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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 45baf4191b02d799453c55b1ebcfd582bae579fe / . / 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>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]53 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]54 </ol>
55 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]56 <li><a href="#typesystem">Type System</a>
57 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]59 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]60 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]61 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_floating">Floating Point Types</a></li>
63 <li><a href="#t_void">Void Type</a></li>
64 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]65 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </ol>
67 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]68 <li><a href="#t_derived">Derived Types</a>
69 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]70 <li><a href="#t_aggregate">Aggregate Types</a>
71 <ol>
72 <li><a href="#t_array">Array Type</a></li>
73 <li><a href="#t_struct">Structure Type</a></li>
74 <li><a href="#t_pstruct">Packed Structure Type</a></li>
75 <li><a href="#t_union">Union Type</a></li>
76 <li><a href="#t_vector">Vector Type</a></li>
77 </ol>
78 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]79 <li><a href="#t_function">Function Type</a></li>
80 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]81 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]84 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]87 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]89 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]90 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
92 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]93 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]94 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]95 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]96 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]98 <li><a href="#othervalues">Other Values</a>
99 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]100 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]101 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]102 </ol>
103 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]104 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
105 <ol>
106 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]107 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
108 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]109 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
110 Global Variable</a></li>
111 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
112 Global Variable</a></li>
113 </ol>
114 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <li><a href="#instref">Instruction Reference</a>
116 <ol>
117 <li><a href="#terminators">Terminator Instructions</a>
118 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]119 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
120 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]122 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]125 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 </ol>
127 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]128 <li><a href="#binaryops">Binary Operations</a>
129 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]136 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
137 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
138 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]139 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
140 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
141 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
145 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]146 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
147 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
148 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]149 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]152 </ol>
153 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]154 <li><a href="#vectorops">Vector Operations</a>
155 <ol>
156 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
157 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
158 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]159 </ol>
160 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]161 <li><a href="#aggregateops">Aggregate Operations</a>
162 <ol>
163 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
164 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
165 </ol>
166 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]167 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]168 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]169 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]170 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
171 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
172 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]173 </ol>
174 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]175 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]176 <ol>
177 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
178 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
179 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]182 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
184 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]186 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
187 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]188 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]189 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]190 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 <li><a href="#otherops">Other Operations</a>
192 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]193 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
194 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]195 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]196 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]198 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]203 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]204 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
206 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]207 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
208 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]210 </ol>
211 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
213 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
215 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]219 <li><a href="#int_codegen">Code Generator Intrinsics</a>
220 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
222 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
224 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
225 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
226 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
227 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]228 </ol>
229 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]230 <li><a href="#int_libc">Standard C Library Intrinsics</a>
231 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]232 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]237 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]240 </ol>
241 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]242 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]245 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
246 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]248 </ol>
249 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]250 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
251 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]252 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
256 <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]257 <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]258 </ol>
259 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]260 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
261 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]262 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
263 <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]264 </ol>
265 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]267 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]268 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]269 <ol>
270 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]271 </ol>
272 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]273 <li><a href="#int_atomics">Atomic intrinsics</a>
274 <ol>
275 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
276 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
277 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
278 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
279 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
280 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
281 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
282 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
283 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
284 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
285 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
286 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
287 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
288 </ol>
289 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]290 <li><a href="#int_memorymarkers">Memory Use Markers</a>
291 <ol>
292 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
293 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
294 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
295 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
296 </ol>
297 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]299 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]302 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]304 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.trap</tt>' Intrinsic</a></li>
306 <li><a href="#int_stackprotector">
307 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]308 <li><a href="#int_objectsize">
309 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]310 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]311 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]312 </ol>
313 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]314</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]315
316<div class="doc_author">
317 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
318 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]320
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]321<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]322<div class="doc_section"> <a name="abstract">Abstract </a></div>
323<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]325<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]326
327<p>This document is a reference manual for the LLVM assembly language. LLVM is
328 a Static Single Assignment (SSA) based representation that provides type
329 safety, low-level operations, flexibility, and the capability of representing
330 'all' high-level languages cleanly. It is the common code representation
331 used throughout all phases of the LLVM compilation strategy.</p>
332
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]333</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]334
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]335<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<div class="doc_section"> <a name="introduction">Introduction</a> </div>
337<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]341<p>The LLVM code representation is designed to be used in three different forms:
342 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
343 for fast loading by a Just-In-Time compiler), and as a human readable
344 assembly language representation. This allows LLVM to provide a powerful
345 intermediate representation for efficient compiler transformations and
346 analysis, while providing a natural means to debug and visualize the
347 transformations. The three different forms of LLVM are all equivalent. This
348 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]349
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]350<p>The LLVM representation aims to be light-weight and low-level while being
351 expressive, typed, and extensible at the same time. It aims to be a
352 "universal IR" of sorts, by being at a low enough level that high-level ideas
353 may be cleanly mapped to it (similar to how microprocessors are "universal
354 IR's", allowing many source languages to be mapped to them). By providing
355 type information, LLVM can be used as the target of optimizations: for
356 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]357 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]358 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]363<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]365<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]367<p>It is important to note that this document describes 'well formed' LLVM
368 assembly language. There is a difference between what the parser accepts and
369 what is considered 'well formed'. For example, the following instruction is
370 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]371
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]373<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]376</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]439<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]443</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]445<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]449%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]451</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]454
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]455<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456<pre>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]457%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
458%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]459%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]461</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
464 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]465
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]466<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]468 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]469
470 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]471 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]473 <li>Unnamed temporaries are numbered sequentially</li>
474</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]476<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477 demonstrating instructions, we will follow an instruction with a comment that
478 defines the type and name of value produced. Comments are shown in italic
479 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]481</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482
483<!-- *********************************************************************** -->
484<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
485<!-- *********************************************************************** -->
486
487<!-- ======================================================================= -->
488<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
489</div>
490
491<div class="doc_text">
492
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]493<p>LLVM programs are composed of "Module"s, each of which is a translation unit
494 of the input programs. Each module consists of functions, global variables,
495 and symbol table entries. Modules may be combined together with the LLVM
496 linker, which merges function (and global variable) definitions, resolves
497 forward declarations, and merges symbol table entries. Here is an example of
498 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]500<div class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]501<pre>
502<i>; Declare the string constant as a global constant.</i>
503<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]504
505<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]506<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
508<i>; Definition of main function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]509define i32 @main() { <i>; i32()* </i>
510 <i>; Convert [13 x i8]* to i8 *...</i>
511 %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]512
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]513 <i>; Call puts function to write out the string to stdout.</i>
514 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]515 <a href="#i_ret">ret</a> i32 0<br>}
516
517<i>; Named metadata</i>
518!1 = metadata !{i32 41}
519!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]520</pre>
521</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<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]524 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]525 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]526 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
527 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]529<p>In general, a module is made up of a list of global values, where both
530 functions and global variables are global values. Global values are
531 represented by a pointer to a memory location (in this case, a pointer to an
532 array of char, and a pointer to a function), and have one of the
533 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]534
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]535</div>
536
537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="linkage">Linkage Types</a>
540</div>
541
542<div class="doc_text">
543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544<p>All Global Variables and Functions have one of the following types of
545 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]546
547<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]549 <dd>Global values with private linkage are only directly accessible by objects
550 in the current module. In particular, linking code into a module with an
551 private global value may cause the private to be renamed as necessary to
552 avoid collisions. Because the symbol is private to the module, all
553 references can be updated. This doesn't show up in any symbol table in the
554 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]555
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]557 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]558 removed by the linker after evaluation. Note that (unlike private
559 symbols) linker_private symbols are subject to coalescing by the linker:
560 weak symbols get merged and redefinitions are rejected. However, unlike
561 normal strong symbols, they are removed by the linker from the final
562 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]565 <dd>Similar to private, but the value shows as a local symbol
566 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
567 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]568
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]570 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]571 into the object file corresponding to the LLVM module. They exist to
572 allow inlining and other optimizations to take place given knowledge of
573 the definition of the global, which is known to be somewhere outside the
574 module. Globals with <tt>available_externally</tt> linkage are allowed to
575 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
576 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]577
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]579 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]580 the same name when linkage occurs. This can be used to implement
581 some forms of inline functions, templates, or other code which must be
582 generated in each translation unit that uses it, but where the body may
583 be overridden with a more definitive definition later. Unreferenced
584 <tt>linkonce</tt> globals are allowed to be discarded. Note that
585 <tt>linkonce</tt> linkage does not actually allow the optimizer to
586 inline the body of this function into callers because it doesn't know if
587 this definition of the function is the definitive definition within the
588 program or whether it will be overridden by a stronger definition.
589 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
590 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]593 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
594 <tt>linkonce</tt> linkage, except that unreferenced globals with
595 <tt>weak</tt> linkage may not be discarded. This is used for globals that
596 are declared "weak" in C source code.</dd>
597
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
600 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
601 global scope.
602 Symbols with "<tt>common</tt>" linkage are merged in the same way as
603 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]604 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]605 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]606 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
607 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]608
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]611 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]612 pointer to array type. When two global variables with appending linkage
613 are linked together, the two global arrays are appended together. This is
614 the LLVM, typesafe, equivalent of having the system linker append together
615 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]616
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]618 <dd>The semantics of this linkage follow the ELF object file model: the symbol
619 is weak until linked, if not linked, the symbol becomes null instead of
620 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
623 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 <dd>Some languages allow differing globals to be merged, such as two functions
625 with different semantics. Other languages, such as <tt>C++</tt>, ensure
626 that only equivalent globals are ever merged (the "one definition rule" -
627 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
628 and <tt>weak_odr</tt> linkage types to indicate that the global will only
629 be merged with equivalent globals. These linkage types are otherwise the
630 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]631
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]632 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]633 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]634 visible, meaning that it participates in linkage and can be used to
635 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]636</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]637
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]638<p>The next two types of linkage are targeted for Microsoft Windows platform
639 only. They are designed to support importing (exporting) symbols from (to)
640 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]641
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]644 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]645 or variable via a global pointer to a pointer that is set up by the DLL
646 exporting the symbol. On Microsoft Windows targets, the pointer name is
647 formed by combining <code>__imp_</code> and the function or variable
648 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]651 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]652 pointer to a pointer in a DLL, so that it can be referenced with the
653 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
654 name is formed by combining <code>__imp_</code> and the function or
655 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]656</dl>
657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]658<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
659 another module defined a "<tt>.LC0</tt>" variable and was linked with this
660 one, one of the two would be renamed, preventing a collision. Since
661 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
662 declarations), they are accessible outside of the current module.</p>
663
664<p>It is illegal for a function <i>declaration</i> to have any linkage type
665 other than "externally visible", <tt>dllimport</tt>
666 or <tt>extern_weak</tt>.</p>
667
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]668<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 or <tt>weak_odr</tt> linkages.</p>
670
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]671</div>
672
673<!-- ======================================================================= -->
674<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]675 <a name="callingconv">Calling Conventions</a>
676</div>
677
678<div class="doc_text">
679
680<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]681 and <a href="#i_invoke">invokes</a> can all have an optional calling
682 convention specified for the call. The calling convention of any pair of
683 dynamic caller/callee must match, or the behavior of the program is
684 undefined. The following calling conventions are supported by LLVM, and more
685 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687<dl>
688 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]689 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]690 specified) matches the target C calling conventions. This calling
691 convention supports varargs function calls and tolerates some mismatch in
692 the declared prototype and implemented declaration of the function (as
693 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]696 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]697 (e.g. by passing things in registers). This calling convention allows the
698 target to use whatever tricks it wants to produce fast code for the
699 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]700 (Application Binary Interface).
701 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]702 when this or the GHC convention is used.</a> This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708 as possible under the assumption that the call is not commonly executed.
709 As such, these calls often preserve all registers so that the call does
710 not break any live ranges in the caller side. This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]714 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
715 <dd>This calling convention has been implemented specifically for use by the
716 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
717 It passes everything in registers, going to extremes to achieve this by
718 disabling callee save registers. This calling convention should not be
719 used lightly but only for specific situations such as an alternative to
720 the <em>register pinning</em> performance technique often used when
721 implementing functional programming languages.At the moment only X86
722 supports this convention and it has the following limitations:
723 <ul>
724 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
725 floating point types are supported.</li>
726 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
727 6 floating point parameters.</li>
728 </ul>
729 This calling convention supports
730 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
731 requires both the caller and callee are using it.
732 </dd>
733
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]734 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]735 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]736 target-specific calling conventions to be used. Target specific calling
737 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]738</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]739
740<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]741 support Pascal conventions or any other well-known target-independent
742 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743
744</div>
745
746<!-- ======================================================================= -->
747<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]748 <a name="visibility">Visibility Styles</a>
749</div>
750
751<div class="doc_text">
752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]753<p>All Global Variables and Functions have one of the following visibility
754 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]755
756<dl>
757 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]758 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]759 that the declaration is visible to other modules and, in shared libraries,
760 means that the declared entity may be overridden. On Darwin, default
761 visibility means that the declaration is visible to other modules. Default
762 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]765 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]766 object if they are in the same shared object. Usually, hidden visibility
767 indicates that the symbol will not be placed into the dynamic symbol
768 table, so no other module (executable or shared library) can reference it
769 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]770
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]771 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]772 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]773 the dynamic symbol table, but that references within the defining module
774 will bind to the local symbol. That is, the symbol cannot be overridden by
775 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]776</dl>
777
778</div>
779
780<!-- ======================================================================= -->
781<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]782 <a name="namedtypes">Named Types</a>
783</div>
784
785<div class="doc_text">
786
787<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]788 it easier to read the IR and make the IR more condensed (particularly when
789 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790
791<div class="doc_code">
792<pre>
793%mytype = type { %mytype*, i32 }
794</pre>
795</div>
796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]797<p>You may give a name to any <a href="#typesystem">type</a> except
798 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
799 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800
801<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802 and that you can therefore specify multiple names for the same type. This
803 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
804 uses structural typing, the name is not part of the type. When printing out
805 LLVM IR, the printer will pick <em>one name</em> to render all types of a
806 particular shape. This means that if you have code where two different
807 source types end up having the same LLVM type, that the dumper will sometimes
808 print the "wrong" or unexpected type. This is an important design point and
809 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]810
811</div>
812
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]813<!-- ======================================================================= -->
814<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]815 <a name="globalvars">Global Variables</a>
816</div>
817
818<div class="doc_text">
819
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]820<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]821 instead of run-time. Global variables may optionally be initialized, may
822 have an explicit section to be placed in, and may have an optional explicit
823 alignment specified. A variable may be defined as "thread_local", which
824 means that it will not be shared by threads (each thread will have a
825 separated copy of the variable). A variable may be defined as a global
826 "constant," which indicates that the contents of the variable
827 will <b>never</b> be modified (enabling better optimization, allowing the
828 global data to be placed in the read-only section of an executable, etc).
829 Note that variables that need runtime initialization cannot be marked
830 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]831
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
833 constant, even if the final definition of the global is not. This capability
834 can be used to enable slightly better optimization of the program, but
835 requires the language definition to guarantee that optimizations based on the
836 'constantness' are valid for the translation units that do not include the
837 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]838
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]839<p>As SSA values, global variables define pointer values that are in scope
840 (i.e. they dominate) all basic blocks in the program. Global variables
841 always define a pointer to their "content" type because they describe a
842 region of memory, and all memory objects in LLVM are accessed through
843 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>A global variable may be declared to reside in a target-specific numbered
846 address space. For targets that support them, address spaces may affect how
847 optimizations are performed and/or what target instructions are used to
848 access the variable. The default address space is zero. The address space
849 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]850
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]851<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]852 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]853
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]854<p>An explicit alignment may be specified for a global, which must be a power
855 of 2. If not present, or if the alignment is set to zero, the alignment of
856 the global is set by the target to whatever it feels convenient. If an
857 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]858 alignment. Targets and optimizers are not allowed to over-align the global
859 if the global has an assigned section. In this case, the extra alignment
860 could be observable: for example, code could assume that the globals are
861 densely packed in their section and try to iterate over them as an array,
862 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]863
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]864<p>For example, the following defines a global in a numbered address space with
865 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]866
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]867<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]868<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]869@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]870</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]871</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]872
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]873</div>
874
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
878 <a name="functionstructure">Functions</a>
879</div>
880
881<div class="doc_text">
882
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]883<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]884 optional <a href="#linkage">linkage type</a>, an optional
885 <a href="#visibility">visibility style</a>, an optional
886 <a href="#callingconv">calling convention</a>, a return type, an optional
887 <a href="#paramattrs">parameter attribute</a> for the return type, a function
888 name, a (possibly empty) argument list (each with optional
889 <a href="#paramattrs">parameter attributes</a>), optional
890 <a href="#fnattrs">function attributes</a>, an optional section, an optional
891 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
892 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]894<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
895 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]896 <a href="#visibility">visibility style</a>, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>, a return type, an optional
898 <a href="#paramattrs">parameter attribute</a> for the return type, a function
899 name, a possibly empty list of arguments, an optional alignment, and an
900 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]901
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]902<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]903 (Control Flow Graph) for the function. Each basic block may optionally start
904 with a label (giving the basic block a symbol table entry), contains a list
905 of instructions, and ends with a <a href="#terminators">terminator</a>
906 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]907
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]908<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]909 executed on entrance to the function, and it is not allowed to have
910 predecessor basic blocks (i.e. there can not be any branches to the entry
911 block of a function). Because the block can have no predecessors, it also
912 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]913
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]914<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]915 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]916
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]917<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]918 the alignment is set to zero, the alignment of the function is set by the
919 target to whatever it feels convenient. If an explicit alignment is
920 specified, the function is forced to have at least that much alignment. All
921 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]922
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]923<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]924<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]925<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]926define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]927 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
928 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
929 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
930 [<a href="#gc">gc</a>] { ... }
931</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]932</div>
933
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]949<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]950<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]951@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]952</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]953</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]954
955</div>
956
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]957<!-- ======================================================================= -->
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]958<div class="doc_subsection">
959 <a name="namedmetadatastructure">Named Metadata</a>
960</div>
961
962<div class="doc_text">
963
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]964<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
965 nodes</a> (but not metadata strings) and null are the only valid operands for
966 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]967
968<h5>Syntax:</h5>
969<div class="doc_code">
970<pre>
971!1 = metadata !{metadata !"one"}
972!name = !{null, !1}
973</pre>
974</div>
975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]993
994<div class="doc_code">
995<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]996declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]997declare i32 @atoi(i8 zeroext)
998declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]999</pre>
1000</div>
1001
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1002<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1003 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1007<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates to the code generator that the parameter or return value
1010 should be zero-extended to a 32-bit value by the caller (for a parameter)
1011 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1012
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>signext</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 sign-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>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates that this parameter or return value should be treated in a
1020 special target-dependent fashion during while emitting code for a function
1021 call or return (usually, by putting it in a register as opposed to memory,
1022 though some targets use it to distinguish between two different kinds of
1023 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1024
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter should really be passed by value
1027 to the function. The attribute implies that a hidden copy of the pointee
1028 is made between the caller and the callee, so the callee is unable to
1029 modify the value in the callee. This attribute is only valid on LLVM
1030 pointer arguments. It is generally used to pass structs and arrays by
1031 value, but is also valid on pointers to scalars. The copy is considered
1032 to belong to the caller not the callee (for example,
1033 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1034 <tt>byval</tt> parameters). This is not a valid attribute for return
1035 values. The byval attribute also supports specifying an alignment with
1036 the align attribute. This has a target-specific effect on the code
1037 generator that usually indicates a desired alignment for the synthesized
1038 stack slot.</dd>
1039
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1040 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This indicates that the pointer parameter specifies the address of a
1042 structure that is the return value of the function in the source program.
