There is no restriction on indexing beyond the end of the array implied by
1705 a static type (though there are restrictions on indexing beyond the bounds
1706 of an allocated object in some cases). This means that single-dimension
1707 'variable sized array' addressing can be implemented in LLVM with a zero
1708 length array type. An implementation of 'pascal style arrays' in LLVM could
1709 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1711</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1715
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1716<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1717
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1719<p>The function type can be thought of as a function signature. It consists of
1720 a return type and a list of formal parameter types. The return type of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1721 function type is a scalar type, a void type, a struct type, or a union
1722 type. If the return type is a struct type then all struct elements must be
1723 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1724
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1725<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1726<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1727 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1728</pre>
1729
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1730<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]1731 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1732 which indicates that the function takes a variable number of arguments.
1733 Variable argument functions can access their arguments with
1734 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1735 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1736 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1739<table class="layout">
1740 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1741 <td class="left"><tt>i32 (i32)</tt></td>
1742 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1743 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1744 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1745 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1746 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1747 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1748 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1749 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1750 </td>
1751 </tr><tr class="layout">
1752 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1753 <td class="left">A vararg function that takes at least one
1754 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1755 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1756 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1757 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1758 </tr><tr class="layout">
1759 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1760 <td class="left">A function taking an <tt>i32</tt>, returning a
1761 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1762 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1763 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1765
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1766</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1768<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1769<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1770
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1771<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1773<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1774<p>The structure type is used to represent a collection of data members together
1775 in memory. The packing of the field types is defined to match the ABI of the
1776 underlying processor. The elements of a structure may be any type that has a
1777 size.</p>
1778
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1779<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1780 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1781 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1782 Structures in registers are accessed using the
1783 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1784 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1785<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1786<pre>
1787 { &lt;type list&gt; }
1788</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1790<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1791<table class="layout">
1792 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1793 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1794 <td class="left">A triple of three <tt>i32</tt> values</td>
1795 </tr><tr class="layout">
1796 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1797 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1798 second element is a <a href="#t_pointer">pointer</a> to a
1799 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1800 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1801 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1802</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1804</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1807<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1808</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1809
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1810<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1811
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1812<h5>Overview:</h5>
1813<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1814 together in memory. There is no padding between fields. Further, the
1815 alignment of a packed structure is 1 byte. The elements of a packed
1816 structure may be any type that has a size.</p>
1817
1818<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1819 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1820 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1821
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1822<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1823<pre>
1824 &lt; { &lt;type list&gt; } &gt;
1825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1826
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1827<h5>Examples:</h5>
1828<table class="layout">
1829 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1830 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1831 <td class="left">A triple of three <tt>i32</tt> values</td>
1832 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1833 <td class="left">
1834<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1835 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1836 second element is a <a href="#t_pointer">pointer</a> to a
1837 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1838 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1839 </tr>
1840</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1841
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1842</div>
1843
1844<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1845<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1846
1847<div class="doc_text">
1848
1849<h5>Overview:</h5>
1850<p>A union type describes an object with size and alignment suitable for
1851 an object of any one of a given set of types (also known as an "untagged"
1852 union). It is similar in concept and usage to a
1853 <a href="#t_struct">struct</a>, except that all members of the union
1854 have an offset of zero. The elements of a union may be any type that has a
1855 size. Unions must have at least one member - empty unions are not allowed.
1856 </p>
1857
1858<p>The size of the union as a whole will be the size of its largest member,
1859 and the alignment requirements of the union as a whole will be the largest
1860 alignment requirement of any member.</p>
1861
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1862<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1863 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1864 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1865 Since all members are at offset zero, the getelementptr instruction does
1866 not affect the address, only the type of the resulting pointer.</p>
1867
1868<h5>Syntax:</h5>
1869<pre>
1870 union { &lt;type list&gt; }
1871</pre>
1872
1873<h5>Examples:</h5>
1874<table class="layout">
1875 <tr class="layout">
1876 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1877 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1878 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1879 </tr><tr class="layout">
1880 <td class="left">
1881 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1882 <td class="left">A union, where the first element is a <tt>float</tt> and the
1883 second element is a <a href="#t_pointer">pointer</a> to a
1884 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1885 an <tt>i32</tt>.</td>
1886 </tr>
1887</table>
1888
1889</div>
1890
1891<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1892<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894<div class="doc_text">
1895
1896<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1897<p>The pointer type is used to specify memory locations.
1898 Pointers are commonly used to reference objects in memory.</p>
1899
1900<p>Pointer types may have an optional address space attribute defining the
1901 numbered address space where the pointed-to object resides. The default
1902 address space is number zero. The semantics of non-zero address
1903 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1904
1905<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1906 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1907
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1908<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1909<pre>
1910 &lt;type&gt; *
1911</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1912
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1913<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1914<table class="layout">
1915 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1916 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1917 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1918 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1919 </tr>
1920 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]1921 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1922 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1923 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1924 <tt>i32</tt>.</td>
1925 </tr>
1926 <tr class="layout">
1927 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1928 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1929 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1930 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1931</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1932
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1933</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1934
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1935<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1936<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1939
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1940<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1941<p>A vector type is a simple derived type that represents a vector of elements.
1942 Vector types are used when multiple primitive data are operated in parallel
1943 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1944 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1945 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1946
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1947<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1948<pre>
1949 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1950</pre>
1951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1952<p>The number of elements is a constant integer value; elementtype may be any
1953 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1954
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1955<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +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>&lt;4 x i32&gt;</tt></td>
1959 <td class="left">Vector of 4 32-bit integer values.</td>
1960 </tr>
1961 <tr class="layout">
1962 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1963 <td class="left">Vector of 8 32-bit floating-point values.</td>
1964 </tr>
1965 <tr class="layout">
1966 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1967 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1968 </tr>
1969</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1971</div>
1972
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1973<!-- _______________________________________________________________________ -->
1974<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1975<div class="doc_text">
1976
1977<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1979 corresponds (for example) to the C notion of a forward declared structure
1980 type. In LLVM, opaque types can eventually be resolved to any type (not just
1981 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1982
1983<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1984<pre>
1985 opaque
1986</pre>
1987
1988<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1989<table class="layout">
1990 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1991 <td class="left"><tt>opaque</tt></td>
1992 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1993 </tr>
1994</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1995
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1996</div>
1997
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1998<!-- ======================================================================= -->
1999<div class="doc_subsection">
2000 <a name="t_uprefs">Type Up-references</a>
2001</div>
2002
2003<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2004
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2006<p>An "up reference" allows you to refer to a lexically enclosing type without
2007 requiring it to have a name. For instance, a structure declaration may
2008 contain a pointer to any of the types it is lexically a member of. Example
2009 of up references (with their equivalent as named type declarations)
2010 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2011
2012<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]2013 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2014 { \2 }* %y = type { %y }*
2015 \1* %z = type %z*
2016</pre>
2017
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2018<p>An up reference is needed by the asmprinter for printing out cyclic types
2019 when there is no declared name for a type in the cycle. Because the
2020 asmprinter does not want to print out an infinite type string, it needs a
2021 syntax to handle recursive types that have no names (all names are optional
2022 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2023
2024<h5>Syntax:</h5>
2025<pre>
2026 \&lt;level&gt;
2027</pre>
2028
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2029<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]2030
2031<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2032<table class="layout">
2033 <tr class="layout">
2034 <td class="left"><tt>\1*</tt></td>
2035 <td class="left">Self-referential pointer.</td>
2036 </tr>
2037 <tr class="layout">
2038 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2039 <td class="left">Recursive structure where the upref refers to the out-most
2040 structure.</td>
2041 </tr>
2042</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2043
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2045
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046<!-- *********************************************************************** -->
2047<div class="doc_section"> <a name="constants">Constants</a> </div>
2048<!-- *********************************************************************** -->
2049
2050<div class="doc_text">
2051
2052<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2053 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2054
2055</div>
2056
2057<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2058<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2059
2060<div class="doc_text">
2061
2062<dl>
2063 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2064 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2065 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2066
2067 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2068 <dd>Standard integers (such as '4') are constants of
2069 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2070 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2071
2072 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2073 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2074 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2075 notation (see below). The assembler requires the exact decimal value of a
2076 floating-point constant. For example, the assembler accepts 1.25 but
2077 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2078 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2079
2080 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2081 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2082 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2083</dl>
2084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2085<p>The one non-intuitive notation for constants is the hexadecimal form of
2086 floating point constants. For example, the form '<tt>double
2087 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2088 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2089 constants are required (and the only time that they are generated by the
2090 disassembler) is when a floating point constant must be emitted but it cannot
2091 be represented as a decimal floating point number in a reasonable number of
2092 digits. For example, NaN's, infinities, and other special values are
2093 represented in their IEEE hexadecimal format so that assembly and disassembly
2094 do not cause any bits to change in the constants.</p>
2095
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2096<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2097 represented using the 16-digit form shown above (which matches the IEEE754
2098 representation for double); float values must, however, be exactly
2099 representable as IEE754 single precision. Hexadecimal format is always used
2100 for long double, and there are three forms of long double. The 80-bit format
2101 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2102 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2103 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2104 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2105 currently supported target uses this format. Long doubles will only work if
2106 they match the long double format on your target. All hexadecimal formats
2107 are big-endian (sign bit at the left).</p>
2108
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2109</div>
2110
2111<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2112<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2113<a name="aggregateconstants"></a> <!-- old anchor -->
2114<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2115</div>
2116
2117<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2118
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2119<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2120 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2121
2122<dl>
2123 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2124 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2125 type definitions (a comma separated list of elements, surrounded by braces
2126 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2127 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2128 Structure constants must have <a href="#t_struct">structure type</a>, and
2129 the number and types of elements must match those specified by the
2130 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2131
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2132 <dt><b>Union constants</b></dt>
2133 <dd>Union constants are represented with notation similar to a structure with
2134 a single element - that is, a single typed element surrounded
2135 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2136 <a href="#t_union">union type</a> can be initialized with a single-element
2137 struct as long as the type of the struct element matches the type of
2138 one of the union members.</dd>
2139
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2140 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2141 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142 definitions (a comma separated list of elements, surrounded by square
2143 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2144 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2145 the number and types of elements must match those specified by the
2146 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2147
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2148 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2149 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2150 definitions (a comma separated list of elements, surrounded by
2151 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2152 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2153 have <a href="#t_vector">vector type</a>, and the number and types of
2154 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2155
2156 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2157 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2158 value to zero of <em>any</em> type, including scalar and
2159 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2160 This is often used to avoid having to print large zero initializers
2161 (e.g. for large arrays) and is always exactly equivalent to using explicit
2162 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2163
2164 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2165 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2166 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2167 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2168 be interpreted as part of the instruction stream, metadata is a place to
2169 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2170</dl>
2171
2172</div>
2173
2174<!-- ======================================================================= -->
2175<div class="doc_subsection">
2176 <a name="globalconstants">Global Variable and Function Addresses</a>
2177</div>
2178
2179<div class="doc_text">
2180
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181<p>The addresses of <a href="#globalvars">global variables</a>
2182 and <a href="#functionstructure">functions</a> are always implicitly valid
2183 (link-time) constants. These constants are explicitly referenced when
2184 the <a href="#identifiers">identifier for the global</a> is used and always
2185 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2186 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2187
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2188<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2189<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2190@X = global i32 17
2191@Y = global i32 42
2192@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2193</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2194</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2195
2196</div>
2197
2198<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2199<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2200<div class="doc_text">
2201
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2202<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]2203 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2204 Undefined values may be of any type (other than label or void) and be used
2205 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2206
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2207<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2208 program is well defined no matter what value is used. This gives the
2209 compiler more freedom to optimize. Here are some examples of (potentially
2210 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2211
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2212
2213<div class="doc_code">
2214<pre>
2215 %A = add %X, undef
2216 %B = sub %X, undef
2217 %C = xor %X, undef
2218Safe:
2219 %A = undef
2220 %B = undef
2221 %C = undef
2222</pre>
2223</div>
2224
2225<p>This is safe because all of the output bits are affected by the undef bits.
2226Any output bit can have a zero or one depending on the input bits.</p>
2227
2228<div class="doc_code">
2229<pre>
2230 %A = or %X, undef
2231 %B = and %X, undef
2232Safe:
2233 %A = -1
2234 %B = 0
2235Unsafe:
2236 %A = undef
2237 %B = undef
2238</pre>
2239</div>
2240
2241<p>These logical operations have bits that are not always affected by the input.
2242For example, if "%X" has a zero bit, then the output of the 'and' operation will
2243always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2244such, 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]2245However, it is safe to assume that all bits of the undef could be 0, and
2246optimize the and to 0. Likewise, it is safe to assume that all the bits of
2247the 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]2248-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2249
2250<div class="doc_code">
2251<pre>
2252 %A = select undef, %X, %Y
2253 %B = select undef, 42, %Y
2254 %C = select %X, %Y, undef
2255Safe:
2256 %A = %X (or %Y)
2257 %B = 42 (or %Y)
2258 %C = %Y
2259Unsafe:
2260 %A = undef
2261 %B = undef
2262 %C = undef
2263</pre>
2264</div>
2265
2266<p>This set of examples show that undefined select (and conditional branch)
2267conditions can go "either way" but they have to come from one of the two
2268operands. In the %A example, if %X and %Y were both known to have a clear low
2269bit, then %A would have to have a cleared low bit. However, in the %C example,
2270the optimizer is allowed to assume that the undef operand could be the same as
2271%Y, allowing the whole select to be eliminated.</p>
2272
2273
2274<div class="doc_code">
2275<pre>
2276 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2277
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2278 %B = undef
2279 %C = xor %B, %B
2280
2281 %D = undef
2282 %E = icmp lt %D, 4
2283 %F = icmp gte %D, 4
2284
2285Safe:
2286 %A = undef
2287 %B = undef
2288 %C = undef
2289 %D = undef
2290 %E = undef
2291 %F = undef
2292</pre>
2293</div>
2294
2295<p>This example points out that two undef operands are not necessarily the same.
2296This can be surprising to people (and also matches C semantics) where they
2297assume that "X^X" is always zero, even if X is undef. This isn't true for a
2298number of reasons, but the short answer is that an undef "variable" can
2299arbitrarily change its value over its "live range". This is true because the
2300"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2301logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2302so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2303to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2304would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2305
2306<div class="doc_code">
2307<pre>
2308 %A = fdiv undef, %X
2309 %B = fdiv %X, undef
2310Safe:
2311 %A = undef
2312b: unreachable
2313</pre>
2314</div>
2315
2316<p>These examples show the crucial difference between an <em>undefined
2317value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2318allowed to have an arbitrary bit-pattern. This means that the %A operation
2319can be constant folded to undef because the undef could be an SNaN, and fdiv is
2320not (currently) defined on SNaN's. However, in the second example, we can make
2321a more aggressive assumption: because the undef is allowed to be an arbitrary
2322value, 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]2323has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2324does not execute at all. This allows us to delete the divide and all code after
2325it: since the undefined operation "can't happen", the optimizer can assume that
2326it occurs in dead code.
