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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / de17fb6e4dd8f169f707d58d4e124c8d4d2c7dba / . / 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">
8 <meta name="description"
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>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]52 </ol>
53 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]73 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]74 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]78 </ol>
79 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]80 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]81 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]86 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]87 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]88 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]89 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]91 <li><a href="#othervalues">Other Values</a>
92 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]94 </ol>
95 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]96 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
97 <ol>
98 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]99 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
100 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]101 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
102 Global Variable</a></li>
103 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
104 Global Variable</a></li>
105 </ol>
106 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]107 <li><a href="#instref">Instruction Reference</a>
108 <ol>
109 <li><a href="#terminators">Terminator Instructions</a>
110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
112 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]113 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]114 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]115 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]117 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]118 </ol>
119 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]120 <li><a href="#binaryops">Binary Operations</a>
121 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]127 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]128 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
129 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
130 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]131 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
132 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
133 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
137 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]138 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
139 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
140 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]143 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]146 <li><a href="#vectorops">Vector Operations</a>
147 <ol>
148 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
149 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
150 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]151 </ol>
152 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]153 <li><a href="#aggregateops">Aggregate Operations</a>
154 <ol>
155 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
156 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
157 </ol>
158 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]159 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]160 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]167 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]181 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]191 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]195 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]196 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]202 </ol>
203 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]209 </ol>
210 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]220 </ol>
221 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]232 </ol>
233 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]235 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <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]249 <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]250 </ol>
251 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling3c44f5b2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]285 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]295 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296 </ol>
297 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]298</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]303</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]304
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]305<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]308
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]309<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]318
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]319<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]324
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]333
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
341 variable is never accessed outside of the current function... allowing it to
342 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]346<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]348
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]349<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]356<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]361
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]362<p>...because the definition of <tt>%x</tt> does not dominate all of its
363 uses. The LLVM infrastructure provides a verification pass that may be used
364 to verify that an LLVM module is well formed. This pass is automatically run
365 by the parser after parsing input assembly and by the optimizer before it
366 outputs bitcode. The violations pointed out by the verifier pass indicate
367 bugs in transformation passes or input to the parser.</p>
368
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]369</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]373<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]375<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]377<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]378
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]384
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]385<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]397
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]400</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]401
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]421<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]423<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]425%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]427</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]429<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]435</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]437<p>And the hard 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>
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]441%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442%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]443%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]444</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]445</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]450<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]457 <li>Unnamed temporaries are numbered sequentially</li>
458</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]460<p>...and it also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]465</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]484<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]486<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
487 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]488
489<i>; External declaration of the puts function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]494 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495 %cast210 = <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]496 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]497
498 <i>; Call puts function to write out the string to stdout...</i>
499 <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]500 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]502 href="#i_ret">ret</a> i32 0<br>}<br>
503</pre>
504</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]506<p>This example is made up of a <a href="#globalvars">global variable</a> named
507 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
508 a <a href="#functionstructure">function definition</a> for
509 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]511<p>In general, a module is made up of a list of global values, where both
512 functions and global variables are global values. Global values are
513 represented by a pointer to a memory location (in this case, a pointer to an
514 array of char, and a pointer to a function), and have one of the
515 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]516
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]517</div>
518
519<!-- ======================================================================= -->
520<div class="doc_subsection">
521 <a name="linkage">Linkage Types</a>
522</div>
523
524<div class="doc_text">
525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]526<p>All Global Variables and Functions have one of the following types of
527 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528
529<dl>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]531 <dd>Global values with private linkage are only directly accessible by objects
532 in the current module. In particular, linking code into a module with an
533 private global value may cause the private to be renamed as necessary to
534 avoid collisions. Because the symbol is private to the module, all
535 references can be updated. This doesn't show up in any symbol table in the
536 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]537
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]539 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]540 removed by the linker after evaluation. Note that (unlike private
541 symbols) linker_private symbols are subject to coalescing by the linker:
542 weak symbols get merged and redefinitions are rejected. However, unlike
543 normal strong symbols, they are removed by the linker from the final
544 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]545
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]547 <dd>Similar to private, but the value shows as a local symbol
548 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
549 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]550
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]552 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]553 into the object file corresponding to the LLVM module. They exist to
554 allow inlining and other optimizations to take place given knowledge of
555 the definition of the global, which is known to be somewhere outside the
556 module. Globals with <tt>available_externally</tt> linkage are allowed to
557 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
558 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]559
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]561 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]562 the same name when linkage occurs. This is typically used to implement
563 inline functions, templates, or other code which must be generated in each
564 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
565 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]566
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]568 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
569 <tt>linkonce</tt> linkage, except that unreferenced globals with
570 <tt>weak</tt> linkage may not be discarded. This is used for globals that
571 are declared "weak" in C source code.</dd>
572
573 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
574 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
575 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
576 global scope.
577 Symbols with "<tt>common</tt>" linkage are merged in the same way as
578 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]579 <tt>common</tt> symbols may not have an explicit section,
580 must have a zero initializer, and may not be marked '<a
581 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
582 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]583
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]584
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]586 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]587 pointer to array type. When two global variables with appending linkage
588 are linked together, the two global arrays are appended together. This is
589 the LLVM, typesafe, equivalent of having the system linker append together
590 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]591
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]592 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]593 <dd>The semantics of this linkage follow the ELF object file model: the symbol
594 is weak until linked, if not linked, the symbol becomes null instead of
595 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]596
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
598 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]599 <dd>Some languages allow differing globals to be merged, such as two functions
600 with different semantics. Other languages, such as <tt>C++</tt>, ensure
601 that only equivalent globals are ever merged (the "one definition rule" -
602 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
603 and <tt>weak_odr</tt> linkage types to indicate that the global will only
604 be merged with equivalent globals. These linkage types are otherwise the
605 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]606
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]607 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]608 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]609 visible, meaning that it participates in linkage and can be used to
610 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]611</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]613<p>The next two types of linkage are targeted for Microsoft Windows platform
614 only. They are designed to support importing (exporting) symbols from (to)
615 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]619 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 or variable via a global pointer to a pointer that is set up by the DLL
621 exporting the symbol. On Microsoft Windows targets, the pointer name is
622 formed by combining <code>__imp_</code> and the function or variable
623 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]624
625 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]626 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]627 pointer to a pointer in a DLL, so that it can be referenced with the
628 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
629 name is formed by combining <code>__imp_</code> and the function or
630 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631</dl>
632
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]633<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
634 another module defined a "<tt>.LC0</tt>" variable and was linked with this
635 one, one of the two would be renamed, preventing a collision. Since
636 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
637 declarations), they are accessible outside of the current module.</p>
638
639<p>It is illegal for a function <i>declaration</i> to have any linkage type
640 other than "externally visible", <tt>dllimport</tt>
641 or <tt>extern_weak</tt>.</p>
642
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]643<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]644 or <tt>weak_odr</tt> linkages.</p>
645
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]650 <a name="callingconv">Calling Conventions</a>
651</div>
652
653<div class="doc_text">
654
655<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]656 and <a href="#i_invoke">invokes</a> can all have an optional calling
657 convention specified for the call. The calling convention of any pair of
658 dynamic caller/callee must match, or the behavior of the program is
659 undefined. The following calling conventions are supported by LLVM, and more
660 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661
662<dl>
663 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]664 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]665 specified) matches the target C calling conventions. This calling
666 convention supports varargs function calls and tolerates some mismatch in
667 the declared prototype and implemented declaration of the function (as
668 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]669
670 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]671 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]672 (e.g. by passing things in registers). This calling convention allows the
673 target to use whatever tricks it wants to produce fast code for the
674 target, without having to conform to an externally specified ABI
675 (Application Binary Interface). Implementations of this convention should
676 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
677 optimization</a> to be supported. This calling convention does not
678 support varargs and requires the prototype of all callees to exactly match
679 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
681 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 as possible under the assumption that the call is not commonly executed.
684 As such, these calls often preserve all registers so that the call does
685 not break any live ranges in the caller side. This calling convention
686 does not support varargs and requires the prototype of all callees to
687 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]688
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]689 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]691 target-specific calling conventions to be used. Target specific calling
692 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]693</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]696 support Pascal conventions or any other well-known target-independent
697 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]698
699</div>
700
701<!-- ======================================================================= -->
702<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]703 <a name="visibility">Visibility Styles</a>
704</div>
705
706<div class="doc_text">
707
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708<p>All Global Variables and Functions have one of the following visibility
709 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]713 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]714 that the declaration is visible to other modules and, in shared libraries,
715 means that the declared entity may be overridden. On Darwin, default
716 visibility means that the declaration is visible to other modules. Default
717 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718
719 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]720 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]721 object if they are in the same shared object. Usually, hidden visibility
722 indicates that the symbol will not be placed into the dynamic symbol
723 table, so no other module (executable or shared library) can reference it
724 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]725
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]726 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]727 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]728 the dynamic symbol table, but that references within the defining module
729 will bind to the local symbol. That is, the symbol cannot be overridden by
730 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]731</dl>
732
733</div>
734
735<!-- ======================================================================= -->
736<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]737 <a name="namedtypes">Named Types</a>
738</div>
739
740<div class="doc_text">
741
742<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]743 it easier to read the IR and make the IR more condensed (particularly when
744 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]745
746<div class="doc_code">
747<pre>
748%mytype = type { %mytype*, i32 }
749</pre>
750</div>
751
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]752<p>You may give a name to any <a href="#typesystem">type</a> except
753 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
754 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]755
756<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]757 and that you can therefore specify multiple names for the same type. This
758 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
759 uses structural typing, the name is not part of the type. When printing out
760 LLVM IR, the printer will pick <em>one name</em> to render all types of a
761 particular shape. This means that if you have code where two different
762 source types end up having the same LLVM type, that the dumper will sometimes
763 print the "wrong" or unexpected type. This is an important design point and
764 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]765
766</div>
767
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]768<!-- ======================================================================= -->
769<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]770 <a name="globalvars">Global Variables</a>
771</div>
772
773<div class="doc_text">
774
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]775<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]776 instead of run-time. Global variables may optionally be initialized, may
777 have an explicit section to be placed in, and may have an optional explicit
778 alignment specified. A variable may be defined as "thread_local", which
779 means that it will not be shared by threads (each thread will have a
780 separated copy of the variable). A variable may be defined as a global
781 "constant," which indicates that the contents of the variable
782 will <b>never</b> be modified (enabling better optimization, allowing the
783 global data to be placed in the read-only section of an executable, etc).
784 Note that variables that need runtime initialization cannot be marked
785 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]786
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]787<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
788 constant, even if the final definition of the global is not. This capability
789 can be used to enable slightly better optimization of the program, but
790 requires the language definition to guarantee that optimizations based on the
791 'constantness' are valid for the translation units that do not include the
792 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794<p>As SSA values, global variables define pointer values that are in scope
795 (i.e. they dominate) all basic blocks in the program. Global variables
796 always define a pointer to their "content" type because they describe a
797 region of memory, and all memory objects in LLVM are accessed through
798 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]800<p>A global variable may be declared to reside in a target-specific numbered
801 address space. For targets that support them, address spaces may affect how
802 optimizations are performed and/or what target instructions are used to
803 access the variable. The default address space is zero. The address space
804 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]805
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]806<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]808
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]809<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]810 the alignment is set to zero, the alignment of the global is set by the
811 target to whatever it feels convenient. If an explicit alignment is
812 specified, the global is forced to have at least that much alignment. All
813 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]814
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]815<p>For example, the following defines a global in a numbered address space with
816 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]817
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]818<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]819<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]820@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]821</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]822</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]823
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]824</div>
825
826
827<!-- ======================================================================= -->
828<div class="doc_subsection">
829 <a name="functionstructure">Functions</a>
830</div>
831
832<div class="doc_text">
833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]834<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
835 optional <a href="#linkage">linkage type</a>, an optional
836 <a href="#visibility">visibility style</a>, an optional
837 <a href="#callingconv">calling convention</a>, a return type, an optional
838 <a href="#paramattrs">parameter attribute</a> for the return type, a function
839 name, a (possibly empty) argument list (each with optional
840 <a href="#paramattrs">parameter attributes</a>), optional
841 <a href="#fnattrs">function attributes</a>, an optional section, an optional
842 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
843 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
846 optional <a href="#linkage">linkage type</a>, an optional
847 <a href="#visibility">visibility style</a>, an optional
848 <a href="#callingconv">calling convention</a>, a return type, an optional
849 <a href="#paramattrs">parameter attribute</a> for the return type, a function
850 name, a possibly empty list of arguments, an optional alignment, and an
851 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]852
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]853<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]854 (Control Flow Graph) for the function. Each basic block may optionally start
855 with a label (giving the basic block a symbol table entry), contains a list
856 of instructions, and ends with a <a href="#terminators">terminator</a>
857 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]858
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]859<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]860 executed on entrance to the function, and it is not allowed to have
861 predecessor basic blocks (i.e. there can not be any branches to the entry
862 block of a function). Because the block can have no predecessors, it also
863 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]864
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]865<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]866 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]867
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]868<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]869 the alignment is set to zero, the alignment of the function is set by the
870 target to whatever it feels convenient. If an explicit alignment is
871 specified, the function is forced to have at least that much alignment. All
872 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]873
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]874<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]875<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]876<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]877define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]878 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
879 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
880 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
881 [<a href="#gc">gc</a>] { ... }
882</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]883</div>
884
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885</div>
886
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]887<!-- ======================================================================= -->
888<div class="doc_subsection">
889 <a name="aliasstructure">Aliases</a>
890</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]891
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]892<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]893
894<p>Aliases act as "second name" for the aliasee value (which can be either
895 function, global variable, another alias or bitcast of global value). Aliases
896 may have an optional <a href="#linkage">linkage type</a>, and an
897 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]898
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]899<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]900<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]901<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]902@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]903</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]904</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]905
906</div>
907
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]908<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]909<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911<div class="doc_text">
912
913<p>The return type and each parameter of a function type may have a set of
914 <i>parameter attributes</i> associated with them. Parameter attributes are
915 used to communicate additional information about the result or parameters of
916 a function. Parameter attributes are considered to be part of the function,
917 not of the function type, so functions with different parameter attributes
918 can have the same function type.</p>
919
920<p>Parameter attributes are simple keywords that follow the type specified. If
921 multiple parameter attributes are needed, they are space separated. For
922 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]923
924<div class="doc_code">
925<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]926declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]927declare i32 @atoi(i8 zeroext)
928declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]929</pre>
930</div>
931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932<p>Note that any attributes for the function result (<tt>nounwind</tt>,
933 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]936
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]937<dl>
938 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]939 <dd>This indicates to the code generator that the parameter or return value
940 should be zero-extended to a 32-bit value by the caller (for a parameter)
941 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]943 <dt><tt>signext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]944 <dd>This indicates to the code generator that the parameter or return value
945 should be sign-extended to a 32-bit value by the caller (for a parameter)
946 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]947
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948 <dt><tt>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]949 <dd>This indicates that this parameter or return value should be treated in a
950 special target-dependent fashion during while emitting code for a function
951 call or return (usually, by putting it in a register as opposed to memory,
952 though some targets use it to distinguish between two different kinds of
953 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]955 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]956 <dd>This indicates that the pointer parameter should really be passed by value
957 to the function. The attribute implies that a hidden copy of the pointee
958 is made between the caller and the callee, so the callee is unable to
959 modify the value in the callee. This attribute is only valid on LLVM
960 pointer arguments. It is generally used to pass structs and arrays by
961 value, but is also valid on pointers to scalars. The copy is considered
962 to belong to the caller not the callee (for example,
963 <tt><a href="#readonly">readonly</a></tt> functions should not write to
964 <tt>byval</tt> parameters). This is not a valid attribute for return
965 values. The byval attribute also supports specifying an alignment with
966 the align attribute. This has a target-specific effect on the code
967 generator that usually indicates a desired alignment for the synthesized
968 stack slot.</dd>
969
970 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer parameter specifies the address of a
972 structure that is the return value of the function in the source program.
973 This pointer must be guaranteed by the caller to be valid: loads and
974 stores to the structure may be assumed by the callee to not to trap. This
975 may only be applied to the first parameter. This is not a valid attribute
976 for return values. </dd>
977
978 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]979 <dd>This indicates that the pointer does not alias any global or any other
980 parameter. The caller is responsible for ensuring that this is the
981 case. On a function return value, <tt>noalias</tt> additionally indicates
982 that the pointer does not alias any other pointers visible to the
983 caller. For further details, please see the discussion of the NoAlias
984 response in
985 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
986 analysis</a>.</dd>
987
988 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]989 <dd>This indicates that the callee does not make any copies of the pointer
990 that outlive the callee itself. This is not a valid attribute for return
991 values.</dd>
992
993 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter can be excised using the
995 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
996 attribute for return values.</dd>
997</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]998
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]999</div>
1000
1001<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1002<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1003 <a name="gc">Garbage Collector Names</a>
1004</div>
1005
1006<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1008<p>Each function may specify a garbage collector name, which is simply a
1009 string:</p>
1010
1011<div class="doc_code">
1012<pre>
1013define void @f() gc "name" { ...