1043 This pointer must be guaranteed by the caller to be valid: loads and
1044 stores to the structure may be assumed by the callee to not to trap. This
1045 may only be applied to the first parameter. This is not a valid attribute
1046 for return values. </dd>
1047
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1048 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This indicates that the pointer does not alias any global or any other
1050 parameter. The caller is responsible for ensuring that this is the
1051 case. On a function return value, <tt>noalias</tt> additionally indicates
1052 that the pointer does not alias any other pointers visible to the
1053 caller. For further details, please see the discussion of the NoAlias
1054 response in
1055 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1056 analysis</a>.</dd>
1057
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1058 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This indicates that the callee does not make any copies of the pointer
1060 that outlive the callee itself. This is not a valid attribute for return
1061 values.</dd>
1062
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1063 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter can be excised using the
1065 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1066 attribute for return values.</dd>
1067</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1068
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1069</div>
1070
1071<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1072<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1073 <a name="gc">Garbage Collector Names</a>
1074</div>
1075
1076<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078<p>Each function may specify a garbage collector name, which is simply a
1079 string:</p>
1080
1081<div class="doc_code">
1082<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1083define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1084</pre>
1085</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1086
1087<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1088 collector which will cause the compiler to alter its output in order to
1089 support the named garbage collection algorithm.</p>
1090
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1091</div>
1092
1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1095 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are set to communicate additional information about a
1101 function. Function attributes are considered to be part of the function, not
1102 of the function type, so functions with different parameter attributes can
1103 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1104
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1105<p>Function attributes are simple keywords that follow the type specified. If
1106 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1107
1108<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1109<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1110define void @f() noinline { ... }
1111define void @f() alwaysinline { ... }
1112define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1113define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1114</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1117<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1118 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1119 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1120 the backend should forcibly align the stack pointer. Specify the
1121 desired alignment, which must be a power of two, in parentheses.
1122
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1123 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attribute indicates that the inliner should attempt to inline this
1125 function into callers whenever possible, ignoring any active inlining size
1126 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1127
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1128 <dt><tt><b>inlinehint</b></tt></dt>
1129 <dd>This attribute indicates that the source code contained a hint that inlining
1130 this function is desirable (such as the "inline" keyword in C/C++). It
1131 is just a hint; it imposes no requirements on the inliner.</dd>
1132
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1138 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1139 <dd>This attribute suggests that optimization passes and code generator passes
1140 make choices that keep the code size of this function low, and otherwise
1141 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1142
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This function attribute indicates that the function never returns
1145 normally. This produces undefined behavior at runtime if the function
1146 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1147
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1148 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1149 <dd>This function attribute indicates that the function never returns with an
1150 unwind or exceptional control flow. If the function does unwind, its
1151 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1152
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1153 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1154 <dd>This attribute indicates that the function computes its result (or decides
1155 to unwind an exception) based strictly on its arguments, without
1156 dereferencing any pointer arguments or otherwise accessing any mutable
1157 state (e.g. memory, control registers, etc) visible to caller functions.
1158 It does not write through any pointer arguments
1159 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1160 changes any state visible to callers. This means that it cannot unwind
1161 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1162 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1163
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the function does not write through any
1166 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1167 arguments) or otherwise modify any state (e.g. memory, control registers,
1168 etc) visible to caller functions. It may dereference pointer arguments
1169 and read state that may be set in the caller. A readonly function always
1170 returns the same value (or unwinds an exception identically) when called
1171 with the same set of arguments and global state. It cannot unwind an
1172 exception by calling the <tt>C++</tt> exception throwing methods, but may
1173 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1174
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1175 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1176 <dd>This attribute indicates that the function should emit a stack smashing
1177 protector. It is in the form of a "canary"&mdash;a random value placed on
1178 the stack before the local variables that's checked upon return from the
1179 function to see if it has been overwritten. A heuristic is used to
1180 determine if a function needs stack protectors or not.<br>
1181<br>
1182 If a function that has an <tt>ssp</tt> attribute is inlined into a
1183 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1184 function will have an <tt>ssp</tt> attribute.</dd>
1185
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1186 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1187 <dd>This attribute indicates that the function should <em>always</em> emit a
1188 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1189 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1190<br>
1191 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1192 function that doesn't have an <tt>sspreq</tt> attribute or which has
1193 an <tt>ssp</tt> attribute, then the resulting function will have
1194 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attribute indicates that the code generator should not use a red
1198 zone, even if the target-specific ABI normally permits it.</dd>
1199
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attributes disables implicit floating point instructions.</dd>
1202
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute disables prologue / epilogue emission for the function.
1205 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1206</dl>
1207
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1208</div>
1209
1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1212 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216
1217<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1218 the GCC "file scope inline asm" blocks. These blocks are internally
1219 concatenated by LLVM and treated as a single unit, but may be separated in
1220 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1221
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1222<div class="doc_code">
1223<pre>
1224module asm "inline asm code goes here"
1225module asm "more can go here"
1226</pre>
1227</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1228
1229<p>The strings can contain any character by escaping non-printable characters.
1230 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]1231 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1232
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1233<p>The inline asm code is simply printed to the machine code .s file when
1234 assembly code is generated.</p>
1235
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1236</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1237
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1238<!-- ======================================================================= -->
1239<div class="doc_subsection">
1240 <a name="datalayout">Data Layout</a>
1241</div>
1242
1243<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1245<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1246 data is to be laid out in memory. The syntax for the data layout is
1247 simply:</p>
1248
1249<div class="doc_code">
1250<pre>
1251target datalayout = "<i>layout specification</i>"
1252</pre>
1253</div>
1254
1255<p>The <i>layout specification</i> consists of a list of specifications
1256 separated by the minus sign character ('-'). Each specification starts with
1257 a letter and may include other information after the letter to define some
1258 aspect of the data layout. The specifications accepted are as follows:</p>
1259
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1260<dl>
1261 <dt><tt>E</tt></dt>
1262 <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]1263 bits with the most significance have the lowest address location.</dd>
1264
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1265 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1266 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1267 the bits with the least significance have the lowest address
1268 location.</dd>
1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1271 <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]1272 <i>preferred</i> alignments. All sizes are in bits. Specifying
1273 the <i>pref</i> alignment is optional. If omitted, the
1274 preceding <tt>:</tt> should be omitted too.</dd>
1275
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1276 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1277 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1279
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <dt><tt>f<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 floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1287 (double).</dd>
1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
1292
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1293 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1296
1297 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1298 <dd>This specifies a set of native integer widths for the target CPU
1299 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1300 "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]1301 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1302 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1303</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1304
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1305<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1306 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1307 specifications in the <tt>datalayout</tt> keyword. The default specifications
1308 are given in this list:</p>
1309
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1310<ul>
1311 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1312 <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]1313 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1314 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1315 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1316 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1317 <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]1318 alignment of 64-bits</li>
1319 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1320 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1321 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1322 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1323 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1324 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1326
1327<p>When LLVM is determining the alignment for a given type, it uses the
1328 following rules:</p>
1329
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1330<ol>
1331 <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]1332 specification is used.</li>
1333
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1334 <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]1335 smallest integer type that is larger than the bitwidth of the sought type
1336 is used. If none of the specifications are larger than the bitwidth then
1337 the the largest integer type is used. For example, given the default
1338 specifications above, the i7 type will use the alignment of i8 (next
1339 largest) while both i65 and i256 will use the alignment of i64 (largest
1340 specified).</li>
1341
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1342 <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]1343 largest vector type that is smaller than the sought vector type will be
1344 used as a fall back. This happens because &lt;128 x double&gt; can be
1345 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1346</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1347
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1348</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1349
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1350<!-- ======================================================================= -->
1351<div class="doc_subsection">
1352 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1353</div>
1354
1355<div class="doc_text">
1356
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1357<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1358with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1359is undefined. Pointer values are associated with address ranges
1360according to the following rules:</p>
1361
1362<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1363 <li>A pointer value formed from a
1364 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1365 is associated with the addresses associated with the first operand
1366 of the <tt>getelementptr</tt>.</li>
1367 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1368 range of the variable's storage.</li>
1369 <li>The result value of an allocation instruction is associated with
1370 the address range of the allocated storage.</li>
1371 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1372 no address.</li>
1373 <li>A pointer value formed by an
1374 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1375 address ranges of all pointer values that contribute (directly or
1376 indirectly) to the computation of the pointer's value.</li>
1377 <li>The result value of a
1378 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1379 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1380 <li>An integer constant other than zero or a pointer value returned
1381 from a function not defined within LLVM may be associated with address
1382 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1383 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1384 allocated by mechanisms provided by LLVM.</li>
1385 </ul>
1386
1387<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1388<tt><a href="#i_load">load</a></tt> merely indicates the size and
1389alignment of the memory from which to load, as well as the
1390interpretation of the value. The first operand of a
1391<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1392and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1393
1394<p>Consequently, type-based alias analysis, aka TBAA, aka
1395<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1396LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1397additional information which specialized optimization passes may use
1398to implement type-based alias analysis.</p>
1399
1400</div>
1401
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1402<!-- ======================================================================= -->
1403<div class="doc_subsection">
1404 <a name="volatile">Volatile Memory Accesses</a>
1405</div>
1406
1407<div class="doc_text">
1408
1409<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1410href="#i_store"><tt>store</tt></a>s, and <a
1411href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1412The optimizers must not change the number of volatile operations or change their
1413order of execution relative to other volatile operations. The optimizers
1414<i>may</i> change the order of volatile operations relative to non-volatile
1415operations. This is not Java's "volatile" and has no cross-thread
1416synchronization behavior.</p>
1417
1418</div>
1419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1420<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1421<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1422<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1423
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1425
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1426<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1427 intermediate representation. Being typed enables a number of optimizations
1428 to be performed on the intermediate representation directly, without having
1429 to do extra analyses on the side before the transformation. A strong type
1430 system makes it easier to read the generated code and enables novel analyses
1431 and transformations that are not feasible to perform on normal three address
1432 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1433
1434</div>
1435
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1436<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1437<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1439
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1441
1442<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1443
1444<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1445 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1446 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1447 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1449 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1450 </tr>
1451 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1452 <td><a href="#t_floating">floating point</a></td>
1453 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454 </tr>
1455 <tr>
1456 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_integer">integer</a>,
1458 <a href="#t_floating">floating point</a>,
1459 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1460 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1461 <a href="#t_struct">structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1462 <a href="#t_union">union</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1463 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1464 <a href="#t_label">label</a>,
1465 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1466 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1467 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468 <tr>
1469 <td><a href="#t_primitive">primitive</a></td>
1470 <td><a href="#t_label">label</a>,
1471 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1472 <a href="#t_floating">floating point</a>,
1473 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1474 </tr>
1475 <tr>
1476 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1477 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1478 <a href="#t_function">function</a>,
1479 <a href="#t_pointer">pointer</a>,
1480 <a href="#t_struct">structure</a>,
1481 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1482 <a href="#t_union">union</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_vector">vector</a>,
1484 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1485 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1486 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1487 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1488</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1489
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1490<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1491 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1492 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1494</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1496<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1497<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1498
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1499<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1500
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1501<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1502 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1503
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1504</div>
1505
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1506<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1508
1509<div class="doc_text">
1510
1511<h5>Overview:</h5>
1512<p>The integer type is a very simple type that simply specifies an arbitrary
1513 bit width for the integer type desired. Any bit width from 1 bit to
1514 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1515
1516<h5>Syntax:</h5>
1517<pre>
1518 iN
1519</pre>
1520
1521<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1522 value.</p>
1523
1524<h5>Examples:</h5>
1525<table class="layout">
1526 <tr class="layout">
1527 <td class="left"><tt>i1</tt></td>
1528 <td class="left">a single-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i32</tt></td>
1532 <td class="left">a 32-bit integer.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>i1942652</tt></td>
1536 <td class="left">a really big integer of over 1 million bits.</td>
1537 </tr>
1538</table>
1539
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1540</div>
1541
1542<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1544
1545<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1546
1547<table>
1548 <tbody>
1549 <tr><th>Type</th><th>Description</th></tr>
1550 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1551 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1552 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1553 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1554 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1555 </tbody>
1556</table>
1557
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1558</div>
1559
1560<!-- _______________________________________________________________________ -->
1561<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1562
1563<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1564
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1565<h5>Overview:</h5>
1566<p>The void type does not represent any value and has no size.</p>
1567
1568<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1569<pre>
1570 void
1571</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1572
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1577
1578<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1579
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1580<h5>Overview:</h5>
1581<p>The label type represents code labels.</p>
1582
1583<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1584<pre>
1585 label
1586</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1587
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1588</div>
1589
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1590<!-- _______________________________________________________________________ -->
1591<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1592
1593<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1594
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1595<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1596<p>The metadata type represents embedded metadata. No derived types may be
1597 created from metadata except for <a href="#t_function">function</a>
1598 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1599
1600<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1601<pre>
1602 metadata
1603</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1604
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1605</div>
1606
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1607
1608<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1611<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1613<p>The real power in LLVM comes from the derived types in the system. This is
1614 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1615 useful types. Each of these types contain one or more element types which
1616 may be a primitive type, or another derived type. For example, it is
1617 possible to have a two dimensional array, using an array as the element type
1618 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1619
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1620
1621</div>
1622
1623<!-- _______________________________________________________________________ -->
1624<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1625
1626<div class="doc_text">
1627
1628<p>Aggregate Types are a subset of derived types that can contain multiple
1629 member types. <a href="#t_array">Arrays</a>,
1630 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1631 <a href="#t_union">unions</a> are aggregate types.</p>
1632
1633</div>
1634
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1635</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1636
1637<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644 sequentially in memory. The array type requires a size (number of elements)
1645 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1647<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648<pre>
1649 [&lt;# elements&gt; x &lt;elementtype&gt;]
1650</pre>
1651
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1652<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1653 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1654
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1658 <td class="left"><tt>[40 x i32]</tt></td>
1659 <td class="left">Array of 40 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[41 x i32]</tt></td>
1663 <td class="left">Array of 41 32-bit integer values.</td>
1664 </tr>
1665 <tr class="layout">
1666 <td class="left"><tt>[4 x i8]</tt></td>
1667 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1670<p>Here are some examples of multidimensional arrays:</p>
1671<table class="layout">
1672 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1673 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1674 <td class="left">3x4 array of 32-bit integer values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1678 <td class="left">12x10 array of single precision floating point values.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1682 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1683 </tr>
1684</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1685
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1686<p>There is no restriction on indexing beyond the end of the array implied by
1687 a static type (though there are restrictions on indexing beyond the bounds
1688 of an allocated object in some cases). This means that single-dimension
1689 'variable sized array' addressing can be implemented in LLVM with a zero
1690 length array type. An implementation of 'pascal style arrays' in LLVM could
1691 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1693</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1696<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1699
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1700<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1701<p>The function type can be thought of as a function signature. It consists of
1702 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]1703 function type is a scalar type, a void type, a struct type, or a union
1704 type. If the return type is a struct type then all struct elements must be
1705 of first class types, and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1708<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1709 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1710</pre>
1711
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1712<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]1713 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1714 which indicates that the function takes a variable number of arguments.
1715 Variable argument functions can access their arguments with
1716 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1717 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1718 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1721<table class="layout">
1722 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1723 <td class="left"><tt>i32 (i32)</tt></td>
1724 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1725 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1726 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1727 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1728 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1729 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]1730 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1731 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1732 </td>
1733 </tr><tr class="layout">
1734 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1735 <td class="left">A vararg function that takes at least one
1736 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1737 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1738 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1739 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1740 </tr><tr class="layout">
1741 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1742 <td class="left">A function taking an <tt>i32</tt>, returning a
1743 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1744 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1745 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756<p>The structure type is used to represent a collection of data members together
1757 in memory. The packing of the field types is defined to match the ABI of the
1758 underlying processor. The elements of a structure may be any type that has a
1759 size.</p>
1760
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]1761<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1762 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1763 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1764 Structures in registers are accessed using the
1765 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1766 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1768<pre>
1769 { &lt;type list&gt; }
1770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1773<table class="layout">
1774 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1775 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1776 <td class="left">A triple of three <tt>i32</tt> values</td>
1777 </tr><tr class="layout">
1778 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1779 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1780 second element is a <a href="#t_pointer">pointer</a> to a
1781 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1782 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1783 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1784</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1785
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1786</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1789<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1790</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1791
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1792<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1793
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1794<h5>Overview:</h5>
1795<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1796 together in memory. There is no padding between fields. Further, the
1797 alignment of a packed structure is 1 byte. The elements of a packed
1798 structure may be any type that has a size.</p>
1799
1800<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1801 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1802 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1803
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1804<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1805<pre>
1806 &lt; { &lt;type list&gt; } &gt;
1807</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1809<h5>Examples:</h5>
1810<table class="layout">
1811 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1812 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1813 <td class="left">A triple of three <tt>i32</tt> values</td>
1814 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1815 <td class="left">
1816<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1817 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1818 second element is a <a href="#t_pointer">pointer</a> to a
1819 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1820 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1824</div>
1825
1826<!-- _______________________________________________________________________ -->
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1828
1829<div class="doc_text">
1830
1831<h5>Overview:</h5>
1832<p>A union type describes an object with size and alignment suitable for
1833 an object of any one of a given set of types (also known as an "untagged"
1834 union). It is similar in concept and usage to a
1835 <a href="#t_struct">struct</a>, except that all members of the union
1836 have an offset of zero. The elements of a union may be any type that has a
1837 size. Unions must have at least one member - empty unions are not allowed.
1838 </p>
1839
1840<p>The size of the union as a whole will be the size of its largest member,
1841 and the alignment requirements of the union as a whole will be the largest
1842 alignment requirement of any member.</p>
1843
Dan Gohman2eddfef2010-02-25 16:51:31 +0000[diff] [blame]1844<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]1845 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1846 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1847 Since all members are at offset zero, the getelementptr instruction does
1848 not affect the address, only the type of the resulting pointer.</p>
1849
1850<h5>Syntax:</h5>
1851<pre>
1852 union { &lt;type list&gt; }
1853</pre>
1854
1855<h5>Examples:</h5>
1856<table class="layout">
1857 <tr class="layout">
1858 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1859 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1860 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1861 </tr><tr class="layout">
1862 <td class="left">
1863 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1864 <td class="left">A union, where the first element is a <tt>float</tt> and the
1865 second element is a <a href="#t_pointer">pointer</a> to a
1866 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1867 an <tt>i32</tt>.</td>
1868 </tr>
1869</table>
1870
1871</div>
1872
1873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1875
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1876<div class="doc_text">
1877
1878<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]1879<p>The pointer type is used to specify memory locations.
1880 Pointers are commonly used to reference objects in memory.</p>
1881
1882<p>Pointer types may have an optional address space attribute defining the
1883 numbered address space where the pointed-to object resides. The default
1884 address space is number zero. The semantics of non-zero address
1885 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1886
1887<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1888 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1889
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1890<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1891<pre>
1892 &lt;type&gt; *
1893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1895<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1896<table class="layout">
1897 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1898 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1899 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1900 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1901 </tr>
1902 <tr class="layout">
1903 <td class="left"><tt>i32 (i32 *) *</tt></td>
1904 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1905 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1906 <tt>i32</tt>.</td>
1907 </tr>
1908 <tr class="layout">
1909 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1910 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1911 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1912 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1913</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1915</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1916
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1917<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1918<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1920<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1921
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923<p>A vector type is a simple derived type that represents a vector of elements.