2327</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2328
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2329<div class="doc_code">
2330<pre>
2331a: store undef -> %X
2332b: store %X -> undef
2333Safe:
2334a: &lt;deleted&gt;
2335b: unreachable
2336</pre>
2337</div>
2338
2339<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2340can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2341overwritten with bits that happen to match what was already there. However, a
2342store "to" an undefined location could clobber arbitrary memory, therefore, it
2343has undefined behavior.</p>
2344
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2345</div>
2346
2347<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2348<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2349<div class="doc_text">
2350
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2351<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2352 instead of representing an unspecified bit pattern, they represent the
2353 fact that an instruction or constant expression which cannot evoke side
2354 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2355 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2356
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2357<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]2358 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2359 <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]2360
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2361<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2362
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2363<p>
2364<ul>
2365<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2366 their operands.</li>
2367
2368<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2369 to their dynamic predecessor basic block.</li>
2370
2371<li>Function arguments depend on the corresponding actual argument values in
2372 the dynamic callers of their functions.</li>
2373
2374<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2375 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2376 control back to them.</li>
2377
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2378<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2379 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2380 or exception-throwing call instructions that dynamically transfer control
2381 back to them.</li>
2382
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2383<li>Non-volatile loads and stores depend on the most recent stores to all of the
2384 referenced memory addresses, following the order in the IR
2385 (including loads and stores implied by intrinsics such as
2386 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2387
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2388<!-- TODO: In the case of multiple threads, this only applies if the store
2389 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2390
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2391<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2392
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2393<li>An instruction with externally visible side effects depends on the most
2394 recent preceding instruction with externally visible side effects, following
2395 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2396
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2397<li>An instruction <i>control-depends</i> on a
2398 <a href="#terminators">terminator instruction</a>
2399 if the terminator instruction has multiple successors and the instruction
2400 is always executed when control transfers to one of the successors, and
2401 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2402
2403<li>Dependence is transitive.</li>
2404
2405</ul>
2406</p>
2407
2408<p>Whenever a trap value is generated, all values which depend on it evaluate
2409 to trap. If they have side effects, the evoke their side effects as if each
2410 operand with a trap value were undef. If they have externally-visible side
2411 effects, the behavior is undefined.</p>
2412
2413<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2414
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2415<div class="doc_code">
2416<pre>
2417entry:
2418 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2419 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2420 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2421 store i32 0, i32* %trap_yet_again ; undefined behavior
2422
2423 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2424 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2425
2426 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2427
2428 %narrowaddr = bitcast i32* @g to i16*
2429 %wideaddr = bitcast i32* @g to i64*
2430 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2431 %trap4 = load i64* %widaddr ; Returns a trap value.
2432
2433 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2434 %br i1 %cmp, %true, %end ; Branch to either destination.
2435
2436true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2437 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2438 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2439 br label %end
2440
2441end:
2442 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2443 ; Both edges into this PHI are
2444 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2445 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2446
2447 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2448 ; so this is defined (ignoring earlier
2449 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2450</pre>
2451</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2452
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2453</div>
2454
2455<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2456<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2457 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2458<div class="doc_text">
2459
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2460<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2461
2462<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2463 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2464 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2465
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2466<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2467 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2468 against null. Pointer equality tests between labels addresses is undefined
2469 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2470 equal to the null pointer. This may also be passed around as an opaque
2471 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2472 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2473 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2474
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2475<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2476 using the value as the operand to an inline assembly, but that is target
2477 specific.
2478 </p>
2479
2480</div>
2481
2482
2483<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2484<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2485</div>
2486
2487<div class="doc_text">
2488
2489<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2490 to be used as constants. Constant expressions may be of
2491 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2492 operation that does not have side effects (e.g. load and call are not
2493 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2494
2495<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2496 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2497 <dd>Truncate a constant to another type. The bit size of CST must be larger
2498 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2499
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501 <dd>Zero extend a constant to another type. The bit size of CST must be
2502 smaller or equal to the bit size of TYPE. Both types must be
2503 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2504
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2505 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506 <dd>Sign extend a constant to another type. The bit size of CST must be
2507 smaller or equal to the bit size of TYPE. Both types must be
2508 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2509
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2510 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2511 <dd>Truncate a floating point constant to another floating point type. The
2512 size of CST must be larger than the size of TYPE. Both types must be
2513 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2514
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2515 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2516 <dd>Floating point extend a constant to another type. The size of CST must be
2517 smaller or equal to the size of TYPE. Both types must be floating
2518 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2519
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2520 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2521 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2522 constant. TYPE must be a scalar or vector integer type. CST must be of
2523 scalar or vector floating point type. Both CST and TYPE must be scalars,
2524 or vectors of the same number of elements. If the value won't fit in the
2525 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2526
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2527 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2528 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2529 constant. TYPE must be a scalar or vector integer type. CST must be of
2530 scalar or vector floating point type. Both CST and TYPE must be scalars,
2531 or vectors of the same number of elements. If the value won't fit in the
2532 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2533
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2534 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2535 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2536 constant. TYPE must be a scalar or vector floating point type. CST must be
2537 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2538 vectors of the same number of elements. If the value won't fit in the
2539 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2540
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2541 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2542 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2543 constant. TYPE must be a scalar or vector floating point type. CST must be
2544 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2545 vectors of the same number of elements. If the value won't fit in the
2546 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2547
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2548 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2549 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2550 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2551 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2552 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2553
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2554 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2556 type. CST must be of integer type. The CST value is zero extended,
2557 truncated, or unchanged to make it fit in a pointer size. This one is
2558 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2559
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2560 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2561 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2562 are the same as those for the <a href="#i_bitcast">bitcast
2563 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2564
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2565 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2566 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2567 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2568 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2569 instruction, the index list may have zero or more indexes, which are
2570 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2571
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2572 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2573 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2574
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2575 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2576 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2577
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2578 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2579 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2580
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2581 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2582 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2583 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2584
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2585 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2586 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2587 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2588
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2589 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2590 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2591 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2592
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2593 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2594 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2595 constants. The index list is interpreted in a similar manner as indices in
2596 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2597 index value must be specified.</dd>
2598
2599 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2600 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2601 constants. The index list is interpreted in a similar manner as indices in
2602 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2603 index value must be specified.</dd>
2604
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2605 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2606 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2607 be any of the <a href="#binaryops">binary</a>
2608 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2609 on operands are the same as those for the corresponding instruction
2610 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2611</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2613</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2616<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2617<!-- *********************************************************************** -->
2618
2619<!-- ======================================================================= -->
2620<div class="doc_subsection">
2621<a name="inlineasm">Inline Assembler Expressions</a>
2622</div>
2623
2624<div class="doc_text">
2625
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2626<p>LLVM supports inline assembler expressions (as opposed
2627 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2628 a special value. This value represents the inline assembler as a string
2629 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2630 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2631 expression has side effects, and a flag indicating whether the function
2632 containing the asm needs to align its stack conservatively. An example
2633 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2634
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2635<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2636<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2637i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2638</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2639</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2640
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2641<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2642 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2643 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2644
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2645<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2646<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2647%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]2648</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2649</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2650
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2651<p>Inline asms with side effects not visible in the constraint list must be
2652 marked as having side effects. This is done through the use of the
2653 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2654
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2655<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2656<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2657call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2658</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2659</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2660
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2661<p>In some cases inline asms will contain code that will not work unless the
2662 stack is aligned in some way, such as calls or SSE instructions on x86,
2663 yet will not contain code that does that alignment within the asm.
2664 The compiler should make conservative assumptions about what the asm might
2665 contain and should generate its usual stack alignment code in the prologue
2666 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2667
2668<div class="doc_code">
2669<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2670call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2671</pre>
2672</div>
2673
2674<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2675 first.</p>
2676
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2677<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2678 documented here. Constraints on what can be done (e.g. duplication, moving,
2679 etc need to be documented). This is probably best done by reference to
2680 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2681</div>
2682
2683<div class="doc_subsubsection">
2684<a name="inlineasm_md">Inline Asm Metadata</a>
2685</div>
2686
2687<div class="doc_text">
2688
2689<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2690 attached to it that contains a constant integer. If present, the code
2691 generator will use the integer as the location cookie value when report
2692 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2693 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2694 source code that produced it. For example:</p>
2695
2696<div class="doc_code">
2697<pre>
2698call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2699...
2700!42 = !{ i32 1234567 }
2701</pre>
2702</div>
2703
2704<p>It is up to the front-end to make sense of the magic numbers it places in the
2705 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2706
2707</div>
2708
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2709<!-- ======================================================================= -->
2710<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2711 Strings</a>
2712</div>
2713
2714<div class="doc_text">
2715
2716<p>LLVM IR allows metadata to be attached to instructions in the program that
2717 can convey extra information about the code to the optimizers and code
2718 generator. One example application of metadata is source-level debug
2719 information. There are two metadata primitives: strings and nodes. All
2720 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2721 preceding exclamation point ('<tt>!</tt>').</p>
2722
2723<p>A metadata string is a string surrounded by double quotes. It can contain
2724 any character by escaping non-printable characters with "\xx" where "xx" is
2725 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2726
2727<p>Metadata nodes are represented with notation similar to structure constants
2728 (a comma separated list of elements, surrounded by braces and preceded by an
2729 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2730 10}</tt>". Metadata nodes can have any values as their operand.</p>
2731
2732<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2733 metadata nodes, which can be looked up in the module symbol table. For
2734 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2735
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2736<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2737 function is using two metadata arguments.
2738
2739 <div class="doc_code">
2740 <pre>
2741 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2742 </pre>
2743 </div></p>
2744
2745<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2746 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2747
2748 <div class="doc_code">
2749 <pre>
2750 %indvar.next = add i64 %indvar, 1, !dbg !21
2751 </pre>
2752 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2753</div>
2754
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2755
2756<!-- *********************************************************************** -->
2757<div class="doc_section">
2758 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2759</div>
2760<!-- *********************************************************************** -->
2761
2762<p>LLVM has a number of "magic" global variables that contain data that affect
2763code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2764of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2765section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2766by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2767
2768<!-- ======================================================================= -->
2769<div class="doc_subsection">
2770<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2771</div>
2772
2773<div class="doc_text">
2774
2775<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2776href="#linkage_appending">appending linkage</a>. This array contains a list of
2777pointers to global variables and functions which may optionally have a pointer
2778cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2779
2780<pre>
2781 @X = global i8 4
2782 @Y = global i32 123
2783
2784 @llvm.used = appending global [2 x i8*] [
2785 i8* @X,
2786 i8* bitcast (i32* @Y to i8*)
2787 ], section "llvm.metadata"
2788</pre>
2789
2790<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2791compiler, assembler, and linker are required to treat the symbol as if there is
2792a reference to the global that it cannot see. For example, if a variable has
2793internal linkage and no references other than that from the <tt>@llvm.used</tt>
2794list, it cannot be deleted. This is commonly used to represent references from
2795inline asms and other things the compiler cannot "see", and corresponds to
2796"attribute((used))" in GNU C.</p>
2797
2798<p>On some targets, the code generator must emit a directive to the assembler or
2799object file to prevent the assembler and linker from molesting the symbol.</p>
2800
2801</div>
2802
2803<!-- ======================================================================= -->
2804<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2805<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2806</div>
2807
2808<div class="doc_text">
2809
2810<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2811<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2812touching the symbol. On targets that support it, this allows an intelligent
2813linker to optimize references to the symbol without being impeded as it would be
2814by <tt>@llvm.used</tt>.</p>
2815
2816<p>This is a rare construct that should only be used in rare circumstances, and
2817should not be exposed to source languages.</p>
2818
2819</div>
2820
2821<!-- ======================================================================= -->
2822<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2823<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2824</div>
2825
2826<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2827<pre>
2828%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2829@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2830</pre>
2831<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.
2832</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2833
2834</div>
2835
2836<!-- ======================================================================= -->
2837<div class="doc_subsection">
2838<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2839</div>
2840
2841<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2842<pre>
2843%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2844@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2845</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2846
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2847<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.