1014</pre>
1015</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1016
1017<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1018 collector which will cause the compiler to alter its output in order to
1019 support the named garbage collection algorithm.</p>
1020
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1021</div>
1022
1023<!-- ======================================================================= -->
1024<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1025 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1026</div>
1027
1028<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1029
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1030<p>Function attributes are set to communicate additional information about a
1031 function. Function attributes are considered to be part of the function, not
1032 of the function type, so functions with different parameter attributes can
1033 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1034
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035<p>Function attributes are simple keywords that follow the type specified. If
1036 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1037
1038<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1040define void @f() noinline { ... }
1041define void @f() alwaysinline { ... }
1042define void @f() alwaysinline optsize { ... }
1043define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1045</div>
1046
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1047<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1048 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This attribute indicates that the inliner should attempt to inline this
1050 function into callers whenever possible, ignoring any active inlining size
1051 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1052
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1053 <dt><tt>inlinehint</tt></dt>
1054 <dd>This attribute indicates that the source code contained a hint that inlining
1055 this function is desirable (such as the "inline" keyword in C/C++). It
1056 is just a hint; it imposes no requirements on the inliner.</dd>
1057
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1058 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This attribute indicates that the inliner should never inline this
1060 function in any situation. This attribute may not be used together with
1061 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1062
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1063 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This attribute suggests that optimization passes and code generator passes
1065 make choices that keep the code size of this function low, and otherwise
1066 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1068 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This function attribute indicates that the function never returns
1070 normally. This produces undefined behavior at runtime if the function
1071 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1072
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1073 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This function attribute indicates that the function never returns with an
1075 unwind or exceptional control flow. If the function does unwind, its
1076 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1077
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1078 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1079 <dd>This attribute indicates that the function computes its result (or decides
1080 to unwind an exception) based strictly on its arguments, without
1081 dereferencing any pointer arguments or otherwise accessing any mutable
1082 state (e.g. memory, control registers, etc) visible to caller functions.
1083 It does not write through any pointer arguments
1084 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1085 changes any state visible to callers. This means that it cannot unwind
1086 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1087 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This attribute indicates that the function does not write through any
1091 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1092 arguments) or otherwise modify any state (e.g. memory, control registers,
1093 etc) visible to caller functions. It may dereference pointer arguments
1094 and read state that may be set in the caller. A readonly function always
1095 returns the same value (or unwinds an exception identically) when called
1096 with the same set of arguments and global state. It cannot unwind an
1097 exception by calling the <tt>C++</tt> exception throwing methods, but may
1098 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1099
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1100 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This attribute indicates that the function should emit a stack smashing
1102 protector. It is in the form of a "canary"&mdash;a random value placed on
1103 the stack before the local variables that's checked upon return from the
1104 function to see if it has been overwritten. A heuristic is used to
1105 determine if a function needs stack protectors or not.<br>
1106<br>
1107 If a function that has an <tt>ssp</tt> attribute is inlined into a
1108 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1109 function will have an <tt>ssp</tt> attribute.</dd>
1110
1111 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the function should <em>always</em> emit a
1113 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1114 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1115<br>
1116 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1117 function that doesn't have an <tt>sspreq</tt> attribute or which has
1118 an <tt>ssp</tt> attribute, then the resulting function will have
1119 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1120
1121 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the code generator should not use a red
1123 zone, even if the target-specific ABI normally permits it.</dd>
1124
1125 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attributes disables implicit floating point instructions.</dd>
1127
1128 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute disables prologue / epilogue emission for the function.
1130 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1131</dl>
1132
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1133</div>
1134
1135<!-- ======================================================================= -->
1136<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1137 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1138</div>
1139
1140<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1141
1142<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1143 the GCC "file scope inline asm" blocks. These blocks are internally
1144 concatenated by LLVM and treated as a single unit, but may be separated in
1145 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1146
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1147<div class="doc_code">
1148<pre>
1149module asm "inline asm code goes here"
1150module asm "more can go here"
1151</pre>
1152</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1153
1154<p>The strings can contain any character by escaping non-printable characters.
1155 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]1156 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1158<p>The inline asm code is simply printed to the machine code .s file when
1159 assembly code is generated.</p>
1160
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1161</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1162
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1163<!-- ======================================================================= -->
1164<div class="doc_subsection">
1165 <a name="datalayout">Data Layout</a>
1166</div>
1167
1168<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1169
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1170<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1171 data is to be laid out in memory. The syntax for the data layout is
1172 simply:</p>
1173
1174<div class="doc_code">
1175<pre>
1176target datalayout = "<i>layout specification</i>"
1177</pre>
1178</div>
1179
1180<p>The <i>layout specification</i> consists of a list of specifications
1181 separated by the minus sign character ('-'). Each specification starts with
1182 a letter and may include other information after the letter to define some
1183 aspect of the data layout. The specifications accepted are as follows:</p>
1184
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1185<dl>
1186 <dt><tt>E</tt></dt>
1187 <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]1188 bits with the most significance have the lowest address location.</dd>
1189
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1190 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1191 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1192 the bits with the least significance have the lowest address
1193 location.</dd>
1194
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1195 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1196 <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]1197 <i>preferred</i> alignments. All sizes are in bits. Specifying
1198 the <i>pref</i> alignment is optional. If omitted, the
1199 preceding <tt>:</tt> should be omitted too.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1204
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1205 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1206 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1207 <i>size</i>.</dd>
1208
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1209 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1210 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1211 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1212 (double).</dd>
1213
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1214 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1215 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 <i>size</i>.</dd>
1217
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1218 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1219 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1220 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1221</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1222
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1223<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1224 default set of specifications which are then (possibly) overriden by the
1225 specifications in the <tt>datalayout</tt> keyword. The default specifications
1226 are given in this list:</p>
1227
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1228<ul>
1229 <li><tt>E</tt> - big endian</li>
1230 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1231 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1232 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1233 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1234 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1235 <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]1236 alignment of 64-bits</li>
1237 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1238 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1239 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1240 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1241 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1242 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1243</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1244
1245<p>When LLVM is determining the alignment for a given type, it uses the
1246 following rules:</p>
1247
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1248<ol>
1249 <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]1250 specification is used.</li>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252 <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]1253 smallest integer type that is larger than the bitwidth of the sought type
1254 is used. If none of the specifications are larger than the bitwidth then
1255 the the largest integer type is used. For example, given the default
1256 specifications above, the i7 type will use the alignment of i8 (next
1257 largest) while both i65 and i256 will use the alignment of i64 (largest
1258 specified).</li>
1259
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1260 <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]1261 largest vector type that is smaller than the sought vector type will be
1262 used as a fall back. This happens because &lt;128 x double&gt; can be
1263 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1265
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1266</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1267
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1271</div>
1272
1273<div class="doc_text">
1274
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1275<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1276with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1277is undefined. Pointer values are associated with address ranges
1278according to the following rules:</p>
1279
1280<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1281 <li>A pointer value formed from a
1282 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1283 is associated with the addresses associated with the first operand
1284 of the <tt>getelementptr</tt>.</li>
1285 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1286 range of the variable's storage.</li>
1287 <li>The result value of an allocation instruction is associated with
1288 the address range of the allocated storage.</li>
1289 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1290 no address.</li>
1291 <li>A pointer value formed by an
1292 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1293 address ranges of all pointer values that contribute (directly or
1294 indirectly) to the computation of the pointer's value.</li>
1295 <li>The result value of a
1296 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1297 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1298 <li>An integer constant other than zero or a pointer value returned
1299 from a function not defined within LLVM may be associated with address
1300 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1301 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1302 allocated by mechanisms provided by LLVM.</li>
1303 </ul>
1304
1305<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1306<tt><a href="#i_load">load</a></tt> merely indicates the size and
1307alignment of the memory from which to load, as well as the
1308interpretation of the value. The first operand of a
1309<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1310and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1311
1312<p>Consequently, type-based alias analysis, aka TBAA, aka
1313<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1314LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1315additional information which specialized optimization passes may use
1316to implement type-based alias analysis.</p>
1317
1318</div>
1319
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1320<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1321<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1322<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1324<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1326<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1327 intermediate representation. Being typed enables a number of optimizations
1328 to be performed on the intermediate representation directly, without having
1329 to do extra analyses on the side before the transformation. A strong type
1330 system makes it easier to read the generated code and enables novel analyses
1331 and transformations that are not feasible to perform on normal three address
1332 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1333
1334</div>
1335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1336<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1337<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1338Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1340<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1343
1344<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1345 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1346 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1347 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1348 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1349 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1350 </tr>
1351 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_floating">floating point</a></td>
1353 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354 </tr>
1355 <tr>
1356 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1357 <td><a href="#t_integer">integer</a>,
1358 <a href="#t_floating">floating point</a>,
1359 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1360 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1361 <a href="#t_struct">structure</a>,
1362 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_label">label</a>,
1364 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1365 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1366 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1367 <tr>
1368 <td><a href="#t_primitive">primitive</a></td>
1369 <td><a href="#t_label">label</a>,
1370 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1373 </tr>
1374 <tr>
1375 <td><a href="#t_derived">derived</a></td>
1376 <td><a href="#t_integer">integer</a>,
1377 <a href="#t_array">array</a>,
1378 <a href="#t_function">function</a>,
1379 <a href="#t_pointer">pointer</a>,
1380 <a href="#t_struct">structure</a>,
1381 <a href="#t_pstruct">packed structure</a>,
1382 <a href="#t_vector">vector</a>,
1383 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1384 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1385 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1386 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1387</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1388
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1389<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1390 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1391 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1392
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1393</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1395<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1396<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1397
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1398<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1399
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1400<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1401 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1403</div>
1404
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1405<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1406<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1407
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411<p>The integer type is a very simple type that simply specifies an arbitrary
1412 bit width for the integer type desired. Any bit width from 1 bit to
1413 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1414
1415<h5>Syntax:</h5>
1416<pre>
1417 iN
1418</pre>
1419
1420<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1421 value.</p>
1422
1423<h5>Examples:</h5>
1424<table class="layout">
1425 <tr class="layout">
1426 <td class="left"><tt>i1</tt></td>
1427 <td class="left">a single-bit integer.</td>
1428 </tr>
1429 <tr class="layout">
1430 <td class="left"><tt>i32</tt></td>
1431 <td class="left">a 32-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i1942652</tt></td>
1435 <td class="left">a really big integer of over 1 million bits.</td>
1436 </tr>
1437</table>
1438
1439<p>Note that the code generator does not yet support large integer types to be
1440 used as function return types. The specific limit on how large a return type
1441 the code generator can currently handle is target-dependent; currently it's
1442 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1443
1444</div>
1445
1446<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1448
1449<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1450
1451<table>
1452 <tbody>
1453 <tr><th>Type</th><th>Description</th></tr>
1454 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1455 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1456 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1457 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1458 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1459 </tbody>
1460</table>
1461
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1462</div>
1463
1464<!-- _______________________________________________________________________ -->
1465<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1466
1467<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1469<h5>Overview:</h5>
1470<p>The void type does not represent any value and has no size.</p>
1471
1472<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1473<pre>
1474 void
1475</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1477</div>
1478
1479<!-- _______________________________________________________________________ -->
1480<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1481
1482<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484<h5>Overview:</h5>
1485<p>The label type represents code labels.</p>
1486
1487<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1488<pre>
1489 label
1490</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1492</div>
1493
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1494<!-- _______________________________________________________________________ -->
1495<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1496
1497<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1498
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1499<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1500<p>The metadata type represents embedded metadata. No derived types may be
1501 created from metadata except for <a href="#t_function">function</a>
1502 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1503
1504<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1505<pre>
1506 metadata
1507</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1508
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1509</div>
1510
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1511
1512<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1514
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1515<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1517<p>The real power in LLVM comes from the derived types in the system. This is
1518 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1519 useful types. Each of these types contain one or more element types which
1520 may be a primitive type, or another derived type. For example, it is
1521 possible to have a two dimensional array, using an array as the element type
1522 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1523
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1524</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1525
1526<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1527<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1529<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1532<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533 sequentially in memory. The array type requires a size (number of elements)
1534 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1536<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537<pre>
1538 [&lt;# elements&gt; x &lt;elementtype&gt;]
1539</pre>
1540
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1541<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1542 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1544<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1545<table class="layout">
1546 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1547 <td class="left"><tt>[40 x i32]</tt></td>
1548 <td class="left">Array of 40 32-bit integer values.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>[41 x i32]</tt></td>
1552 <td class="left">Array of 41 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[4 x i8]</tt></td>
1556 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1557 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1558</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1559<p>Here are some examples of multidimensional arrays:</p>
1560<table class="layout">
1561 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1562 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1563 <td class="left">3x4 array of 32-bit integer values.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1567 <td class="left">12x10 array of single precision floating point values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1571 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1572 </tr>
1573</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1574
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1575<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1576 length array. Normally, accesses past the end of an array are undefined in
1577 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1578 a special case, however, zero length arrays are recognized to be variable
1579 length. This allows implementation of 'pascal style arrays' with the LLVM
1580 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1581
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1582<p>Note that the code generator does not yet support large aggregate types to be
1583 used as function return types. The specific limit on how large an aggregate
1584 return type the code generator can currently handle is target-dependent, and
1585 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1587</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1592<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1595<p>The function type can be thought of as a function signature. It consists of
1596 a return type and a list of formal parameter types. The return type of a
1597 function type is a scalar type, a void type, or a struct type. If the return
1598 type is a struct type then all struct elements must be of first class types,
1599 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1601<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1602<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1603 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1604</pre>
1605
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1606<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]1607 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1608 which indicates that the function takes a variable number of arguments.
1609 Variable argument functions can access their arguments with
1610 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1611 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1612 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1615<table class="layout">
1616 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 <td class="left"><tt>i32 (i32)</tt></td>
1618 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1619 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1621 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1622 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1623 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1624 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1625 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1626 <tt>float</tt>.
1627 </td>
1628 </tr><tr class="layout">
1629 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1630 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1631 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1632 which returns an integer. This is the signature for <tt>printf</tt> in
1633 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1634 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1635 </tr><tr class="layout">
1636 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1637 <td class="left">A function taking an <tt>i32</tt>, returning a
1638 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1639 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1640 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1641</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1643</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1647
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1649
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The structure type is used to represent a collection of data members together
1652 in memory. The packing of the field types is defined to match the ABI of the
1653 underlying processor. The elements of a structure may be any type that has a
1654 size.</p>
1655
1656<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1657 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1658 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1659
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1661<pre>
1662 { &lt;type list&gt; }
1663</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1666<table class="layout">
1667 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1668 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1669 <td class="left">A triple of three <tt>i32</tt> values</td>
1670 </tr><tr class="layout">
1671 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1672 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1673 second element is a <a href="#t_pointer">pointer</a> to a
1674 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1675 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1676 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1679<p>Note that the code generator does not yet support large aggregate types to be
1680 used as function return types. The specific limit on how large an aggregate
1681 return type the code generator can currently handle is target-dependent, and
1682 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1684</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1687<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1688</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1689
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1690<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1691
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Overview:</h5>
1693<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1694 together in memory. There is no padding between fields. Further, the
1695 alignment of a packed structure is 1 byte. The elements of a packed
1696 structure may be any type that has a size.</p>
1697
1698<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1699 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1700 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1701
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1702<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1703<pre>
1704 &lt; { &lt;type list&gt; } &gt;
1705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1706
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1707<h5>Examples:</h5>
1708<table class="layout">
1709 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1710 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1711 <td class="left">A triple of three <tt>i32</tt> values</td>
1712 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1713 <td class="left">
1714<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1715 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1716 second element is a <a href="#t_pointer">pointer</a> to a
1717 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1718 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1719 </tr>
1720</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1721
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1722</div>
1723
1724<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1726
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1727<div class="doc_text">
1728
1729<h5>Overview:</h5>
1730<p>As in many languages, the pointer type represents a pointer or reference to
1731 another object, which must live in memory. Pointer types may have an optional
1732 address space attribute defining the target-specific numbered address space
1733 where the pointed-to object resides. The default address space is zero.</p>
1734
1735<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1736 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1737
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1738<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1739<pre>
1740 &lt;type&gt; *
1741</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1742
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1743<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1744<table class="layout">
1745 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1746 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1747 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1748 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1749 </tr>
1750 <tr class="layout">
1751 <td class="left"><tt>i32 (i32 *) *</tt></td>
1752 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1753 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1754 <tt>i32</tt>.</td>
1755 </tr>
1756 <tr class="layout">
1757 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1758 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1759 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1760 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1763</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1764
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1765<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771<p>A vector type is a simple derived type that represents a vector of elements.