1924 Vector types are used when multiple primitive data are operated in parallel
1925 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]1926 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1927 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1928
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1929<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1930<pre>
1931 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1932</pre>
1933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1934<p>The number of elements is a constant integer value; elementtype may be any
1935 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1936
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1937<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1938<table class="layout">
1939 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1940 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1941 <td class="left">Vector of 4 32-bit integer values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1945 <td class="left">Vector of 8 32-bit floating-point values.</td>
1946 </tr>
1947 <tr class="layout">
1948 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1949 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1950 </tr>
1951</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1952
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1953</div>
1954
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1955<!-- _______________________________________________________________________ -->
1956<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1957<div class="doc_text">
1958
1959<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1960<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 corresponds (for example) to the C notion of a forward declared structure
1962 type. In LLVM, opaque types can eventually be resolved to any type (not just
1963 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1964
1965<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1966<pre>
1967 opaque
1968</pre>
1969
1970<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1971<table class="layout">
1972 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1973 <td class="left"><tt>opaque</tt></td>
1974 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1975 </tr>
1976</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1977
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1978</div>
1979
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1980<!-- ======================================================================= -->
1981<div class="doc_subsection">
1982 <a name="t_uprefs">Type Up-references</a>
1983</div>
1984
1985<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1987<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>An "up reference" allows you to refer to a lexically enclosing type without
1989 requiring it to have a name. For instance, a structure declaration may
1990 contain a pointer to any of the types it is lexically a member of. Example
1991 of up references (with their equivalent as named type declarations)
1992 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1993
1994<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1995 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1996 { \2 }* %y = type { %y }*
1997 \1* %z = type %z*
1998</pre>
1999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000<p>An up reference is needed by the asmprinter for printing out cyclic types
2001 when there is no declared name for a type in the cycle. Because the
2002 asmprinter does not want to print out an infinite type string, it needs a
2003 syntax to handle recursive types that have no names (all names are optional
2004 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2005
2006<h5>Syntax:</h5>
2007<pre>
2008 \&lt;level&gt;
2009</pre>
2010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2011<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]2012
2013<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
2016 <td class="left"><tt>\1*</tt></td>
2017 <td class="left">Self-referential pointer.</td>
2018 </tr>
2019 <tr class="layout">
2020 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2021 <td class="left">Recursive structure where the upref refers to the out-most
2022 structure.</td>
2023 </tr>
2024</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]2025
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2026</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2027
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2028<!-- *********************************************************************** -->
2029<div class="doc_section"> <a name="constants">Constants</a> </div>
2030<!-- *********************************************************************** -->
2031
2032<div class="doc_text">
2033
2034<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2035 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2036
2037</div>
2038
2039<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]2040<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2041
2042<div class="doc_text">
2043
2044<dl>
2045 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2046 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2047 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2048
2049 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2050 <dd>Standard integers (such as '4') are constants of
2051 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2052 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2053
2054 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2055 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2056 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2057 notation (see below). The assembler requires the exact decimal value of a
2058 floating-point constant. For example, the assembler accepts 1.25 but
2059 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2060 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2061
2062 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2063 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2065</dl>
2066
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2067<p>The one non-intuitive notation for constants is the hexadecimal form of
2068 floating point constants. For example, the form '<tt>double
2069 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2070 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2071 constants are required (and the only time that they are generated by the
2072 disassembler) is when a floating point constant must be emitted but it cannot
2073 be represented as a decimal floating point number in a reasonable number of
2074 digits. For example, NaN's, infinities, and other special values are
2075 represented in their IEEE hexadecimal format so that assembly and disassembly
2076 do not cause any bits to change in the constants.</p>
2077
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]2078<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2079 represented using the 16-digit form shown above (which matches the IEEE754
2080 representation for double); float values must, however, be exactly
2081 representable as IEE754 single precision. Hexadecimal format is always used
2082 for long double, and there are three forms of long double. The 80-bit format
2083 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2084 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2085 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2086 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2087 currently supported target uses this format. Long doubles will only work if
2088 they match the long double format on your target. All hexadecimal formats
2089 are big-endian (sign bit at the left).</p>
2090
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2091</div>
2092
2093<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2094<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2095<a name="aggregateconstants"></a> <!-- old anchor -->
2096<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2097</div>
2098
2099<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2100
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2101<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2102 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2103
2104<dl>
2105 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2106 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2107 type definitions (a comma separated list of elements, surrounded by braces
2108 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2109 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2110 Structure constants must have <a href="#t_struct">structure type</a>, and
2111 the number and types of elements must match those specified by the
2112 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2113
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2114 <dt><b>Union constants</b></dt>
2115 <dd>Union constants are represented with notation similar to a structure with
2116 a single element - that is, a single typed element surrounded
2117 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2118 <a href="#t_union">union type</a> can be initialized with a single-element
2119 struct as long as the type of the struct element matches the type of
2120 one of the union members.</dd>
2121
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2122 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2123 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2124 definitions (a comma separated list of elements, surrounded by square
2125 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2126 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2127 the number and types of elements must match those specified by the
2128 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2129
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2130 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2131 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2132 definitions (a comma separated list of elements, surrounded by
2133 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2134 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2135 have <a href="#t_vector">vector type</a>, and the number and types of
2136 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2137
2138 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2139 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2140 value to zero of <em>any</em> type, including scalar and
2141 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142 This is often used to avoid having to print large zero initializers
2143 (e.g. for large arrays) and is always exactly equivalent to using explicit
2144 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2145
2146 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2147 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2148 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2149 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2150 be interpreted as part of the instruction stream, metadata is a place to
2151 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2152</dl>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection">
2158 <a name="globalconstants">Global Variable and Function Addresses</a>
2159</div>
2160
2161<div class="doc_text">
2162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2163<p>The addresses of <a href="#globalvars">global variables</a>
2164 and <a href="#functionstructure">functions</a> are always implicitly valid
2165 (link-time) constants. These constants are explicitly referenced when
2166 the <a href="#identifiers">identifier for the global</a> is used and always
2167 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2168 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2169
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2170<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2171<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2175</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2176</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2177
2178</div>
2179
2180<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2181<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2184<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]2185 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2186 Undefined values may be of any type (other than label or void) and be used
2187 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2188
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2189<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2190 program is well defined no matter what value is used. This gives the
2191 compiler more freedom to optimize. Here are some examples of (potentially
2192 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2193
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2194
2195<div class="doc_code">
2196<pre>
2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
2205</div>
2206
2207<p>This is safe because all of the output bits are affected by the undef bits.
2208Any output bit can have a zero or one depending on the input bits.</p>
2209
2210<div class="doc_code">
2211<pre>
2212 %A = or %X, undef
2213 %B = and %X, undef
2214Safe:
2215 %A = -1
2216 %B = 0
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220</pre>
2221</div>
2222
2223<p>These logical operations have bits that are not always affected by the input.
2224For example, if "%X" has a zero bit, then the output of the 'and' operation will
2225always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2226such, 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]2227However, it is safe to assume that all bits of the undef could be 0, and
2228optimize the and to 0. Likewise, it is safe to assume that all the bits of
2229the 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]2230-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2231
2232<div class="doc_code">
2233<pre>
2234 %A = select undef, %X, %Y
2235 %B = select undef, 42, %Y
2236 %C = select %X, %Y, undef
2237Safe:
2238 %A = %X (or %Y)
2239 %B = 42 (or %Y)
2240 %C = %Y
2241Unsafe:
2242 %A = undef
2243 %B = undef
2244 %C = undef
2245</pre>
2246</div>
2247
2248<p>This set of examples show that undefined select (and conditional branch)
2249conditions can go "either way" but they have to come from one of the two
2250operands. In the %A example, if %X and %Y were both known to have a clear low
2251bit, then %A would have to have a cleared low bit. However, in the %C example,
2252the optimizer is allowed to assume that the undef operand could be the same as
2253%Y, allowing the whole select to be eliminated.</p>
2254
2255
2256<div class="doc_code">
2257<pre>
2258 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2259
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2260 %B = undef
2261 %C = xor %B, %B
2262
2263 %D = undef
2264 %E = icmp lt %D, 4
2265 %F = icmp gte %D, 4
2266
2267Safe:
2268 %A = undef
2269 %B = undef
2270 %C = undef
2271 %D = undef
2272 %E = undef
2273 %F = undef
2274</pre>
2275</div>
2276
2277<p>This example points out that two undef operands are not necessarily the same.
2278This can be surprising to people (and also matches C semantics) where they
2279assume that "X^X" is always zero, even if X is undef. This isn't true for a
2280number of reasons, but the short answer is that an undef "variable" can
2281arbitrarily change its value over its "live range". This is true because the
2282"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2283logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2284so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2285to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2286would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2287
2288<div class="doc_code">
2289<pre>
2290 %A = fdiv undef, %X
2291 %B = fdiv %X, undef
2292Safe:
2293 %A = undef
2294b: unreachable
2295</pre>
2296</div>
2297
2298<p>These examples show the crucial difference between an <em>undefined
2299value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2300allowed to have an arbitrary bit-pattern. This means that the %A operation
2301can be constant folded to undef because the undef could be an SNaN, and fdiv is
2302not (currently) defined on SNaN's. However, in the second example, we can make
2303a more aggressive assumption: because the undef is allowed to be an arbitrary
2304value, 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]2305has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2306does not execute at all. This allows us to delete the divide and all code after
2307it: since the undefined operation "can't happen", the optimizer can assume that
2308it occurs in dead code.
2309</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2310
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2311<div class="doc_code">
2312<pre>
2313a: store undef -> %X
2314b: store %X -> undef
2315Safe:
2316a: &lt;deleted&gt;
2317b: unreachable
2318</pre>
2319</div>
2320
2321<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2322can be assumed to not have any effect: we can assume that the value is
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2323overwritten with bits that happen to match what was already there. However, a
2324store "to" an undefined location could clobber arbitrary memory, therefore, it
2325has undefined behavior.</p>
2326
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2327</div>
2328
2329<!-- ======================================================================= -->
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2330<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2331<div class="doc_text">
2332
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2333<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2334 instead of representing an unspecified bit pattern, they represent the
2335 fact that an instruction or constant expression which cannot evoke side
2336 effects has nevertheless detected a condition which results in undefined
Dan Gohmanc68ce062010-04-26 20:21:21 +0000[diff] [blame]2337 behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2338
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2339<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]2340 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2341 <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]2342
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2343<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2344
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2345<p>
2346<ul>
2347<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2348 their operands.</li>
2349
2350<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2351 to their dynamic predecessor basic block.</li>
2352
2353<li>Function arguments depend on the corresponding actual argument values in
2354 the dynamic callers of their functions.</li>
2355
2356<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2357 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2358 control back to them.</li>
2359
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2360<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2361 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2362 or exception-throwing call instructions that dynamically transfer control
2363 back to them.</li>
2364
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2365<li>Non-volatile loads and stores depend on the most recent stores to all of the
2366 referenced memory addresses, following the order in the IR
2367 (including loads and stores implied by intrinsics such as
2368 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2369
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2370<!-- TODO: In the case of multiple threads, this only applies to loads and
2371 stores from the same thread as the store, or which are sequenced after the
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2372 store by synchronization. -->
2373
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2374<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2375
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2376<li>An instruction with externally visible side effects depends on the most
2377 recent preceding instruction with externally visible side effects, following
2378 the order in the IR. (This includes volatile loads and stores.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2379
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2380<li>An instruction <i>control-depends</i> on a
2381 <a href="#terminators">terminator instruction</a>
2382 if the terminator instruction has multiple successors and the instruction
2383 is always executed when control transfers to one of the successors, and
2384 may not be executed when control is transfered to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2385
2386<li>Dependence is transitive.</li>
2387
2388</ul>
2389</p>
2390
2391<p>Whenever a trap value is generated, all values which depend on it evaluate
2392 to trap. If they have side effects, the evoke their side effects as if each
2393 operand with a trap value were undef. If they have externally-visible side
2394 effects, the behavior is undefined.</p>
2395
2396<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2397
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2398<div class="doc_code">
2399<pre>
2400entry:
2401 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2402 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2403 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2404 store i32 0, i32* %trap_yet_again ; undefined behavior
2405
2406 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2407 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2408
2409 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2410
2411 %narrowaddr = bitcast i32* @g to i16*
2412 %wideaddr = bitcast i32* @g to i64*
2413 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2414 %trap4 = load i64* %widaddr ; Returns a trap value.
2415
2416 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2417 %br i1 %cmp, %true, %end ; Branch to either destination.
2418
2419true:
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2420 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2421 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2422 br label %end
2423
2424end:
2425 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2426 ; Both edges into this PHI are
2427 ; control-dependent on %cmp, so this
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2428 ; always results in a trap value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2429
2430 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2431 ; so this is defined (ignoring earlier
2432 ; undefined behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2433</pre>
2434</div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2435
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2436</div>
2437
2438<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2439<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2440 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2441<div class="doc_text">
2442
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2443<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2444
2445<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2446 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2447 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2448
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2449<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2450 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2451 against null. Pointer equality tests between labels addresses is undefined
2452 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2453 equal to the null pointer. This may also be passed around as an opaque
2454 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2455 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2456 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2457
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2458<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2459 using the value as the operand to an inline assembly, but that is target
2460 specific.
2461 </p>
2462
2463</div>
2464
2465
2466<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2467<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2468</div>
2469
2470<div class="doc_text">
2471
2472<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2473 to be used as constants. Constant expressions may be of
2474 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2475 operation that does not have side effects (e.g. load and call are not
2476 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2477
2478<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2479 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2480 <dd>Truncate a constant to another type. The bit size of CST must be larger
2481 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2482
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2483 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2484 <dd>Zero extend a constant to another type. The bit size of CST must be
2485 smaller or equal to the bit size of TYPE. Both types must be
2486 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2487
2488 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2489 <dd>Sign extend a constant to another type. The bit size of CST must be
2490 smaller or equal to the bit size of TYPE. Both types must be
2491 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2492
2493 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2494 <dd>Truncate a floating point constant to another floating point type. The
2495 size of CST must be larger than the size of TYPE. Both types must be
2496 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2497
2498 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499 <dd>Floating point extend a constant to another type. The size of CST must be
2500 smaller or equal to the size of TYPE. Both types must be floating
2501 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2502
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2503 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2504 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2505 constant. TYPE must be a scalar or vector integer type. CST must be of
2506 scalar or vector floating point type. Both CST and TYPE must be scalars,
2507 or vectors of the same number of elements. If the value won't fit in the
2508 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2509
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2510 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2511 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2512 constant. TYPE must be a scalar or vector integer type. CST must be of
2513 scalar or vector floating point type. Both CST and TYPE must be scalars,
2514 or vectors of the same number of elements. If the value won't fit in the
2515 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2516
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2517 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2518 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2519 constant. TYPE must be a scalar or vector floating point type. CST must be
2520 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2521 vectors of the same number of elements. If the value won't fit in the
2522 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2523
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2524 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2525 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2526 constant. TYPE must be a scalar or vector floating point type. CST must be
2527 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2528 vectors of the same number of elements. If the value won't fit in the
2529 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2530
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2531 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2532 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2533 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2534 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2535 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2536
2537 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2538 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2539 type. CST must be of integer type. The CST value is zero extended,
2540 truncated, or unchanged to make it fit in a pointer size. This one is
2541 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2542
2543 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2544 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2545 are the same as those for the <a href="#i_bitcast">bitcast
2546 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2547
2548 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2549 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2550 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2551 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2552 instruction, the index list may have zero or more indexes, which are
2553 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2554
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2555 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2557
2558 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2559 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2560
2561 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2562 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2563
2564 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2565 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2566 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2567
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2568 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2569 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2570 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2571
2572 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2573 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2574 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2575
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2576 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2577 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2578 be any of the <a href="#binaryops">binary</a>
2579 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2580 on operands are the same as those for the corresponding instruction
2581 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2582</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2583
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2584</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2586<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2587<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2588<!-- *********************************************************************** -->
2589
2590<!-- ======================================================================= -->
2591<div class="doc_subsection">
2592<a name="inlineasm">Inline Assembler Expressions</a>
2593</div>
2594
2595<div class="doc_text">
2596
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2597<p>LLVM supports inline assembler expressions (as opposed
2598 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2599 a special value. This value represents the inline assembler as a string
2600 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2601 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2602 expression has side effects, and a flag indicating whether the function
2603 containing the asm needs to align its stack conservatively. An example
2604 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2605
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2606<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2607<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2608i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2609</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2610</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2611
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2613 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2614 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2615
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2616<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2617<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2618%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]2619</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2620</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2621
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2622<p>Inline asms with side effects not visible in the constraint list must be
2623 marked as having side effects. This is done through the use of the
2624 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2625
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2626<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2627<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2628call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2629</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2630</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2631
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2632<p>In some cases inline asms will contain code that will not work unless the
2633 stack is aligned in some way, such as calls or SSE instructions on x86,
2634 yet will not contain code that does that alignment within the asm.
2635 The compiler should make conservative assumptions about what the asm might
2636 contain and should generate its usual stack alignment code in the prologue
2637 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2638
2639<div class="doc_code">
2640<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2641call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2642</pre>
2643</div>
2644
2645<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2646 first.</p>
2647
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2648<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2649 documented here. Constraints on what can be done (e.g. duplication, moving,
2650 etc need to be documented). This is probably best done by reference to
2651 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2652</div>
2653
2654<div class="doc_subsubsection">
2655<a name="inlineasm_md">Inline Asm Metadata</a>
2656</div>
2657
2658<div class="doc_text">
2659
2660<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2661 attached to it that contains a constant integer. If present, the code
2662 generator will use the integer as the location cookie value when report
2663 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]2664 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2665 source code that produced it. For example:</p>
2666
2667<div class="doc_code">
2668<pre>
2669call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2670...
2671!42 = !{ i32 1234567 }
2672</pre>
2673</div>
2674
2675<p>It is up to the front-end to make sense of the magic numbers it places in the
2676 IR.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2677
2678</div>
2679
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2680<!-- ======================================================================= -->
2681<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2682 Strings</a>
2683</div>
2684
2685<div class="doc_text">
2686
2687<p>LLVM IR allows metadata to be attached to instructions in the program that
2688 can convey extra information about the code to the optimizers and code
2689 generator. One example application of metadata is source-level debug
2690 information. There are two metadata primitives: strings and nodes. All
2691 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2692 preceding exclamation point ('<tt>!</tt>').</p>
2693
2694<p>A metadata string is a string surrounded by double quotes. It can contain
2695 any character by escaping non-printable characters with "\xx" where "xx" is
2696 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2697
2698<p>Metadata nodes are represented with notation similar to structure constants
2699 (a comma separated list of elements, surrounded by braces and preceded by an
2700 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2701 10}</tt>". Metadata nodes can have any values as their operand.</p>
2702
2703<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2704 metadata nodes, which can be looked up in the module symbol table. For
2705 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2706
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2707<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2708 function is using two metadata arguments.