2848</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2849
2850</div>
2851
2852
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2853<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2854<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2855<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2856
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2857<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2858
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2859<p>The LLVM instruction set consists of several different classifications of
2860 instructions: <a href="#terminators">terminator
2861 instructions</a>, <a href="#binaryops">binary instructions</a>,
2862 <a href="#bitwiseops">bitwise binary instructions</a>,
2863 <a href="#memoryops">memory instructions</a>, and
2864 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2866</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2867
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_subsection"> <a name="terminators">Terminator
2870Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2871
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2872<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2875 in a program ends with a "Terminator" instruction, which indicates which
2876 block should be executed after the current block is finished. These
2877 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2878 control flow, not values (the one exception being the
2879 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2880
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2881<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2882 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2883 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2884 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2885 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2886 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2887 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2888 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2889
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2890</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2892<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2893<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2894Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2896<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2898<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2899<pre>
2900 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]2901 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2902</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2905<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2906 a value) from a function back to the caller.</p>
2907
2908<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2909 value and then causes control flow, and one that just causes control flow to
2910 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2913<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2914 return value. The type of the return value must be a
2915 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2916
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2917<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2918 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2919 value or a return value with a type that does not match its type, or if it
2920 has a void return type and contains a '<tt>ret</tt>' instruction with a
2921 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2925 the calling function's context. If the caller is a
2926 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2927 instruction after the call. If the caller was an
2928 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2929 the beginning of the "normal" destination block. If the instruction returns
2930 a value, that value shall set the call or invoke instruction's return
2931 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2933<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2934<pre>
2935 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2936 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2937 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]2938</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2939
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2940</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2941<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2942<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2944<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2946<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2947<pre>
2948 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]2949</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2950
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2951<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2953 different basic block in the current function. There are two forms of this
2954 instruction, corresponding to a conditional branch and an unconditional
2955 branch.</p>
2956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2957<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2958<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2959 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2960 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2961 target.</p>
2962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2963<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2964<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2966 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2967 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2969<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2970<pre>
2971Test:
2972 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2973 br i1 %cond, label %IfEqual, label %IfUnequal
2974IfEqual:
2975 <a href="#i_ret">ret</a> i32 1
2976IfUnequal:
2977 <a href="#i_ret">ret</a> i32 0
2978</pre>
2979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2980</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2981
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2982<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2983<div class="doc_subsubsection">
2984 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2985</div>
2986
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2987<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2988
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2989<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2990<pre>
2991 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2992</pre>
2993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2994<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2995<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]2996 several different places. It is a generalization of the '<tt>br</tt>'
2997 instruction, allowing a branch to occur to one of many possible
2998 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2999
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3000<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3001<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3002 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3003 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3004 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3005
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3006<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3007<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3008 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3009 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3010 transferred to the corresponding destination; otherwise, control flow is
3011 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3012
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3013<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3014<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3015 <tt>switch</tt> instruction, this instruction may be code generated in
3016 different ways. For example, it could be generated as a series of chained
3017 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3018
3019<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3020<pre>
3021 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3022 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3023 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3024
3025 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3026 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3027
3028 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3029 switch i32 %val, label %otherwise [ i32 0, label %onzero
3030 i32 1, label %onone
3031 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3032</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3033
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3034</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3035
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3036
3037<!-- _______________________________________________________________________ -->
3038<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3039 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3040</div>
3041
3042<div class="doc_text">
3043
3044<h5>Syntax:</h5>
3045<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3046 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]3047</pre>
3048
3049<h5>Overview:</h5>
3050
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3051<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3052 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3053 "<tt>address</tt>". Address must be derived from a <a
3054 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3055
3056<h5>Arguments:</h5>
3057
3058<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3059 rest of the arguments indicate the full set of possible destinations that the
3060 address may point to. Blocks are allowed to occur multiple times in the
3061 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3062
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3063<p>This destination list is required so that dataflow analysis has an accurate
3064 understanding of the CFG.</p>
3065
3066<h5>Semantics:</h5>
3067
3068<p>Control transfers to the block specified in the address argument. All
3069 possible destination blocks must be listed in the label list, otherwise this
3070 instruction has undefined behavior. This implies that jumps to labels
3071 defined in other functions have undefined behavior as well.</p>
3072
3073<h5>Implementation:</h5>
3074
3075<p>This is typically implemented with a jump through a register.</p>
3076
3077<h5>Example:</h5>
3078<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3079 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3080</pre>
3081
3082</div>
3083
3084
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3085<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3086<div class="doc_subsubsection">
3087 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3088</div>
3089
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3090<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3091
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3092<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3093<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3094 &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]3095 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3096</pre>
3097
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3098<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3099<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3100 function, with the possibility of control flow transfer to either the
3101 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3102 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3103 control flow will return to the "normal" label. If the callee (or any
3104 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3105 instruction, control is interrupted and continued at the dynamically nearest
3106 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3109<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3110
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3111<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3113 convention</a> the call should use. If none is specified, the call
3114 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3115
3116 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3118 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3119
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3120 <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]3121 function value being invoked. In most cases, this is a direct function
3122 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3123 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3124
3125 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3127
3128 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3129 signature argument types and parameter attributes. All arguments must be
3130 of <a href="#t_firstclass">first class</a> type. If the function
3131 signature indicates the function accepts a variable number of arguments,
3132 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3133
3134 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3136
3137 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3138 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3139
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3140 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3141 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3142 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3143</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3144
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3145<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146<p>This instruction is designed to operate as a standard
3147 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3148 primary difference is that it establishes an association with a label, which
3149 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3150
3151<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3153 exception. Additionally, this is important for implementation of
3154 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156<p>For the purposes of the SSA form, the definition of the value returned by the
3157 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3158 block to the "normal" label. If the callee unwinds then no return value is
3159 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3160
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3161<p>Note that the code generator does not yet completely support unwind, and
3162that the invoke/unwind semantics are likely to change in future versions.</p>
3163
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3164<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3165<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3166 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3167 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3168 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3169 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3170</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3171
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3173
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3174<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3175
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3176<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3177Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3178
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3179<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3180
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3181<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3182<pre>
3183 unwind
3184</pre>
3185
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3186<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3187<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3188 at the first callee in the dynamic call stack which used
3189 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3190 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3191
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3192<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3193<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3194 immediately halt. The dynamic call stack is then searched for the
3195 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3196 Once found, execution continues at the "exceptional" destination block
3197 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3198 instruction in the dynamic call chain, undefined behavior results.</p>
3199
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3200<p>Note that the code generator does not yet completely support unwind, and
3201that the invoke/unwind semantics are likely to change in future versions.</p>
3202
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3203</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3204
3205<!-- _______________________________________________________________________ -->
3206
3207<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3208Instruction</a> </div>
3209
3210<div class="doc_text">
3211
3212<h5>Syntax:</h5>
3213<pre>
3214 unreachable
3215</pre>
3216
3217<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3218<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3219 instruction is used to inform the optimizer that a particular portion of the
3220 code is not reachable. This can be used to indicate that the code after a
3221 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3222
3223<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3224<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3225
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3226</div>
3227
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3228<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3229<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3231<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232
3233<p>Binary operators are used to do most of the computation in a program. They
3234 require two operands of the same type, execute an operation on them, and
3235 produce a single value. The operands might represent multiple data, as is
3236 the case with the <a href="#t_vector">vector</a> data type. The result value
3237 has the same type as its operands.</p>
3238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3239<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3241</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3242
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3243<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3244<div class="doc_subsubsection">
3245 <a name="i_add">'<tt>add</tt>' Instruction</a>
3246</div>
3247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3248<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3249
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3250<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3251<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3252 &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]3253 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3254 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3255 &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]3256</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3259<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3260
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3261<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262<p>The two arguments to the '<tt>add</tt>' instruction must
3263 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3264 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3265
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3266<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3267<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3268
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3269<p>If the sum has unsigned overflow, the result returned is the mathematical
3270 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]3271
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272<p>Because LLVM integers use a two's complement representation, this instruction
3273 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3274
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3275<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3276 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3277 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3278 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3279 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3280
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3281<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282<pre>
3283 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3284</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3286</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3287
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3288<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3289<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3290 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3291</div>
3292
3293<div class="doc_text">
3294
3295<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3296<pre>
3297 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3298</pre>
3299
3300<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3301<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3302
3303<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3304<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3305 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3306 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3307
3308<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3309<p>The value produced is the floating point sum of the two operands.</p>
3310
3311<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3312<pre>
3313 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3314</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3315
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3316</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318<!-- _______________________________________________________________________ -->
3319<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3320 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3321</div>
3322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3323<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3325<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3326<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3327 &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]3328 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3329 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3330 &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]3331</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3333<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3334<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3335 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3336
3337<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338 '<tt>neg</tt>' instruction present in most other intermediate
3339 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3341<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3342<p>The two arguments to the '<tt>sub</tt>' instruction must
3343 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3344 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3346<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3347<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3348
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3349<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3351 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3352
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3353<p>Because LLVM integers use a two's complement representation, this instruction
3354 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3355
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3356<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3357 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3358 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3359 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3360 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3362<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3363<pre>
3364 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3365 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3366</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3368</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3369
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3370<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3371<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3372 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3373</div>
3374
3375<div class="doc_text">
3376
3377<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3378<pre>
3379 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3380</pre>
3381
3382<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3383<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3384 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3385
3386<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3387 '<tt>fneg</tt>' instruction present in most other intermediate
3388 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3389
3390<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3391<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3393 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3394
3395<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3396<p>The value produced is the floating point difference of the two operands.</p>
3397
3398<h5>Example:</h5>
3399<pre>
3400 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3401 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3402</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3404</div>
3405
3406<!-- _______________________________________________________________________ -->
3407<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3408 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3409</div>
3410
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3411<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3415 &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]3416 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3417 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3418 &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]3419</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3422<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3423
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3424<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3425<p>The two arguments to the '<tt>mul</tt>' instruction must
3426 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3427 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3428
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3429<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3430<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3431
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432<p>If the result of the multiplication has unsigned overflow, the result
3433 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3434 width of the result.</p>
3435
3436<p>Because LLVM integers use a two's complement representation, and the result
3437 is the same width as the operands, this instruction returns the correct
3438 result for both signed and unsigned integers. If a full product
3439 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3440 be sign-extended or zero-extended as appropriate to the width of the full
3441 product.</p>
3442
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3443<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3444 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3445 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3446 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3447 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3448
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3449<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3450<pre>
3451 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3452</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3454</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3455
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3456<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3457<div class="doc_subsubsection">
3458 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3459</div>
3460
3461<div class="doc_text">
3462
3463<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &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]3466</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3468<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3470
3471<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3472<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3474 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3475
3476<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3477<p>The value produced is the floating point product of the two operands.</p>
3478
3479<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480<pre>
3481 &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]3482</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3484</div>
3485
3486<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3488</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3490<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3492<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3493<pre>
3494 &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]3495</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3497<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3499
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3500<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3501<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3502 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3503 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3504
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3505<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3506<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3507
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3508<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3509 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3510
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3511<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3513<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3514<pre>
3515 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3518</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3520<!-- _______________________________________________________________________ -->
3521<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3522</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3524<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3526<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3527<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3528 &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]3529 &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]3530</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3531
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3534
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3535<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3536<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3538 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3539
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3540<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3541<p>The value produced is the signed integer quotient of the two operands rounded
3542 towards zero.</p>
3543
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3544<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3545 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3546
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3547<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548 undefined behavior; this is a rare case, but can occur, for example, by doing
3549 a 32-bit division of -2147483648 by -1.</p>
3550
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3551<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3552 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3553 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3554
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3555<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3556<pre>
3557 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3560</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3562<!-- _______________________________________________________________________ -->
3563<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3564Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3565
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3566<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3568<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3569<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3570 &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]3571</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3572
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3573<h5>Overview:</h5>
3574<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3575
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3576<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3577<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3578 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3579 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3580
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3581<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3582<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3583
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3584<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3585<pre>
3586 &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]3587</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3589</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3590
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3592<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3593</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3595<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3596
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3597<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598<pre>
3599 &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]3600</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3601
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3602<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3604 division of its two arguments.</p>
3605
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3606<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3607<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3608 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3609 values. Both arguments must have identical types.</p>
3610
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3611<h5>Semantics:</h5>
3612<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613 This instruction always performs an unsigned division to get the
3614 remainder.</p>
3615
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3616<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3618
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3619<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3621<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3624</pre>
3625
3626</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3629<div class="doc_subsubsection">
3630 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3631</div>
3632
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3633<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3634
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3635<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3636<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3637 &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]3638</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3639
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3640<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3642 division of its two operands. This instruction can also take
3643 <a href="#t_vector">vector</a> versions of the values in which case the
3644 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3645
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3646<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3647<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3649 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3650
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3651<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3652<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3654 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3655 a value. For more information about the difference,
3656 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3657 Math Forum</a>. For a table of how this is implemented in various languages,
3658 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3659 Wikipedia: modulo operation</a>.</p>
3660
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3661<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3663
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3664<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665 Overflow also leads to undefined behavior; this is a rare case, but can
3666 occur, for example, by taking the remainder of a 32-bit division of
3667 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3668 lets srem be implemented using instructions that return both the result of
3669 the division and the remainder.)</p>
3670
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3671<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3672<pre>
3673 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3674</pre>
3675
3676</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3678<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3679<div class="doc_subsubsection">
3680 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3681
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3682<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3683
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3684<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3685<pre>
3686 &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]3687</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3689<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3691 its two operands.</p>
3692
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3693<h5>Arguments:</h5>
3694<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3695 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3696 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3697
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3698<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699<p>This instruction returns the <i>remainder</i> of a division. The remainder
3700 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3701
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3702<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3703<pre>
3704 &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]3705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3707</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3708
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3709<!-- ======================================================================= -->
3710<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3711Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3713<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714
3715<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3716 program. They are generally very efficient instructions and can commonly be
3717 strength reduced from other instructions. They require two operands of the
3718 same type, execute an operation on them, and produce a single value. The
3719 resulting value is the same type as its operands.</p>
3720
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3721</div>
3722
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3723<!-- _______________________________________________________________________ -->
3724<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3725Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3727<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3729<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3730<pre>
3731 &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]3732</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3733
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3734<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3735<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3736 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3737
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3738<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3739<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3740 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3741 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3742
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3743<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3745 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3746 is (statically or dynamically) negative or equal to or larger than the number
3747 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3748 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3749 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3750
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751<h5>Example:</h5>
3752<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3753 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3754 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3755 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3756 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3757 &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]3758</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3759
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3760</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3761
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3762<!-- _______________________________________________________________________ -->
3763<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3764Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3766<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3767
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3768<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769<pre>
3770 &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]3771</pre>
3772
3773<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3774<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3775 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3776
3777<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3778<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3779 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3780 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3781
3782<h5>Semantics:</h5>
3783<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784 significant bits of the result will be filled with zero bits after the shift.
3785 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3786 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3787 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3788 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3789
3790<h5>Example:</h5>
3791<pre>
3792 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3793 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3794 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3795 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3796 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3797 &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]3798</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3799
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3800</div>
3801
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3802<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3803<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3804Instruction</a> </div>
3805<div class="doc_text">
3806
3807<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3808<pre>
3809 &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]3810</pre>
3811
3812<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3813<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3814 operand shifted to the right a specified number of bits with sign
3815 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3816
3817<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3818<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3819 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3820 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3821
3822<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823<p>This instruction always performs an arithmetic shift right operation, The
3824 most significant bits of the result will be filled with the sign bit
3825 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3826 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3827 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3828 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3829
3830<h5>Example:</h5>
3831<pre>
3832 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3833 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3834 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3835 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3836 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3837 &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]3838</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3839
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3840</div>
3841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3842<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3843<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3844Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3845
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3846<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3848<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3849<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3850 &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]3851</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3854<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3855 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3858<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3859 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3860 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3862<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3863<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3865<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3866 <tbody>
3867 <tr>
3868 <td>In0</td>
3869 <td>In1</td>
3870 <td>Out</td>
3871 </tr>
3872 <tr>
3873 <td>0</td>
3874 <td>0</td>
3875 <td>0</td>
3876 </tr>
3877 <tr>
3878 <td>0</td>
3879 <td>1</td>
3880 <td>0</td>
3881 </tr>
3882 <tr>
3883 <td>1</td>
3884 <td>0</td>
3885 <td>0</td>
3886 </tr>
3887 <tr>
3888 <td>1</td>
3889 <td>1</td>
3890 <td>1</td>
3891 </tr>
3892 </tbody>
3893</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3895<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3896<pre>
3897 &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]3898 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3899 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3900</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3901</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3903<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3905<div class="doc_text">
3906
3907<h5>Syntax:</h5>
3908<pre>
3909 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3910</pre>
3911
3912<h5>Overview:</h5>
3913<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3914 two operands.</p>
3915
3916<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3917<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3919 values. Both arguments must have identical types.</p>
3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3922<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3923
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3924<table border="1" cellspacing="0" cellpadding="4">
3925 <tbody>
3926 <tr>
3927 <td>In0</td>
3928 <td>In1</td>
3929 <td>Out</td>
3930 </tr>
3931 <tr>
3932 <td>0</td>
3933 <td>0</td>
3934 <td>0</td>
3935 </tr>
3936 <tr>
3937 <td>0</td>
3938 <td>1</td>
3939 <td>1</td>
3940 </tr>
3941 <tr>
3942 <td>1</td>
3943 <td>0</td>
3944 <td>1</td>
3945 </tr>
3946 <tr>
3947 <td>1</td>
3948 <td>1</td>
3949 <td>1</td>
3950 </tr>
3951 </tbody>
3952</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3954<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955<pre>
3956 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3957 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3958 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3959</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3961</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3963<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3964<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3965Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3966
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3967<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3968
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3969<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3970<pre>
3971 &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]3972</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3974<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3975<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3976 its two operands. The <tt>xor</tt> is used to implement the "one's
3977 complement" operation, which is the "~" operator in C.</p>
3978
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3979<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3980<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3982 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3983
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3984<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3985<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3986
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3987<table border="1" cellspacing="0" cellpadding="4">
3988 <tbody>
3989 <tr>
3990 <td>In0</td>
3991 <td>In1</td>
3992 <td>Out</td>
3993 </tr>
3994 <tr>
3995 <td>0</td>
3996 <td>0</td>
3997 <td>0</td>
3998 </tr>
3999 <tr>
4000 <td>0</td>
4001 <td>1</td>
4002 <td>1</td>
4003 </tr>
4004 <tr>
4005 <td>1</td>
4006 <td>0</td>
4007 <td>1</td>
4008 </tr>
4009 <tr>
4010 <td>1</td>
4011 <td>1</td>
4012 <td>0</td>
4013 </tr>
4014 </tbody>
4015</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4017<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4018<pre>
4019 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4020 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4021 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4022 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4023</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4024
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4025</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4026
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4027<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4028<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4029 <a name="vectorops">Vector Operations</a>
4030</div>
4031
4032<div class="doc_text">
4033
4034<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4035 target-independent manner. These instructions cover the element-access and
4036 vector-specific operations needed to process vectors effectively. While LLVM
4037 does directly support these vector operations, many sophisticated algorithms
4038 will want to use target-specific intrinsics to take full advantage of a
4039 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4040
4041</div>
4042
4043<!-- _______________________________________________________________________ -->
4044<div class="doc_subsubsection">
4045 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4046</div>
4047
4048<div class="doc_text">
4049
4050<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4051<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4052 &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]4053</pre>
4054
4055<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4056<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4057 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4058
4059
4060<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4061<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4062 of <a href="#t_vector">vector</a> type. The second operand is an index
4063 indicating the position from which to extract the element. The index may be
4064 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4065
4066<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067<p>The result is a scalar of the same type as the element type of
4068 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4069 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4070 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4071
4072<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4073<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4074 &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]4075</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4076
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4077</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<!-- _______________________________________________________________________ -->
4080<div class="doc_subsubsection">
4081 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4082</div>
4083
4084<div class="doc_text">
4085
4086<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4087<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4088 &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]4089</pre>
4090
4091<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4092<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4093 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4097 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4098 whose type must equal the element type of the first operand. The third
4099 operand is an index indicating the position at which to insert the value.