1772 Vector types are used when multiple primitive data are operated in parallel
1773 using a single instruction (SIMD). A vector type requires a size (number of
1774 elements) and an underlying primitive data type. Vectors must have a power
1775 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1776 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1777
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1778<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1779<pre>
1780 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1781</pre>
1782
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1783<p>The number of elements is a constant integer value; elementtype may be any
1784 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1785
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1786<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1789 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1790 <td class="left">Vector of 4 32-bit integer values.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1794 <td class="left">Vector of 8 32-bit floating-point values.</td>
1795 </tr>
1796 <tr class="layout">
1797 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1798 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1799 </tr>
1800</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1802<p>Note that the code generator does not yet support large vector types to be
1803 used as function return types. The specific limit on how large a vector
1804 return type codegen can currently handle is target-dependent; currently it's
1805 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1806
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1807</div>
1808
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1809<!-- _______________________________________________________________________ -->
1810<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1811<div class="doc_text">
1812
1813<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1814<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1815 corresponds (for example) to the C notion of a forward declared structure
1816 type. In LLVM, opaque types can eventually be resolved to any type (not just
1817 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1818
1819<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1820<pre>
1821 opaque
1822</pre>
1823
1824<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1825<table class="layout">
1826 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1827 <td class="left"><tt>opaque</tt></td>
1828 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1829 </tr>
1830</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1831
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1832</div>
1833
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1834<!-- ======================================================================= -->
1835<div class="doc_subsection">
1836 <a name="t_uprefs">Type Up-references</a>
1837</div>
1838
1839<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1840
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1841<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1842<p>An "up reference" allows you to refer to a lexically enclosing type without
1843 requiring it to have a name. For instance, a structure declaration may
1844 contain a pointer to any of the types it is lexically a member of. Example
1845 of up references (with their equivalent as named type declarations)
1846 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1847
1848<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1849 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1850 { \2 }* %y = type { %y }*
1851 \1* %z = type %z*
1852</pre>
1853
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1854<p>An up reference is needed by the asmprinter for printing out cyclic types
1855 when there is no declared name for a type in the cycle. Because the
1856 asmprinter does not want to print out an infinite type string, it needs a
1857 syntax to handle recursive types that have no names (all names are optional
1858 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1859
1860<h5>Syntax:</h5>
1861<pre>
1862 \&lt;level&gt;
1863</pre>
1864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1865<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]1866
1867<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1868<table class="layout">
1869 <tr class="layout">
1870 <td class="left"><tt>\1*</tt></td>
1871 <td class="left">Self-referential pointer.</td>
1872 </tr>
1873 <tr class="layout">
1874 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1875 <td class="left">Recursive structure where the upref refers to the out-most
1876 structure.</td>
1877 </tr>
1878</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1879
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1880</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1881
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882<!-- *********************************************************************** -->
1883<div class="doc_section"> <a name="constants">Constants</a> </div>
1884<!-- *********************************************************************** -->
1885
1886<div class="doc_text">
1887
1888<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1889 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890
1891</div>
1892
1893<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1894<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1895
1896<div class="doc_text">
1897
1898<dl>
1899 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1900 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1901 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1902
1903 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1904 <dd>Standard integers (such as '4') are constants of
1905 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1906 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1909 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1911 notation (see below). The assembler requires the exact decimal value of a
1912 floating-point constant. For example, the assembler accepts 1.25 but
1913 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1914 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1915
1916 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1917 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1918 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1919</dl>
1920
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1921<p>The one non-intuitive notation for constants is the hexadecimal form of
1922 floating point constants. For example, the form '<tt>double
1923 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1924 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1925 constants are required (and the only time that they are generated by the
1926 disassembler) is when a floating point constant must be emitted but it cannot
1927 be represented as a decimal floating point number in a reasonable number of
1928 digits. For example, NaN's, infinities, and other special values are
1929 represented in their IEEE hexadecimal format so that assembly and disassembly
1930 do not cause any bits to change in the constants.</p>
1931
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1932<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1933 represented using the 16-digit form shown above (which matches the IEEE754
1934 representation for double); float values must, however, be exactly
1935 representable as IEE754 single precision. Hexadecimal format is always used
1936 for long double, and there are three forms of long double. The 80-bit format
1937 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1938 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1939 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1940 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1941 currently supported target uses this format. Long doubles will only work if
1942 they match the long double format on your target. All hexadecimal formats
1943 are big-endian (sign bit at the left).</p>
1944
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1945</div>
1946
1947<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1948<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1949<a name="aggregateconstants"></a> <!-- old anchor -->
1950<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1951</div>
1952
1953<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1954
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1955<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1956 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1957
1958<dl>
1959 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1960 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 type definitions (a comma separated list of elements, surrounded by braces
1962 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1963 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1964 Structure constants must have <a href="#t_struct">structure type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
1968 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1969 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by square
1971 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1972 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1973 the number and types of elements must match those specified by the
1974 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1976 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1977 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978 definitions (a comma separated list of elements, surrounded by
1979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1980 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1981 have <a href="#t_vector">vector type</a>, and the number and types of
1982 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1983
1984 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1985 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1986 value to zero of <em>any</em> type, including scalar and aggregate types.
1987 This is often used to avoid having to print large zero initializers
1988 (e.g. for large arrays) and is always exactly equivalent to using explicit
1989 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1990
1991 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1992 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1993 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1994 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1995 be interpreted as part of the instruction stream, metadata is a place to
1996 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1997</dl>
1998
1999</div>
2000
2001<!-- ======================================================================= -->
2002<div class="doc_subsection">
2003 <a name="globalconstants">Global Variable and Function Addresses</a>
2004</div>
2005
2006<div class="doc_text">
2007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2008<p>The addresses of <a href="#globalvars">global variables</a>
2009 and <a href="#functionstructure">functions</a> are always implicitly valid
2010 (link-time) constants. These constants are explicitly referenced when
2011 the <a href="#identifiers">identifier for the global</a> is used and always
2012 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2013 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2014
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2015<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2017@X = global i32 17
2018@Y = global i32 42
2019@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2020</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2021</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2022
2023</div>
2024
2025<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2026<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2027<div class="doc_text">
2028
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2029<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]2030 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2031 Undefined values may be of any type (other than label or void) and be used
2032 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2033
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2034<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2035 program is well defined no matter what value is used. This gives the
2036 compiler more freedom to optimize. Here are some examples of (potentially
2037 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2038
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2039
2040<div class="doc_code">
2041<pre>
2042 %A = add %X, undef
2043 %B = sub %X, undef
2044 %C = xor %X, undef
2045Safe:
2046 %A = undef
2047 %B = undef
2048 %C = undef
2049</pre>
2050</div>
2051
2052<p>This is safe because all of the output bits are affected by the undef bits.
2053Any output bit can have a zero or one depending on the input bits.</p>
2054
2055<div class="doc_code">
2056<pre>
2057 %A = or %X, undef
2058 %B = and %X, undef
2059Safe:
2060 %A = -1
2061 %B = 0
2062Unsafe:
2063 %A = undef
2064 %B = undef
2065</pre>
2066</div>
2067
2068<p>These logical operations have bits that are not always affected by the input.
2069For example, if "%X" has a zero bit, then the output of the 'and' operation will
2070always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2071such, it is unsafe to optimize or assume that the result of the and is undef.
2072However, it is safe to assume that all bits of the undef could be 0, and
2073optimize the and to 0. Likewise, it is safe to assume that all the bits of
2074the undef operand to the or could be set, allowing the or to be folded to
2075-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2076
2077<div class="doc_code">
2078<pre>
2079 %A = select undef, %X, %Y
2080 %B = select undef, 42, %Y
2081 %C = select %X, %Y, undef
2082Safe:
2083 %A = %X (or %Y)
2084 %B = 42 (or %Y)
2085 %C = %Y
2086Unsafe:
2087 %A = undef
2088 %B = undef
2089 %C = undef
2090</pre>
2091</div>
2092
2093<p>This set of examples show that undefined select (and conditional branch)
2094conditions can go "either way" but they have to come from one of the two
2095operands. In the %A example, if %X and %Y were both known to have a clear low
2096bit, then %A would have to have a cleared low bit. However, in the %C example,
2097the optimizer is allowed to assume that the undef operand could be the same as
2098%Y, allowing the whole select to be eliminated.</p>
2099
2100
2101<div class="doc_code">
2102<pre>
2103 %A = xor undef, undef
2104
2105 %B = undef
2106 %C = xor %B, %B
2107
2108 %D = undef
2109 %E = icmp lt %D, 4
2110 %F = icmp gte %D, 4
2111
2112Safe:
2113 %A = undef
2114 %B = undef
2115 %C = undef
2116 %D = undef
2117 %E = undef
2118 %F = undef
2119</pre>
2120</div>
2121
2122<p>This example points out that two undef operands are not necessarily the same.
2123This can be surprising to people (and also matches C semantics) where they
2124assume that "X^X" is always zero, even if X is undef. This isn't true for a
2125number of reasons, but the short answer is that an undef "variable" can
2126arbitrarily change its value over its "live range". This is true because the
2127"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2128logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2129so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2130to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2131would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2132
2133<div class="doc_code">
2134<pre>
2135 %A = fdiv undef, %X
2136 %B = fdiv %X, undef
2137Safe:
2138 %A = undef
2139b: unreachable
2140</pre>
2141</div>
2142
2143<p>These examples show the crucial difference between an <em>undefined
2144value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2145allowed to have an arbitrary bit-pattern. This means that the %A operation
2146can be constant folded to undef because the undef could be an SNaN, and fdiv is
2147not (currently) defined on SNaN's. However, in the second example, we can make
2148a more aggressive assumption: because the undef is allowed to be an arbitrary
2149value, 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]2150has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2151does not execute at all. This allows us to delete the divide and all code after
2152it: since the undefined operation "can't happen", the optimizer can assume that
2153it occurs in dead code.
2154</p>
2155
2156<div class="doc_code">
2157<pre>
2158a: store undef -> %X
2159b: store %X -> undef
2160Safe:
2161a: &lt;deleted&gt;
2162b: unreachable
2163</pre>
2164</div>
2165
2166<p>These examples reiterate the fdiv example: a store "of" an undefined value
2167can be assumed to not have any effect: we can assume that the value is
2168overwritten with bits that happen to match what was already there. However, a
2169store "to" an undefined location could clobber arbitrary memory, therefore, it
2170has undefined behavior.</p>
2171
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2172</div>
2173
2174<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2175<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2176 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2177<div class="doc_text">
2178
Chris Lattner7d83ebc2009-10-31 20:08:37 +0000[diff] [blame]2179<p><b><tt>blockaddress(@function, %block)</tt></b><br>
2180 <b><tt>blockaddress(@function, null)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2181
2182<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2183 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner7d83ebc2009-10-31 20:08:37 +0000[diff] [blame]2184 the address of the entry block is illegal. The BasicBlock operand may also
2185 be null.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2186
2187<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2188 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2189 against null. Pointer equality tests between labels addresses is undefined
2190 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2191 equal to the null pointer. This may also be passed around as an opaque
2192 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2193 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2194 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2195
2196<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2197 using the value as the operand to an inline assembly, but that is target
2198 specific.
2199 </p>
2200
2201</div>
2202
2203
2204<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2205<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2206</div>
2207
2208<div class="doc_text">
2209
2210<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2211 to be used as constants. Constant expressions may be of
2212 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2213 operation that does not have side effects (e.g. load and call are not
2214 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2215
2216<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2217 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2218 <dd>Truncate a constant to another type. The bit size of CST must be larger
2219 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2220
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2221 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2222 <dd>Zero extend a constant to another type. The bit size of CST must be
2223 smaller or equal to the bit size of TYPE. Both types must be
2224 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2225
2226 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2227 <dd>Sign extend a constant to another type. The bit size of CST must be
2228 smaller or equal to the bit size of TYPE. Both types must be
2229 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2230
2231 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2232 <dd>Truncate a floating point constant to another floating point type. The
2233 size of CST must be larger than the size of TYPE. Both types must be
2234 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2235
2236 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2237 <dd>Floating point extend a constant to another type. The size of CST must be
2238 smaller or equal to the size of TYPE. Both types must be floating
2239 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2240
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2241 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2242 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2243 constant. TYPE must be a scalar or vector integer type. CST must be of
2244 scalar or vector floating point type. Both CST and TYPE must be scalars,
2245 or vectors of the same number of elements. If the value won't fit in the
2246 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2247
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2248 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2249 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2250 constant. TYPE must be a scalar or vector integer type. CST must be of
2251 scalar or vector floating point type. Both CST and TYPE must be scalars,
2252 or vectors of the same number of elements. If the value won't fit in the
2253 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2254
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2255 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2256 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2257 constant. TYPE must be a scalar or vector floating point type. CST must be
2258 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2259 vectors of the same number of elements. If the value won't fit in the
2260 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2261
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2262 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2263 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2264 constant. TYPE must be a scalar or vector floating point type. CST must be
2265 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2266 vectors of the same number of elements. If the value won't fit in the
2267 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2268
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2269 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2270 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2271 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2272 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2273 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2274
2275 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2276 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2277 type. CST must be of integer type. The CST value is zero extended,
2278 truncated, or unchanged to make it fit in a pointer size. This one is
2279 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2280
2281 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2282 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2283 are the same as those for the <a href="#i_bitcast">bitcast
2284 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2285
2286 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2287 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2288 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2290 instruction, the index list may have zero or more indexes, which are
2291 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2292
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2293 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2294 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2295
2296 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2297 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2298
2299 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2300 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2301
2302 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2304 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2305
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2306 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2307 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2308 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2309
2310 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2311 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2312 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2313
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2314 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2315 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2316 be any of the <a href="#binaryops">binary</a>
2317 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2318 on operands are the same as those for the corresponding instruction
2319 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2320</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2321
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2322</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2323
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2324<!-- ======================================================================= -->
2325<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2326</div>
2327
2328<div class="doc_text">
2329
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2330<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2331 stream without affecting the behaviour of the program. There are two
2332 metadata primitives, strings and nodes. All metadata has the
2333 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2334 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2335
2336<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2337 any character by escaping non-printable characters with "\xx" where "xx" is
2338 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2339
2340<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2341 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2342 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2343 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2344
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2345<p>A metadata node will attempt to track changes to the values it holds. In the
2346 event that a value is deleted, it will be replaced with a typeless
2347 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2348
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2349<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2350 the program that isn't available in the instructions, or that isn't easily
2351 computable. Similarly, the code generator may expect a certain metadata
2352 format to be used to express debugging information.</p>
2353
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2354</div>
2355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2356<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2358<!-- *********************************************************************** -->
2359
2360<!-- ======================================================================= -->
2361<div class="doc_subsection">
2362<a name="inlineasm">Inline Assembler Expressions</a>
2363</div>
2364
2365<div class="doc_text">
2366
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2367<p>LLVM supports inline assembler expressions (as opposed
2368 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2369 a special value. This value represents the inline assembler as a string
2370 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2371 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2372 expression has side effects, and a flag indicating whether the function
2373 containing the asm needs to align its stack conservatively. An example
2374 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2375
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2376<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2377<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2378i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2379</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2380</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2381
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2382<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2383 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2384 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2385
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2386<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2387<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2388%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]2389</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2390</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2391
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2392<p>Inline asms with side effects not visible in the constraint list must be
2393 marked as having side effects. This is done through the use of the
2394 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2395
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2396<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2397<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2398call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2399</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2400</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2401
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2402<p>In some cases inline asms will contain code that will not work unless the
2403 stack is aligned in some way, such as calls or SSE instructions on x86,
2404 yet will not contain code that does that alignment within the asm.