2709
2710 <div class="doc_code">
2711 <pre>
2712 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2713 </pre>
2714 </div></p>
2715
2716<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2717 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2718
2719 <div class="doc_code">
2720 <pre>
2721 %indvar.next = add i64 %indvar, 1, !dbg !21
2722 </pre>
2723 </div></p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2724</div>
2725
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2726
2727<!-- *********************************************************************** -->
2728<div class="doc_section">
2729 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2730</div>
2731<!-- *********************************************************************** -->
2732
2733<p>LLVM has a number of "magic" global variables that contain data that affect
2734code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2735of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2736section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2737by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2738
2739<!-- ======================================================================= -->
2740<div class="doc_subsection">
2741<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2742</div>
2743
2744<div class="doc_text">
2745
2746<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2747href="#linkage_appending">appending linkage</a>. This array contains a list of
2748pointers to global variables and functions which may optionally have a pointer
2749cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2750
2751<pre>
2752 @X = global i8 4
2753 @Y = global i32 123
2754
2755 @llvm.used = appending global [2 x i8*] [
2756 i8* @X,
2757 i8* bitcast (i32* @Y to i8*)
2758 ], section "llvm.metadata"
2759</pre>
2760
2761<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2762compiler, assembler, and linker are required to treat the symbol as if there is
2763a reference to the global that it cannot see. For example, if a variable has
2764internal linkage and no references other than that from the <tt>@llvm.used</tt>
2765list, it cannot be deleted. This is commonly used to represent references from
2766inline asms and other things the compiler cannot "see", and corresponds to
2767"attribute((used))" in GNU C.</p>
2768
2769<p>On some targets, the code generator must emit a directive to the assembler or
2770object file to prevent the assembler and linker from molesting the symbol.</p>
2771
2772</div>
2773
2774<!-- ======================================================================= -->
2775<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2776<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2777</div>
2778
2779<div class="doc_text">
2780
2781<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2782<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2783touching the symbol. On targets that support it, this allows an intelligent
2784linker to optimize references to the symbol without being impeded as it would be
2785by <tt>@llvm.used</tt>.</p>
2786
2787<p>This is a rare construct that should only be used in rare circumstances, and
2788should not be exposed to source languages.</p>
2789
2790</div>
2791
2792<!-- ======================================================================= -->
2793<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2794<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2795</div>
2796
2797<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2798<pre>
2799%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2800@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2801</pre>
2802<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.
2803</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2804
2805</div>
2806
2807<!-- ======================================================================= -->
2808<div class="doc_subsection">
2809<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2810</div>
2811
2812<div class="doc_text">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2813<pre>
2814%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]2815@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2816</pre>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2817
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]2818<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.
2819</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2820
2821</div>
2822
2823
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2824<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2825<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2826<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2827
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2828<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2829
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2830<p>The LLVM instruction set consists of several different classifications of
2831 instructions: <a href="#terminators">terminator
2832 instructions</a>, <a href="#binaryops">binary instructions</a>,
2833 <a href="#bitwiseops">bitwise binary instructions</a>,
2834 <a href="#memoryops">memory instructions</a>, and
2835 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2836
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2837</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2840<div class="doc_subsection"> <a name="terminators">Terminator
2841Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2842
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2843<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2845<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2846 in a program ends with a "Terminator" instruction, which indicates which
2847 block should be executed after the current block is finished. These
2848 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2849 control flow, not values (the one exception being the
2850 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2851
Duncan Sands83821c82010-04-15 20:35:54 +0000[diff] [blame]2852<p>There are seven different terminator instructions: the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2854 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2855 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2856 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2857 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2858 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2859 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2860
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2861</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2863<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2864<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2865Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2867<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2869<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2870<pre>
2871 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]2872 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2873</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2875<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2876<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2877 a value) from a function back to the caller.</p>
2878
2879<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2880 value and then causes control flow, and one that just causes control flow to
2881 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2884<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2885 return value. The type of the return value must be a
2886 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2887
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2888<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2889 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2890 value or a return value with a type that does not match its type, or if it
2891 has a void return type and contains a '<tt>ret</tt>' instruction with a
2892 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2894<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2896 the calling function's context. If the caller is a
2897 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2898 instruction after the call. If the caller was an
2899 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2900 the beginning of the "normal" destination block. If the instruction returns
2901 a value, that value shall set the call or invoke instruction's return
2902 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2904<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2905<pre>
2906 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2907 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2908 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]2909</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2910
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2911</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2913<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2915<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2917<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2918<pre>
2919 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]2920</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2923<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2924 different basic block in the current function. There are two forms of this
2925 instruction, corresponding to a conditional branch and an unconditional
2926 branch.</p>
2927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2929<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2930 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2931 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2932 target.</p>
2933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2934<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2935<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2936 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2937 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2938 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2940<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2941<pre>
2942Test:
2943 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2944 br i1 %cond, label %IfEqual, label %IfUnequal
2945IfEqual:
2946 <a href="#i_ret">ret</a> i32 1
2947IfUnequal:
2948 <a href="#i_ret">ret</a> i32 0
2949</pre>
2950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2951</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2952
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2953<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2954<div class="doc_subsubsection">
2955 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2956</div>
2957
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2958<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2959
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2960<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2961<pre>
2962 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2963</pre>
2964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2965<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2966<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]2967 several different places. It is a generalization of the '<tt>br</tt>'
2968 instruction, allowing a branch to occur to one of many possible
2969 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2970
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2971<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2972<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2973 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2974 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2975 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2977<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2978<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2979 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2980 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2981 transferred to the corresponding destination; otherwise, control flow is
2982 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2983
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2984<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2985<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2986 <tt>switch</tt> instruction, this instruction may be code generated in
2987 different ways. For example, it could be generated as a series of chained
2988 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2989
2990<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2991<pre>
2992 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2993 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2994 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2995
2996 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2997 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2998
2999 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3000 switch i32 %val, label %otherwise [ i32 0, label %onzero
3001 i32 1, label %onone
3002 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3004
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3005</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3006
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3007
3008<!-- _______________________________________________________________________ -->
3009<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3010 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3011</div>
3012
3013<div class="doc_text">
3014
3015<h5>Syntax:</h5>
3016<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3017 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]3018</pre>
3019
3020<h5>Overview:</h5>
3021
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3022<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3023 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3024 "<tt>address</tt>". Address must be derived from a <a
3025 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3026
3027<h5>Arguments:</h5>
3028
3029<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3030 rest of the arguments indicate the full set of possible destinations that the
3031 address may point to. Blocks are allowed to occur multiple times in the
3032 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3033
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3034<p>This destination list is required so that dataflow analysis has an accurate
3035 understanding of the CFG.</p>
3036
3037<h5>Semantics:</h5>
3038
3039<p>Control transfers to the block specified in the address argument. All
3040 possible destination blocks must be listed in the label list, otherwise this
3041 instruction has undefined behavior. This implies that jumps to labels
3042 defined in other functions have undefined behavior as well.</p>
3043
3044<h5>Implementation:</h5>
3045
3046<p>This is typically implemented with a jump through a register.</p>
3047
3048<h5>Example:</h5>
3049<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3050 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3051</pre>
3052
3053</div>
3054
3055
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3056<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3057<div class="doc_subsubsection">
3058 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3059</div>
3060
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3061<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3062
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3063<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3064<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3065 &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]3066 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3067</pre>
3068
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3069<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3070<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3071 function, with the possibility of control flow transfer to either the
3072 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3073 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3074 control flow will return to the "normal" label. If the callee (or any
3075 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3076 instruction, control is interrupted and continued at the dynamically nearest
3077 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3078
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3079<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3080<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3081
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3082<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3084 convention</a> the call should use. If none is specified, the call
3085 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3086
3087 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3089 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3090
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3091 <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]3092 function value being invoked. In most cases, this is a direct function
3093 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3094 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3095
3096 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3097 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3098
3099 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3100 signature argument types and parameter attributes. All arguments must be
3101 of <a href="#t_firstclass">first class</a> type. If the function
3102 signature indicates the function accepts a variable number of arguments,
3103 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3104
3105 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3106 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3107
3108 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3110
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3111 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3113 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3114</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3115
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3116<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117<p>This instruction is designed to operate as a standard
3118 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3119 primary difference is that it establishes an association with a label, which
3120 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3121
3122<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3124 exception. Additionally, this is important for implementation of
3125 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3126
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3127<p>For the purposes of the SSA form, the definition of the value returned by the
3128 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3129 block to the "normal" label. If the callee unwinds then no return value is
3130 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3131
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3132<p>Note that the code generator does not yet completely support unwind, and
3133that the invoke/unwind semantics are likely to change in future versions.</p>
3134
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3135<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3136<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3137 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3138 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3139 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3140 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3141</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3142
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3143</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3144
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3145<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3146
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3147<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3148Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3149
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3150<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3151
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3152<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3153<pre>
3154 unwind
3155</pre>
3156
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3157<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3158<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3159 at the first callee in the dynamic call stack which used
3160 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3161 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3162
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3163<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3164<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165 immediately halt. The dynamic call stack is then searched for the
3166 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3167 Once found, execution continues at the "exceptional" destination block
3168 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3169 instruction in the dynamic call chain, undefined behavior results.</p>
3170
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3171<p>Note that the code generator does not yet completely support unwind, and
3172that the invoke/unwind semantics are likely to change in future versions.</p>
3173
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3174</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3175
3176<!-- _______________________________________________________________________ -->
3177
3178<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3179Instruction</a> </div>
3180
3181<div class="doc_text">
3182
3183<h5>Syntax:</h5>
3184<pre>
3185 unreachable
3186</pre>
3187
3188<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3189<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3190 instruction is used to inform the optimizer that a particular portion of the
3191 code is not reachable. This can be used to indicate that the code after a
3192 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3193
3194<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3195<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3197</div>
3198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3199<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3200<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3202<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203
3204<p>Binary operators are used to do most of the computation in a program. They
3205 require two operands of the same type, execute an operation on them, and
3206 produce a single value. The operands might represent multiple data, as is
3207 the case with the <a href="#t_vector">vector</a> data type. The result value
3208 has the same type as its operands.</p>
3209
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3210<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3211
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3212</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3213
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3214<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3215<div class="doc_subsubsection">
3216 <a name="i_add">'<tt>add</tt>' Instruction</a>
3217</div>
3218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3219<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3221<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3222<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3223 &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]3224 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3225 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3226 &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]3227</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3228
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3229<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3230<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3232<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3233<p>The two arguments to the '<tt>add</tt>' instruction must
3234 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3235 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3237<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3238<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240<p>If the sum has unsigned overflow, the result returned is the mathematical
3241 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]3242
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3243<p>Because LLVM integers use a two's complement representation, this instruction
3244 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3245
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3246<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3247 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3248 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3249 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3250 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3253<pre>
3254 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3256
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3257</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3258
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3259<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3260<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3261 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3262</div>
3263
3264<div class="doc_text">
3265
3266<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3267<pre>
3268 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3269</pre>
3270
3271<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3272<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3273
3274<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3275<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3277 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3278
3279<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3280<p>The value produced is the floating point sum of the two operands.</p>
3281
3282<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3283<pre>
3284 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3285</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3287</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3288
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3289<!-- _______________________________________________________________________ -->
3290<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3291 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3292</div>
3293
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3294<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3297<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3298 &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]3299 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3300 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3301 &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]3302</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3304<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3305<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3306 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3307
3308<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3309 '<tt>neg</tt>' instruction present in most other intermediate
3310 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3312<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3313<p>The two arguments to the '<tt>sub</tt>' instruction must
3314 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3315 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3316
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3317<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3318<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3319
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3320<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3322 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3323
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324<p>Because LLVM integers use a two's complement representation, this instruction
3325 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3326
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3327<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3328 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3329 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3330 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3331 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3332
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3333<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3334<pre>
3335 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3336 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3339</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3340
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3341<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3342<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3343 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3344</div>
3345
3346<div class="doc_text">
3347
3348<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3349<pre>
3350 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3351</pre>
3352
3353<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3354<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3355 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3356
3357<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358 '<tt>fneg</tt>' instruction present in most other intermediate
3359 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3360
3361<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3362<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3363 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3364 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3365
3366<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3367<p>The value produced is the floating point difference of the two operands.</p>
3368
3369<h5>Example:</h5>
3370<pre>
3371 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3372 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3373</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3375</div>
3376
3377<!-- _______________________________________________________________________ -->
3378<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3379 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3380</div>
3381
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3382<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3386 &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]3387 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3388 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3389 &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]3390</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3392<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3393<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3396<p>The two arguments to the '<tt>mul</tt>' instruction must
3397 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3398 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3399
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3400<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3401<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3402
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403<p>If the result of the multiplication has unsigned overflow, the result
3404 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3405 width of the result.</p>
3406
3407<p>Because LLVM integers use a two's complement representation, and the result
3408 is the same width as the operands, this instruction returns the correct
3409 result for both signed and unsigned integers. If a full product
3410 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3411 be sign-extended or zero-extended as appropriate to the width of the full
3412 product.</p>
3413
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3414<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3415 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3416 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3417 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3418 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3420<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421<pre>
3422 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3423</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3424
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3425</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3427<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3428<div class="doc_subsubsection">
3429 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3430</div>
3431
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3435<pre>
3436 &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]3437</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3439<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3441
3442<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3443<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3445 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3446
3447<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3448<p>The value produced is the floating point product of the two operands.</p>
3449
3450<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451<pre>
3452 &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]3453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3454
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3455</div>
3456
3457<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3458<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3459</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3460
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3461<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3463<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &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]3466</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3468<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3470
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3471<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3472<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3474 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3475
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3476<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3477<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3479<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3480 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3481
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3482<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3483
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3484<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3485<pre>
3486 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3488
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3489</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3490
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3491<!-- _______________________________________________________________________ -->
3492<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3493</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3494
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3495<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3497<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3498<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3499 &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]3500 &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]3501</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3502
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3503<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3505
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3506<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3507<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3509 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3510
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3511<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512<p>The value produced is the signed integer quotient of the two operands rounded
3513 towards zero.</p>
3514
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3515<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3516 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3517
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3518<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519 undefined behavior; this is a rare case, but can occur, for example, by doing
3520 a 32-bit division of -2147483648 by -1.</p>
3521
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3522<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]3523 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3524 be rounded or if overflow would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3525
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3526<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3527<pre>
3528 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3529</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3530
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3531</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3533<!-- _______________________________________________________________________ -->
3534<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3535Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3537<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3539<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3540<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3541 &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]3542</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544<h5>Overview:</h5>
3545<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3546
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3547<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3548<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3549 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3550 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3551
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3552<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3553<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3554
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3555<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3556<pre>
3557 &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]3558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3559
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3560</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3561
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3563<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3564</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3565
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3566<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3568<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3569<pre>
3570 &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]3571</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3572
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3573<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3574<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3575 division of its two arguments.</p>
3576
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3577<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3578<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3579 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3580 values. Both arguments must have identical types.</p>
3581
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3582<h5>Semantics:</h5>
3583<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3584 This instruction always performs an unsigned division to get the
3585 remainder.</p>
3586
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3587<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3589
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3590<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3591
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3592<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3593<pre>
3594 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3595</pre>
3596
3597</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3599<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3600<div class="doc_subsubsection">
3601 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3602</div>
3603
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3604<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3605
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3606<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3607<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3608 &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]3609</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3610
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3611<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3613 division of its two operands. This instruction can also take
3614 <a href="#t_vector">vector</a> versions of the values in which case the
3615 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3616
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3617<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3618<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3619 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3620 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3622<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3623<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3624 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3625 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3626 a value. For more information about the difference,
3627 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3628 Math Forum</a>. For a table of how this is implemented in various languages,
3629 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3630 Wikipedia: modulo operation</a>.</p>
3631
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3632<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3633 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3634
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3635<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3636 Overflow also leads to undefined behavior; this is a rare case, but can
3637 occur, for example, by taking the remainder of a 32-bit division of
3638 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3639 lets srem be implemented using instructions that return both the result of
3640 the division and the remainder.)</p>
3641
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3642<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643<pre>
3644 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3645</pre>
3646
3647</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3649<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3650<div class="doc_subsubsection">
3651 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3652
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3653<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3654
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3655<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656<pre>
3657 &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]3658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3660<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3662 its two operands.</p>
3663
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3664<h5>Arguments:</h5>
3665<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3666 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3667 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3668
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3669<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3670<p>This instruction returns the <i>remainder</i> of a division. The remainder
3671 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3672
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3673<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3674<pre>
3675 &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]3676</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3678</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3679
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3680<!-- ======================================================================= -->
3681<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3682Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3684<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3685
3686<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3687 program. They are generally very efficient instructions and can commonly be
3688 strength reduced from other instructions. They require two operands of the
3689 same type, execute an operation on them, and produce a single value. The
3690 resulting value is the same type as its operands.</p>
3691
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3692</div>
3693
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3696Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3698<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3700<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3701<pre>
3702 &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]3703</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3704
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3705<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3706<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3707 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3708
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3709<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3710<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3711 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3712 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3713
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3714<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3716 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3717 is (statically or dynamically) negative or equal to or larger than the number
3718 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3719 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3720 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3721
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3722<h5>Example:</h5>
3723<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3724 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3725 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3726 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3727 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3728 &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]3729</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3730
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3731</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3732
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3733<!-- _______________________________________________________________________ -->
3734<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3735Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3737<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3739<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<pre>
3741 &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]3742</pre>
3743
3744<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3745<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3746 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3747
3748<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3749<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3750 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3751 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3752
3753<h5>Semantics:</h5>
3754<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3755 significant bits of the result will be filled with zero bits after the shift.