4100 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4101
4102<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4103<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4104 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4105 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4106 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4107
4108<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4109<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4110 &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]4111</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4112
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4113</div>
4114
4115<!-- _______________________________________________________________________ -->
4116<div class="doc_subsubsection">
4117 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4118</div>
4119
4120<div class="doc_text">
4121
4122<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4123<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4124 &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]4125</pre>
4126
4127<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4129 from two input vectors, returning a vector with the same element type as the
4130 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4131
4132<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4134 with types that match each other. The third argument is a shuffle mask whose
4135 element type is always 'i32'. The result of the instruction is a vector
4136 whose length is the same as the shuffle mask and whose element type is the
4137 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4138
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139<p>The shuffle mask operand is required to be a constant vector with either
4140 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4141
4142<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4143<p>The elements of the two input vectors are numbered from left to right across
4144 both of the vectors. The shuffle mask operand specifies, for each element of
4145 the result vector, which element of the two input vectors the result element
4146 gets. The element selector may be undef (meaning "don't care") and the
4147 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4148
4149<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4150<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4151 &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]4152 &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]4153 &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]4154 &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]4155 &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]4156 &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]4157 &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]4158 &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]4159</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4160
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4161</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4162
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4163<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4164<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4165 <a name="aggregateops">Aggregate Operations</a>
4166</div>
4167
4168<div class="doc_text">
4169
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4170<p>LLVM supports several instructions for working with
4171 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4172
4173</div>
4174
4175<!-- _______________________________________________________________________ -->
4176<div class="doc_subsubsection">
4177 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4178</div>
4179
4180<div class="doc_text">
4181
4182<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4183<pre>
4184 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4185</pre>
4186
4187<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4188<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4189 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4190
4191<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4193 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4194 <a href="#t_array">array</a> type. The operands are constant indices to
4195 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4196 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4197
4198<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4199<p>The result is the value at the position in the aggregate specified by the
4200 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4201
4202<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4203<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4204 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4205</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4206
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4208
4209<!-- _______________________________________________________________________ -->
4210<div class="doc_subsubsection">
4211 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4212</div>
4213
4214<div class="doc_text">
4215
4216<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4217<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4218 &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]4219</pre>
4220
4221<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4222<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4223 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4224
4225<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4226<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4227 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4228 <a href="#t_array">array</a> type. The second operand is a first-class
4229 value to insert. The following operands are constant indices indicating
4230 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]4231 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4232 value to insert must have the same type as the value identified by the
4233 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4234
4235<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4236<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4237 that of <tt>val</tt> except that the value at the position specified by the
4238 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4239
4240<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4241<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4242 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4243 %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]4244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4246</div>
4247
4248
4249<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4250<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4251 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4252</div>
4253
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4254<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4255
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256<p>A key design point of an SSA-based representation is how it represents
4257 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4258 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4259 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4260
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4261</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4262
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4263<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4264<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4265 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4266</div>
4267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4268<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4269
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4270<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4271<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4272 &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]4273</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4276<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4277 currently executing function, to be automatically released when this function
4278 returns to its caller. The object is always allocated in the generic address
4279 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4280
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4281<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282<p>The '<tt>alloca</tt>' instruction
4283 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4284 runtime stack, returning a pointer of the appropriate type to the program.
4285 If "NumElements" is specified, it is the number of elements allocated,
4286 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4287 specified, the value result of the allocation is guaranteed to be aligned to
4288 at least that boundary. If not specified, or if zero, the target can choose
4289 to align the allocation on any convenient boundary compatible with the
4290 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4291
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4292<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4294<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4295<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4297 memory is automatically released when the function returns. The
4298 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4299 variables that must have an address available. When the function returns
4300 (either with the <tt><a href="#i_ret">ret</a></tt>
4301 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4302 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4304<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4305<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4306 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4307 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4308 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4309 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4310</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4312</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4313
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4314<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4315<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4316Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4318<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4320<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4321<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4322 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4323 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4324 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4325</pre>
4326
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4327<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4328<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4330<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4331<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4332 from which to load. The pointer must point to
4333 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4334 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4335 number or order of execution of this <tt>load</tt> with other <a
4336 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4337
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4338<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339 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]4340 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341 alignment for the target. It is the responsibility of the code emitter to
4342 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4343 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4344 produce less efficient code. An alignment of 1 is always safe.</p>
4345
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4346<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4347 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4348 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4349 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4350 and code generator that this load is not expected to be reused in the cache.
4351 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4352 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4353
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4354<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355<p>The location of memory pointed to is loaded. If the value being loaded is of
4356 scalar type then the number of bytes read does not exceed the minimum number
4357 of bytes needed to hold all bits of the type. For example, loading an
4358 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4359 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4360 is undefined if the value was not originally written using a store of the
4361 same type.</p>
4362
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4363<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4364<pre>
4365 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4366 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4367 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4368</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4370</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4371
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4372<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4373<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4374Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4375
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4376<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4378<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4379<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4380 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4381 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4382</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4383
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4384<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4385<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4386
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4387<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4388<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4389 and an address at which to store it. The type of the
4390 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4391 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4392 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4393 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4394 order of execution of this <tt>store</tt> with other <a
4395 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396
4397<p>The optional constant "align" argument specifies the alignment of the
4398 operation (that is, the alignment of the memory address). A value of 0 or an
4399 omitted "align" argument means that the operation has the preferential
4400 alignment for the target. It is the responsibility of the code emitter to
4401 ensure that the alignment information is correct. Overestimating the
4402 alignment results in an undefined behavior. Underestimating the alignment may
4403 produce less efficient code. An alignment of 1 is always safe.</p>
4404
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4405<p>The optional !nontemporal metadata must reference a single metatadata
4406 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4407 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4408 instruction tells the optimizer and code generator that this load is
4409 not expected to be reused in the cache. The code generator may
4410 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4411 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4412
4413
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4414<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4415<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4416 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4417 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4418 does not exceed the minimum number of bytes needed to hold all bits of the
4419 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4420 writing a value of a type like <tt>i20</tt> with a size that is not an
4421 integral number of bytes, it is unspecified what happens to the extra bits
4422 that do not belong to the type, but they will typically be overwritten.</p>
4423
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4424<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4425<pre>
4426 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4427 store i32 3, i32* %ptr <i>; yields {void}</i>
4428 %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]4429</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4430
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4431</div>
4432
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4433<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4434<div class="doc_subsubsection">
4435 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4436</div>
4437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4438<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4440<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4441<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4442 &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]4443 &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]4444</pre>
4445
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4446<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4447<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4448 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4449 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4450
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4451<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4452<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4453 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454 elements of the aggregate object are indexed. The interpretation of each
4455 index is dependent on the type being indexed into. The first index always
4456 indexes the pointer value given as the first argument, the second index
4457 indexes a value of the type pointed to (not necessarily the value directly
4458 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4459 indexed into must be a pointer value, subsequent types can be arrays,
4460 vectors, structs and unions. Note that subsequent types being indexed into
4461 can never be pointers, since that would require loading the pointer before
4462 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4463
4464<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4465 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4466 integer <b>constants</b> are allowed. When indexing into an array, pointer
4467 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]4468 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4469
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4470<p>For example, let's consider a C code fragment and how it gets compiled to
4471 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4472
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4473<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4474<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4475struct RT {
4476 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4477 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4478 char C;
4479};
4480struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4481 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4482 double Y;
4483 struct RT Z;
4484};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4485
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4486int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4487 return &amp;s[1].Z.B[5][13];
4488}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4489</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4490</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4491
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4492<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4493
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4494<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4495<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4496%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4497%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4498
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4499define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4500entry:
4501 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4502 ret i32* %reg
4503}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4504</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4505</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4506
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4507<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4508<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]4509 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4510 }</tt>' type, a structure. The second index indexes into the third element
4511 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4512 i8 }</tt>' type, another structure. The third index indexes into the second
4513 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4514 array. The two dimensions of the array are subscripted into, yielding an
4515 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4516 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4518<p>Note that it is perfectly legal to index partially through a structure,
4519 returning a pointer to an inner element. Because of this, the LLVM code for
4520 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4521
4522<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4523 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4524 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4525 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4526 %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]4527 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4528 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4529 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4530 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4531</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4532
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4533<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4534 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4535 base pointer is not an <i>in bounds</i> address of an allocated object,
4536 or if any of the addresses that would be formed by successive addition of
4537 the offsets implied by the indices to the base address with infinitely
4538 precise arithmetic are not an <i>in bounds</i> address of that allocated
4539 object. The <i>in bounds</i> addresses for an allocated object are all
4540 the addresses that point into the object, plus the address one byte past
4541 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4542
4543<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4544 the base address with silently-wrapping two's complement arithmetic, and
4545 the result value of the <tt>getelementptr</tt> may be outside the object
4546 pointed to by the base pointer. The result value may not necessarily be
4547 used to access memory though, even if it happens to point into allocated
4548 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4549 section for more information.</p>
4550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4551<p>The getelementptr instruction is often confusing. For some more insight into
4552 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4553
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4554<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4555<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4556 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4557 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4558 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4559 %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]4560 <i>; yields i8*:eptr</i>
4561 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4562 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4563 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4564</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4565
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4566</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4568<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4569<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4570</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4571
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4572<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4573
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4574<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575 which all take a single operand and a type. They perform various bit
4576 conversions on the operand.</p>
4577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4578</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4579
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4580<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4581<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4582 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4583</div>
4584<div class="doc_text">
4585
4586<h5>Syntax:</h5>
4587<pre>
4588 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4589</pre>
4590
4591<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4592<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4593 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4594
4595<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4597 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4598 size and type of the result, which must be
4599 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4600 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4601 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4602
4603<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4604<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4605 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4606 source size must be larger than the destination size, <tt>trunc</tt> cannot
4607 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4608
4609<h5>Example:</h5>
4610<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4611 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4612 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4613 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616</div>
4617
4618<!-- _______________________________________________________________________ -->
4619<div class="doc_subsubsection">
4620 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4621</div>
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
4625<pre>
4626 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4627</pre>
4628
4629<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4630<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4632
4633
4634<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4635<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]4636 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4637 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]4638 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4639 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4640
4641<h5>Semantics:</h5>
4642<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]4643 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4644
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4645<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]4646
4647<h5>Example:</h5>
4648<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4649 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4650 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4651</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4652
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
4657 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4658</div>
4659<div class="doc_text">
4660
4661<h5>Syntax:</h5>
4662<pre>
4663 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4664</pre>
4665
4666<h5>Overview:</h5>
4667<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4668
4669<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4670<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]4671 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4672 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]4673 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4674 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4675
4676<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4678 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4679 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4680
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4681<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]4682
4683<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4684<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4685 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4686 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4687</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4689</div>
4690
4691<!-- _______________________________________________________________________ -->
4692<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4693 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4694</div>
4695
4696<div class="doc_text">
4697
4698<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4699<pre>
4700 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4701</pre>
4702
4703<h5>Overview:</h5>
4704<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4706
4707<h5>Arguments:</h5>
4708<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4710 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]4711 <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]4712 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4713
4714<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4716 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717 <a href="#t_floating">floating point</a> type. If the value cannot fit
4718 within the destination type, <tt>ty2</tt>, then the results are
4719 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4720
4721<h5>Example:</h5>
4722<pre>
4723 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4724 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4725</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4726
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4727</div>
4728
4729<!-- _______________________________________________________________________ -->
4730<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4731 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4732</div>
4733<div class="doc_text">
4734
4735<h5>Syntax:</h5>
4736<pre>
4737 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4738</pre>
4739
4740<h5>Overview:</h5>
4741<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]4742 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4743
4744<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4745<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4746 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4747 a <a href="#t_floating">floating point</a> type to cast it to. The source
4748 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4749
4750<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4751<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752 <a href="#t_floating">floating point</a> type to a larger
4753 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4754 used to make a <i>no-op cast</i> because it always changes bits. Use
4755 <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]4756
4757<h5>Example:</h5>
4758<pre>
4759 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4760 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4761</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4767 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4768</div>
4769<div class="doc_text">
4770
4771<h5>Syntax:</h5>
4772<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4773 &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]4774</pre>
4775
4776<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4777<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4779
4780<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4782 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4783 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4784 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4785 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4786
4787<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4788<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4790 towards zero) unsigned integer value. If the value cannot fit
4791 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4792
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4793<h5>Example:</h5>
4794<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4795 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4796 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4797 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4798</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4800</div>
4801
4802<!-- _______________________________________________________________________ -->
4803<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4804 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4805</div>
4806<div class="doc_text">
4807
4808<h5>Syntax:</h5>
4809<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4810 &lt;result&gt; = 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]4811</pre>
4812
4813<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4814<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4815 <a href="#t_floating">floating point</a> <tt>value</tt> to
4816 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4817
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4818<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4819<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4820 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4821 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4822 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4823 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4824
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4825<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4826<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4827 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4828 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4829 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4830
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4831<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4832<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4833 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4834 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4835 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4836</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4837
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4838</div>
4839
4840<!-- _______________________________________________________________________ -->
4841<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4842 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4843</div>
4844<div class="doc_text">
4845
4846<h5>Syntax:</h5>
4847<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4848 &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]4849</pre>
4850
4851<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4852<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4854
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4855<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4856<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]4857 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4858 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4859 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4860 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4861
4862<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4863<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4864 integer quantity and converts it to the corresponding floating point
4865 value. If the value cannot fit in the floating point value, the results are
4866 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4867
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4868<h5>Example:</h5>
4869<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4870 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4871 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4872</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4873
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4874</div>
4875
4876<!-- _______________________________________________________________________ -->
4877<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4878 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4879</div>
4880<div class="doc_text">
4881
4882<h5>Syntax:</h5>
4883<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4884 &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]4885</pre>
4886
4887<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4889 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4890
4891<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4892<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]4893 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4894 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4895 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4896 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4897
4898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4900 quantity and converts it to the corresponding floating point value. If the
4901 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4902
4903<h5>Example:</h5>
4904<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4905 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4906 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4907</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4908
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4909</div>
4910
4911<!-- _______________________________________________________________________ -->
4912<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4913 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4914</div>
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
4919 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4920</pre>
4921
4922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4923<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4924 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4925
4926<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4927<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4928 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4929 <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]4930
4931<h5>Semantics:</h5>
4932<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4933 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4934 truncating or zero extending that value to the size of the integer type. If
4935 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4936 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4937 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4938 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4939
4940<h5>Example:</h5>
4941<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4942 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4943 %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]4944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4946</div>
4947
4948<!-- _______________________________________________________________________ -->
4949<div class="doc_subsubsection">
4950 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4951</div>
4952<div class="doc_text">
4953
4954<h5>Syntax:</h5>
4955<pre>
4956 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4957</pre>
4958
4959<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4960<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4961 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4962
4963<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4964<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4965 value to cast, and a type to cast it to, which must be a
4966 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4967
4968<h5>Semantics:</h5>
4969<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4970 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4971 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4972 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4973 than the size of a pointer then a zero extension is done. If they are the
4974 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4975
4976<h5>Example:</h5>
4977<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4978 %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]4979 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4980 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4981</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4982
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4983</div>
4984
4985<!-- _______________________________________________________________________ -->
4986<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4987 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4988</div>
4989<div class="doc_text">
4990
4991<h5>Syntax:</h5>
4992<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4993 &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]4994</pre>
4995
4996<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4997<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4998 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4999
5000<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5001<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5002 non-aggregate first class value, and a type to cast it to, which must also be
5003 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5004 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5005 identical. If the source type is a pointer, the destination type must also be
5006 a pointer. This instruction supports bitwise conversion of vectors to
5007 integers and to vectors of other types (as long as they have the same
5008 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5009
5010<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5011<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5013 this conversion. The conversion is done as if the <tt>value</tt> had been