2405 The compiler should make conservative assumptions about what the asm might
2406 contain and should generate its usual stack alignment code in the prologue
2407 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2408
2409<div class="doc_code">
2410<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2411call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2412</pre>
2413</div>
2414
2415<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2416 first.</p>
2417
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2418<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2419 documented here. Constraints on what can be done (e.g. duplication, moving,
2420 etc need to be documented). This is probably best done by reference to
2421 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2422
2423</div>
2424
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2425
2426<!-- *********************************************************************** -->
2427<div class="doc_section">
2428 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2429</div>
2430<!-- *********************************************************************** -->
2431
2432<p>LLVM has a number of "magic" global variables that contain data that affect
2433code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2434of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2435section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2436by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2437
2438<!-- ======================================================================= -->
2439<div class="doc_subsection">
2440<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2441</div>
2442
2443<div class="doc_text">
2444
2445<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2446href="#linkage_appending">appending linkage</a>. This array contains a list of
2447pointers to global variables and functions which may optionally have a pointer
2448cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2449
2450<pre>
2451 @X = global i8 4
2452 @Y = global i32 123
2453
2454 @llvm.used = appending global [2 x i8*] [
2455 i8* @X,
2456 i8* bitcast (i32* @Y to i8*)
2457 ], section "llvm.metadata"
2458</pre>
2459
2460<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2461compiler, assembler, and linker are required to treat the symbol as if there is
2462a reference to the global that it cannot see. For example, if a variable has
2463internal linkage and no references other than that from the <tt>@llvm.used</tt>
2464list, it cannot be deleted. This is commonly used to represent references from
2465inline asms and other things the compiler cannot "see", and corresponds to
2466"attribute((used))" in GNU C.</p>
2467
2468<p>On some targets, the code generator must emit a directive to the assembler or
2469object file to prevent the assembler and linker from molesting the symbol.</p>
2470
2471</div>
2472
2473<!-- ======================================================================= -->
2474<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2475<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2476</div>
2477
2478<div class="doc_text">
2479
2480<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2481<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2482touching the symbol. On targets that support it, this allows an intelligent
2483linker to optimize references to the symbol without being impeded as it would be
2484by <tt>@llvm.used</tt>.</p>
2485
2486<p>This is a rare construct that should only be used in rare circumstances, and
2487should not be exposed to source languages.</p>
2488
2489</div>
2490
2491<!-- ======================================================================= -->
2492<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2493<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2494</div>
2495
2496<div class="doc_text">
2497
2498<p>TODO: Describe this.</p>
2499
2500</div>
2501
2502<!-- ======================================================================= -->
2503<div class="doc_subsection">
2504<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2505</div>
2506
2507<div class="doc_text">
2508
2509<p>TODO: Describe this.</p>
2510
2511</div>
2512
2513
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2514<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2515<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2516<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2517
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2518<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2519
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2520<p>The LLVM instruction set consists of several different classifications of
2521 instructions: <a href="#terminators">terminator
2522 instructions</a>, <a href="#binaryops">binary instructions</a>,
2523 <a href="#bitwiseops">bitwise binary instructions</a>,
2524 <a href="#memoryops">memory instructions</a>, and
2525 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2526
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2527</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2529<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2530<div class="doc_subsection"> <a name="terminators">Terminator
2531Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2532
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2533<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2534
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2535<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2536 in a program ends with a "Terminator" instruction, which indicates which
2537 block should be executed after the current block is finished. These
2538 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2539 control flow, not values (the one exception being the
2540 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2541
2542<p>There are six different terminator instructions: the
2543 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2544 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2545 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2546 '<a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2547 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2548 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2549 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2550
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2551</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2553<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2554<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2555Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2557<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2559<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2560<pre>
2561 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]2562 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2563</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2565<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2566<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2567 a value) from a function back to the caller.</p>
2568
2569<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2570 value and then causes control flow, and one that just causes control flow to
2571 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2572
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2573<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2574<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2575 return value. The type of the return value must be a
2576 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2577
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2578<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2579 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2580 value or a return value with a type that does not match its type, or if it
2581 has a void return type and contains a '<tt>ret</tt>' instruction with a
2582 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2584<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2586 the calling function's context. If the caller is a
2587 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2588 instruction after the call. If the caller was an
2589 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2590 the beginning of the "normal" destination block. If the instruction returns
2591 a value, that value shall set the call or invoke instruction's return
2592 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2594<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2595<pre>
2596 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2597 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2598 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]2599</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2600
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2601<p>Note that the code generator does not yet fully support large
2602 return values. The specific sizes that are currently supported are
2603 dependent on the target. For integers, on 32-bit targets the limit
2604 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2605 For aggregate types, the current limits are dependent on the element
2606 types; for example targets are often limited to 2 total integer
2607 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2608
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2609</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2610<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2611<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2613<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2616<pre>
2617 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]2618</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2619
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2620<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2621<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2622 different basic block in the current function. There are two forms of this
2623 instruction, corresponding to a conditional branch and an unconditional
2624 branch.</p>
2625
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2626<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2627<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2628 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2629 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2630 target.</p>
2631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2632<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2633<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2634 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2635 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2636 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2638<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2639<pre>
2640Test:
2641 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2642 br i1 %cond, label %IfEqual, label %IfUnequal
2643IfEqual:
2644 <a href="#i_ret">ret</a> i32 1
2645IfUnequal:
2646 <a href="#i_ret">ret</a> i32 0
2647</pre>
2648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2649</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2650
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2651<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2652<div class="doc_subsubsection">
2653 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2654</div>
2655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2656<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2657
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2658<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2659<pre>
2660 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2661</pre>
2662
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2663<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2664<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]2665 several different places. It is a generalization of the '<tt>br</tt>'
2666 instruction, allowing a branch to occur to one of many possible
2667 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2670<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2671 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2672 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2673 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2675<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2676<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2678 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2679 transferred to the corresponding destination; otherwise, control flow is
2680 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2681
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2682<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2683<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2684 <tt>switch</tt> instruction, this instruction may be code generated in
2685 different ways. For example, it could be generated as a series of chained
2686 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2687
2688<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2689<pre>
2690 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2691 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2692 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2693
2694 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2695 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2696
2697 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2698 switch i32 %val, label %otherwise [ i32 0, label %onzero
2699 i32 1, label %onone
2700 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2701</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2702
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2703</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2704
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2705
2706<!-- _______________________________________________________________________ -->
2707<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2708 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2709</div>
2710
2711<div class="doc_text">
2712
2713<h5>Syntax:</h5>
2714<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2715 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]2716</pre>
2717
2718<h5>Overview:</h5>
2719
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2720<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2721 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2722 "<tt>address</tt>". Address must be derived from a <a
2723 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2724
2725<h5>Arguments:</h5>
2726
2727<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2728 rest of the arguments indicate the full set of possible destinations that the
2729 address may point to. Blocks are allowed to occur multiple times in the
2730 destination list, though this isn't particularly useful.</p>
2731
2732<p>This destination list is required so that dataflow analysis has an accurate
2733 understanding of the CFG.</p>
2734
2735<h5>Semantics:</h5>
2736
2737<p>Control transfers to the block specified in the address argument. All
2738 possible destination blocks must be listed in the label list, otherwise this
2739 instruction has undefined behavior. This implies that jumps to labels
2740 defined in other functions have undefined behavior as well.</p>
2741
2742<h5>Implementation:</h5>
2743
2744<p>This is typically implemented with a jump through a register.</p>
2745
2746<h5>Example:</h5>
2747<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2748 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2749</pre>
2750
2751</div>
2752
2753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2754<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2755<div class="doc_subsubsection">
2756 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2757</div>
2758
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2759<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2761<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2762<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2763 &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]2764 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2765</pre>
2766
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2767<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2768<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2769 function, with the possibility of control flow transfer to either the
2770 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2771 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2772 control flow will return to the "normal" label. If the callee (or any
2773 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2774 instruction, control is interrupted and continued at the dynamically nearest
2775 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2777<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2778<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2780<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2781 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2782 convention</a> the call should use. If none is specified, the call
2783 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2784
2785 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2787 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2788
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2789 <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]2790 function value being invoked. In most cases, this is a direct function
2791 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2792 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2793
2794 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2795 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2796
2797 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798 signature argument types. If the function signature indicates the
2799 function accepts a variable number of arguments, the extra arguments can
2800 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2801
2802 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2803 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2804
2805 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2806 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2807
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2808 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2810 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2811</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2813<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2814<p>This instruction is designed to operate as a standard
2815 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2816 primary difference is that it establishes an association with a label, which
2817 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2818
2819<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2820 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2821 exception. Additionally, this is important for implementation of
2822 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2823
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2824<p>For the purposes of the SSA form, the definition of the value returned by the
2825 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2826 block to the "normal" label. If the callee unwinds then no return value is
2827 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2828
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2829<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2830<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2831 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2832 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2833 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2834 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2835</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2838
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2839<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2840
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2841<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2842Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2843
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2844<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2845
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2846<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2847<pre>
2848 unwind
2849</pre>
2850
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2851<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2852<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853 at the first callee in the dynamic call stack which used
2854 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2855 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2856
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2857<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2858<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2859 immediately halt. The dynamic call stack is then searched for the
2860 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2861 Once found, execution continues at the "exceptional" destination block
2862 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2863 instruction in the dynamic call chain, undefined behavior results.</p>
2864
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2865</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2866
2867<!-- _______________________________________________________________________ -->
2868
2869<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2870Instruction</a> </div>
2871
2872<div class="doc_text">
2873
2874<h5>Syntax:</h5>
2875<pre>
2876 unreachable
2877</pre>
2878
2879<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2880<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2881 instruction is used to inform the optimizer that a particular portion of the
2882 code is not reachable. This can be used to indicate that the code after a
2883 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2884
2885<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2886<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2888</div>
2889
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2891<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2893<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894
2895<p>Binary operators are used to do most of the computation in a program. They
2896 require two operands of the same type, execute an operation on them, and
2897 produce a single value. The operands might represent multiple data, as is
2898 the case with the <a href="#t_vector">vector</a> data type. The result value
2899 has the same type as its operands.</p>
2900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2901<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2904
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2905<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2906<div class="doc_subsubsection">
2907 <a name="i_add">'<tt>add</tt>' Instruction</a>
2908</div>
2909
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2910<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2912<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2913<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2914 &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]2915 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2916 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2917 &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]2918</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2919
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2920<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2921<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2922
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2923<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924<p>The two arguments to the '<tt>add</tt>' instruction must
2925 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2926 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2928<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2929<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2930
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2931<p>If the sum has unsigned overflow, the result returned is the mathematical
2932 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]2933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2934<p>Because LLVM integers use a two's complement representation, this instruction
2935 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2936
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2937<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2938 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2939 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2940 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2941
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2942<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2943<pre>
2944 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2945</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2947</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2949<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2950<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2951 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2952</div>
2953
2954<div class="doc_text">
2955
2956<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2957<pre>
2958 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2959</pre>
2960
2961<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2962<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2963
2964<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2965<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2967 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2968
2969<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2970<p>The value produced is the floating point sum of the two operands.</p>
2971
2972<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2973<pre>
2974 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2975</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2976
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2977</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2978
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2979<!-- _______________________________________________________________________ -->
2980<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2981 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2982</div>
2983
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2984<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2985
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2986<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2987<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2988 &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]2989 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2990 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2991 &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]2992</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2994<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2995<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2996 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2997
2998<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2999 '<tt>neg</tt>' instruction present in most other intermediate
3000 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3002<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3003<p>The two arguments to the '<tt>sub</tt>' instruction must
3004 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3005 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3007<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3008<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3009
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3010<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3011 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3012 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3013
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3014<p>Because LLVM integers use a two's complement representation, this instruction
3015 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3016
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3017<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3018 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3019 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3020 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3021
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3022<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3023<pre>
3024 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3025 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3026</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3027
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3028</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3029
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3030<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3031<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3032 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3033</div>
3034
3035<div class="doc_text">
3036
3037<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3038<pre>
3039 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3040</pre>
3041
3042<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3043<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3045
3046<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047 '<tt>fneg</tt>' instruction present in most other intermediate
3048 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3049
3050<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3051<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3052 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3053 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3054
3055<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3056<p>The value produced is the floating point difference of the two operands.</p>
3057
3058<h5>Example:</h5>
3059<pre>
3060 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3061 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3062</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3064</div>
3065
3066<!-- _______________________________________________________________________ -->
3067<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3068 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3069</div>
3070
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3071<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3072
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3073<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3074<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3075 &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]3076 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3077 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3078 &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]3079</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3080
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3081<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3083
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3084<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085<p>The two arguments to the '<tt>mul</tt>' instruction must
3086 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3087 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3088
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3089<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3090<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3092<p>If the result of the multiplication has unsigned overflow, the result
3093 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3094 width of the result.</p>
3095
3096<p>Because LLVM integers use a two's complement representation, and the result
3097 is the same width as the operands, this instruction returns the correct
3098 result for both signed and unsigned integers. If a full product
3099 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3100 be sign-extended or zero-extended as appropriate to the width of the full
3101 product.</p>
3102
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3103<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3104 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3105 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3106 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3107
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3108<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<pre>
3110 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3111</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3113</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3114
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3115<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3116<div class="doc_subsubsection">
3117 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3118</div>
3119
3120<div class="doc_text">
3121
3122<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<pre>
3124 &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]3125</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3127<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3128<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3129
3130<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3131<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3132 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3133 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3134
3135<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3136<p>The value produced is the floating point product of the two operands.</p>
3137
3138<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3139<pre>
3140 &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]3141</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3142
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3143</div>
3144
3145<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3146<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3147</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3148
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3149<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3150
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3151<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152<pre>
3153 &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]3154</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3155
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3156<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3158
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3159<h5>Arguments:</h5>
3160<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3162 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3163
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3164<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3165<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3167<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3168 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3169
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3170<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3172<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
3174 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3175</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3176
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3177</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3178
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
3180<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3181</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3182
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3183<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3184
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3185<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3187 &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]3188 &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]3189</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3190
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3191<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3193
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3194<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3195<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3196 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3197 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3198
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3199<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3200<p>The value produced is the signed integer quotient of the two operands rounded
3201 towards zero.</p>
3202
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3203<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3205
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3206<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3207 undefined behavior; this is a rare case, but can occur, for example, by doing
3208 a 32-bit division of -2147483648 by -1.</p>
3209
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3210<p>If the <tt>exact</tt> keyword is present, the result value of the
3211 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3212 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3213
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3214<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215<pre>
3216 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3217</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3218
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3219</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3220
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3221<!-- _______________________________________________________________________ -->
3222<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3223Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3225<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3227<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3228<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3229 &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]3230</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3231
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3232<h5>Overview:</h5>
3233<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3235<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3236<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3238 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3240<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3241<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3242
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3243<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3244<pre>
3245 &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]3246</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3248</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3250<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3251<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3252</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3253
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3254<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3255
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3256<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3257<pre>
3258 &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]3259</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3261<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3263 division of its two arguments.</p>
3264
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3265<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3266<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3268 values. Both arguments must have identical types.</p>
3269
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3270<h5>Semantics:</h5>
3271<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3272 This instruction always performs an unsigned division to get the
3273 remainder.</p>
3274
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3275<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3277
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3278<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3280<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281<pre>
3282 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3283</pre>
3284
3285</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3287<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3288<div class="doc_subsubsection">
3289 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3290</div>
3291
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3292<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3293
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3294<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3295<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3296 &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]3297</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3298
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3299<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3300<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3301 division of its two operands. This instruction can also take
3302 <a href="#t_vector">vector</a> versions of the values in which case the
3303 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3304
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3305<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3306<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3307 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3308 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3309
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3310<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3311<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3312 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3313 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3314 a value. For more information about the difference,
3315 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3316 Math Forum</a>. For a table of how this is implemented in various languages,
3317 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3318 Wikipedia: modulo operation</a>.</p>
3319
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3320<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3321 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3322
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3323<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324 Overflow also leads to undefined behavior; this is a rare case, but can
3325 occur, for example, by taking the remainder of a 32-bit division of
3326 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3327 lets srem be implemented using instructions that return both the result of
3328 the division and the remainder.)</p>
3329
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3330<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331<pre>
3332 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3333</pre>
3334
3335</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3336
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3337<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3338<div class="doc_subsubsection">
3339 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3340
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3341<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3342
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3343<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344<pre>
3345 &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]3346</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3347
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3348<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3350 its two operands.</p>
3351
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3352<h5>Arguments:</h5>
3353<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3354 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3355 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3356
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3357<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358<p>This instruction returns the <i>remainder</i> of a division. The remainder
3359 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3360
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3361<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3362<pre>
3363 &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]3364</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3366</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3367
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3368<!-- ======================================================================= -->
3369<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3370Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3372<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373
3374<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3375 program. They are generally very efficient instructions and can commonly be
3376 strength reduced from other instructions. They require two operands of the
3377 same type, execute an operation on them, and produce a single value. The
3378 resulting value is the same type as its operands.</p>
3379
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3380</div>
3381
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3382<!-- _______________________________________________________________________ -->
3383<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3384Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3385
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3386<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3387
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3388<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389<pre>
3390 &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]3391</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3392
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3393<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3394<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3395 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3396
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3397<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3398<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3399 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3400 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3401
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3402<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3403<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3404 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3405 is (statically or dynamically) negative or equal to or larger than the number
3406 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3407 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3408 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3409
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410<h5>Example:</h5>
3411<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3412 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3413 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3414 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3415 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3416 &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]3417</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3419</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3420
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3423Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3424
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3425<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3427<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3428<pre>
3429 &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]3430</pre>
3431
3432<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3433<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3434 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3435
3436<h5>Arguments:</h5>
3437<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3438 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3439 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3440
3441<h5>Semantics:</h5>
3442<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3443 significant bits of the result will be filled with zero bits after the shift.
3444 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3445 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3446 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3447 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3448
3449<h5>Example:</h5>
3450<pre>
3451 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3452 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3453 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3454 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3455 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3456 &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]3457</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3459</div>
3460
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3461<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3462<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3463Instruction</a> </div>
3464<div class="doc_text">
3465
3466<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3467<pre>
3468 &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]3469</pre>
3470
3471<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3473 operand shifted to the right a specified number of bits with sign
3474 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3475
3476<h5>Arguments:</h5>
3477<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3479 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3480
3481<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482<p>This instruction always performs an arithmetic shift right operation, The
3483 most significant bits of the result will be filled with the sign bit
3484 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3485 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3486 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3487 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3488
3489<h5>Example:</h5>
3490<pre>
3491 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3492 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3493 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3494 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3495 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3496 &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]3497</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3498
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3499</div>
3500
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3501<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3502<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3503Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3504
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3505<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3506
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3508<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3509 &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]3510</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3511
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3512<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3514 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3516<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3517<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3519 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3521<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3522<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3524<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3525 <tbody>
3526 <tr>
3527 <td>In0</td>
3528 <td>In1</td>
3529 <td>Out</td>
3530 </tr>
3531 <tr>
3532 <td>0</td>
3533 <td>0</td>
3534 <td>0</td>
3535 </tr>
3536 <tr>
3537 <td>0</td>
3538 <td>1</td>
3539 <td>0</td>
3540 </tr>
3541 <tr>
3542 <td>1</td>
3543 <td>0</td>
3544 <td>0</td>
3545 </tr>
3546 <tr>
3547 <td>1</td>
3548 <td>1</td>
3549 <td>1</td>
3550 </tr>
3551 </tbody>
3552</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3554<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3555<pre>
3556 &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]3557 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3558 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3559</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3561<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3563
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3564<div class="doc_text">
3565
3566<h5>Syntax:</h5>
3567<pre>
3568 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3569</pre>
3570
3571<h5>Overview:</h5>
3572<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3573 two operands.</p>
3574
3575<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3576<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3578 values. Both arguments must have identical types.</p>
3579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3580<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3581<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3582
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<table border="1" cellspacing="0" cellpadding="4">
3584 <tbody>
3585 <tr>
3586 <td>In0</td>
3587 <td>In1</td>
3588 <td>Out</td>
3589 </tr>
3590 <tr>
3591 <td>0</td>
3592 <td>0</td>
3593 <td>0</td>
3594 </tr>
3595 <tr>
3596 <td>0</td>
3597 <td>1</td>
3598 <td>1</td>
3599 </tr>
3600 <tr>
3601 <td>1</td>
3602 <td>0</td>
3603 <td>1</td>
3604 </tr>
3605 <tr>
3606 <td>1</td>
3607 <td>1</td>
3608 <td>1</td>
3609 </tr>
3610 </tbody>
3611</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3613<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614<pre>
3615 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3616 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3617 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3618</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3619
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3620</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3622<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3623<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3624Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3625
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3626<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629<pre>
3630 &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]3631</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3632
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3634<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3635 its two operands. The <tt>xor</tt> is used to implement the "one's
3636 complement" operation, which is the "~" operator in C.</p>
3637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3638<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3639<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3640 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3641 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3642
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3643<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3644<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3645
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3646<table border="1" cellspacing="0" cellpadding="4">
3647 <tbody>
3648 <tr>
3649 <td>In0</td>
3650 <td>In1</td>
3651 <td>Out</td>
3652 </tr>
3653 <tr>
3654 <td>0</td>
3655 <td>0</td>
3656 <td>0</td>
3657 </tr>
3658 <tr>
3659 <td>0</td>
3660 <td>1</td>
3661 <td>1</td>
3662 </tr>
3663 <tr>
3664 <td>1</td>
3665 <td>0</td>
3666 <td>1</td>
3667 </tr>
3668 <tr>
3669 <td>1</td>
3670 <td>1</td>
3671 <td>0</td>
3672 </tr>
3673 </tbody>
3674</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3676<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3677<pre>
3678 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3679 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3680 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3681 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3682</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3684</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3685
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3686<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3687<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3688 <a name="vectorops">Vector Operations</a>
3689</div>
3690
3691<div class="doc_text">
3692
3693<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694 target-independent manner. These instructions cover the element-access and
3695 vector-specific operations needed to process vectors effectively. While LLVM
3696 does directly support these vector operations, many sophisticated algorithms
3697 will want to use target-specific intrinsics to take full advantage of a
3698 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3699
3700</div>
3701
3702<!-- _______________________________________________________________________ -->
3703<div class="doc_subsubsection">
3704 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3705</div>
3706
3707<div class="doc_text">
3708
3709<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3710<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3711 &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]3712</pre>
3713
3714<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3715<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3716 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3717
3718
3719<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3721 of <a href="#t_vector">vector</a> type. The second operand is an index
3722 indicating the position from which to extract the element. The index may be
3723 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3724
3725<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3726<p>The result is a scalar of the same type as the element type of
3727 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3728 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3729 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3730
3731<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3732<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3733 &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]3734</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3735
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3737
3738<!-- _______________________________________________________________________ -->
3739<div class="doc_subsubsection">
3740 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3741</div>
3742
3743<div class="doc_text">
3744
3745<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3746<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3747 &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]3748</pre>
3749
3750<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3752 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3753
3754<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3755<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3756 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3757 whose type must equal the element type of the first operand. The third
3758 operand is an index indicating the position at which to insert the value.