3756 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3757 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3758 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3759 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3760
3761<h5>Example:</h5>
3762<pre>
3763 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3764 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3765 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3766 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3767 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3768 &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]3769</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3770
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3771</div>
3772
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3773<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3774<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3775Instruction</a> </div>
3776<div class="doc_text">
3777
3778<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3779<pre>
3780 &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]3781</pre>
3782
3783<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3784<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3785 operand shifted to the right a specified number of bits with sign
3786 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3787
3788<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3789<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3790 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3791 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3792
3793<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794<p>This instruction always performs an arithmetic shift right operation, The
3795 most significant bits of the result will be filled with the sign bit
3796 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3797 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3798 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3799 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3800
3801<h5>Example:</h5>
3802<pre>
3803 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3804 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3805 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3806 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3807 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3808 &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]3809</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3810
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3811</div>
3812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3813<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3814<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3815Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3817<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3819<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3820<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3821 &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]3822</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3824<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3826 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3828<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3829<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3831 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3833<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3834<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3835
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3836<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3837 <tbody>
3838 <tr>
3839 <td>In0</td>
3840 <td>In1</td>
3841 <td>Out</td>
3842 </tr>
3843 <tr>
3844 <td>0</td>
3845 <td>0</td>
3846 <td>0</td>
3847 </tr>
3848 <tr>
3849 <td>0</td>
3850 <td>1</td>
3851 <td>0</td>
3852 </tr>
3853 <tr>
3854 <td>1</td>
3855 <td>0</td>
3856 <td>0</td>
3857 </tr>
3858 <tr>
3859 <td>1</td>
3860 <td>1</td>
3861 <td>1</td>
3862 </tr>
3863 </tbody>
3864</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3866<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3867<pre>
3868 &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]3869 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3870 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3871</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3872</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3874<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3875
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3876<div class="doc_text">
3877
3878<h5>Syntax:</h5>
3879<pre>
3880 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3881</pre>
3882
3883<h5>Overview:</h5>
3884<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3885 two operands.</p>
3886
3887<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3888<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3890 values. Both arguments must have identical types.</p>
3891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3892<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3893<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3895<table border="1" cellspacing="0" cellpadding="4">
3896 <tbody>
3897 <tr>
3898 <td>In0</td>
3899 <td>In1</td>
3900 <td>Out</td>
3901 </tr>
3902 <tr>
3903 <td>0</td>
3904 <td>0</td>
3905 <td>0</td>
3906 </tr>
3907 <tr>
3908 <td>0</td>
3909 <td>1</td>
3910 <td>1</td>
3911 </tr>
3912 <tr>
3913 <td>1</td>
3914 <td>0</td>
3915 <td>1</td>
3916 </tr>
3917 <tr>
3918 <td>1</td>
3919 <td>1</td>
3920 <td>1</td>
3921 </tr>
3922 </tbody>
3923</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3925<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3926<pre>
3927 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3928 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3929 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3930</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3932</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3934<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3935<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3936Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3938<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3940<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3941<pre>
3942 &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]3943</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3945<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3946<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3947 its two operands. The <tt>xor</tt> is used to implement the "one's
3948 complement" operation, which is the "~" operator in C.</p>
3949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3950<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3951<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3953 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3954
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3955<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3956<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3958<table border="1" cellspacing="0" cellpadding="4">
3959 <tbody>
3960 <tr>
3961 <td>In0</td>
3962 <td>In1</td>
3963 <td>Out</td>
3964 </tr>
3965 <tr>
3966 <td>0</td>
3967 <td>0</td>
3968 <td>0</td>
3969 </tr>
3970 <tr>
3971 <td>0</td>
3972 <td>1</td>
3973 <td>1</td>
3974 </tr>
3975 <tr>
3976 <td>1</td>
3977 <td>0</td>
3978 <td>1</td>
3979 </tr>
3980 <tr>
3981 <td>1</td>
3982 <td>1</td>
3983 <td>0</td>
3984 </tr>
3985 </tbody>
3986</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3988<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3989<pre>
3990 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3991 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3992 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3993 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3994</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3996</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3997
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3998<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3999<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4000 <a name="vectorops">Vector Operations</a>
4001</div>
4002
4003<div class="doc_text">
4004
4005<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006 target-independent manner. These instructions cover the element-access and
4007 vector-specific operations needed to process vectors effectively. While LLVM
4008 does directly support these vector operations, many sophisticated algorithms
4009 will want to use target-specific intrinsics to take full advantage of a
4010 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4011
4012</div>
4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
4016 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4017</div>
4018
4019<div class="doc_text">
4020
4021<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4022<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4023 &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]4024</pre>
4025
4026<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4028 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4029
4030
4031<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4033 of <a href="#t_vector">vector</a> type. The second operand is an index
4034 indicating the position from which to extract the element. The index may be
4035 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4036
4037<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038<p>The result is a scalar of the same type as the element type of
4039 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4040 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4041 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4042
4043<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4044<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4045 &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]4046</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4047
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4048</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4049
4050<!-- _______________________________________________________________________ -->
4051<div class="doc_subsubsection">
4052 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4053</div>
4054
4055<div class="doc_text">
4056
4057<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4058<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4059 &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]4060</pre>
4061
4062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4064 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4065
4066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4068 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4069 whose type must equal the element type of the first operand. The third
4070 operand is an index indicating the position at which to insert the value.
4071 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4072
4073<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4074<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4075 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4076 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4077 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4080<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4081 &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]4082</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4083
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4084</div>
4085
4086<!-- _______________________________________________________________________ -->
4087<div class="doc_subsubsection">
4088 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4089</div>
4090
4091<div class="doc_text">
4092
4093<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4094<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4095 &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]4096</pre>
4097
4098<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4099<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4100 from two input vectors, returning a vector with the same element type as the
4101 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4102
4103<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4104<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4105 with types that match each other. The third argument is a shuffle mask whose
4106 element type is always 'i32'. The result of the instruction is a vector
4107 whose length is the same as the shuffle mask and whose element type is the
4108 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4110<p>The shuffle mask operand is required to be a constant vector with either
4111 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4112
4113<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4114<p>The elements of the two input vectors are numbered from left to right across
4115 both of the vectors. The shuffle mask operand specifies, for each element of
4116 the result vector, which element of the two input vectors the result element
4117 gets. The element selector may be undef (meaning "don't care") and the
4118 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4119
4120<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4121<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4122 &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]4123 &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]4124 &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]4125 &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]4126 &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]4127 &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]4128 &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]4129 &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]4130</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4131
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4132</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4133
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4134<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4135<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4136 <a name="aggregateops">Aggregate Operations</a>
4137</div>
4138
4139<div class="doc_text">
4140
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4141<p>LLVM supports several instructions for working with
4142 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4143
4144</div>
4145
4146<!-- _______________________________________________________________________ -->
4147<div class="doc_subsubsection">
4148 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4149</div>
4150
4151<div class="doc_text">
4152
4153<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4154<pre>
4155 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4156</pre>
4157
4158<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4159<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4160 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4161
4162<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4163<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4164 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4165 <a href="#t_array">array</a> type. The operands are constant indices to
4166 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4167 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4168
4169<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4170<p>The result is the value at the position in the aggregate specified by the
4171 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4172
4173<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4174<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4175 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4176</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4177
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4179
4180<!-- _______________________________________________________________________ -->
4181<div class="doc_subsubsection">
4182 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4183</div>
4184
4185<div class="doc_text">
4186
4187<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4188<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4189 &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]4190</pre>
4191
4192<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4193<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4194 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4195
4196<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4197<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4198 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4199 <a href="#t_array">array</a> type. The second operand is a first-class
4200 value to insert. The following operands are constant indices indicating
4201 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]4202 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4203 value to insert must have the same type as the value identified by the
4204 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4205
4206<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4208 that of <tt>val</tt> except that the value at the position specified by the
4209 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4210
4211<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4212<pre>
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]4213 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4214 %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]4215</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4216
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4217</div>
4218
4219
4220<!-- ======================================================================= -->
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4221<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4222 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4223</div>
4224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4225<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4227<p>A key design point of an SSA-based representation is how it represents
4228 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4229 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4231
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4232</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4233
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4234<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4235<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4236 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4237</div>
4238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4239<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4242<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4243 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4244</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4246<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4247<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248 currently executing function, to be automatically released when this function
4249 returns to its caller. The object is always allocated in the generic address
4250 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4252<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4253<p>The '<tt>alloca</tt>' instruction
4254 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4255 runtime stack, returning a pointer of the appropriate type to the program.
4256 If "NumElements" is specified, it is the number of elements allocated,
4257 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4258 specified, the value result of the allocation is guaranteed to be aligned to
4259 at least that boundary. If not specified, or if zero, the target can choose
4260 to align the allocation on any convenient boundary compatible with the
4261 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4262
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4263<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4265<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4266<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4268 memory is automatically released when the function returns. The
4269 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4270 variables that must have an address available. When the function returns
4271 (either with the <tt><a href="#i_ret">ret</a></tt>
4272 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4273 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4275<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4276<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4277 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4278 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4279 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4280 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4281</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4282
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4283</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4284
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4285<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4286<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4287Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4289<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4290
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4291<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292<pre>
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4293 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4294 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4295 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296</pre>
4297
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4298<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4299<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4300
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4301<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4303 from which to load. The pointer must point to
4304 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4305 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4306 number or order of execution of this <tt>load</tt> with other <a
4307 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4308
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4309<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4310 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]4311 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4312 alignment for the target. It is the responsibility of the code emitter to
4313 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4314 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4315 produce less efficient code. An alignment of 1 is always safe.</p>
4316
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4317<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4318 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4319 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4320 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4321 and code generator that this load is not expected to be reused in the cache.
4322 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4323 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4324
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4325<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4326<p>The location of memory pointed to is loaded. If the value being loaded is of
4327 scalar type then the number of bytes read does not exceed the minimum number
4328 of bytes needed to hold all bits of the type. For example, loading an
4329 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4330 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4331 is undefined if the value was not originally written using a store of the
4332 same type.</p>
4333
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4334<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4335<pre>
4336 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4337 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4338 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4339</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4341</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4343<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4344<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4345Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4347<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4349<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4350<pre>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4351 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4352 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]4353</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4354
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4355<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4356<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4358<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4359<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4360 and an address at which to store it. The type of the
4361 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4362 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4363 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4364 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4365 order of execution of this <tt>store</tt> with other <a
4366 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367
4368<p>The optional constant "align" argument specifies the alignment of the
4369 operation (that is, the alignment of the memory address). A value of 0 or an
4370 omitted "align" argument means that the operation has the preferential
4371 alignment for the target. It is the responsibility of the code emitter to
4372 ensure that the alignment information is correct. Overestimating the
4373 alignment results in an undefined behavior. Underestimating the alignment may
4374 produce less efficient code. An alignment of 1 is always safe.</p>
4375
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4376<p>The optional !nontemporal metadata must reference a single metatadata
4377 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4378 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4379 instruction tells the optimizer and code generator that this load is
4380 not expected to be reused in the cache. The code generator may
4381 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4382 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4383
4384
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4385<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4386<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4387 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4388 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4389 does not exceed the minimum number of bytes needed to hold all bits of the
4390 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4391 writing a value of a type like <tt>i20</tt> with a size that is not an
4392 integral number of bytes, it is unspecified what happens to the extra bits
4393 that do not belong to the type, but they will typically be overwritten.</p>
4394
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4395<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<pre>
4397 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4398 store i32 3, i32* %ptr <i>; yields {void}</i>
4399 %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]4400</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4401
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4402</div>
4403
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4404<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4405<div class="doc_subsubsection">
4406 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4407</div>
4408
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4409<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4410
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4411<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4412<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4413 &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]4414 &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]4415</pre>
4416
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4417<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4418<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4419 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4420 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4421
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4422<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4423<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4424 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4425 elements of the aggregate object are indexed. The interpretation of each
4426 index is dependent on the type being indexed into. The first index always
4427 indexes the pointer value given as the first argument, the second index
4428 indexes a value of the type pointed to (not necessarily the value directly
4429 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4430 indexed into must be a pointer value, subsequent types can be arrays,
4431 vectors, structs and unions. Note that subsequent types being indexed into
4432 can never be pointers, since that would require loading the pointer before
4433 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4434
4435<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]4436 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4437 integer <b>constants</b> are allowed. When indexing into an array, pointer
4438 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]4439 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4440
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441<p>For example, let's consider a C code fragment and how it gets compiled to
4442 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4443
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4444<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4445<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4446struct RT {
4447 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4448 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4449 char C;
4450};
4451struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4452 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4453 double Y;
4454 struct RT Z;
4455};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4456
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4457int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4458 return &amp;s[1].Z.B[5][13];
4459}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4460</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4461</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4463<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4464
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4465<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4466<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4467%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4468%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4469
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4470define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4471entry:
4472 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4473 ret i32* %reg
4474}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4475</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4476</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4477
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4478<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4479<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]4480 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4481 }</tt>' type, a structure. The second index indexes into the third element
4482 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4483 i8 }</tt>' type, another structure. The third index indexes into the second
4484 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4485 array. The two dimensions of the array are subscripted into, yielding an
4486 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4487 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4489<p>Note that it is perfectly legal to index partially through a structure,
4490 returning a pointer to an inner element. Because of this, the LLVM code for
4491 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4492
4493<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4494 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4495 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4496 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4497 %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]4498 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4499 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4500 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4501 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4502</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4503
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4504<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]4505 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4506 base pointer is not an <i>in bounds</i> address of an allocated object,
4507 or if any of the addresses that would be formed by successive addition of
4508 the offsets implied by the indices to the base address with infinitely
4509 precise arithmetic are not an <i>in bounds</i> address of that allocated
4510 object. The <i>in bounds</i> addresses for an allocated object are all
4511 the addresses that point into the object, plus the address one byte past
4512 the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4513
4514<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4515 the base address with silently-wrapping two's complement arithmetic, and
4516 the result value of the <tt>getelementptr</tt> may be outside the object
4517 pointed to by the base pointer. The result value may not necessarily be
4518 used to access memory though, even if it happens to point into allocated
4519 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4520 section for more information.</p>
4521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4522<p>The getelementptr instruction is often confusing. For some more insight into
4523 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4524
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4525<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4526<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4527 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4528 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4529 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4530 %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]4531 <i>; yields i8*:eptr</i>
4532 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4533 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4534 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4535</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4536
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4537</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4539<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4540<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4541</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4543<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4545<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4546 which all take a single operand and a type. They perform various bit
4547 conversions on the operand.</p>
4548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4549</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4550
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4551<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4552<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4553 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4554</div>
4555<div class="doc_text">
4556
4557<h5>Syntax:</h5>
4558<pre>
4559 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4560</pre>
4561
4562<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4563<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4564 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4565
4566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4567<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4568 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4569 size and type of the result, which must be
4570 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4571 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4572 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4573
4574<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4576 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4577 source size must be larger than the destination size, <tt>trunc</tt> cannot
4578 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4579
4580<h5>Example:</h5>
4581<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4582 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4583 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4584 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4585</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4586
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4587</div>
4588
4589<!-- _______________________________________________________________________ -->
4590<div class="doc_subsubsection">
4591 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4592</div>
4593<div class="doc_text">
4594
4595<h5>Syntax:</h5>
4596<pre>
4597 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4598</pre>
4599
4600<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4601<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603
4604
4605<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4606<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]4607 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4608 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]4609 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4610 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4611
4612<h5>Semantics:</h5>
4613<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]4614 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4615
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4616<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]4617
4618<h5>Example:</h5>
4619<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4620 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4621 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4622</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4623
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624</div>
4625
4626<!-- _______________________________________________________________________ -->
4627<div class="doc_subsubsection">
4628 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4629</div>
4630<div class="doc_text">
4631
4632<h5>Syntax:</h5>
4633<pre>
4634 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4635</pre>
4636
4637<h5>Overview:</h5>
4638<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4639
4640<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4641<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]4642 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4643 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]4644 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4646
4647<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4648<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4649 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4650 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4651
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4652<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]4653
4654<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4655<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4656 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4657 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4660</div>
4661
4662<!-- _______________________________________________________________________ -->
4663<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4664 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4665</div>
4666
4667<div class="doc_text">
4668
4669<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4670<pre>
4671 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4672</pre>
4673
4674<h5>Overview:</h5>
4675<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4676 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4677
4678<h5>Arguments:</h5>
4679<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4680 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4681 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]4682 <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]4683 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4687 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_floating">floating point</a> type. If the value cannot fit
4689 within the destination type, <tt>ty2</tt>, then the results are
4690 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4691
4692<h5>Example:</h5>
4693<pre>
4694 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4695 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4696</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4697
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4698</div>
4699
4700<!-- _______________________________________________________________________ -->
4701<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4702 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4703</div>
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<pre>
4708 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4709</pre>
4710
4711<h5>Overview:</h5>
4712<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]4713 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4714
4715<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4716<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4718 a <a href="#t_floating">floating point</a> type to cast it to. The source
4719 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4720
4721<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4722<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723 <a href="#t_floating">floating point</a> type to a larger
4724 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4725 used to make a <i>no-op cast</i> because it always changes bits. Use
4726 <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]4727
4728<h5>Example:</h5>
4729<pre>
4730 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4731 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4732</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4734</div>
4735
4736<!-- _______________________________________________________________________ -->
4737<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4738 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4739</div>
4740<div class="doc_text">
4741
4742<h5>Syntax:</h5>
4743<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4744 &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]4745</pre>
4746
4747<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4748<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4749 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4750
4751<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4752<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4753 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4754 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4755 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4756 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4757
4758<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4759<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4761 towards zero) unsigned integer value. If the value cannot fit
4762 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4763
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4764<h5>Example:</h5>
4765<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4766 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4767 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4768 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4769</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4770
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4771</div>
4772
4773<!-- _______________________________________________________________________ -->
4774<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4775 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4776</div>
4777<div class="doc_text">
4778
4779<h5>Syntax:</h5>
4780<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4781 &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]4782</pre>
4783
4784<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4785<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786 <a href="#t_floating">floating point</a> <tt>value</tt> to
4787 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4788
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4789<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4790<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4791 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4792 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4793 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4794 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4795
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4796<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4797<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4799 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4800 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4801
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4802<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4803<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4804 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4805 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4806 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4807</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4808
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4809</div>
4810
4811<!-- _______________________________________________________________________ -->
4812<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4813 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4814</div>
4815<div class="doc_text">
4816
4817<h5>Syntax:</h5>
4818<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4819 &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]4820</pre>
4821
4822<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4823<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4824 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4825
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4826<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4827<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]4828 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4829 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4830 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4831 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4832
4833<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4834<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4835 integer quantity and converts it to the corresponding floating point
4836 value. If the value cannot fit in the floating point value, the results are
4837 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4838
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4839<h5>Example:</h5>
4840<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4841 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4842 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4843</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4844
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4845</div>
4846
4847<!-- _______________________________________________________________________ -->
4848<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4849 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4850</div>
4851<div class="doc_text">
4852
4853<h5>Syntax:</h5>
4854<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4855 &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]4856</pre>
4857
4858<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4859<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4860 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4861
4862<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4863<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]4864 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4865 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4866 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4867 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4868
4869<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4870<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4871 quantity and converts it to the corresponding floating point value. If the
4872 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4873
4874<h5>Example:</h5>
4875<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4876 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4877 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4878</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4879
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4880</div>
4881
4882<!-- _______________________________________________________________________ -->
4883<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4884 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4885</div>
4886<div class="doc_text">
4887
4888<h5>Syntax:</h5>
4889<pre>
4890 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4891</pre>
4892
4893<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4895 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4896
4897<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4899 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4900 <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]4901
4902<h5>Semantics:</h5>
4903<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4904 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4905 truncating or zero extending that value to the size of the integer type. If
4906 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4907 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4908 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4909 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4910
4911<h5>Example:</h5>
4912<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4913 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4914 %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]4915</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4916
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4917</div>
4918
4919<!-- _______________________________________________________________________ -->
4920<div class="doc_subsubsection">
4921 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4922</div>
4923<div class="doc_text">
4924
4925<h5>Syntax:</h5>
4926<pre>
4927 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4928</pre>
4929
4930<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4931<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4932 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4933
4934<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4935<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4936 value to cast, and a type to cast it to, which must be a
4937 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4938
4939<h5>Semantics:</h5>
4940<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4941 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4942 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4943 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4944 than the size of a pointer then a zero extension is done. If they are the
4945 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4946
4947<h5>Example:</h5>
4948<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4949 %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]4950 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4951 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4952</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4954</div>
4955
4956<!-- _______________________________________________________________________ -->
4957<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4958 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4959</div>
4960<div class="doc_text">
4961
4962<h5>Syntax:</h5>
4963<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4964 &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]4965</pre>
4966
4967<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4968<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4969 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4970
4971<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4972<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4973 non-aggregate first class value, and a type to cast it to, which must also be
4974 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4975 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4976 identical. If the source type is a pointer, the destination type must also be
4977 a pointer. This instruction supports bitwise conversion of vectors to
4978 integers and to vectors of other types (as long as they have the same
4979 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4980
4981<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4982<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4983 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4984 this conversion. The conversion is done as if the <tt>value</tt> had been
4985 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4986 be converted to other pointer types with this instruction. To convert
4987 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4988 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4989
4990<h5>Example:</h5>
4991<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4992 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4993 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4994 %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]4995</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4997</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4998
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4999<!-- ======================================================================= -->
5000<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5001
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5002<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5003
5004<p>The instructions in this category are the "miscellaneous" instructions, which
5005 defy better classification.</p>
5006
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5007</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5008
5009<!-- _______________________________________________________________________ -->
5010<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5011</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5012
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5013<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5014
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5015<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5016<pre>
5017 &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]5018</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5019
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5020<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5022 boolean values based on comparison of its two integer, integer vector, or
5023 pointer operands.</p>
5024
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5025<h5>Arguments:</h5>
5026<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027 the condition code indicating the kind of comparison to perform. It is not a
5028 value, just a keyword. The possible condition code are:</p>
5029
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5030<ol>
5031 <li><tt>eq</tt>: equal</li>
5032 <li><tt>ne</tt>: not equal </li>
5033 <li><tt>ugt</tt>: unsigned greater than</li>
5034 <li><tt>uge</tt>: unsigned greater or equal</li>
5035 <li><tt>ult</tt>: unsigned less than</li>
5036 <li><tt>ule</tt>: unsigned less or equal</li>
5037 <li><tt>sgt</tt>: signed greater than</li>
5038 <li><tt>sge</tt>: signed greater or equal</li>
5039 <li><tt>slt</tt>: signed less than</li>
5040 <li><tt>sle</tt>: signed less or equal</li>
5041</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5042
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5043<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5044 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5045 typed. They must also be identical types.</p>
5046
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5047<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5048<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5049 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5050 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]5051 result, as follows:</p>
5052
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5053<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5054 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5055 <tt>false</tt> otherwise. No sign interpretation is necessary or
5056 performed.</li>
5057
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5058 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059 <tt>false</tt> otherwise. No sign interpretation is necessary or
5060 performed.</li>
5061
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5062 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5063 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5064
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5065 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5066 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5067 to <tt>op2</tt>.</li>
5068
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5069 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5071
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5072 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5074
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5075 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5077
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5078 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5079 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5080 to <tt>op2</tt>.</li>
5081
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5082 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5083 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5084
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5085 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5086 <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]5087</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5089<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5090 values are compared as if they were integers.</p>
5091
5092<p>If the operands are integer vectors, then they are compared element by
5093 element. The result is an <tt>i1</tt> vector with the same number of elements
5094 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5095
5096<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5097<pre>
5098 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5099 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5100 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5101 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5102 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5103 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5104</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5105
5106<p>Note that the code generator does not yet support vector types with
5107 the <tt>icmp</tt> instruction.</p>
5108
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5109</div>
5110
5111<!-- _______________________________________________________________________ -->
5112<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5113</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5114
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5115<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5117<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5118<pre>
5119 &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]5120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5121
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5122<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5123<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5124 values based on comparison of its operands.</p>
5125
5126<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]5127(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5128
5129<p>If the operands are floating point vectors, then the result type is a vector
5130 of boolean with the same number of elements as the operands being
5131 compared.</p>
5132
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5133<h5>Arguments:</h5>
5134<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135 the condition code indicating the kind of comparison to perform. It is not a
5136 value, just a keyword. The possible condition code are:</p>
5137
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5138<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5139 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5140 <li><tt>oeq</tt>: ordered and equal</li>
5141 <li><tt>ogt</tt>: ordered and greater than </li>
5142 <li><tt>oge</tt>: ordered and greater than or equal</li>
5143 <li><tt>olt</tt>: ordered and less than </li>
5144 <li><tt>ole</tt>: ordered and less than or equal</li>
5145 <li><tt>one</tt>: ordered and not equal</li>
5146 <li><tt>ord</tt>: ordered (no nans)</li>
5147 <li><tt>ueq</tt>: unordered or equal</li>
5148 <li><tt>ugt</tt>: unordered or greater than </li>
5149 <li><tt>uge</tt>: unordered or greater than or equal</li>
5150 <li><tt>ult</tt>: unordered or less than </li>
5151 <li><tt>ule</tt>: unordered or less than or equal</li>
5152 <li><tt>une</tt>: unordered or not equal</li>
5153 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5154 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5155</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5156
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5157<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158 <i>unordered</i> means that either operand may be a QNAN.</p>
5159
5160<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5161 a <a href="#t_floating">floating point</a> type or
5162 a <a href="#t_vector">vector</a> of floating point type. They must have
5163 identical types.</p>
5164
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5165<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5166<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5167 according to the condition code given as <tt>cond</tt>. If the operands are
5168 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5169 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5170 follows:</p>
5171
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5172<ol>
5173 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5174
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5175 <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]5176 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5177
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5180
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5181 <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]5182 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5183
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5184 <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]5185 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5186
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5189
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5190 <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]5191 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5192
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5193 <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]5194
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5195 <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]5196 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5197
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5198 <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]5199 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5200
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5201 <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]5202 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5203
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5204 <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]5205 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5206
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5207 <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]5208 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5209
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5210 <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]5211 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5212
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5213 <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]5214
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5215 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5216</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5217
5218<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5219<pre>
5220 &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]5221 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5222 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5223 &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]5224</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5225
5226<p>Note that the code generator does not yet support vector types with
5227 the <tt>fcmp</tt> instruction.</p>
5228
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5229</div>
5230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5231<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]5232<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5233 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5234</div>
5235
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5236<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5237
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5238<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5239<pre>
5240 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5241</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5242
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5243<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5244<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5245 SSA graph representing the function.</p>
5246
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5247<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5248<p>The type of the incoming values is specified with the first type field. After
5249 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5250 one pair for each predecessor basic block of the current block. Only values
5251 of <a href="#t_firstclass">first class</a> type may be used as the value
5252 arguments to the PHI node. Only labels may be used as the label
5253 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5254
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5255<p>There must be no non-phi instructions between the start of a basic block and
5256 the PHI instructions: i.e. PHI instructions must be first in a basic
5257 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5258
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5259<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5260 occur on the edge from the corresponding predecessor block to the current
5261 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5262 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5263
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5264<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5265<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5266 specified by the pair corresponding to the predecessor basic block that
5267 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5268
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5269<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5270<pre>
5271Loop: ; Infinite loop that counts from 0 on up...