5014 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5015 be converted to other pointer types with this instruction. To convert
5016 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5017 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5018
5019<h5>Example:</h5>
5020<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5021 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5022 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5023 %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]5024</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5026</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5027
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5028<!-- ======================================================================= -->
5029<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5030
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5031<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5032
5033<p>The instructions in this category are the "miscellaneous" instructions, which
5034 defy better classification.</p>
5035
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5036</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5037
5038<!-- _______________________________________________________________________ -->
5039<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5040</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5041
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5042<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5043
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5044<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5045<pre>
5046 &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]5047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5049<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5050<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5051 boolean values based on comparison of its two integer, integer vector, or
5052 pointer operands.</p>
5053
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5054<h5>Arguments:</h5>
5055<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5056 the condition code indicating the kind of comparison to perform. It is not a
5057 value, just a keyword. The possible condition code are:</p>
5058
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5059<ol>
5060 <li><tt>eq</tt>: equal</li>
5061 <li><tt>ne</tt>: not equal </li>
5062 <li><tt>ugt</tt>: unsigned greater than</li>
5063 <li><tt>uge</tt>: unsigned greater or equal</li>
5064 <li><tt>ult</tt>: unsigned less than</li>
5065 <li><tt>ule</tt>: unsigned less or equal</li>
5066 <li><tt>sgt</tt>: signed greater than</li>
5067 <li><tt>sge</tt>: signed greater or equal</li>
5068 <li><tt>slt</tt>: signed less than</li>
5069 <li><tt>sle</tt>: signed less or equal</li>
5070</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5072<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5074 typed. They must also be identical types.</p>
5075
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5076<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5077<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5078 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5079 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]5080 result, as follows:</p>
5081
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5082<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5083 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5084 <tt>false</tt> otherwise. No sign interpretation is necessary or
5085 performed.</li>
5086
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5087 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088 <tt>false</tt> otherwise. No sign interpretation is necessary or
5089 performed.</li>
5090
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5091 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5092 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5093
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5094 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5095 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5096 to <tt>op2</tt>.</li>
5097
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5098 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5099 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5100
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5101 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5103
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5104 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5105 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5106
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5107 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5109 to <tt>op2</tt>.</li>
5110
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5111 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5112 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5113
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5114 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115 <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]5116</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5118<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5119 values are compared as if they were integers.</p>
5120
5121<p>If the operands are integer vectors, then they are compared element by
5122 element. The result is an <tt>i1</tt> vector with the same number of elements
5123 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5124
5125<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5126<pre>
5127 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5128 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5129 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5130 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5131 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5132 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5134
5135<p>Note that the code generator does not yet support vector types with
5136 the <tt>icmp</tt> instruction.</p>
5137
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5138</div>
5139
5140<!-- _______________________________________________________________________ -->
5141<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5142</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5143
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5144<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5145
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5146<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5147<pre>
5148 &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]5149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5151<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5153 values based on comparison of its operands.</p>
5154
5155<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]5156(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5157
5158<p>If the operands are floating point vectors, then the result type is a vector
5159 of boolean with the same number of elements as the operands being
5160 compared.</p>
5161
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5162<h5>Arguments:</h5>
5163<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5164 the condition code indicating the kind of comparison to perform. It is not a
5165 value, just a keyword. The possible condition code are:</p>
5166
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5167<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5168 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5169 <li><tt>oeq</tt>: ordered and equal</li>
5170 <li><tt>ogt</tt>: ordered and greater than </li>
5171 <li><tt>oge</tt>: ordered and greater than or equal</li>
5172 <li><tt>olt</tt>: ordered and less than </li>
5173 <li><tt>ole</tt>: ordered and less than or equal</li>
5174 <li><tt>one</tt>: ordered and not equal</li>
5175 <li><tt>ord</tt>: ordered (no nans)</li>
5176 <li><tt>ueq</tt>: unordered or equal</li>
5177 <li><tt>ugt</tt>: unordered or greater than </li>
5178 <li><tt>uge</tt>: unordered or greater than or equal</li>
5179 <li><tt>ult</tt>: unordered or less than </li>
5180 <li><tt>ule</tt>: unordered or less than or equal</li>
5181 <li><tt>une</tt>: unordered or not equal</li>
5182 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5183 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5184</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5185
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5186<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5187 <i>unordered</i> means that either operand may be a QNAN.</p>
5188
5189<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5190 a <a href="#t_floating">floating point</a> type or
5191 a <a href="#t_vector">vector</a> of floating point type. They must have
5192 identical types.</p>
5193
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5194<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5195<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5196 according to the condition code given as <tt>cond</tt>. If the operands are
5197 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5198 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5199 follows:</p>
5200
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5201<ol>
5202 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5203
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5204 <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]5205 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5206
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5207 <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]5208 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5210 <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]5211 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5212
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5213 <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]5214 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5215
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5216 <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]5217 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5218
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5221
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5222 <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]5223
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5224 <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]5225 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5226
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5227 <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]5228 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5229
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5230 <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]5231 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5232
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5233 <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]5234 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5235
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5236 <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]5237 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5238
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5239 <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]5240 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5241
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5242 <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]5243
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5244 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5245</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5246
5247<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5248<pre>
5249 &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]5250 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5251 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5252 &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]5253</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5254
5255<p>Note that the code generator does not yet support vector types with
5256 the <tt>fcmp</tt> instruction.</p>
5257
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5258</div>
5259
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5260<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5261<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5262 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5263</div>
5264
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5265<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5266
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5267<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5268<pre>
5269 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5270</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5271
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5272<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5273<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5274 SSA graph representing the function.</p>
5275
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5276<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277<p>The type of the incoming values is specified with the first type field. After
5278 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5279 one pair for each predecessor basic block of the current block. Only values
5280 of <a href="#t_firstclass">first class</a> type may be used as the value
5281 arguments to the PHI node. Only labels may be used as the label
5282 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5283
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5284<p>There must be no non-phi instructions between the start of a basic block and
5285 the PHI instructions: i.e. PHI instructions must be first in a basic
5286 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5287
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5288<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5289 occur on the edge from the corresponding predecessor block to the current
5290 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5291 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5292
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5293<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5294<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295 specified by the pair corresponding to the predecessor basic block that
5296 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5297
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5298<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5299<pre>
5300Loop: ; Infinite loop that counts from 0 on up...
5301 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5302 %nextindvar = add i32 %indvar, 1
5303 br label %Loop
5304</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5305
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5306</div>
5307
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5308<!-- _______________________________________________________________________ -->
5309<div class="doc_subsubsection">
5310 <a name="i_select">'<tt>select</tt>' Instruction</a>
5311</div>
5312
5313<div class="doc_text">
5314
5315<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5316<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5317 &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>
5318
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5319 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5320</pre>
5321
5322<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5323<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5324 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5325
5326
5327<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5329 values indicating the condition, and two values of the
5330 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5331 vectors and the condition is a scalar, then entire vectors are selected, not
5332 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5333
5334<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5335<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5336 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5337
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5338<p>If the condition is a vector of i1, then the value arguments must be vectors
5339 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5340
5341<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5342<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5343 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5344</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5345
5346<p>Note that the code generator does not yet support conditions
5347 with vector type.</p>
5348
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5349</div>
5350
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5351<!-- _______________________________________________________________________ -->
5352<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5353 <a name="i_call">'<tt>call</tt>' Instruction</a>
5354</div>
5355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5356<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5357
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5358<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5359<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5360 &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]5361</pre>
5362
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5363<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5364<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5366<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5367<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5368
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5369<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5370 <li>The optional "tail" marker indicates that the callee function does not
5371 access any allocas or varargs in the caller. Note that calls may be
5372 marked "tail" even if they do not occur before
5373 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5374 present, the function call is eligible for tail call optimization,
5375 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5376 optimized into a jump</a>. The code generator may optimize calls marked
5377 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5378 sibling call optimization</a> when the caller and callee have
5379 matching signatures, or 2) forced tail call optimization when the
5380 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5381 <ul>
5382 <li>Caller and callee both have the calling
5383 convention <tt>fastcc</tt>.</li>
5384 <li>The call is in tail position (ret immediately follows call and ret
5385 uses value of call or is void).</li>
5386 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5387 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5388 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5389 constraints are met.</a></li>
5390 </ul>
5391 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5392
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5393 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5394 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5395 defaults to using C calling conventions. The calling convention of the
5396 call must match the calling convention of the target function, or else the
5397 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5398
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5399 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5400 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5401 '<tt>inreg</tt>' attributes are valid here.</li>
5402
5403 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5404 type of the return value. Functions that return no value are marked
5405 <tt><a href="#t_void">void</a></tt>.</li>
5406
5407 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5408 being invoked. The argument types must match the types implied by this
5409 signature. This type can be omitted if the function is not varargs and if
5410 the function type does not return a pointer to a function.</li>
5411
5412 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5413 be invoked. In most cases, this is a direct function invocation, but
5414 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5415 to function value.</li>
5416
5417 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5418 signature argument types and parameter attributes. All arguments must be
5419 of <a href="#t_firstclass">first class</a> type. If the function
5420 signature indicates the function accepts a variable number of arguments,
5421 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5422
5423 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5424 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5425 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5426</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5427
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5428<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5429<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5430 a specified function, with its incoming arguments bound to the specified
5431 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5432 function, control flow continues with the instruction after the function
5433 call, and the return value of the function is bound to the result
5434 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5436<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5437<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5438 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5439 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5440 %X = tail call i32 @foo() <i>; yields i32</i>
5441 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5442 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5443
5444 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5445 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5446 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5447 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5448 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5449 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5450</pre>
5451
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5452<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5453standard C99 library as being the C99 library functions, and may perform
5454optimizations or generate code for them under that assumption. This is
5455something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5456freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5457
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5458</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5459
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5460<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5461<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5462 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5463</div>
5464
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5465<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5466
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5467<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5468<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5469 &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]5470</pre>
5471
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5472<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5473<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474 the "variable argument" area of a function call. It is used to implement the
5475 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5476
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5477<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5478<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5479 argument. It returns a value of the specified argument type and increments
5480 the <tt>va_list</tt> to point to the next argument. The actual type
5481 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5482
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5483<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5484<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5485 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5486 to the next argument. For more information, see the variable argument
5487 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5488
5489<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]5490 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5491 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5492
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493<p><tt>va_arg</tt> is an LLVM instruction instead of
5494 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5495 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5496
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5497<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5498<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5499
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5500<p>Note that the code generator does not yet fully support va_arg on many
5501 targets. Also, it does not currently support va_arg with aggregate types on
5502 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5503
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5504</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5505
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5506<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5507<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5508<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5510<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5511
5512<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5513 well known names and semantics and are required to follow certain
5514 restrictions. Overall, these intrinsics represent an extension mechanism for
5515 the LLVM language that does not require changing all of the transformations
5516 in LLVM when adding to the language (or the bitcode reader/writer, the
5517 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5518
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5519<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5520 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5521 begin with this prefix. Intrinsic functions must always be external
5522 functions: you cannot define the body of intrinsic functions. Intrinsic
5523 functions may only be used in call or invoke instructions: it is illegal to
5524 take the address of an intrinsic function. Additionally, because intrinsic
5525 functions are part of the LLVM language, it is required if any are added that
5526 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5527
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5528<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5529 family of functions that perform the same operation but on different data
5530 types. Because LLVM can represent over 8 million different integer types,
5531 overloading is used commonly to allow an intrinsic function to operate on any
5532 integer type. One or more of the argument types or the result type can be
5533 overloaded to accept any integer type. Argument types may also be defined as
5534 exactly matching a previous argument's type or the result type. This allows
5535 an intrinsic function which accepts multiple arguments, but needs all of them
5536 to be of the same type, to only be overloaded with respect to a single
5537 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5539<p>Overloaded intrinsics will have the names of its overloaded argument types
5540 encoded into its function name, each preceded by a period. Only those types
5541 which are overloaded result in a name suffix. Arguments whose type is matched
5542 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5543 can take an integer of any width and returns an integer of exactly the same
5544 integer width. This leads to a family of functions such as
5545 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5546 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5547 suffix is required. Because the argument's type is matched against the return
5548 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5549
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5550<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5551 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5552
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5553</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5554
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5555<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5556<div class="doc_subsection">
5557 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5558</div>
5559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5560<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5561
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562<p>Variable argument support is defined in LLVM with
5563 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5564 intrinsic functions. These functions are related to the similarly named
5565 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5566
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p>All of these functions operate on arguments that use a target-specific value
5568 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5569 not define what this type is, so all transformations should be prepared to
5570 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5571
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5572<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]5573 instruction and the variable argument handling intrinsic functions are
5574 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5575
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5576<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5577<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5578define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5579 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5580 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5581 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5582 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5583
5584 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5585 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5586
5587 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5588 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5589 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5590 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5591 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5592
5593 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5594 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5595 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5596}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5597
5598declare void @llvm.va_start(i8*)
5599declare void @llvm.va_copy(i8*, i8*)
5600declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5601</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5602</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5603
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5604</div>
5605
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5606<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5607<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5608 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5609</div>
5610
5611
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5612<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5613
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5614<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5615<pre>
5616 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5617</pre>
5618
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5619<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5620<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5621 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]5622
5623<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5624<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]5625
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5626<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5627<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]5628 macro available in C. In a target-dependent way, it initializes
5629 the <tt>va_list</tt> element to which the argument points, so that the next
5630 call to <tt>va_arg</tt> will produce the first variable argument passed to
5631 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5632 need to know the last argument of the function as the compiler can figure
5633 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5634
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5635</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5636
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5637<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5638<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5639 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5640</div>
5641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5642<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5643
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5644<h5>Syntax:</h5>
5645<pre>
5646 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5647</pre>
5648
5649<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5650<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5651 which has been initialized previously
5652 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5653 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5654
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5655<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5656<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]5657
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5658<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5659<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]5660 macro available in C. In a target-dependent way, it destroys
5661 the <tt>va_list</tt> element to which the argument points. Calls
5662 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5663 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5664 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5665
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5666</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5667
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5668<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5669<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5670 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5671</div>
5672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5673<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5674
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5675<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5676<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5677 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5678</pre>
5679
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5680<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5681<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5682 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5683
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5684<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5685<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]5686 The second argument is a pointer to a <tt>va_list</tt> element to copy
5687 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5688
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5689<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5690<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]5691 macro available in C. In a target-dependent way, it copies the
5692 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5693 element. This intrinsic is necessary because
5694 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5695 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5697</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5698
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5699<!-- ======================================================================= -->
5700<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5701 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5702</div>
5703
5704<div class="doc_text">
5705
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5706<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5707Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5708intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5709roots on the stack</a>, as well as garbage collector implementations that
5710require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5711barriers. Front-ends for type-safe garbage collected languages should generate
5712these intrinsics to make use of the LLVM garbage collectors. For more details,
5713see <a href="GarbageCollection.html">Accurate Garbage Collection with
5714LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5716<p>The garbage collection intrinsics only operate on objects in the generic
5717 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5718
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5719</div>
5720
5721<!-- _______________________________________________________________________ -->
5722<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5723 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5724</div>
5725
5726<div class="doc_text">
5727
5728<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5729<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5730 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731</pre>
5732
5733<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5734<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]5735 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5736
5737<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5738<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5739 root pointer. The second pointer (which must be either a constant or a
5740 global value address) contains the meta-data to be associated with the
5741 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5742
5743<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5744<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]5745 location. At compile-time, the code generator generates information to allow
5746 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5747 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5748 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5749
5750</div>
5751
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5754 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5760<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5761 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5762</pre>
5763
5764<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5765<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5766 locations, allowing garbage collector implementations that require read
5767 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5768
5769<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5770<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]5771 allocated from the garbage collector. The first object is a pointer to the
5772 start of the referenced object, if needed by the language runtime (otherwise
5773 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5774
5775<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5776<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777 instruction, but may be replaced with substantially more complex code by the
5778 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5779 may only be used in a function which <a href="#gc">specifies a GC
5780 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5781
5782</div>
5783
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5786 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5787</div>
5788
5789<div class="doc_text">
5790
5791<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5792<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5793 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5794</pre>
5795
5796<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5797<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5798 locations, allowing garbage collector implementations that require write
5799 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5800
5801<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5802<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]5803 object to store it to, and the third is the address of the field of Obj to
5804 store to. If the runtime does not require a pointer to the object, Obj may
5805 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5806
5807<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5808<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809 instruction, but may be replaced with substantially more complex code by the
5810 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5811 may only be used in a function which <a href="#gc">specifies a GC
5812 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5813
5814</div>
5815
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5816<!-- ======================================================================= -->
5817<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5818 <a name="int_codegen">Code Generator Intrinsics</a>
5819</div>
5820
5821<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822
5823<p>These intrinsics are provided by LLVM to expose special features that may
5824 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5825
5826</div>
5827
5828<!-- _______________________________________________________________________ -->
5829<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5830 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5831</div>
5832
5833<div class="doc_text">
5834
5835<h5>Syntax:</h5>
5836<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5837 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5838</pre>
5839
5840<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5841<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5842 target-specific value indicating the return address of the current function
5843 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5844
5845<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<p>The argument to this intrinsic indicates which function to return the address
5847 for. Zero indicates the calling function, one indicates its caller, etc.