3759 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3760
3761<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3762<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3763 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3764 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3765 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3766
3767<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3768<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3769 &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]3770</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3772</div>
3773
3774<!-- _______________________________________________________________________ -->
3775<div class="doc_subsubsection">
3776 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3777</div>
3778
3779<div class="doc_text">
3780
3781<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3782<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3783 &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]3784</pre>
3785
3786<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3788 from two input vectors, returning a vector with the same element type as the
3789 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3790
3791<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3792<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3793 with types that match each other. The third argument is a shuffle mask whose
3794 element type is always 'i32'. The result of the instruction is a vector
3795 whose length is the same as the shuffle mask and whose element type is the
3796 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3797
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3798<p>The shuffle mask operand is required to be a constant vector with either
3799 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3800
3801<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802<p>The elements of the two input vectors are numbered from left to right across
3803 both of the vectors. The shuffle mask operand specifies, for each element of
3804 the result vector, which element of the two input vectors the result element
3805 gets. The element selector may be undef (meaning "don't care") and the
3806 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3807
3808<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3809<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3810 &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]3811 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3812 &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]3813 &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.
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3814 &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]3815 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3816 &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]3817 &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]3818</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3819
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3820</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3821
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3822<!-- ======================================================================= -->
3823<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3824 <a name="aggregateops">Aggregate Operations</a>
3825</div>
3826
3827<div class="doc_text">
3828
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3829<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3830
3831</div>
3832
3833<!-- _______________________________________________________________________ -->
3834<div class="doc_subsubsection">
3835 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3836</div>
3837
3838<div class="doc_text">
3839
3840<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3841<pre>
3842 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3843</pre>
3844
3845<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3846<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3847 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3848
3849<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3850<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3851 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3852 operands are constant indices to specify which value to extract in a similar
3853 manner as indices in a
3854 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3855
3856<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857<p>The result is the value at the position in the aggregate specified by the
3858 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3859
3860<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3861<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3862 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3863</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3864
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3866
3867<!-- _______________________________________________________________________ -->
3868<div class="doc_subsubsection">
3869 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3870</div>
3871
3872<div class="doc_text">
3873
3874<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3875<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3876 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3877</pre>
3878
3879<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3880<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3881 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3882
3883
3884<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3886 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3887 second operand is a first-class value to insert. The following operands are
3888 constant indices indicating the position at which to insert the value in a
3889 similar manner as indices in a
3890 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3891 value to insert must have the same type as the value identified by the
3892 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3893
3894<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3896 that of <tt>val</tt> except that the value at the position specified by the
3897 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3898
3899<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3900<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3901 &lt;result&gt; = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3902</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3904</div>
3905
3906
3907<!-- ======================================================================= -->
3908<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3909 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3910</div>
3911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3912<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3913
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914<p>A key design point of an SSA-based representation is how it represents
3915 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]3916 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3917 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3919</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3922<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3923 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3924</div>
3925
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3926<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3928<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3929<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3930 &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]3931</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3933<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3934<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3935 currently executing function, to be automatically released when this function
3936 returns to its caller. The object is always allocated in the generic address
3937 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3938
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3939<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3940<p>The '<tt>alloca</tt>' instruction
3941 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3942 runtime stack, returning a pointer of the appropriate type to the program.
3943 If "NumElements" is specified, it is the number of elements allocated,
3944 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3945 specified, the value result of the allocation is guaranteed to be aligned to
3946 at least that boundary. If not specified, or if zero, the target can choose
3947 to align the allocation on any convenient boundary compatible with the
3948 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3950<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3951
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3952<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3953<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3954 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3955 memory is automatically released when the function returns. The
3956 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3957 variables that must have an address available. When the function returns
3958 (either with the <tt><a href="#i_ret">ret</a></tt>
3959 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3960 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3961
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3962<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3963<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3964 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3965 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3966 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3967 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3968</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3970</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3972<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3973<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3974Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3975
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3976<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3977
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3978<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979<pre>
3980 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3981 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3982</pre>
3983
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3984<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3985<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3986
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3987<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3989 from which to load. The pointer must point to
3990 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3991 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3992 number or order of execution of this <tt>load</tt> with other
3993 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3994 instructions. </p>
3995
3996<p>The optional constant "align" argument specifies the alignment of the
3997 operation (that is, the alignment of the memory address). A value of 0 or an
3998 omitted "align" argument means that the operation has the preferential
3999 alignment for the target. It is the responsibility of the code emitter to
4000 ensure that the alignment information is correct. Overestimating the
4001 alignment results in an undefined behavior. Underestimating the alignment may
4002 produce less efficient code. An alignment of 1 is always safe.</p>
4003
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4004<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005<p>The location of memory pointed to is loaded. If the value being loaded is of
4006 scalar type then the number of bytes read does not exceed the minimum number
4007 of bytes needed to hold all bits of the type. For example, loading an
4008 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4009 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4010 is undefined if the value was not originally written using a store of the
4011 same type.</p>
4012
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4013<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014<pre>
4015 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4016 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4017 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4018</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4019
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4020</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4021
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4022<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4023<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4024Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4025
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4026<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4028<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4029<pre>
4030 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]4031 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4032</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4034<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4035<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4036
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4037<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4038<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4039 and an address at which to store it. The type of the
4040 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4041 the <a href="#t_firstclass">first class</a> type of the
4042 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4043 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4044 or order of execution of this <tt>store</tt> with other
4045 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4046 instructions.</p>
4047
4048<p>The optional constant "align" argument specifies the alignment of the
4049 operation (that is, the alignment of the memory address). A value of 0 or an
4050 omitted "align" argument means that the operation has the preferential
4051 alignment for the target. It is the responsibility of the code emitter to
4052 ensure that the alignment information is correct. Overestimating the
4053 alignment results in an undefined behavior. Underestimating the alignment may
4054 produce less efficient code. An alignment of 1 is always safe.</p>
4055
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4056<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4058 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4059 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4060 does not exceed the minimum number of bytes needed to hold all bits of the
4061 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4062 writing a value of a type like <tt>i20</tt> with a size that is not an
4063 integral number of bytes, it is unspecified what happens to the extra bits
4064 that do not belong to the type, but they will typically be overwritten.</p>
4065
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4066<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4067<pre>
4068 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4069 store i32 3, i32* %ptr <i>; yields {void}</i>
4070 %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]4071</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4072
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4073</div>
4074
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4075<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4076<div class="doc_subsubsection">
4077 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4078</div>
4079
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4080<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4082<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4083<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4084 &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]4085 &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]4086</pre>
4087
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4088<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4089<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4090 subelement of an aggregate data structure. It performs address calculation
4091 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4092
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4093<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4094<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4095 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096 elements of the aggregate object are indexed. The interpretation of each
4097 index is dependent on the type being indexed into. The first index always
4098 indexes the pointer value given as the first argument, the second index
4099 indexes a value of the type pointed to (not necessarily the value directly
4100 pointed to, since the first index can be non-zero), etc. The first type
4101 indexed into must be a pointer value, subsequent types can be arrays, vectors
4102 and structs. Note that subsequent types being indexed into can never be
4103 pointers, since that would require loading the pointer before continuing
4104 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4105
4106<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4107 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4108 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4109 vector, integers of any width are allowed, and they are not required to be
4110 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4111
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4112<p>For example, let's consider a C code fragment and how it gets compiled to
4113 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4114
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4115<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4116<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4117struct RT {
4118 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4119 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4120 char C;
4121};
4122struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4123 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4124 double Y;
4125 struct RT Z;
4126};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4127
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4128int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4129 return &amp;s[1].Z.B[5][13];
4130}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4131</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4132</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4134<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4135
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4136<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4137<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4138%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4139%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4140
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4141define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4142entry:
4143 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4144 ret i32* %reg
4145}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4146</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4147</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4148
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4149<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4150<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]4151 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4152 }</tt>' type, a structure. The second index indexes into the third element
4153 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4154 i8 }</tt>' type, another structure. The third index indexes into the second
4155 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4156 array. The two dimensions of the array are subscripted into, yielding an
4157 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4158 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4160<p>Note that it is perfectly legal to index partially through a structure,
4161 returning a pointer to an inner element. Because of this, the LLVM code for
4162 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4163
4164<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4165 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4166 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4167 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4168 %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]4169 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4170 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4171 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4172 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4173</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4174
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4175<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4176 <tt>getelementptr</tt> is undefined if the base pointer is not an
4177 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4178 that would be formed by successive addition of the offsets implied by the
4179 indices to the base address with infinitely precise arithmetic are not an
4180 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4181 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4182 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4183
4184<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4185 the base address with silently-wrapping two's complement arithmetic, and
4186 the result value of the <tt>getelementptr</tt> may be outside the object
4187 pointed to by the base pointer. The result value may not necessarily be
4188 used to access memory though, even if it happens to point into allocated
4189 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4190 section for more information.</p>
4191
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192<p>The getelementptr instruction is often confusing. For some more insight into
4193 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4194
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4195<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4196<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4197 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4198 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4199 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4200 %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]4201 <i>; yields i8*:eptr</i>
4202 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4203 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4204 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4205</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4207</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4208
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4209<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4210<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4211</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4212
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4213<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4214
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4215<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4216 which all take a single operand and a type. They perform various bit
4217 conversions on the operand.</p>
4218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4219</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4220
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4222<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4223 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4224</div>
4225<div class="doc_text">
4226
4227<h5>Syntax:</h5>
4228<pre>
4229 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4230</pre>
4231
4232<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4233<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4234 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4235
4236<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4237<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4238 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4239 size and type of the result, which must be
4240 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4241 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4242 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4243
4244<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4246 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4247 source size must be larger than the destination size, <tt>trunc</tt> cannot
4248 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4249
4250<h5>Example:</h5>
4251<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4252 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4253 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4254 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4256
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4257</div>
4258
4259<!-- _______________________________________________________________________ -->
4260<div class="doc_subsubsection">
4261 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4262</div>
4263<div class="doc_text">
4264
4265<h5>Syntax:</h5>
4266<pre>
4267 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4268</pre>
4269
4270<h5>Overview:</h5>
4271<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4272 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4273
4274
4275<h5>Arguments:</h5>
4276<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]4277 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4278 also be of <a href="#t_integer">integer</a> type. The bit size of the
4279 <tt>value</tt> must be smaller than the bit size of the destination type,
4280 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4281
4282<h5>Semantics:</h5>
4283<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]4284 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4285
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4286<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]4287
4288<h5>Example:</h5>
4289<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4290 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4291 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4292</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4293
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4294</div>
4295
4296<!-- _______________________________________________________________________ -->
4297<div class="doc_subsubsection">
4298 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4299</div>
4300<div class="doc_text">
4301
4302<h5>Syntax:</h5>
4303<pre>
4304 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4305</pre>
4306
4307<h5>Overview:</h5>
4308<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4309
4310<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4311<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4312 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4313 also be of <a href="#t_integer">integer</a> type. The bit size of the
4314 <tt>value</tt> must be smaller than the bit size of the destination type,
4315 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4316
4317<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4318<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4319 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4320 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4321
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4322<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]4323
4324<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4325<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4326 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4327 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4328</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4330</div>
4331
4332<!-- _______________________________________________________________________ -->
4333<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4334 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4335</div>
4336
4337<div class="doc_text">
4338
4339<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4340<pre>
4341 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4342</pre>
4343
4344<h5>Overview:</h5>
4345<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4347
4348<h5>Arguments:</h5>
4349<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4350 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4351 to cast it to. The size of <tt>value</tt> must be larger than the size of
4352 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4353 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4354
4355<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4357 <a href="#t_floating">floating point</a> type to a smaller
4358 <a href="#t_floating">floating point</a> type. If the value cannot fit
4359 within the destination type, <tt>ty2</tt>, then the results are
4360 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4361
4362<h5>Example:</h5>
4363<pre>
4364 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4365 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4366</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4368</div>
4369
4370<!-- _______________________________________________________________________ -->
4371<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4372 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4373</div>
4374<div class="doc_text">
4375
4376<h5>Syntax:</h5>
4377<pre>
4378 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4379</pre>
4380
4381<h5>Overview:</h5>
4382<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]4383 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4384
4385<h5>Arguments:</h5>
4386<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4387 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4388 a <a href="#t_floating">floating point</a> type to cast it to. The source
4389 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4390
4391<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4392<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393 <a href="#t_floating">floating point</a> type to a larger
4394 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4395 used to make a <i>no-op cast</i> because it always changes bits. Use
4396 <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]4397
4398<h5>Example:</h5>
4399<pre>
4400 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4401 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4402</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4404</div>
4405
4406<!-- _______________________________________________________________________ -->
4407<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4408 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4409</div>
4410<div class="doc_text">
4411
4412<h5>Syntax:</h5>
4413<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4414 &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]4415</pre>
4416
4417<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4418<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4419 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4420
4421<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4422<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4423 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4424 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4425 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4426 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4427
4428<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429<p>The '<tt>fptoui</tt>' instruction converts its
4430 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4431 towards zero) unsigned integer value. If the value cannot fit
4432 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4433
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4434<h5>Example:</h5>
4435<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4436 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4437 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4438 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4439</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4440
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4441</div>
4442
4443<!-- _______________________________________________________________________ -->
4444<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4445 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4446</div>
4447<div class="doc_text">
4448
4449<h5>Syntax:</h5>
4450<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4451 &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]4452</pre>
4453
4454<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4455<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4456 <a href="#t_floating">floating point</a> <tt>value</tt> to
4457 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4458
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4459<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4460<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4461 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4462 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4463 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4464 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4465
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4466<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4467<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4468 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4469 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4470 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4471
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4472<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4473<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4474 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4475 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4476 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4477</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4478
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4479</div>
4480
4481<!-- _______________________________________________________________________ -->
4482<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4483 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4484</div>
4485<div class="doc_text">
4486
4487<h5>Syntax:</h5>
4488<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4489 &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]4490</pre>
4491
4492<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4493<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4495
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4496<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4497<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]4498 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4499 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4500 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4501 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4502
4503<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4504<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4505 integer quantity and converts it to the corresponding floating point
4506 value. If the value cannot fit in the floating point value, the results are
4507 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4508
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4509<h5>Example:</h5>
4510<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4511 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4512 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4513</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4515</div>
4516
4517<!-- _______________________________________________________________________ -->
4518<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4519 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4520</div>
4521<div class="doc_text">
4522
4523<h5>Syntax:</h5>
4524<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4525 &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]4526</pre>
4527
4528<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4529<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4530 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4531
4532<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4533<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]4534 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4535 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4536 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4537 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4538
4539<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4541 quantity and converts it to the corresponding floating point value. If the
4542 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4543
4544<h5>Example:</h5>
4545<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4546 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4547 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4548</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4549
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4550</div>
4551
4552<!-- _______________________________________________________________________ -->
4553<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4554 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4555</div>
4556<div class="doc_text">
4557
4558<h5>Syntax:</h5>
4559<pre>
4560 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4561</pre>
4562
4563<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4565 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4566
4567<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4569 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4570 <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]4571
4572<h5>Semantics:</h5>
4573<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4575 truncating or zero extending that value to the size of the integer type. If
4576 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4577 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4578 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4579 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4580
4581<h5>Example:</h5>
4582<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4583 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4584 %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]4585</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4586
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4587</div>
4588
4589<!-- _______________________________________________________________________ -->
4590<div class="doc_subsubsection">
4591 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4592</div>
4593<div class="doc_text">
4594
4595<h5>Syntax:</h5>
4596<pre>
4597 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4598</pre>
4599
4600<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4601<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4602 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4603
4604<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4605<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4606 value to cast, and a type to cast it to, which must be a
4607 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4608
4609<h5>Semantics:</h5>
4610<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4611 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4612 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4613 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4614 than the size of a pointer then a zero extension is done. If they are the
4615 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4616
4617<h5>Example:</h5>
4618<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4619 %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]4620 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4621 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4622</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4623
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4624</div>
4625
4626<!-- _______________________________________________________________________ -->
4627<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4628 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4629</div>
4630<div class="doc_text">
4631
4632<h5>Syntax:</h5>
4633<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4634 &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]4635</pre>
4636
4637<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4638<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4639 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4640
4641<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4643 non-aggregate first class value, and a type to cast it to, which must also be
4644 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4645 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4646 identical. If the source type is a pointer, the destination type must also be
4647 a pointer. This instruction supports bitwise conversion of vectors to
4648 integers and to vectors of other types (as long as they have the same
4649 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4650
4651<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4652<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4653 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4654 this conversion. The conversion is done as if the <tt>value</tt> had been
4655 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4656 be converted to other pointer types with this instruction. To convert