5272 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5273 %nextindvar = add i32 %indvar, 1
5274 br label %Loop
5275</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5276
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5277</div>
5278
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5279<!-- _______________________________________________________________________ -->
5280<div class="doc_subsubsection">
5281 <a name="i_select">'<tt>select</tt>' Instruction</a>
5282</div>
5283
5284<div class="doc_text">
5285
5286<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5287<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5288 &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>
5289
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5290 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5291</pre>
5292
5293<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5294<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5295 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5296
5297
5298<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5299<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5300 values indicating the condition, and two values of the
5301 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5302 vectors and the condition is a scalar, then entire vectors are selected, not
5303 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5304
5305<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5306<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5307 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5308
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5309<p>If the condition is a vector of i1, then the value arguments must be vectors
5310 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5311
5312<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5313<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5314 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5315</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5316
5317<p>Note that the code generator does not yet support conditions
5318 with vector type.</p>
5319
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5320</div>
5321
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]5322<!-- _______________________________________________________________________ -->
5323<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5324 <a name="i_call">'<tt>call</tt>' Instruction</a>
5325</div>
5326
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5327<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5328
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5329<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5330<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5331 &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]5332</pre>
5333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5334<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5335<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5337<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5338<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5339
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5340<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5341 <li>The optional "tail" marker indicates that the callee function does not
5342 access any allocas or varargs in the caller. Note that calls may be
5343 marked "tail" even if they do not occur before
5344 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5345 present, the function call is eligible for tail call optimization,
5346 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]5347 optimized into a jump</a>. The code generator may optimize calls marked
5348 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5349 sibling call optimization</a> when the caller and callee have
5350 matching signatures, or 2) forced tail call optimization when the
5351 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5352 <ul>
5353 <li>Caller and callee both have the calling
5354 convention <tt>fastcc</tt>.</li>
5355 <li>The call is in tail position (ret immediately follows call and ret
5356 uses value of call or is void).</li>
5357 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]5358 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5359 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5360 constraints are met.</a></li>
5361 </ul>
5362 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5363
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5364 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5365 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]5366 defaults to using C calling conventions. The calling convention of the
5367 call must match the calling convention of the target function, or else the
5368 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5369
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5370 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5371 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5372 '<tt>inreg</tt>' attributes are valid here.</li>
5373
5374 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5375 type of the return value. Functions that return no value are marked
5376 <tt><a href="#t_void">void</a></tt>.</li>
5377
5378 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5379 being invoked. The argument types must match the types implied by this
5380 signature. This type can be omitted if the function is not varargs and if
5381 the function type does not return a pointer to a function.</li>
5382
5383 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5384 be invoked. In most cases, this is a direct function invocation, but
5385 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5386 to function value.</li>
5387
5388 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]5389 signature argument types and parameter attributes. All arguments must be
5390 of <a href="#t_firstclass">first class</a> type. If the function
5391 signature indicates the function accepts a variable number of arguments,
5392 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5393
5394 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5395 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5396 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5397</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5399<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5400<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5401 a specified function, with its incoming arguments bound to the specified
5402 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5403 function, control flow continues with the instruction after the function
5404 call, and the return value of the function is bound to the result
5405 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5407<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5408<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5409 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5410 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5411 %X = tail call i32 @foo() <i>; yields i32</i>
5412 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5413 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5414
5415 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5416 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5417 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5418 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5419 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5420 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5421</pre>
5422
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5423<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5424standard C99 library as being the C99 library functions, and may perform
5425optimizations or generate code for them under that assumption. This is
5426something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5427freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5429</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5430
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5431<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5432<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5433 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5434</div>
5435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5436<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5437
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5438<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5439<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5440 &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]5441</pre>
5442
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5443<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5444<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5445 the "variable argument" area of a function call. It is used to implement the
5446 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5447
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5448<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5449<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5450 argument. It returns a value of the specified argument type and increments
5451 the <tt>va_list</tt> to point to the next argument. The actual type
5452 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5453
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5454<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5455<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5456 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5457 to the next argument. For more information, see the variable argument
5458 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5459
5460<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]5461 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5462 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5464<p><tt>va_arg</tt> is an LLVM instruction instead of
5465 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5466 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5467
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5468<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5469<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5470
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5471<p>Note that the code generator does not yet fully support va_arg on many
5472 targets. Also, it does not currently support va_arg with aggregate types on
5473 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5475</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5476
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5477<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5478<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5479<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5481<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5482
5483<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5484 well known names and semantics and are required to follow certain
5485 restrictions. Overall, these intrinsics represent an extension mechanism for
5486 the LLVM language that does not require changing all of the transformations
5487 in LLVM when adding to the language (or the bitcode reader/writer, the
5488 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5489
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5490<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5491 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5492 begin with this prefix. Intrinsic functions must always be external
5493 functions: you cannot define the body of intrinsic functions. Intrinsic
5494 functions may only be used in call or invoke instructions: it is illegal to
5495 take the address of an intrinsic function. Additionally, because intrinsic
5496 functions are part of the LLVM language, it is required if any are added that
5497 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5498
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5500 family of functions that perform the same operation but on different data
5501 types. Because LLVM can represent over 8 million different integer types,
5502 overloading is used commonly to allow an intrinsic function to operate on any
5503 integer type. One or more of the argument types or the result type can be
5504 overloaded to accept any integer type. Argument types may also be defined as
5505 exactly matching a previous argument's type or the result type. This allows
5506 an intrinsic function which accepts multiple arguments, but needs all of them
5507 to be of the same type, to only be overloaded with respect to a single
5508 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5509
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5510<p>Overloaded intrinsics will have the names of its overloaded argument types
5511 encoded into its function name, each preceded by a period. Only those types
5512 which are overloaded result in a name suffix. Arguments whose type is matched
5513 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5514 can take an integer of any width and returns an integer of exactly the same
5515 integer width. This leads to a family of functions such as
5516 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5517 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5518 suffix is required. Because the argument's type is matched against the return
5519 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5520
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5521<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5522 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5523
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5524</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5525
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5526<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5527<div class="doc_subsection">
5528 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5529</div>
5530
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5531<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5532
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5533<p>Variable argument support is defined in LLVM with
5534 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5535 intrinsic functions. These functions are related to the similarly named
5536 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5537
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5538<p>All of these functions operate on arguments that use a target-specific value
5539 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5540 not define what this type is, so all transformations should be prepared to
5541 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5542
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5543<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]5544 instruction and the variable argument handling intrinsic functions are
5545 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5546
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5547<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5548<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5549define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5550 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5551 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5552 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5553 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5554
5555 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5556 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5557
5558 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5559 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5560 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5561 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5562 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5563
5564 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5565 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5566 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5567}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5568
5569declare void @llvm.va_start(i8*)
5570declare void @llvm.va_copy(i8*, i8*)
5571declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5572</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5573</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5574
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5575</div>
5576
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5577<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5578<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5579 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5580</div>
5581
5582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5583<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5584
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5585<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586<pre>
5587 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5588</pre>
5589
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5590<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5592 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]5593
5594<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5595<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]5596
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5597<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5598<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]5599 macro available in C. In a target-dependent way, it initializes
5600 the <tt>va_list</tt> element to which the argument points, so that the next
5601 call to <tt>va_arg</tt> will produce the first variable argument passed to
5602 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5603 need to know the last argument of the function as the compiler can figure
5604 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5605
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5606</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5607
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5608<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5609<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5610 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5611</div>
5612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5613<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5614
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5615<h5>Syntax:</h5>
5616<pre>
5617 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5618</pre>
5619
5620<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5621<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622 which has been initialized previously
5623 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5624 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5625
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5626<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5627<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]5628
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5629<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5630<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]5631 macro available in C. In a target-dependent way, it destroys
5632 the <tt>va_list</tt> element to which the argument points. Calls
5633 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5634 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5635 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5636
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5637</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5638
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5639<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5640<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5641 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5642</div>
5643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5644<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5645
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5646<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5647<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5648 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5649</pre>
5650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5651<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5652<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5653 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5654
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5655<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5656<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]5657 The second argument is a pointer to a <tt>va_list</tt> element to copy
5658 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5659
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5660<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5661<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]5662 macro available in C. In a target-dependent way, it copies the
5663 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5664 element. This intrinsic is necessary because
5665 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5666 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5667
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5668</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5669
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5670<!-- ======================================================================= -->
5671<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5672 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5673</div>
5674
5675<div class="doc_text">
5676
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5677<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5678Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5680roots on the stack</a>, as well as garbage collector implementations that
5681require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5682barriers. Front-ends for type-safe garbage collected languages should generate
5683these intrinsics to make use of the LLVM garbage collectors. For more details,
5684see <a href="GarbageCollection.html">Accurate Garbage Collection with
5685LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5686
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The garbage collection intrinsics only operate on objects in the generic
5688 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5689
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5690</div>
5691
5692<!-- _______________________________________________________________________ -->
5693<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5694 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5695</div>
5696
5697<div class="doc_text">
5698
5699<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5700<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5701 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5702</pre>
5703
5704<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5705<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]5706 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5707
5708<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5709<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5710 root pointer. The second pointer (which must be either a constant or a
5711 global value address) contains the meta-data to be associated with the
5712 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5713
5714<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5715<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]5716 location. At compile-time, the code generator generates information to allow
5717 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5718 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5719 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5720
5721</div>
5722
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5723<!-- _______________________________________________________________________ -->
5724<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5725 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5726</div>
5727
5728<div class="doc_text">
5729
5730<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5731<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5732 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5733</pre>
5734
5735<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5736<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5737 locations, allowing garbage collector implementations that require read
5738 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5739
5740<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5741<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]5742 allocated from the garbage collector. The first object is a pointer to the
5743 start of the referenced object, if needed by the language runtime (otherwise
5744 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5745
5746<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5747<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5748 instruction, but may be replaced with substantially more complex code by the
5749 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5750 may only be used in a function which <a href="#gc">specifies a GC
5751 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5752
5753</div>
5754
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5755<!-- _______________________________________________________________________ -->
5756<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5757 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5758</div>
5759
5760<div class="doc_text">
5761
5762<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5763<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5764 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5765</pre>
5766
5767<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5768<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5769 locations, allowing garbage collector implementations that require write
5770 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5771
5772<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5773<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]5774 object to store it to, and the third is the address of the field of Obj to
5775 store to. If the runtime does not require a pointer to the object, Obj may
5776 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5777
5778<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5779<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5780 instruction, but may be replaced with substantially more complex code by the
5781 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5782 may only be used in a function which <a href="#gc">specifies a GC
5783 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5784
5785</div>
5786
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5787<!-- ======================================================================= -->
5788<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789 <a name="int_codegen">Code Generator Intrinsics</a>
5790</div>
5791
5792<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5793
5794<p>These intrinsics are provided by LLVM to expose special features that may
5795 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796
5797</div>
5798
5799<!-- _______________________________________________________________________ -->
5800<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5801 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5802</div>
5803
5804<div class="doc_text">
5805
5806<h5>Syntax:</h5>
5807<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5808 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5809</pre>
5810
5811<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5813 target-specific value indicating the return address of the current function
5814 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5815
5816<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817<p>The argument to this intrinsic indicates which function to return the address
5818 for. Zero indicates the calling function, one indicates its caller, etc.
5819 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5820
5821<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5823 indicating the return address of the specified call frame, or zero if it
5824 cannot be identified. The value returned by this intrinsic is likely to be
5825 incorrect or 0 for arguments other than zero, so it should only be used for
5826 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5827
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5828<p>Note that calling this intrinsic does not prevent function inlining or other
5829 aggressive transformations, so the value returned may not be that of the
5830 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5831
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5832</div>
5833
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5834<!-- _______________________________________________________________________ -->
5835<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5836 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5837</div>
5838
5839<div class="doc_text">
5840
5841<h5>Syntax:</h5>
5842<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5843 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5848 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5849
5850<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The argument to this intrinsic indicates which function to return the frame
5852 pointer for. Zero indicates the calling function, one indicates its caller,
5853 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5854
5855<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5857 indicating the frame address of the specified call frame, or zero if it
5858 cannot be identified. The value returned by this intrinsic is likely to be
5859 incorrect or 0 for arguments other than zero, so it should only be used for
5860 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5861
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>Note that calling this intrinsic does not prevent function inlining or other
5863 aggressive transformations, so the value returned may not be that of the
5864 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5865
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5866</div>
5867
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5868<!-- _______________________________________________________________________ -->
5869<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5870 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5871</div>
5872
5873<div class="doc_text">
5874
5875<h5>Syntax:</h5>
5876<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5877 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5878</pre>
5879
5880<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5882 of the function stack, for use
5883 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5884 useful for implementing language features like scoped automatic variable
5885 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5886
5887<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5888<p>This intrinsic returns a opaque pointer value that can be passed
5889 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5890 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5891 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5892 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5893 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5894 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5895
5896</div>
5897
5898<!-- _______________________________________________________________________ -->
5899<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5900 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5901</div>
5902
5903<div class="doc_text">
5904
5905<h5>Syntax:</h5>
5906<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5907 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5908</pre>
5909
5910<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5911<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5912 the function stack to the state it was in when the
5913 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5914 executed. This is useful for implementing language features like scoped
5915 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5916
5917<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5918<p>See the description
5919 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5920
5921</div>
5922
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5923<!-- _______________________________________________________________________ -->
5924<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5925 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5926</div>
5927
5928<div class="doc_text">
5929
5930<h5>Syntax:</h5>
5931<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5932 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]5933</pre>
5934
5935<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5936<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5937 insert a prefetch instruction if supported; otherwise, it is a noop.