5848 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5849
5850<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5852 indicating the return address of the specified call frame, or zero if it
5853 cannot be identified. The value returned by this intrinsic is likely to be
5854 incorrect or 0 for arguments other than zero, so it should only be used for
5855 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>Note that calling this intrinsic does not prevent function inlining or other
5858 aggressive transformations, so the value returned may not be that of the
5859 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5860
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5861</div>
5862
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5863<!-- _______________________________________________________________________ -->
5864<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5865 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5866</div>
5867
5868<div class="doc_text">
5869
5870<h5>Syntax:</h5>
5871<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5872 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5873</pre>
5874
5875<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5876<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5877 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5878
5879<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>The argument to this intrinsic indicates which function to return the frame
5881 pointer for. Zero indicates the calling function, one indicates its caller,
5882 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5883
5884<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5886 indicating the frame address of the specified call frame, or zero if it
5887 cannot be identified. The value returned by this intrinsic is likely to be
5888 incorrect or 0 for arguments other than zero, so it should only be used for
5889 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5890
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5891<p>Note that calling this intrinsic does not prevent function inlining or other
5892 aggressive transformations, so the value returned may not be that of the
5893 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5894
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5895</div>
5896
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5897<!-- _______________________________________________________________________ -->
5898<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5899 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5900</div>
5901
5902<div class="doc_text">
5903
5904<h5>Syntax:</h5>
5905<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5906 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5907</pre>
5908
5909<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5910<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5911 of the function stack, for use
5912 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5913 useful for implementing language features like scoped automatic variable
5914 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5915
5916<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5917<p>This intrinsic returns a opaque pointer value that can be passed
5918 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5919 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5920 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5921 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5922 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5923 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5924
5925</div>
5926
5927<!-- _______________________________________________________________________ -->
5928<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5929 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5930</div>
5931
5932<div class="doc_text">
5933
5934<h5>Syntax:</h5>
5935<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]5936 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5937</pre>
5938
5939<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5940<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5941 the function stack to the state it was in when the
5942 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5943 executed. This is useful for implementing language features like scoped
5944 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5945
5946<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5947<p>See the description
5948 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5949
5950</div>
5951
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5952<!-- _______________________________________________________________________ -->
5953<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5954 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5955</div>
5956
5957<div class="doc_text">
5958
5959<h5>Syntax:</h5>
5960<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5961 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]5962</pre>
5963
5964<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5966 insert a prefetch instruction if supported; otherwise, it is a noop.
5967 Prefetches have no effect on the behavior of the program but can change its
5968 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5969
5970<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5972 specifier determining if the fetch should be for a read (0) or write (1),
5973 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5974 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5975 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5976
5977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5978<p>This intrinsic does not modify the behavior of the program. In particular,
5979 prefetches cannot trap and do not produce a value. On targets that support
5980 this intrinsic, the prefetch can provide hints to the processor cache for
5981 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5982
5983</div>
5984
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5985<!-- _______________________________________________________________________ -->
5986<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5987 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5988</div>
5989
5990<div class="doc_text">
5991
5992<h5>Syntax:</h5>
5993<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5994 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +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.pcmarker</tt>' intrinsic is a method to export a Program
5999 Counter (PC) in a region of code to simulators and other tools. The method
6000 is target specific, but it is expected that the marker will use exported
6001 symbols to transmit the PC of the marker. The marker makes no guarantees
6002 that it will remain with any specific instruction after optimizations. It is
6003 possible that the presence of a marker will inhibit optimizations. The
6004 intended use is to be inserted after optimizations to allow correlations of
6005 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6006
6007<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6009
6010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6012 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6013
6014</div>
6015
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6016<!-- _______________________________________________________________________ -->
6017<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6018 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6019</div>
6020
6021<div class="doc_text">
6022
6023<h5>Syntax:</h5>
6024<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6025 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6026</pre>
6027
6028<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6029<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6030 counter register (or similar low latency, high accuracy clocks) on those
6031 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6032 should map to RPCC. As the backing counters overflow quickly (on the order
6033 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6034
6035<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6036<p>When directly supported, reading the cycle counter should not modify any
6037 memory. Implementations are allowed to either return a application specific
6038 value or a system wide value. On backends without support, this is lowered
6039 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6040
6041</div>
6042
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6043<!-- ======================================================================= -->
6044<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6045 <a name="int_libc">Standard C Library Intrinsics</a>
6046</div>
6047
6048<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049
6050<p>LLVM provides intrinsics for a few important standard C library functions.
6051 These intrinsics allow source-language front-ends to pass information about
6052 the alignment of the pointer arguments to the code generator, providing
6053 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6054
6055</div>
6056
6057<!-- _______________________________________________________________________ -->
6058<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6059 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6060</div>
6061
6062<div class="doc_text">
6063
6064<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6065<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]6066 integer bit width and for different address spaces. Not all targets support
6067 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6068
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6069<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6070 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]6071 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6072 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]6073 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6074</pre>
6075
6076<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6078 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6079
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6081 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6082 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6083
6084<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6085
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6086<p>The first argument is a pointer to the destination, the second is a pointer
6087 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6088 number of bytes to copy, the fourth argument is the alignment of the
6089 source and destination locations, and the fifth is a boolean indicating a
6090 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6091
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6092<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]6093 then the caller guarantees that both the source and destination pointers are
6094 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6095
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6096<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6097 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6098 The detailed access behavior is not very cleanly specified and it is unwise
6099 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6100
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6101<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6102
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6104 source location to the destination location, which are not allowed to
6105 overlap. It copies "len" bytes of memory over. If the argument is known to
6106 be aligned to some boundary, this can be specified as the fourth argument,
6107 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6108
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6109</div>
6110
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6111<!-- _______________________________________________________________________ -->
6112<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6113 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6114</div>
6115
6116<div class="doc_text">
6117
6118<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6119<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]6120 width and for different address space. Not all targets support all bit
6121 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6123<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6124 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]6125 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6126 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]6127 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128</pre>
6129
6130<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6132 source location to the destination location. It is similar to the
6133 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6134 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6135
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6136<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6137 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6138 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6139
6140<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6141
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6142<p>The first argument is a pointer to the destination, the second is a pointer
6143 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6144 number of bytes to copy, the fourth argument is the alignment of the
6145 source and destination locations, and the fifth is a boolean indicating a
6146 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6147
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6148<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]6149 then the caller guarantees that the source and destination pointers are
6150 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6151
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6152<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6153 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6154 The detailed access behavior is not very cleanly specified and it is unwise
6155 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6156
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6157<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6158
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6159<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6160 source location to the destination location, which may overlap. It copies
6161 "len" bytes of memory over. If the argument is known to be aligned to some
6162 boundary, this can be specified as the fourth argument, otherwise it should
6163 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6164
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6165</div>
6166
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6167<!-- _______________________________________________________________________ -->
6168<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6169 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6170</div>
6171
6172<div class="doc_text">
6173
6174<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6175<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6176 width and for different address spaces. Not all targets support all bit
6177 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6178
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6179<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6180 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6181 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6182 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6183 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6184</pre>
6185
6186<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6187<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6188 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6189
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6190<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6191 intrinsic does not return a value, takes extra alignment/volatile arguments,
6192 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6193
6194<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6195<p>The first argument is a pointer to the destination to fill, the second is the
6196 byte value to fill it with, the third argument is an integer argument
6197 specifying the number of bytes to fill, and the fourth argument is the known
6198 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6199
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6200<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]6201 then the caller guarantees that the destination pointer is aligned to that
6202 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6203
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6204<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6205 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6206 The detailed access behavior is not very cleanly specified and it is unwise
6207 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6208
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6209<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6211 at the destination location. If the argument is known to be aligned to some
6212 boundary, this can be specified as the fourth argument, otherwise it should
6213 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6214
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6215</div>
6216
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6217<!-- _______________________________________________________________________ -->
6218<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6219 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6220</div>
6221
6222<div class="doc_text">
6223
6224<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6225<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6226 floating point or vector of floating point type. Not all targets support all
6227 types however.</p>
6228
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6229<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6230 declare float @llvm.sqrt.f32(float %Val)
6231 declare double @llvm.sqrt.f64(double %Val)
6232 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6233 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6234 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6235</pre>
6236
6237<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6238<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6239 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6240 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6241 behavior for negative numbers other than -0.0 (which allows for better
6242 optimization, because there is no need to worry about errno being
6243 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]6244
6245<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6246<p>The argument and return value are floating point numbers of the same
6247 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6248
6249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6250<p>This function returns the sqrt of the specified operand if it is a
6251 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6252
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6253</div>
6254
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6255<!-- _______________________________________________________________________ -->
6256<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6257 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6258</div>
6259
6260<div class="doc_text">
6261
6262<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6263<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6264 floating point or vector of floating point type. Not all targets support all
6265 types however.</p>
6266
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6267<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6268 declare float @llvm.powi.f32(float %Val, i32 %power)
6269 declare double @llvm.powi.f64(double %Val, i32 %power)
6270 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6271 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6272 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6273</pre>
6274
6275<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6276<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6277 specified (positive or negative) power. The order of evaluation of
6278 multiplications is not defined. When a vector of floating point type is
6279 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6280
6281<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6282<p>The second argument is an integer power, and the first is a value to raise to
6283 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6284
6285<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6286<p>This function returns the first value raised to the second power with an
6287 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6288
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6289</div>
6290
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6291<!-- _______________________________________________________________________ -->
6292<div class="doc_subsubsection">
6293 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6294</div>
6295
6296<div class="doc_text">
6297
6298<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6299<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6300 floating point or vector of floating point type. Not all targets support all
6301 types however.</p>
6302
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6303<pre>
6304 declare float @llvm.sin.f32(float %Val)
6305 declare double @llvm.sin.f64(double %Val)
6306 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6307 declare fp128 @llvm.sin.f128(fp128 %Val)
6308 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6309</pre>
6310
6311<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6313
6314<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315<p>The argument and return value are floating point numbers of the same
6316 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6317
6318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6319<p>This function returns the sine of the specified operand, returning the same
6320 values as the libm <tt>sin</tt> functions would, and handles error conditions
6321 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6322
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6323</div>
6324
6325<!-- _______________________________________________________________________ -->
6326<div class="doc_subsubsection">
6327 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6328</div>
6329
6330<div class="doc_text">
6331
6332<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6333<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6334 floating point or vector of floating point type. Not all targets support all
6335 types however.</p>
6336
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6337<pre>
6338 declare float @llvm.cos.f32(float %Val)
6339 declare double @llvm.cos.f64(double %Val)
6340 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6341 declare fp128 @llvm.cos.f128(fp128 %Val)
6342 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6343</pre>
6344
6345<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6346<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6347
6348<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6349<p>The argument and return value are floating point numbers of the same
6350 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6351
6352<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6353<p>This function returns the cosine of the specified operand, returning the same
6354 values as the libm <tt>cos</tt> functions would, and handles error conditions
6355 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6356
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6357</div>
6358
6359<!-- _______________________________________________________________________ -->
6360<div class="doc_subsubsection">
6361 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6362</div>
6363
6364<div class="doc_text">
6365
6366<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6367<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6368 floating point or vector of floating point type. Not all targets support all
6369 types however.</p>
6370
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6371<pre>
6372 declare float @llvm.pow.f32(float %Val, float %Power)
6373 declare double @llvm.pow.f64(double %Val, double %Power)
6374 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6375 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6376 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6377</pre>
6378
6379<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6380<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6381 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6382
6383<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6384<p>The second argument is a floating point power, and the first is a value to
6385 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6386
6387<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6388<p>This function returns the first value raised to the second power, returning
6389 the same values as the libm <tt>pow</tt> functions would, and handles error
6390 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6391
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6392</div>
6393
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6394<!-- ======================================================================= -->
6395<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6396 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6397</div>
6398
6399<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6400
6401<p>LLVM provides intrinsics for a few important bit manipulation operations.