4657 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4658 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4659
4660<h5>Example:</h5>
4661<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4662 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4663 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4664 %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]4665</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4666
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4667</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4668
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4669<!-- ======================================================================= -->
4670<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4672<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4673
4674<p>The instructions in this category are the "miscellaneous" instructions, which
4675 defy better classification.</p>
4676
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4677</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4678
4679<!-- _______________________________________________________________________ -->
4680<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4681</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4682
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4683<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4684
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4685<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686<pre>
4687 &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]4688</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4689
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4690<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4692 boolean values based on comparison of its two integer, integer vector, or
4693 pointer operands.</p>
4694
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4695<h5>Arguments:</h5>
4696<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4697 the condition code indicating the kind of comparison to perform. It is not a
4698 value, just a keyword. The possible condition code are:</p>
4699
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4700<ol>
4701 <li><tt>eq</tt>: equal</li>
4702 <li><tt>ne</tt>: not equal </li>
4703 <li><tt>ugt</tt>: unsigned greater than</li>
4704 <li><tt>uge</tt>: unsigned greater or equal</li>
4705 <li><tt>ult</tt>: unsigned less than</li>
4706 <li><tt>ule</tt>: unsigned less or equal</li>
4707 <li><tt>sgt</tt>: signed greater than</li>
4708 <li><tt>sge</tt>: signed greater or equal</li>
4709 <li><tt>slt</tt>: signed less than</li>
4710 <li><tt>sle</tt>: signed less or equal</li>
4711</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4713<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4715 typed. They must also be identical types.</p>
4716
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4717<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4718<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4719 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4720 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]4721 result, as follows:</p>
4722
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4723<ol>
4724 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725 <tt>false</tt> otherwise. No sign interpretation is necessary or
4726 performed.</li>
4727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4728 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729 <tt>false</tt> otherwise. No sign interpretation is necessary or
4730 performed.</li>
4731
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4732 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4734
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4735 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4736 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4737 to <tt>op2</tt>.</li>
4738
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4739 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4741
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4742 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4744
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4745 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4746 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4747
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4748 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4749 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4750 to <tt>op2</tt>.</li>
4751
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4752 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4754
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4755 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4756 <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]4757</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4759<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760 values are compared as if they were integers.</p>
4761
4762<p>If the operands are integer vectors, then they are compared element by
4763 element. The result is an <tt>i1</tt> vector with the same number of elements
4764 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4765
4766<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767<pre>
4768 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4769 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4770 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4771 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4772 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4773 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4774</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4775
4776<p>Note that the code generator does not yet support vector types with
4777 the <tt>icmp</tt> instruction.</p>
4778
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4779</div>
4780
4781<!-- _______________________________________________________________________ -->
4782<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4783</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4784
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4785<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4786
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4787<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4788<pre>
4789 &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]4790</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4791
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4792<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4794 values based on comparison of its operands.</p>
4795
4796<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]4797(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798
4799<p>If the operands are floating point vectors, then the result type is a vector
4800 of boolean with the same number of elements as the operands being
4801 compared.</p>
4802
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4803<h5>Arguments:</h5>
4804<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4805 the condition code indicating the kind of comparison to perform. It is not a
4806 value, just a keyword. The possible condition code are:</p>
4807
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4808<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4809 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4810 <li><tt>oeq</tt>: ordered and equal</li>
4811 <li><tt>ogt</tt>: ordered and greater than </li>
4812 <li><tt>oge</tt>: ordered and greater than or equal</li>
4813 <li><tt>olt</tt>: ordered and less than </li>
4814 <li><tt>ole</tt>: ordered and less than or equal</li>
4815 <li><tt>one</tt>: ordered and not equal</li>
4816 <li><tt>ord</tt>: ordered (no nans)</li>
4817 <li><tt>ueq</tt>: unordered or equal</li>
4818 <li><tt>ugt</tt>: unordered or greater than </li>
4819 <li><tt>uge</tt>: unordered or greater than or equal</li>
4820 <li><tt>ult</tt>: unordered or less than </li>
4821 <li><tt>ule</tt>: unordered or less than or equal</li>
4822 <li><tt>une</tt>: unordered or not equal</li>
4823 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4824 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4825</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4826
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4827<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4828 <i>unordered</i> means that either operand may be a QNAN.</p>
4829
4830<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4831 a <a href="#t_floating">floating point</a> type or
4832 a <a href="#t_vector">vector</a> of floating point type. They must have
4833 identical types.</p>
4834
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4835<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4836<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4837 according to the condition code given as <tt>cond</tt>. If the operands are
4838 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4839 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4840 follows:</p>
4841
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4842<ol>
4843 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4844
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4847
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4848 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4849 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4850
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4851 <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]4852 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4853
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4854 <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]4855 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4856
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4857 <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]4858 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4859
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4860 <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]4861 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4862
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4863 <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]4864
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4865 <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]4866 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4867
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4868 <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]4869 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4870
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4871 <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]4872 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4873
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4874 <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]4875 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4876
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4877 <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]4878 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4879
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4880 <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]4881 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4882
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4883 <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]4884
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4885 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4886</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4887
4888<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4889<pre>
4890 &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]4891 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4892 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4893 &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]4894</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4895
4896<p>Note that the code generator does not yet support vector types with
4897 the <tt>fcmp</tt> instruction.</p>
4898
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4899</div>
4900
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4901<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4902<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4903 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4904</div>
4905
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4906<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4907
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4908<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4909<pre>
4910 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4911</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4912
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4913<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4914<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4915 SSA graph representing the function.</p>
4916
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4917<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4918<p>The type of the incoming values is specified with the first type field. After
4919 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4920 one pair for each predecessor basic block of the current block. Only values
4921 of <a href="#t_firstclass">first class</a> type may be used as the value
4922 arguments to the PHI node. Only labels may be used as the label
4923 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4924
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4925<p>There must be no non-phi instructions between the start of a basic block and
4926 the PHI instructions: i.e. PHI instructions must be first in a basic
4927 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4929<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4930 occur on the edge from the corresponding predecessor block to the current
4931 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4932 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4933
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4934<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4935<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4936 specified by the pair corresponding to the predecessor basic block that
4937 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4938
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4939<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4940<pre>
4941Loop: ; Infinite loop that counts from 0 on up...
4942 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4943 %nextindvar = add i32 %indvar, 1
4944 br label %Loop
4945</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4946
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4947</div>
4948
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4949<!-- _______________________________________________________________________ -->
4950<div class="doc_subsubsection">
4951 <a name="i_select">'<tt>select</tt>' Instruction</a>
4952</div>
4953
4954<div class="doc_text">
4955
4956<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4957<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4958 &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>
4959
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4960 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4961</pre>
4962
4963<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4965 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4966
4967
4968<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4969<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4970 values indicating the condition, and two values of the
4971 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4972 vectors and the condition is a scalar, then entire vectors are selected, not
4973 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4974
4975<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4976<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4977 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4978
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4979<p>If the condition is a vector of i1, then the value arguments must be vectors
4980 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4981
4982<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4983<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4984 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4985</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4986
4987<p>Note that the code generator does not yet support conditions
4988 with vector type.</p>
4989
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4990</div>
4991
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4992<!-- _______________________________________________________________________ -->
4993<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4994 <a name="i_call">'<tt>call</tt>' Instruction</a>
4995</div>
4996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4997<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4998
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4999<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5000<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]5001 &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]5002</pre>
5003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5004<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5005<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5007<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5008<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5009
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5010<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5011 <li>The optional "tail" marker indicates whether the callee function accesses
5012 any allocas or varargs in the caller. If the "tail" marker is present,
5013 the function call is eligible for tail call optimization. Note that calls
5014 may be marked "tail" even if they do not occur before
5015 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5017 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5018 convention</a> the call should use. If none is specified, the call
5019 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5021 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5022 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5023 '<tt>inreg</tt>' attributes are valid here.</li>
5024
5025 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5026 type of the return value. Functions that return no value are marked
5027 <tt><a href="#t_void">void</a></tt>.</li>
5028
5029 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5030 being invoked. The argument types must match the types implied by this
5031 signature. This type can be omitted if the function is not varargs and if
5032 the function type does not return a pointer to a function.</li>
5033
5034 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5035 be invoked. In most cases, this is a direct function invocation, but
5036 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5037 to function value.</li>
5038
5039 <li>'<tt>function args</tt>': argument list whose types match the function
5040 signature argument types. All arguments must be of
5041 <a href="#t_firstclass">first class</a> type. If the function signature
5042 indicates the function accepts a variable number of arguments, the extra
5043 arguments can be specified.</li>
5044
5045 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5046 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5047 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5048</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5049
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5050<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5051<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5052 a specified function, with its incoming arguments bound to the specified
5053 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5054 function, control flow continues with the instruction after the function
5055 call, and the return value of the function is bound to the result
5056 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5057
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5058<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5059<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5060 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5061 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5062 %X = tail call i32 @foo() <i>; yields i32</i>
5063 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5064 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5065
5066 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5067 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5068 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5069 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5070 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5071 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5072</pre>
5073
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5074<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5075standard C99 library as being the C99 library functions, and may perform
5076optimizations or generate code for them under that assumption. This is
5077something we'd like to change in the future to provide better support for
5078freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5079
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5080</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5081
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5082<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5083<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5084 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5085</div>
5086
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5087<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5088
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5089<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5090<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5091 &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]5092</pre>
5093
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5094<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5095<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5096 the "variable argument" area of a function call. It is used to implement the
5097 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5098
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5099<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5100<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5101 argument. It returns a value of the specified argument type and increments
5102 the <tt>va_list</tt> to point to the next argument. The actual type
5103 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5104
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5105<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5106<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5107 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5108 to the next argument. For more information, see the variable argument
5109 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5110
5111<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]5112 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5113 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5114
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115<p><tt>va_arg</tt> is an LLVM instruction instead of
5116 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5117 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5118
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5119<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5120<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5121
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5122<p>Note that the code generator does not yet fully support va_arg on many
5123 targets. Also, it does not currently support va_arg with aggregate types on
5124 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5125
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5126</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5127
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5128<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5129<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5130<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5131
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5132<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5133
5134<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135 well known names and semantics and are required to follow certain
5136 restrictions. Overall, these intrinsics represent an extension mechanism for
5137 the LLVM language that does not require changing all of the transformations
5138 in LLVM when adding to the language (or the bitcode reader/writer, the
5139 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5140
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5141<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5142 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5143 begin with this prefix. Intrinsic functions must always be external
5144 functions: you cannot define the body of intrinsic functions. Intrinsic
5145 functions may only be used in call or invoke instructions: it is illegal to
5146 take the address of an intrinsic function. Additionally, because intrinsic
5147 functions are part of the LLVM language, it is required if any are added that
5148 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5151 family of functions that perform the same operation but on different data
5152 types. Because LLVM can represent over 8 million different integer types,
5153 overloading is used commonly to allow an intrinsic function to operate on any
5154 integer type. One or more of the argument types or the result type can be
5155 overloaded to accept any integer type. Argument types may also be defined as
5156 exactly matching a previous argument's type or the result type. This allows
5157 an intrinsic function which accepts multiple arguments, but needs all of them
5158 to be of the same type, to only be overloaded with respect to a single
5159 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5160
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5161<p>Overloaded intrinsics will have the names of its overloaded argument types
5162 encoded into its function name, each preceded by a period. Only those types
5163 which are overloaded result in a name suffix. Arguments whose type is matched
5164 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5165 can take an integer of any width and returns an integer of exactly the same
5166 integer width. This leads to a family of functions such as
5167 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5168 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5169 suffix is required. Because the argument's type is matched against the return
5170 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5171
5172<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5173 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5174
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5175</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5176
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5177<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5178<div class="doc_subsection">
5179 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5180</div>
5181
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5182<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5183
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5184<p>Variable argument support is defined in LLVM with
5185 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5186 intrinsic functions. These functions are related to the similarly named
5187 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5188
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5189<p>All of these functions operate on arguments that use a target-specific value
5190 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5191 not define what this type is, so all transformations should be prepared to
5192 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5193
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5194<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]5195 instruction and the variable argument handling intrinsic functions are
5196 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5197
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5198<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5199<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5200define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5201 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5202 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5203 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5204 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5205
5206 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5207 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5208
5209 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5210 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5211 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5212 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5213 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5214
5215 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5216 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5217 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5218}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5219
5220declare void @llvm.va_start(i8*)
5221declare void @llvm.va_copy(i8*, i8*)
5222declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5223</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5224</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5225
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5226</div>
5227
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5228<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5229<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5230 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5231</div>
5232
5233
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5234<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5235
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5236<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5237<pre>
5238 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5239</pre>
5240
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5241<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5242<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5243 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]5244
5245<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5246<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]5247
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5248<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5249<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]5250 macro available in C. In a target-dependent way, it initializes
5251 the <tt>va_list</tt> element to which the argument points, so that the next
5252 call to <tt>va_arg</tt> will produce the first variable argument passed to
5253 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5254 need to know the last argument of the function as the compiler can figure
5255 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5256
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5257</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5258
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5259<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5260<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5261 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5262</div>
5263
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5264<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5265
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5266<h5>Syntax:</h5>
5267<pre>
5268 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5269</pre>
5270
5271<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5272<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5273 which has been initialized previously
5274 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5275 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5276
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5277<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5278<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]5279
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5280<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5281<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]5282 macro available in C. In a target-dependent way, it destroys
5283 the <tt>va_list</tt> element to which the argument points. Calls
5284 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5285 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5286 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5287
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5288</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5289
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5290<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5291<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5292 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5293</div>
5294
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5295<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5296
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5297<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5298<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5299 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5300</pre>
5301
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5302<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5303<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5304 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5305
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5306<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5307<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]5308 The second argument is a pointer to a <tt>va_list</tt> element to copy
5309 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5310
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5311<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5312<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]5313 macro available in C. In a target-dependent way, it copies the
5314 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5315 element. This intrinsic is necessary because
5316 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5317 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5318
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5319</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5320
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5321<!-- ======================================================================= -->
5322<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5323 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5324</div>
5325
5326<div class="doc_text">
5327
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5329Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5330intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5331roots on the stack</a>, as well as garbage collector implementations that
5332require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5333barriers. Front-ends for type-safe garbage collected languages should generate
5334these intrinsics to make use of the LLVM garbage collectors. For more details,
5335see <a href="GarbageCollection.html">Accurate Garbage Collection with
5336LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5337
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5338<p>The garbage collection intrinsics only operate on objects in the generic
5339 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5340
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5341</div>
5342
5343<!-- _______________________________________________________________________ -->
5344<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5345 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5346</div>
5347
5348<div class="doc_text">
5349
5350<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5351<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5352 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5353</pre>
5354
5355<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5356<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]5357 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5358
5359<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5360<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5361 root pointer. The second pointer (which must be either a constant or a
5362 global value address) contains the meta-data to be associated with the
5363 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5364
5365<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5366<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]5367 location. At compile-time, the code generator generates information to allow
5368 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5369 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5370 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5371
5372</div>
5373
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5374<!-- _______________________________________________________________________ -->
5375<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5376 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5377</div>
5378
5379<div class="doc_text">
5380
5381<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5382<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5383 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5384</pre>
5385
5386<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5387<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5388 locations, allowing garbage collector implementations that require read
5389 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5390
5391<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5392<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]5393 allocated from the garbage collector. The first object is a pointer to the
5394 start of the referenced object, if needed by the language runtime (otherwise
5395 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5396
5397<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5398<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5399 instruction, but may be replaced with substantially more complex code by the
5400 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5401 may only be used in a function which <a href="#gc">specifies a GC
5402 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5403
5404</div>
5405
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5406<!-- _______________________________________________________________________ -->
5407<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5408 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5409</div>
5410
5411<div class="doc_text">
5412
5413<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5414<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5415 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5416</pre>
5417
5418<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5419<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5420 locations, allowing garbage collector implementations that require write
5421 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5422
5423<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5424<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]5425 object to store it to, and the third is the address of the field of Obj to
5426 store to. If the runtime does not require a pointer to the object, Obj may
5427 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5428
5429<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5430<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5431 instruction, but may be replaced with substantially more complex code by the
5432 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5433 may only be used in a function which <a href="#gc">specifies a GC
5434 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5435
5436</div>
5437
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5438<!-- ======================================================================= -->
5439<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5440 <a name="int_codegen">Code Generator Intrinsics</a>
5441</div>
5442
5443<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5444
5445<p>These intrinsics are provided by LLVM to expose special features that may
5446 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5447
5448</div>
5449
5450<!-- _______________________________________________________________________ -->
5451<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5452 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5453</div>
5454
5455<div class="doc_text">
5456
5457<h5>Syntax:</h5>
5458<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5459 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5460</pre>
5461
5462<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5463<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5464 target-specific value indicating the return address of the current function
5465 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5466
5467<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5468<p>The argument to this intrinsic indicates which function to return the address
5469 for. Zero indicates the calling function, one indicates its caller, etc.