5938 Prefetches have no effect on the behavior of the program but can change its
5939 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5940
5941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5942<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5943 specifier determining if the fetch should be for a read (0) or write (1),
5944 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5945 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5946 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5947
5948<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5949<p>This intrinsic does not modify the behavior of the program. In particular,
5950 prefetches cannot trap and do not produce a value. On targets that support
5951 this intrinsic, the prefetch can provide hints to the processor cache for
5952 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5953
5954</div>
5955
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5956<!-- _______________________________________________________________________ -->
5957<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5958 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5959</div>
5960
5961<div class="doc_text">
5962
5963<h5>Syntax:</h5>
5964<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5965 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5966</pre>
5967
5968<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5970 Counter (PC) in a region of code to simulators and other tools. The method
5971 is target specific, but it is expected that the marker will use exported
5972 symbols to transmit the PC of the marker. The marker makes no guarantees
5973 that it will remain with any specific instruction after optimizations. It is
5974 possible that the presence of a marker will inhibit optimizations. The
5975 intended use is to be inserted after optimizations to allow correlations of
5976 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5977
5978<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5979<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5980
5981<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5982<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5983 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5984
5985</div>
5986
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5987<!-- _______________________________________________________________________ -->
5988<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5989 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5990</div>
5991
5992<div class="doc_text">
5993
5994<h5>Syntax:</h5>
5995<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5996 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5997</pre>
5998
5999<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6001 counter register (or similar low latency, high accuracy clocks) on those
6002 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6003 should map to RPCC. As the backing counters overflow quickly (on the order
6004 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6005
6006<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>When directly supported, reading the cycle counter should not modify any
6008 memory. Implementations are allowed to either return a application specific
6009 value or a system wide value. On backends without support, this is lowered
6010 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6011
6012</div>
6013
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6014<!-- ======================================================================= -->
6015<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6016 <a name="int_libc">Standard C Library Intrinsics</a>
6017</div>
6018
6019<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6020
6021<p>LLVM provides intrinsics for a few important standard C library functions.
6022 These intrinsics allow source-language front-ends to pass information about
6023 the alignment of the pointer arguments to the code generator, providing
6024 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6025
6026</div>
6027
6028<!-- _______________________________________________________________________ -->
6029<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6030 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6031</div>
6032
6033<div class="doc_text">
6034
6035<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6036<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]6037 integer bit width and for different address spaces. Not all targets support
6038 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6039
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6040<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6041 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6042 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6043 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6044 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6045</pre>
6046
6047<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6048<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6049 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6050
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6051<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6052 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6053 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6054
6055<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6056
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6057<p>The first argument is a pointer to the destination, the second is a pointer
6058 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6059 number of bytes to copy, the fourth argument is the alignment of the
6060 source and destination locations, and the fifth is a boolean indicating a
6061 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6062
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6063<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]6064 then the caller guarantees that both the source and destination pointers are
6065 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6066
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6067<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6068 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6069 The detailed access behavior is not very cleanly specified and it is unwise
6070 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6071
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6072<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6073
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6075 source location to the destination location, which are not allowed to
6076 overlap. It copies "len" bytes of memory over. If the argument is known to
6077 be aligned to some boundary, this can be specified as the fourth argument,
6078 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6079
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6080</div>
6081
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6084 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6090<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]6091 width and for different address space. Not all targets support all bit
6092 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6093
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6094<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6095 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6096 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6097 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6098 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6103 source location to the destination location. It is similar to the
6104 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6105 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6106
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6107<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6108 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6109 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6110
6111<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6112
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6113<p>The first argument is a pointer to the destination, the second is a pointer
6114 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6115 number of bytes to copy, the fourth argument is the alignment of the
6116 source and destination locations, and the fifth is a boolean indicating a
6117 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6118
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6119<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]6120 then the caller guarantees that the source and destination pointers are
6121 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6122
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6123<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6124 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6125 The detailed access behavior is not very cleanly specified and it is unwise
6126 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6127
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6128<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6129
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6130<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6131 source location to the destination location, which may overlap. It copies
6132 "len" bytes of memory over. If the argument is known to be aligned to some
6133 boundary, this can be specified as the fourth argument, otherwise it should
6134 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6135
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6136</div>
6137
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6138<!-- _______________________________________________________________________ -->
6139<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6140 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6141</div>
6142
6143<div class="doc_text">
6144
6145<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6146<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]6147 width and for different address spaces. Not all targets support all bit
6148 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6150<pre>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6151 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6152 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6153 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6154 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6155</pre>
6156
6157<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6158<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6159 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6160
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6161<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6162 intrinsic does not return a value, takes extra alignment/volatile arguments,
6163 and the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6164
6165<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6166<p>The first argument is a pointer to the destination to fill, the second is the
6167 byte value to fill it with, the third argument is an integer argument
6168 specifying the number of bytes to fill, and the fourth argument is the known
6169 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6170
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6171<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]6172 then the caller guarantees that the destination pointer is aligned to that
6173 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6174
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6175<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6176 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6177 The detailed access behavior is not very cleanly specified and it is unwise
6178 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6179
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6180<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6181<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6182 at the destination location. If the argument is known to be aligned to some
6183 boundary, this can be specified as the fourth argument, otherwise it should
6184 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6185
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6186</div>
6187
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6188<!-- _______________________________________________________________________ -->
6189<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6190 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6191</div>
6192
6193<div class="doc_text">
6194
6195<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6196<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6197 floating point or vector of floating point type. Not all targets support all
6198 types however.</p>
6199
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6200<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6201 declare float @llvm.sqrt.f32(float %Val)
6202 declare double @llvm.sqrt.f64(double %Val)
6203 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6204 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6205 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6206</pre>
6207
6208<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6210 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6211 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6212 behavior for negative numbers other than -0.0 (which allows for better
6213 optimization, because there is no need to worry about errno being
6214 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]6215
6216<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6217<p>The argument and return value are floating point numbers of the same
6218 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6219
6220<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6221<p>This function returns the sqrt of the specified operand if it is a
6222 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6223
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6224</div>
6225
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6226<!-- _______________________________________________________________________ -->
6227<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6228 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6229</div>
6230
6231<div class="doc_text">
6232
6233<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6234<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6235 floating point or vector of floating point type. Not all targets support all
6236 types however.</p>
6237
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6238<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6239 declare float @llvm.powi.f32(float %Val, i32 %power)
6240 declare double @llvm.powi.f64(double %Val, i32 %power)
6241 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6242 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6243 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6244</pre>
6245
6246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6247<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6248 specified (positive or negative) power. The order of evaluation of
6249 multiplications is not defined. When a vector of floating point type is
6250 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6251
6252<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6253<p>The second argument is an integer power, and the first is a value to raise to
6254 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6255
6256<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257<p>This function returns the first value raised to the second power with an
6258 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6259
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]6260</div>
6261
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6262<!-- _______________________________________________________________________ -->
6263<div class="doc_subsubsection">
6264 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6265</div>
6266
6267<div class="doc_text">
6268
6269<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6270<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6271 floating point or vector of floating point type. Not all targets support all
6272 types however.</p>
6273
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6274<pre>
6275 declare float @llvm.sin.f32(float %Val)
6276 declare double @llvm.sin.f64(double %Val)
6277 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6278 declare fp128 @llvm.sin.f128(fp128 %Val)
6279 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6280</pre>
6281
6282<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6283<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6284
6285<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6286<p>The argument and return value are floating point numbers of the same
6287 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6288
6289<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6290<p>This function returns the sine of the specified operand, returning the same
6291 values as the libm <tt>sin</tt> functions would, and handles error conditions
6292 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6293
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6294</div>
6295
6296<!-- _______________________________________________________________________ -->
6297<div class="doc_subsubsection">
6298 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6299</div>
6300
6301<div class="doc_text">
6302
6303<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6304<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6305 floating point or vector of floating point type. Not all targets support all
6306 types however.</p>
6307
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6308<pre>
6309 declare float @llvm.cos.f32(float %Val)
6310 declare double @llvm.cos.f64(double %Val)
6311 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6312 declare fp128 @llvm.cos.f128(fp128 %Val)
6313 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6314</pre>
6315
6316<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6317<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6318
6319<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6320<p>The argument and return value are floating point numbers of the same
6321 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6322
6323<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6324<p>This function returns the cosine of the specified operand, returning the same
6325 values as the libm <tt>cos</tt> functions would, and handles error conditions
6326 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6327
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6328</div>
6329
6330<!-- _______________________________________________________________________ -->
6331<div class="doc_subsubsection">
6332 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6333</div>
6334
6335<div class="doc_text">
6336
6337<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6338<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6339 floating point or vector of floating point type. Not all targets support all
6340 types however.</p>
6341
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6342<pre>
6343 declare float @llvm.pow.f32(float %Val, float %Power)
6344 declare double @llvm.pow.f64(double %Val, double %Power)
6345 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6346 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6347 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6348</pre>
6349
6350<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6351<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6352 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6353
6354<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6355<p>The second argument is a floating point power, and the first is a value to
6356 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6357
6358<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6359<p>This function returns the first value raised to the second power, returning
6360 the same values as the libm <tt>pow</tt> functions would, and handles error
6361 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6362
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]6363</div>
6364
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6365<!-- ======================================================================= -->
6366<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6367 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6368</div>
6369
6370<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6371
6372<p>LLVM provides intrinsics for a few important bit manipulation operations.
6373 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6374
6375</div>
6376
6377<!-- _______________________________________________________________________ -->
6378<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6379 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6380</div>
6381
6382<div class="doc_text">
6383
6384<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6385<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6386 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6387
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6388<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6389 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6390 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6391 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6392</pre>
6393
6394<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6395<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6396 values with an even number of bytes (positive multiple of 16 bits). These
6397 are useful for performing operations on data that is not in the target's
6398 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6399
6400<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6401<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6402 and low byte of the input i16 swapped. Similarly,
6403 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6404 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6405 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6406 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6407 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6408 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6409
6410</div>
6411
6412<!-- _______________________________________________________________________ -->
6413<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6414 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6415</div>
6416
6417<div class="doc_text">
6418
6419<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6420<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]6421 width. Not all targets support all bit widths however.</p>
6422
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6423<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6424 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6425 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6426 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6427 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6428 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6429</pre>
6430
6431<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6433 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6434
6435<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6436<p>The only argument is the value to be counted. The argument may be of any
6437 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6438
6439<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6440<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]6441
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6442</div>
6443
6444<!-- _______________________________________________________________________ -->
6445<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6446 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6447</div>
6448
6449<div class="doc_text">
6450
6451<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6452<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6453 integer bit width. Not all targets support all bit widths however.</p>
6454
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6455<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6456 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6457 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6458 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6459 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6460 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6461</pre>
6462
6463<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6465 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6466
6467<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6468<p>The only argument is the value to be counted. The argument may be of any
6469 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6470
6471<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6472<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6473 zeros in a variable. If the src == 0 then the result is the size in bits of
6474 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6475
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6476</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6477
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6478<!-- _______________________________________________________________________ -->
6479<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6480 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6481</div>
6482
6483<div class="doc_text">
6484
6485<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6486<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6487 integer bit width. Not all targets support all bit widths however.</p>
6488
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6489<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6490 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6491 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6492 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6493 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6494 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6495</pre>
6496
6497<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6499 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6500
6501<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6502<p>The only argument is the value to be counted. The argument may be of any
6503 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6504
6505<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6507 zeros in a variable. If the src == 0 then the result is the size in bits of
6508 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6509
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6510</div>
6511
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6512<!-- ======================================================================= -->
6513<div class="doc_subsection">
6514 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6515</div>
6516
6517<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6518
6519<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6520
6521</div>
6522
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6523<!-- _______________________________________________________________________ -->
6524<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6525 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6526</div>
6527
6528<div class="doc_text">
6529
6530<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6531<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]6532 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6533
6534<pre>
6535 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6536 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6537 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6538</pre>
6539
6540<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6541<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6542 a signed addition of the two arguments, and indicate whether an overflow
6543 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6544
6545<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6546<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]6547 be of integer types of any bit width, but they must have the same bit
6548 width. The second element of the result structure must be of
6549 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6550 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6551
6552<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6553<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6554 a signed addition of the two variables. They return a structure &mdash; the
6555 first element of which is the signed summation, and the second element of
6556 which is a bit specifying if the signed summation resulted in an
6557 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6558
6559<h5>Examples:</h5>
6560<pre>
6561 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6562 %sum = extractvalue {i32, i1} %res, 0
6563 %obit = extractvalue {i32, i1} %res, 1
6564 br i1 %obit, label %overflow, label %normal
6565</pre>
6566
6567</div>
6568
6569<!-- _______________________________________________________________________ -->
6570<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6571 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6572</div>
6573
6574<div class="doc_text">
6575
6576<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6577<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]6578 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6579
6580<pre>
6581 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6582 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6583 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6584</pre>
6585
6586<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6587<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6588 an unsigned addition of the two arguments, and indicate whether a carry
6589 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6590
6591<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6592<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]6593 be of integer types of any bit width, but they must have the same bit
6594 width. The second element of the result structure must be of
6595 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6596 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6597
6598<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6599<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6600 an unsigned addition of the two arguments. They return a structure &mdash;
6601 the first element of which is the sum, and the second element of which is a
6602 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6603
6604<h5>Examples:</h5>
6605<pre>
6606 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6607 %sum = extractvalue {i32, i1} %res, 0
6608 %obit = extractvalue {i32, i1} %res, 1
6609 br i1 %obit, label %carry, label %normal
6610</pre>
6611
6612</div>
6613
6614<!-- _______________________________________________________________________ -->
6615<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6616 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6617</div>
6618
6619<div class="doc_text">
6620
6621<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6622<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]6623 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6624
6625<pre>
6626 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6627 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6628 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6629</pre>
6630
6631<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6632<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6633 a signed subtraction of the two arguments, and indicate whether an overflow
6634 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6635
6636<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6637<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]6638 be of integer types of any bit width, but they must have the same bit
6639 width. The second element of the result structure must be of
6640 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6641 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6642
6643<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6644<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6645 a signed subtraction of the two arguments. They return a structure &mdash;
6646 the first element of which is the subtraction, and the second element of
6647 which is a bit specifying if the signed subtraction resulted in an
6648 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6649
6650<h5>Examples:</h5>
6651<pre>
6652 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6653 %sum = extractvalue {i32, i1} %res, 0
6654 %obit = extractvalue {i32, i1} %res, 1
6655 br i1 %obit, label %overflow, label %normal
6656</pre>
6657
6658</div>
6659
6660<!-- _______________________________________________________________________ -->
6661<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6662 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6663</div>
6664
6665<div class="doc_text">
6666
6667<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6668<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]6669 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6670
6671<pre>
6672 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6673 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6674 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6675</pre>
6676
6677<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6678<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6679 an unsigned subtraction of the two arguments, and indicate whether an
6680 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6681
6682<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6683<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6684 be of integer types of any bit width, but they must have the same bit
6685 width. The second element of the result structure must be of
6686 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6687 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6688
6689<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6690<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6691 an unsigned subtraction of the two arguments. They return a structure &mdash;
6692 the first element of which is the subtraction, and the second element of
6693 which is a bit specifying if the unsigned subtraction resulted in an
6694 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6695
6696<h5>Examples:</h5>
6697<pre>
6698 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6699 %sum = extractvalue {i32, i1} %res, 0
6700 %obit = extractvalue {i32, i1} %res, 1
6701 br i1 %obit, label %overflow, label %normal
6702</pre>
6703
6704</div>
6705
6706<!-- _______________________________________________________________________ -->
6707<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6708 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6709</div>
6710
6711<div class="doc_text">
6712
6713<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6714<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]6715 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6716
6717<pre>
6718 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6719 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6720 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6721</pre>
6722
6723<h5>Overview:</h5>
6724
6725<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6726 a signed multiplication of the two arguments, and indicate whether an
6727 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6728
6729<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6730<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]6731 be of integer types of any bit width, but they must have the same bit
6732 width. The second element of the result structure must be of
6733 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6734 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6735
6736<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6737<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6738 a signed multiplication of the two arguments. They return a structure &mdash;
6739 the first element of which is the multiplication, and the second element of
6740 which is a bit specifying if the signed multiplication resulted in an
6741 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6742
6743<h5>Examples:</h5>
6744<pre>
6745 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6746 %sum = extractvalue {i32, i1} %res, 0
6747 %obit = extractvalue {i32, i1} %res, 1
6748 br i1 %obit, label %overflow, label %normal
6749</pre>
6750
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6751</div>
6752
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6753<!-- _______________________________________________________________________ -->
6754<div class="doc_subsubsection">
6755 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6756</div>
6757
6758<div class="doc_text">
6759
6760<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6761<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]6762 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6763
6764<pre>
6765 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6766 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6767 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6768</pre>
6769
6770<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6771<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6772 a unsigned multiplication of the two arguments, and indicate whether an
6773 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6774
6775<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6776<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]6777 be of integer types of any bit width, but they must have the same bit
6778 width. The second element of the result structure must be of
6779 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6780 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6781
6782<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6783<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784 an unsigned multiplication of the two arguments. They return a structure
6785 &mdash; the first element of which is the multiplication, and the second
6786 element of which is a bit specifying if the unsigned multiplication resulted
6787 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6788
6789<h5>Examples:</h5>
6790<pre>
6791 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6792 %sum = extractvalue {i32, i1} %res, 0
6793 %obit = extractvalue {i32, i1} %res, 1
6794 br i1 %obit, label %overflow, label %normal
6795</pre>
6796
6797</div>
6798
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6799<!-- ======================================================================= -->
6800<div class="doc_subsection">
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6801 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6802</div>
6803
6804<div class="doc_text">
6805
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6806<p>Half precision floating point is a storage-only format. This means that it is
6807 a dense encoding (in memory) but does not support computation in the
6808 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6809
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6810<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6811 value as an i16, then convert it to float with <a
6812 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6813 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6814 double etc). To store the value back to memory, it is first converted to
6815 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6816 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6817 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6818</div>
6819
6820<!-- _______________________________________________________________________ -->
6821<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6822 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6823</div>
6824
6825<div class="doc_text">
6826
6827<h5>Syntax:</h5>
6828<pre>
6829 declare i16 @llvm.convert.to.fp16(f32 %a)
6830</pre>
6831
6832<h5>Overview:</h5>
6833<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6834 a conversion from single precision floating point format to half precision
6835 floating point format.</p>
6836
6837<h5>Arguments:</h5>
6838<p>The intrinsic function contains single argument - the value to be
6839 converted.</p>
6840
6841<h5>Semantics:</h5>
6842<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6843 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6844 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6845 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6846
6847<h5>Examples:</h5>
6848<pre>
6849 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6850 store i16 %res, i16* @x, align 2
6851</pre>
6852
6853</div>
6854
6855<!-- _______________________________________________________________________ -->
6856<div class="doc_subsubsection">
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6857 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6858</div>
6859
6860<div class="doc_text">
6861
6862<h5>Syntax:</h5>
6863<pre>
6864 declare f32 @llvm.convert.from.fp16(i16 %a)
6865</pre>
6866
6867<h5>Overview:</h5>
6868<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6869 a conversion from half precision floating point format to single precision
6870 floating point format.</p>
6871
6872<h5>Arguments:</h5>
6873<p>The intrinsic function contains single argument - the value to be
6874 converted.</p>
6875
6876<h5>Semantics:</h5>
6877<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]6878 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]6879 precision floating point format. The input half-float value is represented by
6880 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]6881
6882<h5>Examples:</h5>
6883<pre>
6884 %a = load i16* @x, align 2
6885 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6886</pre>
6887
6888</div>
6889
6890<!-- ======================================================================= -->
6891<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6892 <a name="int_debugger">Debugger Intrinsics</a>
6893</div>
6894
6895<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6896
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6897<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6898 prefix), are described in
6899 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6900 Level Debugging</a> document.</p>
6901
6902</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6903
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6904<!-- ======================================================================= -->
6905<div class="doc_subsection">
6906 <a name="int_eh">Exception Handling Intrinsics</a>
6907</div>
6908
6909<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910
6911<p>The LLVM exception handling intrinsics (which all start with
6912 <tt>llvm.eh.</tt> prefix), are described in
6913 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6914 Handling</a> document.</p>
6915
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6916</div>
6917
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6918<!-- ======================================================================= -->
6919<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6920 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6921</div>
6922
6923<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924
6925<p>This intrinsic makes it possible to excise one parameter, marked with
6926 the <tt>nest</tt> attribute, from a function. The result is a callable
6927 function pointer lacking the nest parameter - the caller does not need to
6928 provide a value for it. Instead, the value to use is stored in advance in a
6929 "trampoline", a block of memory usually allocated on the stack, which also
6930 contains code to splice the nest value into the argument list. This is used
6931 to implement the GCC nested function address extension.</p>
6932
6933<p>For example, if the function is
6934 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6935 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6936 follows:</p>
6937
6938<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6939<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6940 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6941 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6942 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6943 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945</div>
6946
6947<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6948 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6949
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6950</div>
6951
6952<!-- _______________________________________________________________________ -->
6953<div class="doc_subsubsection">
6954 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6955</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6956
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6957<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6958
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6959<h5>Syntax:</h5>
6960<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6961 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]6962</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6963
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6964<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6965<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6966 function pointer suitable for executing it.</p>
6967
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6968<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6969<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6970 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6971 sufficiently aligned block of memory; this memory is written to by the
6972 intrinsic. Note that the size and the alignment are target-specific - LLVM
6973 currently provides no portable way of determining them, so a front-end that
6974 generates this intrinsic needs to have some target-specific knowledge.