6402 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6403
6404</div>
6405
6406<!-- _______________________________________________________________________ -->
6407<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6408 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6409</div>
6410
6411<div class="doc_text">
6412
6413<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6414<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6415 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6416
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6417<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6418 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6419 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6420 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6421</pre>
6422
6423<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6424<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6425 values with an even number of bytes (positive multiple of 16 bits). These
6426 are useful for performing operations on data that is not in the target's
6427 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6428
6429<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6430<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6431 and low byte of the input i16 swapped. Similarly,
6432 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6433 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6434 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6435 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6436 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6437 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6438
6439</div>
6440
6441<!-- _______________________________________________________________________ -->
6442<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6443 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6444</div>
6445
6446<div class="doc_text">
6447
6448<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6449<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]6450 width. Not all targets support all bit widths however.</p>
6451
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6452<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6453 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6454 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6455 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6456 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6457 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6458</pre>
6459
6460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6461<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6462 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6463
6464<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6465<p>The only argument is the value to be counted. The argument may be of any
6466 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6467
6468<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6469<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]6470
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6471</div>
6472
6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6475 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6476</div>
6477
6478<div class="doc_text">
6479
6480<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6481<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6482 integer bit width. Not all targets support all bit widths however.</p>
6483
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6484<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6485 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6486 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6487 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6488 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6489 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6490</pre>
6491
6492<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6493<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6494 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6495
6496<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6497<p>The only argument is the value to be counted. The argument may be of any
6498 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6499
6500<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6501<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6502 zeros in a variable. If the src == 0 then the result is the size in bits of
6503 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6504
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6505</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6506
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6507<!-- _______________________________________________________________________ -->
6508<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6509 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6510</div>
6511
6512<div class="doc_text">
6513
6514<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6515<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6516 integer bit width. Not all targets support all bit widths however.</p>
6517
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6518<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6519 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6520 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6521 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6522 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6523 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6524</pre>
6525
6526<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6527<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6528 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6529
6530<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6531<p>The only argument is the value to be counted. The argument may be of any
6532 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6533
6534<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6535<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6536 zeros in a variable. If the src == 0 then the result is the size in bits of
6537 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6538
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6539</div>
6540
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6541<!-- ======================================================================= -->
6542<div class="doc_subsection">
6543 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6544</div>
6545
6546<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547
6548<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6549
6550</div>
6551
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6552<!-- _______________________________________________________________________ -->
6553<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6554 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6555</div>
6556
6557<div class="doc_text">
6558
6559<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6560<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]6561 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6562
6563<pre>
6564 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6565 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6566 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6567</pre>
6568
6569<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6570<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571 a signed addition of the two arguments, and indicate whether an overflow
6572 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6573
6574<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6575<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]6576 be of integer types of any bit width, but they must have the same bit
6577 width. The second element of the result structure must be of
6578 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6579 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6580
6581<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6582<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6583 a signed addition of the two variables. They return a structure &mdash; the
6584 first element of which is the signed summation, and the second element of
6585 which is a bit specifying if the signed summation resulted in an
6586 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587
6588<h5>Examples:</h5>
6589<pre>
6590 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6591 %sum = extractvalue {i32, i1} %res, 0
6592 %obit = extractvalue {i32, i1} %res, 1
6593 br i1 %obit, label %overflow, label %normal
6594</pre>
6595
6596</div>
6597
6598<!-- _______________________________________________________________________ -->
6599<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6600 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6601</div>
6602
6603<div class="doc_text">
6604
6605<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6606<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]6607 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6608
6609<pre>
6610 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6611 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6612 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6613</pre>
6614
6615<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6616<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6617 an unsigned addition of the two arguments, and indicate whether a carry
6618 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6619
6620<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6621<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]6622 be of integer types of any bit width, but they must have the same bit
6623 width. The second element of the result structure must be of
6624 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6625 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6626
6627<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6628<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6629 an unsigned addition of the two arguments. They return a structure &mdash;
6630 the first element of which is the sum, and the second element of which is a
6631 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6632
6633<h5>Examples:</h5>
6634<pre>
6635 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6636 %sum = extractvalue {i32, i1} %res, 0
6637 %obit = extractvalue {i32, i1} %res, 1
6638 br i1 %obit, label %carry, label %normal
6639</pre>
6640
6641</div>
6642
6643<!-- _______________________________________________________________________ -->
6644<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6645 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6646</div>
6647
6648<div class="doc_text">
6649
6650<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6651<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]6652 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6653
6654<pre>
6655 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6656 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6657 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6658</pre>
6659
6660<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6661<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6662 a signed subtraction of the two arguments, and indicate whether an overflow
6663 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6664
6665<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6666<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]6667 be of integer types of any bit width, but they must have the same bit
6668 width. The second element of the result structure must be of
6669 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6670 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6671
6672<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6673<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6674 a signed subtraction of the two arguments. They return a structure &mdash;
6675 the first element of which is the subtraction, and the second element of
6676 which is a bit specifying if the signed subtraction resulted in an
6677 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6678
6679<h5>Examples:</h5>
6680<pre>
6681 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6682 %sum = extractvalue {i32, i1} %res, 0
6683 %obit = extractvalue {i32, i1} %res, 1
6684 br i1 %obit, label %overflow, label %normal
6685</pre>
6686
6687</div>
6688
6689<!-- _______________________________________________________________________ -->
6690<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6691 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6692</div>
6693
6694<div class="doc_text">
6695
6696<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6697<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]6698 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6699
6700<pre>
6701 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6702 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6703 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6704</pre>
6705
6706<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6707<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6708 an unsigned subtraction of the two arguments, and indicate whether an
6709 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6710
6711<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6712<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]6713 be of integer types of any bit width, but they must have the same bit
6714 width. The second element of the result structure must be of
6715 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6716 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6717
6718<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6719<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6720 an unsigned subtraction of the two arguments. They return a structure &mdash;
6721 the first element of which is the subtraction, and the second element of
6722 which is a bit specifying if the unsigned subtraction resulted in an
6723 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6724
6725<h5>Examples:</h5>
6726<pre>
6727 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6728 %sum = extractvalue {i32, i1} %res, 0
6729 %obit = extractvalue {i32, i1} %res, 1
6730 br i1 %obit, label %overflow, label %normal
6731</pre>
6732
6733</div>
6734
6735<!-- _______________________________________________________________________ -->
6736<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6737 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6738</div>
6739
6740<div class="doc_text">
6741
6742<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6743<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]6744 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6745
6746<pre>
6747 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6748 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6749 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6750</pre>
6751
6752<h5>Overview:</h5>
6753
6754<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6755 a signed multiplication of the two arguments, and indicate whether an
6756 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6757
6758<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6759<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]6760 be of integer types of any bit width, but they must have the same bit
6761 width. The second element of the result structure must be of
6762 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6763 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6764
6765<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6766<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767 a signed multiplication of the two arguments. They return a structure &mdash;
6768 the first element of which is the multiplication, and the second element of
6769 which is a bit specifying if the signed multiplication resulted in an
6770 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6771
6772<h5>Examples:</h5>
6773<pre>
6774 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6775 %sum = extractvalue {i32, i1} %res, 0
6776 %obit = extractvalue {i32, i1} %res, 1
6777 br i1 %obit, label %overflow, label %normal
6778</pre>
6779
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6780</div>
6781
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6782<!-- _______________________________________________________________________ -->
6783<div class="doc_subsubsection">
6784 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6785</div>
6786
6787<div class="doc_text">
6788
6789<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6790<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]6791 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6792
6793<pre>
6794 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6795 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6796 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6797</pre>
6798
6799<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6800<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6801 a unsigned multiplication of the two arguments, and indicate whether an
6802 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6803
6804<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6805<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]6806 be of integer types of any bit width, but they must have the same bit
6807 width. The second element of the result structure must be of
6808 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6809 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6810
6811<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6812<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6813 an unsigned multiplication of the two arguments. They return a structure
6814 &mdash; the first element of which is the multiplication, and the second
6815 element of which is a bit specifying if the unsigned multiplication resulted
6816 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6817
6818<h5>Examples:</h5>
6819<pre>
6820 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6821 %sum = extractvalue {i32, i1} %res, 0
6822 %obit = extractvalue {i32, i1} %res, 1
6823 br i1 %obit, label %overflow, label %normal
6824</pre>
6825
6826</div>
6827
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6828<!-- ======================================================================= -->
6829<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6830 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6831</div>
6832
6833<div class="doc_text">
6834
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6835<p>Half precision floating point is a storage-only format. This means that it is
6836 a dense encoding (in memory) but does not support computation in the
6837 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6838
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6839<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6840 value as an i16, then convert it to float with <a
6841 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6842 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6843 double etc). To store the value back to memory, it is first converted to
6844 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6845 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6846 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6847</div>
6848
6849<!-- _______________________________________________________________________ -->
6850<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6851 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6852</div>
6853
6854<div class="doc_text">
6855
6856<h5>Syntax:</h5>
6857<pre>
6858 declare i16 @llvm.convert.to.fp16(f32 %a)
6859</pre>
6860
6861<h5>Overview:</h5>
6862<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6863 a conversion from single precision floating point format to half precision
6864 floating point format.</p>
6865
6866<h5>Arguments:</h5>
6867<p>The intrinsic function contains single argument - the value to be
6868 converted.</p>
6869
6870<h5>Semantics:</h5>
6871<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6872 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6873 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6874 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6875
6876<h5>Examples:</h5>
6877<pre>
6878 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6879 store i16 %res, i16* @x, align 2
6880</pre>
6881
6882</div>
6883
6884<!-- _______________________________________________________________________ -->
6885<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6886 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6887</div>
6888
6889<div class="doc_text">
6890
6891<h5>Syntax:</h5>
6892<pre>
6893 declare f32 @llvm.convert.from.fp16(i16 %a)
6894</pre>
6895
6896<h5>Overview:</h5>
6897<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6898 a conversion from half precision floating point format to single precision
6899 floating point format.</p>
6900
6901<h5>Arguments:</h5>
6902<p>The intrinsic function contains single argument - the value to be
6903 converted.</p>
6904
6905<h5>Semantics:</h5>
6906<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6907 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6908 precision floating point format. The input half-float value is represented by
6909 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6910
6911<h5>Examples:</h5>
6912<pre>
6913 %a = load i16* @x, align 2
6914 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6915</pre>
6916
6917</div>
6918
6919<!-- ======================================================================= -->
6920<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6921 <a name="int_debugger">Debugger Intrinsics</a>
6922</div>
6923
6924<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6926<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6927 prefix), are described in
6928 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6929 Level Debugging</a> document.</p>
6930
6931</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6932
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6933<!-- ======================================================================= -->
6934<div class="doc_subsection">
6935 <a name="int_eh">Exception Handling Intrinsics</a>
6936</div>
6937
6938<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939
6940<p>The LLVM exception handling intrinsics (which all start with
6941 <tt>llvm.eh.</tt> prefix), are described in
6942 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6943 Handling</a> document.</p>
6944
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6945</div>
6946
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6947<!-- ======================================================================= -->
6948<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6949 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6950</div>
6951
6952<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953
6954<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame^]6955 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6956 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6957 function pointer lacking the nest parameter - the caller does not need to
6958 provide a value for it. Instead, the value to use is stored in advance in a
6959 "trampoline", a block of memory usually allocated on the stack, which also
6960 contains code to splice the nest value into the argument list. This is used
6961 to implement the GCC nested function address extension.</p>
6962
6963<p>For example, if the function is
6964 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6965 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6966 follows:</p>
6967
6968<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6969<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6970 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6971 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6972 %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]6973 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6974</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6975</div>
6976
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6977<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6978 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6980</div>
6981
6982<!-- _______________________________________________________________________ -->
6983<div class="doc_subsubsection">
6984 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6985</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6987<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6988
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6989<h5>Syntax:</h5>
6990<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991 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]6992</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6993
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6995<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6996 function pointer suitable for executing it.</p>
6997
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6998<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6999<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7000 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7001 sufficiently aligned block of memory; this memory is written to by the
7002 intrinsic. Note that the size and the alignment are target-specific - LLVM
7003 currently provides no portable way of determining them, so a front-end that
7004 generates this intrinsic needs to have some target-specific knowledge.
7005 The <tt>func</tt> argument must hold a function bitcast to
7006 an <tt>i8*</tt>.</p>
7007
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7008<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7009<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7010 dependent code, turning it into a function. A pointer to this function is
7011 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7012 function pointer type</a> before being called. The new function's signature
7013 is the same as that of <tt>func</tt> with any arguments marked with
7014 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7015 is allowed, and it must be of pointer type. Calling the new function is
7016 equivalent to calling <tt>func</tt> with the same argument list, but
7017 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7018 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7019 by <tt>tramp</tt> is modified, then the effect of any later call to the
7020 returned function pointer is undefined.</p>
7021
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7022</div>
7023
7024<!-- ======================================================================= -->
7025<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7026 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7027</div>
7028
7029<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7030
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7032 hardware constructs for atomic operations and memory synchronization. This
7033 provides an interface to the hardware, not an interface to the programmer. It
7034 is aimed at a low enough level to allow any programming models or APIs
7035 (Application Programming Interfaces) which need atomic behaviors to map
7036 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7037 hardware provides a "universal IR" for source languages, it also provides a
7038 starting point for developing a "universal" atomic operation and
7039 synchronization IR.</p>
7040
7041<p>These do <em>not</em> form an API such as high-level threading libraries,
7042 software transaction memory systems, atomic primitives, and intrinsic
7043 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7044 application libraries. The hardware interface provided by LLVM should allow
7045 a clean implementation of all of these APIs and parallel programming models.