5470 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5471
5472<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5474 indicating the return address of the specified call frame, or zero if it
5475 cannot be identified. The value returned by this intrinsic is likely to be
5476 incorrect or 0 for arguments other than zero, so it should only be used for
5477 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5478
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5479<p>Note that calling this intrinsic does not prevent function inlining or other
5480 aggressive transformations, so the value returned may not be that of the
5481 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5482
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5483</div>
5484
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5485<!-- _______________________________________________________________________ -->
5486<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5487 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5488</div>
5489
5490<div class="doc_text">
5491
5492<h5>Syntax:</h5>
5493<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5494 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5495</pre>
5496
5497<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5498<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5499 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5500
5501<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5502<p>The argument to this intrinsic indicates which function to return the frame
5503 pointer for. Zero indicates the calling function, one indicates its caller,
5504 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5505
5506<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5507<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5508 indicating the frame address of the specified call frame, or zero if it
5509 cannot be identified. The value returned by this intrinsic is likely to be
5510 incorrect or 0 for arguments other than zero, so it should only be used for
5511 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5513<p>Note that calling this intrinsic does not prevent function inlining or other
5514 aggressive transformations, so the value returned may not be that of the
5515 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5516
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5517</div>
5518
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5519<!-- _______________________________________________________________________ -->
5520<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5521 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5522</div>
5523
5524<div class="doc_text">
5525
5526<h5>Syntax:</h5>
5527<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5528 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5529</pre>
5530
5531<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5532<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5533 of the function stack, for use
5534 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5535 useful for implementing language features like scoped automatic variable
5536 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5537
5538<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5539<p>This intrinsic returns a opaque pointer value that can be passed
5540 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5541 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5542 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5543 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5544 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5545 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5546
5547</div>
5548
5549<!-- _______________________________________________________________________ -->
5550<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5551 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5552</div>
5553
5554<div class="doc_text">
5555
5556<h5>Syntax:</h5>
5557<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5558 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5559</pre>
5560
5561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5563 the function stack to the state it was in when the
5564 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5565 executed. This is useful for implementing language features like scoped
5566 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5567
5568<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5569<p>See the description
5570 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5571
5572</div>
5573
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5574<!-- _______________________________________________________________________ -->
5575<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5576 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5577</div>
5578
5579<div class="doc_text">
5580
5581<h5>Syntax:</h5>
5582<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5583 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]5584</pre>
5585
5586<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5587<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5588 insert a prefetch instruction if supported; otherwise, it is a noop.
5589 Prefetches have no effect on the behavior of the program but can change its
5590 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5591
5592<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5593<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5594 specifier determining if the fetch should be for a read (0) or write (1),
5595 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5596 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5597 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5598
5599<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5600<p>This intrinsic does not modify the behavior of the program. In particular,
5601 prefetches cannot trap and do not produce a value. On targets that support
5602 this intrinsic, the prefetch can provide hints to the processor cache for
5603 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5604
5605</div>
5606
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5607<!-- _______________________________________________________________________ -->
5608<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5609 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5610</div>
5611
5612<div class="doc_text">
5613
5614<h5>Syntax:</h5>
5615<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5616 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5617</pre>
5618
5619<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5620<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5621 Counter (PC) in a region of code to simulators and other tools. The method
5622 is target specific, but it is expected that the marker will use exported
5623 symbols to transmit the PC of the marker. The marker makes no guarantees
5624 that it will remain with any specific instruction after optimizations. It is
5625 possible that the presence of a marker will inhibit optimizations. The
5626 intended use is to be inserted after optimizations to allow correlations of
5627 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5628
5629<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5630<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5631
5632<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5633<p>This intrinsic does not modify the behavior of the program. Backends that do
5634 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5635
5636</div>
5637
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5638<!-- _______________________________________________________________________ -->
5639<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5640 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5641</div>
5642
5643<div class="doc_text">
5644
5645<h5>Syntax:</h5>
5646<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5647 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5648</pre>
5649
5650<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5651<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5652 counter register (or similar low latency, high accuracy clocks) on those
5653 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5654 should map to RPCC. As the backing counters overflow quickly (on the order
5655 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5656
5657<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5658<p>When directly supported, reading the cycle counter should not modify any
5659 memory. Implementations are allowed to either return a application specific
5660 value or a system wide value. On backends without support, this is lowered
5661 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5662
5663</div>
5664
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5665<!-- ======================================================================= -->
5666<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5667 <a name="int_libc">Standard C Library Intrinsics</a>
5668</div>
5669
5670<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5671
5672<p>LLVM provides intrinsics for a few important standard C library functions.
5673 These intrinsics allow source-language front-ends to pass information about
5674 the alignment of the pointer arguments to the code generator, providing
5675 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5676
5677</div>
5678
5679<!-- _______________________________________________________________________ -->
5680<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5681 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5682</div>
5683
5684<div class="doc_text">
5685
5686<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5688 integer bit width. Not all targets support all bit widths however.</p>
5689
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5690<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5691 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5693 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5694 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5695 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5696 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5697 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5698 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5699</pre>
5700
5701<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5702<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5703 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5705<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5706 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5707
5708<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5709<p>The first argument is a pointer to the destination, the second is a pointer
5710 to the source. The third argument is an integer argument specifying the
5711 number of bytes to copy, and the fourth argument is the alignment of the
5712 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5715 then the caller guarantees that both the source and destination pointers are
5716 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5717
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5718<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5719<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5720 source location to the destination location, which are not allowed to
5721 overlap. It copies "len" bytes of memory over. If the argument is known to
5722 be aligned to some boundary, this can be specified as the fourth argument,
5723 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5724
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5725</div>
5726
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5727<!-- _______________________________________________________________________ -->
5728<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5729 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5730</div>
5731
5732<div class="doc_text">
5733
5734<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5735<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5736 width. Not all targets support all bit widths however.</p>
5737
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5738<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5739 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5740 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5741 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5742 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5743 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5744 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5745 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5746 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5747</pre>
5748
5749<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5750<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5751 source location to the destination location. It is similar to the
5752 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5753 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5754
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5755<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5756 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5757
5758<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5759<p>The first argument is a pointer to the destination, the second is a pointer
5760 to the source. The third argument is an integer argument specifying the
5761 number of bytes to copy, and the fourth argument is the alignment of the
5762 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5763
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5765 then the caller guarantees that the source and destination pointers are
5766 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5767
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5768<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5769<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5770 source location to the destination location, which may overlap. It copies
5771 "len" bytes of memory over. If the argument is known to be aligned to some
5772 boundary, this can be specified as the fourth argument, otherwise it should
5773 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5774
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5775</div>
5776
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5777<!-- _______________________________________________________________________ -->
5778<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5779 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5780</div>
5781
5782<div class="doc_text">
5783
5784<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5785<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5786 width. Not all targets support all bit widths however.</p>
5787
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5789 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5790 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5791 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5792 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5793 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5794 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5795 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5796 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797</pre>
5798
5799<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5801 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5803<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5804 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5805
5806<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The first argument is a pointer to the destination to fill, the second is the
5808 byte value to fill it with, the third argument is an integer argument
5809 specifying the number of bytes to fill, and the fourth argument is the known
5810 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5813 then the caller guarantees that the destination pointer is aligned to that
5814 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5815
5816<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5818 at the destination location. If the argument is known to be aligned to some
5819 boundary, this can be specified as the fourth argument, otherwise it should
5820 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5821
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5822</div>
5823
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5824<!-- _______________________________________________________________________ -->
5825<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5826 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5827</div>
5828
5829<div class="doc_text">
5830
5831<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5832<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5833 floating point or vector of floating point type. Not all targets support all
5834 types however.</p>
5835
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5836<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5837 declare float @llvm.sqrt.f32(float %Val)
5838 declare double @llvm.sqrt.f64(double %Val)
5839 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5840 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5841 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5842</pre>
5843
5844<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5845<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5846 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5847 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5848 behavior for negative numbers other than -0.0 (which allows for better
5849 optimization, because there is no need to worry about errno being
5850 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]5851
5852<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5853<p>The argument and return value are floating point numbers of the same
5854 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5855
5856<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>This function returns the sqrt of the specified operand if it is a
5858 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5859
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5860</div>
5861
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5862<!-- _______________________________________________________________________ -->
5863<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5864 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5865</div>
5866
5867<div class="doc_text">
5868
5869<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5870<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5871 floating point or vector of floating point type. Not all targets support all
5872 types however.</p>
5873
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5874<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5875 declare float @llvm.powi.f32(float %Val, i32 %power)
5876 declare double @llvm.powi.f64(double %Val, i32 %power)
5877 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5878 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5879 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5880</pre>
5881
5882<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5883<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5884 specified (positive or negative) power. The order of evaluation of
5885 multiplications is not defined. When a vector of floating point type is
5886 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5887
5888<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The second argument is an integer power, and the first is a value to raise to
5890 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5891
5892<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893<p>This function returns the first value raised to the second power with an
5894 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5895
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5896</div>
5897
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5898<!-- _______________________________________________________________________ -->
5899<div class="doc_subsubsection">
5900 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5901</div>
5902
5903<div class="doc_text">
5904
5905<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5906<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5907 floating point or vector of floating point type. Not all targets support all
5908 types however.</p>
5909
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5910<pre>
5911 declare float @llvm.sin.f32(float %Val)
5912 declare double @llvm.sin.f64(double %Val)
5913 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5914 declare fp128 @llvm.sin.f128(fp128 %Val)
5915 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5916</pre>
5917
5918<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5919<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5920
5921<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The argument and return value are floating point numbers of the same
5923 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5924
5925<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5926<p>This function returns the sine of the specified operand, returning the same
5927 values as the libm <tt>sin</tt> functions would, and handles error conditions
5928 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5929
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5930</div>
5931
5932<!-- _______________________________________________________________________ -->
5933<div class="doc_subsubsection">
5934 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5935</div>
5936
5937<div class="doc_text">
5938
5939<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5940<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5941 floating point or vector of floating point type. Not all targets support all
5942 types however.</p>
5943
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5944<pre>
5945 declare float @llvm.cos.f32(float %Val)
5946 declare double @llvm.cos.f64(double %Val)
5947 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5948 declare fp128 @llvm.cos.f128(fp128 %Val)
5949 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5950</pre>
5951
5952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5954
5955<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5956<p>The argument and return value are floating point numbers of the same
5957 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5958
5959<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>This function returns the cosine of the specified operand, returning the same
5961 values as the libm <tt>cos</tt> functions would, and handles error conditions
5962 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5963
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5964</div>
5965
5966<!-- _______________________________________________________________________ -->
5967<div class="doc_subsubsection">
5968 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5969</div>
5970
5971<div class="doc_text">
5972
5973<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5974<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5975 floating point or vector of floating point type. Not all targets support all
5976 types however.</p>
5977
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5978<pre>
5979 declare float @llvm.pow.f32(float %Val, float %Power)
5980 declare double @llvm.pow.f64(double %Val, double %Power)
5981 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5982 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5983 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5984</pre>
5985
5986<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5987<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5988 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5989
5990<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5991<p>The second argument is a floating point power, and the first is a value to
5992 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5993
5994<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5995<p>This function returns the first value raised to the second power, returning
5996 the same values as the libm <tt>pow</tt> functions would, and handles error
5997 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5998
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5999</div>
6000
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6001<!-- ======================================================================= -->
6002<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6003 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6004</div>
6005
6006<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007
6008<p>LLVM provides intrinsics for a few important bit manipulation operations.
6009 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6010
6011</div>
6012
6013<!-- _______________________________________________________________________ -->
6014<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6015 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6016</div>
6017
6018<div class="doc_text">
6019
6020<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6021<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6022 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6023
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6024<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6025 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6026 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6027 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6028</pre>
6029
6030<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6031<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6032 values with an even number of bytes (positive multiple of 16 bits). These
6033 are useful for performing operations on data that is not in the target's
6034 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6035
6036<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6037<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6038 and low byte of the input i16 swapped. Similarly,
6039 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6040 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6041 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6042 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6043 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6044 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6045
6046</div>
6047
6048<!-- _______________________________________________________________________ -->
6049<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6050 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6051</div>
6052
6053<div class="doc_text">
6054
6055<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6056<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]6057 width. Not all targets support all bit widths however.</p>
6058
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6059<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6060 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6061 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6062 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6063 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6064 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6065</pre>
6066
6067<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6068<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6069 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6070
6071<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6072<p>The only argument is the value to be counted. The argument may be of any
6073 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6074
6075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6076<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]6077
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6078</div>
6079
6080<!-- _______________________________________________________________________ -->
6081<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6082 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6083</div>
6084
6085<div class="doc_text">
6086
6087<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6088<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6089 integer bit width. Not all targets support all bit widths however.</p>
6090
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6091<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6092 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6093 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6094 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6095 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6096 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6097</pre>
6098
6099<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6100<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6101 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6102
6103<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6104<p>The only argument is the value to be counted. The argument may be of any
6105 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6106
6107<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6109 zeros in a variable. If the src == 0 then the result is the size in bits of
6110 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6111
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6112</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6113
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6114<!-- _______________________________________________________________________ -->
6115<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6116 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6117</div>
6118
6119<div class="doc_text">
6120
6121<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6122<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6123 integer bit width. Not all targets support all bit widths however.</p>
6124
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6125<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6126 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6127 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6128 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6129 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6130 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6131</pre>
6132
6133<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6134<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6135 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6136
6137<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6138<p>The only argument is the value to be counted. The argument may be of any
6139 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6140
6141<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6142<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6143 zeros in a variable. If the src == 0 then the result is the size in bits of
6144 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6145
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6146</div>
6147
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6148<!-- ======================================================================= -->
6149<div class="doc_subsection">
6150 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6151</div>
6152
6153<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6154
6155<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6156
6157</div>
6158
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6159<!-- _______________________________________________________________________ -->
6160<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6161 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6162</div>
6163
6164<div class="doc_text">
6165
6166<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6167<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]6168 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6169
6170<pre>
6171 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6172 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6173 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6174</pre>
6175
6176<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6177<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6178 a signed addition of the two arguments, and indicate whether an overflow
6179 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6180
6181<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182<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]6183 be of integer types of any bit width, but they must have the same bit
6184 width. The second element of the result structure must be of
6185 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6186 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6187
6188<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6190 a signed addition of the two variables. They return a structure &mdash; the
6191 first element of which is the signed summation, and the second element of
6192 which is a bit specifying if the signed summation resulted in an
6193 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6194
6195<h5>Examples:</h5>
6196<pre>
6197 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6198 %sum = extractvalue {i32, i1} %res, 0
6199 %obit = extractvalue {i32, i1} %res, 1
6200 br i1 %obit, label %overflow, label %normal
6201</pre>
6202
6203</div>
6204
6205<!-- _______________________________________________________________________ -->
6206<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6207 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6208</div>
6209
6210<div class="doc_text">
6211
6212<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6213<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]6214 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6215
6216<pre>
6217 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6218 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6219 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6220</pre>
6221
6222<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6223<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6224 an unsigned addition of the two arguments, and indicate whether a carry
6225 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6226
6227<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6228<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]6229 be of integer types of any bit width, but they must have the same bit
6230 width. The second element of the result structure must be of
6231 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6232 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6233
6234<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6235<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6236 an unsigned addition of the two arguments. They return a structure &mdash;
6237 the first element of which is the sum, and the second element of which is a
6238 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6239
6240<h5>Examples:</h5>
6241<pre>
6242 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6243 %sum = extractvalue {i32, i1} %res, 0
6244 %obit = extractvalue {i32, i1} %res, 1
6245 br i1 %obit, label %carry, label %normal
6246</pre>
6247
6248</div>
6249
6250<!-- _______________________________________________________________________ -->
6251<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6252 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6253</div>
6254
6255<div class="doc_text">
6256
6257<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6258<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]6259 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6260
6261<pre>
6262 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6263 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6264 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6265</pre>
6266
6267<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6268<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6269 a signed subtraction of the two arguments, and indicate whether an overflow
6270 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6271
6272<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273<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]6274 be of integer types of any bit width, but they must have the same bit
6275 width. The second element of the result structure must be of
6276 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6277 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6278
6279<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6281 a signed subtraction of the two arguments. They return a structure &mdash;
6282 the first element of which is the subtraction, and the second element of
6283 which is a bit specifying if the signed subtraction resulted in an
6284 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6285
6286<h5>Examples:</h5>
6287<pre>
6288 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6289 %sum = extractvalue {i32, i1} %res, 0
6290 %obit = extractvalue {i32, i1} %res, 1
6291 br i1 %obit, label %overflow, label %normal
6292</pre>
6293
6294</div>
6295
6296<!-- _______________________________________________________________________ -->
6297<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6298 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6299</div>
6300
6301<div class="doc_text">
6302
6303<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6304<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]6305 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6306
6307<pre>
6308 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6309 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6310 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6311</pre>
6312
6313<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6314<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6315 an unsigned subtraction of the two arguments, and indicate whether an
6316 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6317
6318<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319<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]6320 be of integer types of any bit width, but they must have the same bit
6321 width. The second element of the result structure must be of
6322 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6323 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6324
6325<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6327 an unsigned subtraction of the two arguments. They return a structure &mdash;
6328 the first element of which is the subtraction, and the second element of
6329 which is a bit specifying if the unsigned subtraction resulted in an
6330 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6331
6332<h5>Examples:</h5>
6333<pre>
6334 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6335 %sum = extractvalue {i32, i1} %res, 0
6336 %obit = extractvalue {i32, i1} %res, 1
6337 br i1 %obit, label %overflow, label %normal
6338</pre>
6339
6340</div>
6341
6342<!-- _______________________________________________________________________ -->
6343<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6344 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6345</div>
6346
6347<div class="doc_text">
6348
6349<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6350<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]6351 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6352
6353<pre>
6354 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6355 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6356 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6357</pre>
6358
6359<h5>Overview:</h5>
6360
6361<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6362 a signed multiplication of the two arguments, and indicate whether an
6363 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6364
6365<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6366<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]6367 be of integer types of any bit width, but they must have the same bit
6368 width. The second element of the result structure must be of
6369 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6370 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6371
6372<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6373<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6374 a signed multiplication of the two arguments. They return a structure &mdash;
6375 the first element of which is the multiplication, and the second element of
6376 which is a bit specifying if the signed multiplication resulted in an
6377 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6378
6379<h5>Examples:</h5>
6380<pre>
6381 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6382 %sum = extractvalue {i32, i1} %res, 0
6383 %obit = extractvalue {i32, i1} %res, 1
6384 br i1 %obit, label %overflow, label %normal
6385</pre>
6386
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6387</div>
6388
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6389<!-- _______________________________________________________________________ -->
6390<div class="doc_subsubsection">
6391 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6392</div>
6393
6394<div class="doc_text">
6395
6396<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6397<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]6398 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6399
6400<pre>
6401 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6402 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6403 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6404</pre>
6405
6406<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6407<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408 a unsigned multiplication of the two arguments, and indicate whether an
6409 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6410
6411<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6412<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]6413 be of integer types of any bit width, but they must have the same bit
6414 width. The second element of the result structure must be of
6415 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6416 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6417
6418<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6419<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6420 an unsigned multiplication of the two arguments. They return a structure
6421 &mdash; the first element of which is the multiplication, and the second
6422 element of which is a bit specifying if the unsigned multiplication resulted
6423 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6424
6425<h5>Examples:</h5>
6426<pre>
6427 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6428 %sum = extractvalue {i32, i1} %res, 0
6429 %obit = extractvalue {i32, i1} %res, 1
6430 br i1 %obit, label %overflow, label %normal
6431</pre>
6432
6433</div>
6434
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6435<!-- ======================================================================= -->
6436<div class="doc_subsection">
6437 <a name="int_debugger">Debugger Intrinsics</a>
6438</div>
6439
6440<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6441
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6442<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6443 prefix), are described in
6444 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6445 Level Debugging</a> document.</p>
6446
6447</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6448
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6449<!-- ======================================================================= -->
6450<div class="doc_subsection">
6451 <a name="int_eh">Exception Handling Intrinsics</a>
6452</div>
6453
6454<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6455
6456<p>The LLVM exception handling intrinsics (which all start with
6457 <tt>llvm.eh.</tt> prefix), are described in
6458 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6459 Handling</a> document.</p>
6460
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6461</div>
6462
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6463<!-- ======================================================================= -->
6464<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6465 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6466</div>
6467
6468<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6469
6470<p>This intrinsic makes it possible to excise one parameter, marked with
6471 the <tt>nest</tt> attribute, from a function. The result is a callable
6472 function pointer lacking the nest parameter - the caller does not need to
6473 provide a value for it. Instead, the value to use is stored in advance in a
6474 "trampoline", a block of memory usually allocated on the stack, which also
6475 contains code to splice the nest value into the argument list. This is used
6476 to implement the GCC nested function address extension.</p>
6477
6478<p>For example, if the function is
6479 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6480 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6481 follows:</p>
6482
6483<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6484<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6485 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6486 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6487 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6488 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6489</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490</div>
6491
6492<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6493 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6494
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6495</div>
6496
6497<!-- _______________________________________________________________________ -->
6498<div class="doc_subsubsection">
6499 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6500</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6501
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6502<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6503
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6504<h5>Syntax:</h5>
6505<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6506 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]6507</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6508
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6509<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6510<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6511 function pointer suitable for executing it.</p>
6512
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6513<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6514<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6515 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6516 sufficiently aligned block of memory; this memory is written to by the
6517 intrinsic. Note that the size and the alignment are target-specific - LLVM
6518 currently provides no portable way of determining them, so a front-end that
6519 generates this intrinsic needs to have some target-specific knowledge.