6975 The <tt>func</tt> argument must hold a function bitcast to
6976 an <tt>i8*</tt>.</p>
6977
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6978<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6979<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6980 dependent code, turning it into a function. A pointer to this function is
6981 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6982 function pointer type</a> before being called. The new function's signature
6983 is the same as that of <tt>func</tt> with any arguments marked with
6984 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6985 is allowed, and it must be of pointer type. Calling the new function is
6986 equivalent to calling <tt>func</tt> with the same argument list, but
6987 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6988 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6989 by <tt>tramp</tt> is modified, then the effect of any later call to the
6990 returned function pointer is undefined.</p>
6991
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6992</div>
6993
6994<!-- ======================================================================= -->
6995<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6996 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6997</div>
6998
6999<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7000
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7001<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7002 hardware constructs for atomic operations and memory synchronization. This
7003 provides an interface to the hardware, not an interface to the programmer. It
7004 is aimed at a low enough level to allow any programming models or APIs
7005 (Application Programming Interfaces) which need atomic behaviors to map
7006 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7007 hardware provides a "universal IR" for source languages, it also provides a
7008 starting point for developing a "universal" atomic operation and
7009 synchronization IR.</p>
7010
7011<p>These do <em>not</em> form an API such as high-level threading libraries,
7012 software transaction memory systems, atomic primitives, and intrinsic
7013 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7014 application libraries. The hardware interface provided by LLVM should allow
7015 a clean implementation of all of these APIs and parallel programming models.
7016 No one model or paradigm should be selected above others unless the hardware
7017 itself ubiquitously does so.</p>
7018
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7019</div>
7020
7021<!-- _______________________________________________________________________ -->
7022<div class="doc_subsubsection">
7023 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7024</div>
7025<div class="doc_text">
7026<h5>Syntax:</h5>
7027<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7028 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]7029</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7030
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7031<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7032<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7033 specific pairs of memory access types.</p>
7034
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7035<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7036<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7037 The first four arguments enables a specific barrier as listed below. The
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]7038 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7039 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7040
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7041<ul>
7042 <li><tt>ll</tt>: load-load barrier</li>
7043 <li><tt>ls</tt>: load-store barrier</li>
7044 <li><tt>sl</tt>: store-load barrier</li>
7045 <li><tt>ss</tt>: store-store barrier</li>
7046 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7047</ul>
7048
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7049<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050<p>This intrinsic causes the system to enforce some ordering constraints upon
7051 the loads and stores of the program. This barrier does not
7052 indicate <em>when</em> any events will occur, it only enforces
7053 an <em>order</em> in which they occur. For any of the specified pairs of load
7054 and store operations (f.ex. load-load, or store-load), all of the first
7055 operations preceding the barrier will complete before any of the second
7056 operations succeeding the barrier begin. Specifically the semantics for each
7057 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7058
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7059<ul>
7060 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7061 after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7062 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7063 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7064 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7065 store after the barrier begins.</li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7066 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7067 load after the barrier begins.</li>
7068</ul>
7069
7070<p>These semantics are applied with a logical "and" behavior when more than one
7071 is enabled in a single memory barrier intrinsic.</p>
7072
7073<p>Backends may implement stronger barriers than those requested when they do
7074 not support as fine grained a barrier as requested. Some architectures do
7075 not need all types of barriers and on such architectures, these become
7076 noops.</p>
7077
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7078<h5>Example:</h5>
7079<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7080%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7081%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7082 store i32 4, %ptr
7083
7084%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7085 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7086 <i>; guarantee the above finishes</i>
7087 store i32 8, %ptr <i>; before this begins</i>
7088</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7089
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7090</div>
7091
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7092<!-- _______________________________________________________________________ -->
7093<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7094 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7095</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7096
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7097<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7098
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7099<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7100<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7101 any integer bit width and for different address spaces. Not all targets
7102 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7103
7104<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7105 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7106 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7107 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7108 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]7109</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7110
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7111<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7112<p>This loads a value in memory and compares it to a given value. If they are
7113 equal, it stores a new value into the memory.</p>
7114
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7115<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7116<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7117 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7118 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7119 this integer type. While any bit width integer may be used, targets may only
7120 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7121
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7122<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7123<p>This entire intrinsic must be executed atomically. It first loads the value
7124 in memory pointed to by <tt>ptr</tt> and compares it with the
7125 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7126 memory. The loaded value is yielded in all cases. This provides the
7127 equivalent of an atomic compare-and-swap operation within the SSA
7128 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7129
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7130<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7131<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7132%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7133%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7134 store i32 4, %ptr
7135
7136%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7137%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7138 <i>; yields {i32}:result1 = 4</i>
7139%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7140%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7141
7142%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7143%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7144 <i>; yields {i32}:result2 = 8</i>
7145%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7146
7147%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7149
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7150</div>
7151
7152<!-- _______________________________________________________________________ -->
7153<div class="doc_subsubsection">
7154 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7155</div>
7156<div class="doc_text">
7157<h5>Syntax:</h5>
7158
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7159<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7160 integer bit width. Not all targets support all bit widths however.</p>
7161
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7162<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7163 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7164 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7165 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7166 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]7167</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7168
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7169<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7170<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7171 the value from memory. It then stores the value in <tt>val</tt> in the memory
7172 at <tt>ptr</tt>.</p>
7173
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7174<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7175<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7176 the <tt>val</tt> argument and the result must be integers of the same bit
7177 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7178 integer type. The targets may only lower integer representations they
7179 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7180
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7181<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7182<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7183 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7184 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7185
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7186<h5>Examples:</h5>
7187<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7188%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7189%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7190 store i32 4, %ptr
7191
7192%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7193%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7194 <i>; yields {i32}:result1 = 4</i>
7195%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7196%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7197
7198%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7199%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7200 <i>; yields {i32}:result2 = 8</i>
7201
7202%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7203%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7204</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7205
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7206</div>
7207
7208<!-- _______________________________________________________________________ -->
7209<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7210 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7211
7212</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7213
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7214<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7215
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7216<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7217<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7218 any integer bit width. Not all targets support all bit widths however.</p>
7219
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7220<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7222 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7223 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7224 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]7225</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7226
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7227<h5>Overview:</h5>
7228<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7229 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7230
7231<h5>Arguments:</h5>
7232<p>The intrinsic takes two arguments, the first a pointer to an integer value
7233 and the second an integer value. The result is also an integer value. These
7234 integer types can have any bit width, but they must all have the same bit
7235 width. The targets may only lower integer representations they support.</p>
7236
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7237<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7238<p>This intrinsic does a series of operations atomically. It first loads the
7239 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7240 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]7241
7242<h5>Examples:</h5>
7243<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7244%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7245%ptr = bitcast i8* %mallocP to i32*
7246 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7247%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7248 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7249%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7250 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7251%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7252 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7253%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7254</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]7256</div>
7257
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7258<!-- _______________________________________________________________________ -->
7259<div class="doc_subsubsection">
7260 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7261
7262</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7263
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7264<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7265
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7266<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7267<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7268 any integer bit width and for different address spaces. Not all targets
7269 support all bit widths however.</p>
7270
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7271<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7272 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7273 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7274 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7275 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]7276</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7277
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7279<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7280 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7281
7282<h5>Arguments:</h5>
7283<p>The intrinsic takes two arguments, the first a pointer to an integer value
7284 and the second an integer value. The result is also an integer value. These
7285 integer types can have any bit width, but they must all have the same bit
7286 width. The targets may only lower integer representations they support.</p>
7287
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7288<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7289<p>This intrinsic does a series of operations atomically. It first loads the
7290 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7291 result to <tt>ptr</tt>. It yields the original value stored
7292 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7293
7294<h5>Examples:</h5>
7295<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7296%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7297%ptr = bitcast i8* %mallocP to i32*
7298 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7299%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7300 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7301%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7302 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7303%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7304 <i>; yields {i32}:result3 = 2</i>
7305%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7306</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7307
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7308</div>
7309
7310<!-- _______________________________________________________________________ -->
7311<div class="doc_subsubsection">
7312 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7313 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7314 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7315 <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]7316</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7317
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7318<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7319
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7320<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7321<p>These are overloaded intrinsics. You can
7322 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7323 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7324 bit width and for different address spaces. Not all targets support all bit
7325 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7327<pre>
7328 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7329 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7330 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7331 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]7332</pre>
7333
7334<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7335 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7336 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7337 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7338 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]7339</pre>
7340
7341<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7342 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7343 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7344 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7345 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]7346</pre>
7347
7348<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7349 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7350 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7351 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7352 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]7353</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7354
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7355<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7356<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7357 the value stored in memory at <tt>ptr</tt>. It yields the original value
7358 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7359
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7360<h5>Arguments:</h5>
7361<p>These intrinsics take two arguments, the first a pointer to an integer value
7362 and the second an integer value. The result is also an integer value. These
7363 integer types can have any bit width, but they must all have the same bit
7364 width. The targets may only lower integer representations they support.</p>
7365
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7366<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7367<p>These intrinsics does a series of operations atomically. They first load the
7368 value stored at <tt>ptr</tt>. They then do the bitwise
7369 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7370 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7371
7372<h5>Examples:</h5>
7373<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7374%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7375%ptr = bitcast i8* %mallocP to i32*
7376 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7377%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7378 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7379%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7380 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7381%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7382 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7383%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7384 <i>; yields {i32}:result3 = FF</i>
7385%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7386</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7387
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7388</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7389
7390<!-- _______________________________________________________________________ -->
7391<div class="doc_subsubsection">
7392 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7393 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7394 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7395 <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]7396</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7397
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7398<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7399
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7400<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7401<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7402 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7403 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7404 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7405
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7406<pre>
7407 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7408 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7409 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7410 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]7411</pre>
7412
7413<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7414 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7415 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7416 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7417 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]7418</pre>
7419
7420<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7421 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7422 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7423 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7424 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]7425</pre>
7426
7427<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7428 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7429 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7430 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7431 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]7432</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7433
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7434<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7435<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7436 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7437 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7438
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7439<h5>Arguments:</h5>
7440<p>These intrinsics take two arguments, the first a pointer to an integer value
7441 and the second an integer value. The result is also an integer value. These
7442 integer types can have any bit width, but they must all have the same bit
7443 width. The targets may only lower integer representations they support.</p>
7444
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7445<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7446<p>These intrinsics does a series of operations atomically. They first load the
7447 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7448 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7449 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7450
7451<h5>Examples:</h5>
7452<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]7453%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7454%ptr = bitcast i8* %mallocP to i32*
7455 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7456%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7457 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7458%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7459 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7460%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7461 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7462%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7463 <i>; yields {i32}:result3 = 8</i>
7464%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7465</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7466
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7467</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7468
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7469
7470<!-- ======================================================================= -->
7471<div class="doc_subsection">
7472 <a name="int_memorymarkers">Memory Use Markers</a>
7473</div>
7474
7475<div class="doc_text">
7476
7477<p>This class of intrinsics exists to information about the lifetime of memory
7478 objects and ranges where variables are immutable.</p>
7479
7480</div>
7481
7482<!-- _______________________________________________________________________ -->
7483<div class="doc_subsubsection">
7484 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7485</div>
7486
7487<div class="doc_text">
7488
7489<h5>Syntax:</h5>
7490<pre>
7491 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7492</pre>
7493
7494<h5>Overview:</h5>
7495<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7496 object's lifetime.</p>
7497
7498<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7499<p>The first argument is a constant integer representing the size of the
7500 object, or -1 if it is variable sized. The second argument is a pointer to
7501 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7502
7503<h5>Semantics:</h5>
7504<p>This intrinsic indicates that before this point in the code, the value of the
7505 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]7506 never be used and has an undefined value. A load from the pointer that
7507 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7508 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7509
7510</div>
7511
7512<!-- _______________________________________________________________________ -->
7513<div class="doc_subsubsection">
7514 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7515</div>
7516
7517<div class="doc_text">
7518
7519<h5>Syntax:</h5>
7520<pre>
7521 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7522</pre>
7523
7524<h5>Overview:</h5>
7525<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end 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 after 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
7536 never be used and has an undefined value. Any stores into the memory object
7537 following this intrinsic may be removed as dead.
7538
7539</div>
7540
7541<!-- _______________________________________________________________________ -->
7542<div class="doc_subsubsection">
7543 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7544</div>
7545
7546<div class="doc_text">
7547
7548<h5>Syntax:</h5>
7549<pre>
7550 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7551</pre>
7552
7553<h5>Overview:</h5>
7554<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7555 a memory object will not change.</p>
7556
7557<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7558<p>The first argument is a constant integer representing the size of the
7559 object, or -1 if it is variable sized. The second argument is a pointer to
7560 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7561
7562<h5>Semantics:</h5>
7563<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7564 the return value, the referenced memory location is constant and
7565 unchanging.</p>
7566
7567</div>
7568
7569<!-- _______________________________________________________________________ -->
7570<div class="doc_subsubsection">
7571 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7572</div>
7573
7574<div class="doc_text">
7575
7576<h5>Syntax:</h5>
7577<pre>
7578 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7579</pre>
7580
7581<h5>Overview:</h5>
7582<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7583 a memory object are mutable.</p>
7584
7585<h5>Arguments:</h5>
7586<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7587 The second argument is a constant integer representing the size of the
7588 object, or -1 if it is variable sized and the third argument is a pointer
7589 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7590
7591<h5>Semantics:</h5>
7592<p>This intrinsic indicates that the memory is mutable again.</p>
7593
7594</div>
7595
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7596<!-- ======================================================================= -->
7597<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7598 <a name="int_general">General Intrinsics</a>
7599</div>
7600
7601<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7602
7603<p>This class of intrinsics is designed to be generic and has no specific
7604 purpose.</p>
7605
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7606</div>
7607
7608<!-- _______________________________________________________________________ -->
7609<div class="doc_subsubsection">
7610 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7611</div>
7612
7613<div class="doc_text">
7614
7615<h5>Syntax:</h5>
7616<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7617 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]7618</pre>
7619
7620<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7621<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7622
7623<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7624<p>The first argument is a pointer to a value, the second is a pointer to a
7625 global string, the third is a pointer to a global string which is the source
7626 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7627
7628<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7629<p>This intrinsic allows annotation of local variables with arbitrary strings.
7630 This can be useful for special purpose optimizations that want to look for
7631 these annotations. These have no other defined use, they are ignored by code
7632 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7633
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7634</div>
7635
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7636<!-- _______________________________________________________________________ -->
7637<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7638 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7639</div>
7640
7641<div class="doc_text">
7642
7643<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7644<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7645 any integer bit width.</p>
7646
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7647<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7648 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7649 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7650 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7651 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7652 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]7653</pre>
7654
7655<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7656<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7657
7658<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7659<p>The first argument is an integer value (result of some expression), the
7660 second is a pointer to a global string, the third is a pointer to a global
7661 string which is the source file name, and the last argument is the line
7662 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7663
7664<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7665<p>This intrinsic allows annotations to be put on arbitrary expressions with
7666 arbitrary strings. This can be useful for special purpose optimizations that
7667 want to look for these annotations. These have no other defined use, they
7668 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7669
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7670</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7671
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7672<!-- _______________________________________________________________________ -->
7673<div class="doc_subsubsection">
7674 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7675</div>
7676
7677<div class="doc_text">
7678
7679<h5>Syntax:</h5>
7680<pre>
7681 declare void @llvm.trap()
7682</pre>
7683
7684<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7685<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7686
7687<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7688<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7689
7690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7691<p>This intrinsics is lowered to the target dependent trap instruction. If the
7692 target does not have a trap instruction, this intrinsic will be lowered to
7693 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7694
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7695</div>
7696
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7697<!-- _______________________________________________________________________ -->
7698<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7699 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7700</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7701
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7702<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7703
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7704<h5>Syntax:</h5>
7705<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7706 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7707</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7708
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7709<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7710<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7711 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7712 ensure that it is placed on the stack before local variables.</p>
7713
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7714<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7715<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7716 arguments. The first argument is the value loaded from the stack
7717 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7718 that has enough space to hold the value of the guard.</p>
7719
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7720<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7721<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7722 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7723 stack. This is to ensure that if a local variable on the stack is
7724 overwritten, it will destroy the value of the guard. When the function exits,
7725 the guard on the stack is checked against the original guard. If they're
7726 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7727 function.</p>
7728
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7729</div>
7730
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7731<!-- _______________________________________________________________________ -->
7732<div class="doc_subsubsection">
7733 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7734</div>
7735
7736<div class="doc_text">
7737
7738<h5>Syntax:</h5>
7739<pre>
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7740 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7741 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7742</pre>
7743
7744<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7745<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopherd003c5b2010-01-08 21:42:39 +0000[diff] [blame]7746 to the optimizers to discover at compile time either a) when an
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7747 operation like memcpy will either overflow a buffer that corresponds to
7748 an object, or b) to determine that a runtime check for overflow isn't
7749 necessary. An object in this context means an allocation of a
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7750 specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7751
7752<h5>Arguments:</h5>
7753<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]7754 argument is a pointer to or into the <tt>object</tt>. The second argument
7755 is a boolean 0 or 1. This argument determines whether you want the
7756 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7757 1, variables are not allowed.</p>
7758
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7759<h5>Semantics:</h5>
7760<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]7761 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7762 (depending on the <tt>type</tt> argument if the size cannot be determined
7763 at compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]7764
7765</div>
7766
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7767<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7768<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7769<address>
7770 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7771 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7772 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7773 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7774
7775 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7776 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7777 Last modified: $Date$
7778</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7779
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7780</body>
7781</html>