7046 No one model or paradigm should be selected above others unless the hardware
7047 itself ubiquitously does so.</p>
7048
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7049</div>
7050
7051<!-- _______________________________________________________________________ -->
7052<div class="doc_subsubsection">
7053 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7054</div>
7055<div class="doc_text">
7056<h5>Syntax:</h5>
7057<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7058 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]7059</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7060
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7062<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7063 specific pairs of memory access types.</p>
7064
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7065<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7067 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7068 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7071<ul>
7072 <li><tt>ll</tt>: load-load barrier</li>
7073 <li><tt>ls</tt>: load-store barrier</li>
7074 <li><tt>sl</tt>: store-load barrier</li>
7075 <li><tt>ss</tt>: store-store barrier</li>
7076 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7077</ul>
7078
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7079<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7080<p>This intrinsic causes the system to enforce some ordering constraints upon
7081 the loads and stores of the program. This barrier does not
7082 indicate <em>when</em> any events will occur, it only enforces
7083 an <em>order</em> in which they occur. For any of the specified pairs of load
7084 and store operations (f.ex. load-load, or store-load), all of the first
7085 operations preceding the barrier will complete before any of the second
7086 operations succeeding the barrier begin. Specifically the semantics for each
7087 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7089<ul>
7090 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7091 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7092 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7093 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7094 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7095 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7096 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097 load after the barrier begins.</li>
7098</ul>
7099
7100<p>These semantics are applied with a logical "and" behavior when more than one
7101 is enabled in a single memory barrier intrinsic.</p>
7102
7103<p>Backends may implement stronger barriers than those requested when they do
7104 not support as fine grained a barrier as requested. Some architectures do
7105 not need all types of barriers and on such architectures, these become
7106 noops.</p>
7107
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7108<h5>Example:</h5>
7109<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7110%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7111%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7112 store i32 4, %ptr
7113
7114%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7115 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7116 <i>; guarantee the above finishes</i>
7117 store i32 8, %ptr <i>; before this begins</i>
7118</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7119
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7120</div>
7121
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7122<!-- _______________________________________________________________________ -->
7123<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7124 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7125</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7126
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7127<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7128
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7131 any integer bit width and for different address spaces. Not all targets
7132 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7133
7134<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7135 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7136 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7137 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7138 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]7139</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7140
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7141<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7142<p>This loads a value in memory and compares it to a given value. If they are
7143 equal, it stores a new value into the memory.</p>
7144
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7145<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7146<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7147 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7148 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7149 this integer type. While any bit width integer may be used, targets may only
7150 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7151
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7152<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7153<p>This entire intrinsic must be executed atomically. It first loads the value
7154 in memory pointed to by <tt>ptr</tt> and compares it with the
7155 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7156 memory. The loaded value is yielded in all cases. This provides the
7157 equivalent of an atomic compare-and-swap operation within the SSA
7158 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7160<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7161<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7162%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7163%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7164 store i32 4, %ptr
7165
7166%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7167%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7168 <i>; yields {i32}:result1 = 4</i>
7169%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7170%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7171
7172%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7173%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7174 <i>; yields {i32}:result2 = 8</i>
7175%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7176
7177%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7178</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7179
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180</div>
7181
7182<!-- _______________________________________________________________________ -->
7183<div class="doc_subsubsection">
7184 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7185</div>
7186<div class="doc_text">
7187<h5>Syntax:</h5>
7188
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7189<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7190 integer bit width. Not all targets support all bit widths however.</p>
7191
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7192<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7193 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7194 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7195 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7196 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]7197</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7198
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7199<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7200<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7201 the value from memory. It then stores the value in <tt>val</tt> in the memory
7202 at <tt>ptr</tt>.</p>
7203
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7206 the <tt>val</tt> argument and the result must be integers of the same bit
7207 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7208 integer type. The targets may only lower integer representations they
7209 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7210
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7212<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7213 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7214 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7215
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7216<h5>Examples:</h5>
7217<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7218%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7219%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7220 store i32 4, %ptr
7221
7222%val1 = add i32 4, 4
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7223%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7224 <i>; yields {i32}:result1 = 4</i>
7225%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7226%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7227
7228%val2 = add i32 1, 1
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7229%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7230 <i>; yields {i32}:result2 = 8</i>
7231
7232%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7233%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7234</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7235
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7236</div>
7237
7238<!-- _______________________________________________________________________ -->
7239<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7240 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7241
7242</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7243
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7244<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7245
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7246<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7247<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7248 any integer bit width. Not all targets support all bit widths however.</p>
7249
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7250<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7251 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7252 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7253 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7254 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]7255</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7256
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7257<h5>Overview:</h5>
7258<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7259 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7260
7261<h5>Arguments:</h5>
7262<p>The intrinsic takes two arguments, the first a pointer to an integer value
7263 and the second an integer value. The result is also an integer value. These
7264 integer types can have any bit width, but they must all have the same bit
7265 width. The targets may only lower integer representations they support.</p>
7266
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7267<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7268<p>This intrinsic does a series of operations atomically. It first loads the
7269 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7270 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]7271
7272<h5>Examples:</h5>
7273<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7274%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7275%ptr = bitcast i8* %mallocP to i32*
7276 store i32 4, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7277%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7278 <i>; yields {i32}:result1 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7279%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7280 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7281%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7282 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7283%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7284</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7285
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7286</div>
7287
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7288<!-- _______________________________________________________________________ -->
7289<div class="doc_subsubsection">
7290 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7291
7292</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7293
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7294<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7295
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7296<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7297<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7298 any integer bit width and for different address spaces. Not all targets
7299 support all bit widths however.</p>
7300
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7301<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7302 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7303 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7304 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7305 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]7306</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7307
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7308<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7309<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7310 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7311
7312<h5>Arguments:</h5>
7313<p>The intrinsic takes two arguments, the first a pointer to an integer value
7314 and the second an integer value. The result is also an integer value. These
7315 integer types can have any bit width, but they must all have the same bit
7316 width. The targets may only lower integer representations they support.</p>
7317
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319<p>This intrinsic does a series of operations atomically. It first loads the
7320 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7321 result to <tt>ptr</tt>. It yields the original value stored
7322 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7323
7324<h5>Examples:</h5>
7325<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7326%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7327%ptr = bitcast i8* %mallocP to i32*
7328 store i32 8, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7329%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7330 <i>; yields {i32}:result1 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7331%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7332 <i>; yields {i32}:result2 = 4</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7333%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7334 <i>; yields {i32}:result3 = 2</i>
7335%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7336</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7337
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7338</div>
7339
7340<!-- _______________________________________________________________________ -->
7341<div class="doc_subsubsection">
7342 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7343 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7344 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7345 <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]7346</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7347
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7348<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7350<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7351<p>These are overloaded intrinsics. You can
7352 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7353 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7354 bit width and for different address spaces. Not all targets support all bit
7355 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7356
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7357<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7358 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7359 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7360 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7361 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]7362</pre>
7363
7364<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7365 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7366 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7367 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7368 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]7369</pre>
7370
7371<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7372 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7373 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7374 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7375 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]7376</pre>
7377
7378<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7379 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7380 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7381 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7382 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]7383</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7384
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7385<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7386<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7387 the value stored in memory at <tt>ptr</tt>. It yields the original value
7388 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7389
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7390<h5>Arguments:</h5>
7391<p>These intrinsics take two arguments, the first a pointer to an integer value
7392 and the second an integer value. The result is also an integer value. These
7393 integer types can have any bit width, but they must all have the same bit
7394 width. The targets may only lower integer representations they support.</p>
7395
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7396<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7397<p>These intrinsics does a series of operations atomically. They first load the
7398 value stored at <tt>ptr</tt>. They then do the bitwise
7399 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7400 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7401
7402<h5>Examples:</h5>
7403<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7404%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7405%ptr = bitcast i8* %mallocP to i32*
7406 store i32 0x0F0F, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7407%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7408 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7409%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7410 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7411%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7412 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7413%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7414 <i>; yields {i32}:result3 = FF</i>
7415%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7416</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7417
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7418</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7419
7420<!-- _______________________________________________________________________ -->
7421<div class="doc_subsubsection">
7422 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7423 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7424 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7425 <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]7426</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7427
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7428<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7429
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7430<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7431<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7432 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7433 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7434 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7435
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7436<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7437 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7438 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7439 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7440 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]7441</pre>
7442
7443<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7444 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7445 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7446 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7447 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]7448</pre>
7449
7450<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7451 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7452 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7453 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7454 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]7455</pre>
7456
7457<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7458 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7459 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7460 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7461 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]7462</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7463
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7464<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7465<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7466 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7467 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7468
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7469<h5>Arguments:</h5>
7470<p>These intrinsics take two arguments, the first a pointer to an integer value
7471 and the second an integer value. The result is also an integer value. These
7472 integer types can have any bit width, but they must all have the same bit
7473 width. The targets may only lower integer representations they support.</p>
7474
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7475<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7476<p>These intrinsics does a series of operations atomically. They first load the
7477 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7478 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7479 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7480
7481<h5>Examples:</h5>
7482<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7483%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7484%ptr = bitcast i8* %mallocP to i32*
7485 store i32 7, %ptr
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7486%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7487 <i>; yields {i32}:result0 = 7</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7488%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7489 <i>; yields {i32}:result1 = -2</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7490%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7491 <i>; yields {i32}:result2 = 8</i>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7492%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7493 <i>; yields {i32}:result3 = 8</i>
7494%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7495</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7496
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7497</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7498
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7499
7500<!-- ======================================================================= -->
7501<div class="doc_subsection">
7502 <a name="int_memorymarkers">Memory Use Markers</a>
7503</div>
7504
7505<div class="doc_text">
7506
7507<p>This class of intrinsics exists to information about the lifetime of memory
7508 objects and ranges where variables are immutable.</p>
7509
7510</div>
7511
7512<!-- _______________________________________________________________________ -->
7513<div class="doc_subsubsection">
7514 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7515</div>
7516
7517<div class="doc_text">
7518
7519<h5>Syntax:</h5>
7520<pre>
7521 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7522</pre>
7523
7524<h5>Overview:</h5>
7525<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7526 object's lifetime.</p>
7527
7528<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7529<p>The first argument is a constant integer representing the size of the
7530 object, or -1 if it is variable sized. The second argument is a pointer to
7531 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7532
7533<h5>Semantics:</h5>
7534<p>This intrinsic indicates that before this point in the code, the value of the
7535 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]7536 never be used and has an undefined value. A load from the pointer that
7537 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7538 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7539
7540</div>
7541
7542<!-- _______________________________________________________________________ -->
7543<div class="doc_subsubsection">
7544 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7545</div>
7546
7547<div class="doc_text">
7548
7549<h5>Syntax:</h5>
7550<pre>
7551 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7552</pre>
7553
7554<h5>Overview:</h5>
7555<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7556 object's lifetime.</p>
7557
7558<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7559<p>The first argument is a constant integer representing the size of the
7560 object, or -1 if it is variable sized. The second argument is a pointer to
7561 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7562
7563<h5>Semantics:</h5>
7564<p>This intrinsic indicates that after this point in the code, the value of the
7565 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7566 never be used and has an undefined value. Any stores into the memory object
7567 following this intrinsic may be removed as dead.
7568
7569</div>
7570
7571<!-- _______________________________________________________________________ -->
7572<div class="doc_subsubsection">
7573 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7574</div>
7575
7576<div class="doc_text">
7577
7578<h5>Syntax:</h5>
7579<pre>
7580 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7581</pre>
7582
7583<h5>Overview:</h5>
7584<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7585 a memory object will not change.</p>
7586
7587<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7588<p>The first argument is a constant integer representing the size of the
7589 object, or -1 if it is variable sized. The second argument is a pointer to
7590 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7591
7592<h5>Semantics:</h5>
7593<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7594 the return value, the referenced memory location is constant and
7595 unchanging.</p>
7596
7597</div>
7598
7599<!-- _______________________________________________________________________ -->
7600<div class="doc_subsubsection">
7601 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7602</div>
7603
7604<div class="doc_text">
7605
7606<h5>Syntax:</h5>
7607<pre>
7608 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7609</pre>
7610
7611<h5>Overview:</h5>
7612<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7613 a memory object are mutable.</p>
7614
7615<h5>Arguments:</h5>
7616<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7617 The second argument is a constant integer representing the size of the
7618 object, or -1 if it is variable sized and the third argument is a pointer
7619 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7620
7621<h5>Semantics:</h5>
7622<p>This intrinsic indicates that the memory is mutable again.</p>
7623
7624</div>
7625
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7626<!-- ======================================================================= -->
7627<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7628 <a name="int_general">General Intrinsics</a>
7629</div>
7630
7631<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7632
7633<p>This class of intrinsics is designed to be generic and has no specific
7634 purpose.</p>
7635
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7636</div>
7637
7638<!-- _______________________________________________________________________ -->
7639<div class="doc_subsubsection">
7640 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7641</div>
7642
7643<div class="doc_text">
7644
7645<h5>Syntax:</h5>
7646<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7647 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]7648</pre>
7649
7650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7651<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7652
7653<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7654<p>The first argument is a pointer to a value, the second is a pointer to a
7655 global string, the third is a pointer to a global string which is the source
7656 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7657
7658<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7659<p>This intrinsic allows annotation of local variables with arbitrary strings.
7660 This can be useful for special purpose optimizations that want to look for
7661 these annotations. These have no other defined use, they are ignored by code
7662 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7663
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7664</div>
7665
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7666<!-- _______________________________________________________________________ -->
7667<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7668 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7669</div>
7670
7671<div class="doc_text">
7672
7673<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7674<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7675 any integer bit width.</p>
7676
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7677<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7678 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7679 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7680 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7681 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7682 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]7683</pre>
7684
7685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7686<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7687
7688<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7689<p>The first argument is an integer value (result of some expression), the
7690 second is a pointer to a global string, the third is a pointer to a global
7691 string which is the source file name, and the last argument is the line
7692 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7693
7694<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7695<p>This intrinsic allows annotations to be put on arbitrary expressions with
7696 arbitrary strings. This can be useful for special purpose optimizations that
7697 want to look for these annotations. These have no other defined use, they
7698 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7699
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7700</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7701
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7702<!-- _______________________________________________________________________ -->
7703<div class="doc_subsubsection">
7704 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7705</div>
7706
7707<div class="doc_text">
7708
7709<h5>Syntax:</h5>
7710<pre>
7711 declare void @llvm.trap()
7712</pre>
7713
7714<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7715<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7716
7717<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7718<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7719
7720<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7721<p>This intrinsics is lowered to the target dependent trap instruction. If the
7722 target does not have a trap instruction, this intrinsic will be lowered to
7723 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7724
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7725</div>
7726
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7727<!-- _______________________________________________________________________ -->
7728<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7729 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7730</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7731
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7732<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7733
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7734<h5>Syntax:</h5>
7735<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7736 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7737</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7738
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7739<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7740<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7741 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7742 ensure that it is placed on the stack before local variables.</p>
7743
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7744<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7745<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7746 arguments. The first argument is the value loaded from the stack
7747 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7748 that has enough space to hold the value of the guard.</p>
7749
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7750<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7751<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7752 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7753 stack. This is to ensure that if a local variable on the stack is
7754 overwritten, it will destroy the value of the guard. When the function exits,
7755 the guard on the stack is checked against the original guard. If they're
7756 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7757 function.</p>
7758
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7759</div>
7760
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7761<!-- _______________________________________________________________________ -->
7762<div class="doc_subsubsection">
7763 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7764</div>
7765
7766<div class="doc_text">
7767
7768<h5>Syntax:</h5>
7769<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7770 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7771 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7772</pre>
7773
7774<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7775<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7776 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7777 operation like memcpy will either overflow a buffer that corresponds to
7778 an object, or b) to determine that a runtime check for overflow isn't
7779 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7780 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7781
7782<h5>Arguments:</h5>
7783<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7784 argument is a pointer to or into the <tt>object</tt>. The second argument
7785 is a boolean 0 or 1. This argument determines whether you want the
7786 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7787 1, variables are not allowed.</p>
7788
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7789<h5>Semantics:</h5>
7790<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7791 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7792 (depending on the <tt>type</tt> argument if the size cannot be determined
7793 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7794
7795</div>
7796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7797<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7798<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7799<address>
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7804
7805 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7806 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7807 Last modified: $Date$
7808</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7809
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7810</body>
7811</html>