6520 The <tt>func</tt> argument must hold a function bitcast to
6521 an <tt>i8*</tt>.</p>
6522
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6523<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6524<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6525 dependent code, turning it into a function. A pointer to this function is
6526 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6527 function pointer type</a> before being called. The new function's signature
6528 is the same as that of <tt>func</tt> with any arguments marked with
6529 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6530 is allowed, and it must be of pointer type. Calling the new function is
6531 equivalent to calling <tt>func</tt> with the same argument list, but
6532 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6533 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6534 by <tt>tramp</tt> is modified, then the effect of any later call to the
6535 returned function pointer is undefined.</p>
6536
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6537</div>
6538
6539<!-- ======================================================================= -->
6540<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6541 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6542</div>
6543
6544<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6545
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6546<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6547 hardware constructs for atomic operations and memory synchronization. This
6548 provides an interface to the hardware, not an interface to the programmer. It
6549 is aimed at a low enough level to allow any programming models or APIs
6550 (Application Programming Interfaces) which need atomic behaviors to map
6551 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6552 hardware provides a "universal IR" for source languages, it also provides a
6553 starting point for developing a "universal" atomic operation and
6554 synchronization IR.</p>
6555
6556<p>These do <em>not</em> form an API such as high-level threading libraries,
6557 software transaction memory systems, atomic primitives, and intrinsic
6558 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6559 application libraries. The hardware interface provided by LLVM should allow
6560 a clean implementation of all of these APIs and parallel programming models.
6561 No one model or paradigm should be selected above others unless the hardware
6562 itself ubiquitously does so.</p>
6563
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6564</div>
6565
6566<!-- _______________________________________________________________________ -->
6567<div class="doc_subsubsection">
6568 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6569</div>
6570<div class="doc_text">
6571<h5>Syntax:</h5>
6572<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6573 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]6574</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6575
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6576<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6577<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6578 specific pairs of memory access types.</p>
6579
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6580<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6581<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6582 The first four arguments enables a specific barrier as listed below. The
6583 fith argument specifies that the barrier applies to io or device or uncached
6584 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6585
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6586<ul>
6587 <li><tt>ll</tt>: load-load barrier</li>
6588 <li><tt>ls</tt>: load-store barrier</li>
6589 <li><tt>sl</tt>: store-load barrier</li>
6590 <li><tt>ss</tt>: store-store barrier</li>
6591 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6592</ul>
6593
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6594<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6595<p>This intrinsic causes the system to enforce some ordering constraints upon
6596 the loads and stores of the program. This barrier does not
6597 indicate <em>when</em> any events will occur, it only enforces
6598 an <em>order</em> in which they occur. For any of the specified pairs of load
6599 and store operations (f.ex. load-load, or store-load), all of the first
6600 operations preceding the barrier will complete before any of the second
6601 operations succeeding the barrier begin. Specifically the semantics for each
6602 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6603
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6604<ul>
6605 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6606 after the barrier begins.</li>
6607 <li><tt>ls</tt>: All loads before the barrier must complete before any
6608 store after the barrier begins.</li>
6609 <li><tt>ss</tt>: All stores before the barrier must complete before any
6610 store after the barrier begins.</li>
6611 <li><tt>sl</tt>: All stores before the barrier must complete before any
6612 load after the barrier begins.</li>
6613</ul>
6614
6615<p>These semantics are applied with a logical "and" behavior when more than one
6616 is enabled in a single memory barrier intrinsic.</p>
6617
6618<p>Backends may implement stronger barriers than those requested when they do
6619 not support as fine grained a barrier as requested. Some architectures do
6620 not need all types of barriers and on such architectures, these become
6621 noops.</p>
6622
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6623<h5>Example:</h5>
6624<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6625%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6626%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6627 store i32 4, %ptr
6628
6629%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6630 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6631 <i>; guarantee the above finishes</i>
6632 store i32 8, %ptr <i>; before this begins</i>
6633</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6635</div>
6636
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6637<!-- _______________________________________________________________________ -->
6638<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6639 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6640</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6642<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6644<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6645<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6646 any integer bit width and for different address spaces. Not all targets
6647 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6648
6649<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6650 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6651 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6652 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6653 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]6654</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6655
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6656<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6657<p>This loads a value in memory and compares it to a given value. If they are
6658 equal, it stores a new value into the memory.</p>
6659
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6660<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6661<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6662 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6663 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6664 this integer type. While any bit width integer may be used, targets may only
6665 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6666
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6667<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6668<p>This entire intrinsic must be executed atomically. It first loads the value
6669 in memory pointed to by <tt>ptr</tt> and compares it with the
6670 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6671 memory. The loaded value is yielded in all cases. This provides the
6672 equivalent of an atomic compare-and-swap operation within the SSA
6673 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6674
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6675<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6676<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6677%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6678%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6679 store i32 4, %ptr
6680
6681%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6682%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6683 <i>; yields {i32}:result1 = 4</i>
6684%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6685%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6686
6687%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6688%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6689 <i>; yields {i32}:result2 = 8</i>
6690%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6691
6692%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6693</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6694
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6695</div>
6696
6697<!-- _______________________________________________________________________ -->
6698<div class="doc_subsubsection">
6699 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6700</div>
6701<div class="doc_text">
6702<h5>Syntax:</h5>
6703
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6704<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6705 integer bit width. Not all targets support all bit widths however.</p>
6706
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6707<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6708 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6709 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6710 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6711 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]6712</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6713
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6714<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6715<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6716 the value from memory. It then stores the value in <tt>val</tt> in the memory
6717 at <tt>ptr</tt>.</p>
6718
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6719<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6720<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6721 the <tt>val</tt> argument and the result must be integers of the same bit
6722 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6723 integer type. The targets may only lower integer representations they
6724 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6725
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6726<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6727<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6728 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6729 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6730
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6731<h5>Examples:</h5>
6732<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6733%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6734%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6735 store i32 4, %ptr
6736
6737%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6738%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6739 <i>; yields {i32}:result1 = 4</i>
6740%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6741%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6742
6743%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6744%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6745 <i>; yields {i32}:result2 = 8</i>
6746
6747%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6748%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6749</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6750
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6751</div>
6752
6753<!-- _______________________________________________________________________ -->
6754<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6755 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6756
6757</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6758
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6759<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6760
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6761<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6762<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6763 any integer bit width. Not all targets support all bit widths however.</p>
6764
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6765<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6766 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6767 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6768 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6769 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]6770</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6771
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6772<h5>Overview:</h5>
6773<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6774 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6775
6776<h5>Arguments:</h5>
6777<p>The intrinsic takes two arguments, the first a pointer to an integer value
6778 and the second an integer value. The result is also an integer value. These
6779 integer types can have any bit width, but they must all have the same bit
6780 width. The targets may only lower integer representations they support.</p>
6781
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6782<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6783<p>This intrinsic does a series of operations atomically. It first loads the
6784 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6785 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]6786
6787<h5>Examples:</h5>
6788<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6789%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6790%ptr = bitcast i8* %mallocP to i32*
6791 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6792%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6793 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6794%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6795 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6796%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6797 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6798%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6799</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6800
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6801</div>
6802
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6803<!-- _______________________________________________________________________ -->
6804<div class="doc_subsubsection">
6805 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6806
6807</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6808
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6809<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6810
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6811<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6812<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6813 any integer bit width and for different address spaces. Not all targets
6814 support all bit widths however.</p>
6815
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6816<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6817 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6818 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6819 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6820 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]6821</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6822
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6823<h5>Overview:</h5>
6824<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6825 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6826
6827<h5>Arguments:</h5>
6828<p>The intrinsic takes two arguments, the first a pointer to an integer value
6829 and the second an integer value. The result is also an integer value. These
6830 integer types can have any bit width, but they must all have the same bit
6831 width. The targets may only lower integer representations they support.</p>
6832
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6833<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6834<p>This intrinsic does a series of operations atomically. It first loads the
6835 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6836 result to <tt>ptr</tt>. It yields the original value stored
6837 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6838
6839<h5>Examples:</h5>
6840<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6841%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6842%ptr = bitcast i8* %mallocP to i32*
6843 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6844%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6845 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6846%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6847 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6848%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6849 <i>; yields {i32}:result3 = 2</i>
6850%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6851</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6852
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6853</div>
6854
6855<!-- _______________________________________________________________________ -->
6856<div class="doc_subsubsection">
6857 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6858 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6859 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6860 <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]6861</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6862
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6863<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6864
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6865<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6866<p>These are overloaded intrinsics. You can
6867 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6868 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6869 bit width and for different address spaces. Not all targets support all bit
6870 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6871
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6872<pre>
6873 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6874 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6875 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6876 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]6877</pre>
6878
6879<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6880 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6881 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6882 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6883 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]6884</pre>
6885
6886<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6887 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6888 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6889 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6890 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]6891</pre>
6892
6893<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6894 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6895 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6896 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6897 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]6898</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6899
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6900<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6901<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6902 the value stored in memory at <tt>ptr</tt>. It yields the original value
6903 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905<h5>Arguments:</h5>
6906<p>These intrinsics take two arguments, the first a pointer to an integer value
6907 and the second an integer value. The result is also an integer value. These
6908 integer types can have any bit width, but they must all have the same bit
6909 width. The targets may only lower integer representations they support.</p>
6910
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6911<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912<p>These intrinsics does a series of operations atomically. They first load the
6913 value stored at <tt>ptr</tt>. They then do the bitwise
6914 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6915 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6916
6917<h5>Examples:</h5>
6918<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6919%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6920%ptr = bitcast i8* %mallocP to i32*
6921 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6922%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6923 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6924%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6925 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6926%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6927 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6928%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6929 <i>; yields {i32}:result3 = FF</i>
6930%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6931</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6932
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6933</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6934
6935<!-- _______________________________________________________________________ -->
6936<div class="doc_subsubsection">
6937 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6938 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6939 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6940 <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]6941</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6942
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6943<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6944
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6945<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6947 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6948 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6949 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6950
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6951<pre>
6952 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6953 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6954 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6955 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]6956</pre>
6957
6958<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6959 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6960 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6961 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6962 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]6963</pre>
6964
6965<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6966 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6967 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6968 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6969 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]6970</pre>
6971
6972<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6974 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6975 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6976 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]6977</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6978
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6979<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980<p>These intrinsics takes the signed or unsigned minimum or maximum of
6981 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6982 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6983
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984<h5>Arguments:</h5>
6985<p>These intrinsics take two arguments, the first a pointer to an integer value
6986 and the second an integer value. The result is also an integer value. These
6987 integer types can have any bit width, but they must all have the same bit
6988 width. The targets may only lower integer representations they support.</p>
6989
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6990<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6991<p>These intrinsics does a series of operations atomically. They first load the
6992 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6993 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6994 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6995
6996<h5>Examples:</h5>
6997<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6998%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6999%ptr = bitcast i8* %mallocP to i32*
7000 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7001%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7002 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7003%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7004 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7005%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7006 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]7007%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7008 <i>; yields {i32}:result3 = 8</i>
7009%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7010</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]7012</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7013
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7014
7015<!-- ======================================================================= -->
7016<div class="doc_subsection">
7017 <a name="int_memorymarkers">Memory Use Markers</a>
7018</div>
7019
7020<div class="doc_text">
7021
7022<p>This class of intrinsics exists to information about the lifetime of memory
7023 objects and ranges where variables are immutable.</p>
7024
7025</div>
7026
7027<!-- _______________________________________________________________________ -->
7028<div class="doc_subsubsection">
7029 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7030</div>
7031
7032<div class="doc_text">
7033
7034<h5>Syntax:</h5>
7035<pre>
7036 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7037</pre>
7038
7039<h5>Overview:</h5>
7040<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7041 object's lifetime.</p>
7042
7043<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7044<p>The first argument is a constant integer representing the size of the
7045 object, or -1 if it is variable sized. The second argument is a pointer to
7046 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7047
7048<h5>Semantics:</h5>
7049<p>This intrinsic indicates that before this point in the code, the value of the
7050 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]7051 never be used and has an undefined value. A load from the pointer that
7052 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7053 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7054
7055</div>
7056
7057<!-- _______________________________________________________________________ -->
7058<div class="doc_subsubsection">
7059 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7060</div>
7061
7062<div class="doc_text">
7063
7064<h5>Syntax:</h5>
7065<pre>
7066 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7067</pre>
7068
7069<h5>Overview:</h5>
7070<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7071 object's lifetime.</p>
7072
7073<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7074<p>The first argument is a constant integer representing the size of the
7075 object, or -1 if it is variable sized. The second argument is a pointer to
7076 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7077
7078<h5>Semantics:</h5>
7079<p>This intrinsic indicates that after this point in the code, the value of the
7080 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7081 never be used and has an undefined value. Any stores into the memory object
7082 following this intrinsic may be removed as dead.
7083
7084</div>
7085
7086<!-- _______________________________________________________________________ -->
7087<div class="doc_subsubsection">
7088 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7089</div>
7090
7091<div class="doc_text">
7092
7093<h5>Syntax:</h5>
7094<pre>
7095 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7096</pre>
7097
7098<h5>Overview:</h5>
7099<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7100 a memory object will not change.</p>
7101
7102<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7103<p>The first argument is a constant integer representing the size of the
7104 object, or -1 if it is variable sized. The second argument is a pointer to
7105 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7106
7107<h5>Semantics:</h5>
7108<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7109 the return value, the referenced memory location is constant and
7110 unchanging.</p>
7111
7112</div>
7113
7114<!-- _______________________________________________________________________ -->
7115<div class="doc_subsubsection">
7116 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7117</div>
7118
7119<div class="doc_text">
7120
7121<h5>Syntax:</h5>
7122<pre>
7123 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7124</pre>
7125
7126<h5>Overview:</h5>
7127<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7128 a memory object are mutable.</p>
7129
7130<h5>Arguments:</h5>
7131<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7132 The second argument is a constant integer representing the size of the
7133 object, or -1 if it is variable sized and the third argument is a pointer
7134 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7135
7136<h5>Semantics:</h5>
7137<p>This intrinsic indicates that the memory is mutable again.</p>
7138
7139</div>
7140
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7141<!-- ======================================================================= -->
7142<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7143 <a name="int_general">General Intrinsics</a>
7144</div>
7145
7146<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7147
7148<p>This class of intrinsics is designed to be generic and has no specific
7149 purpose.</p>
7150
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7151</div>
7152
7153<!-- _______________________________________________________________________ -->
7154<div class="doc_subsubsection">
7155 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7156</div>
7157
7158<div class="doc_text">
7159
7160<h5>Syntax:</h5>
7161<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7162 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]7163</pre>
7164
7165<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7166<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7167
7168<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7169<p>The first argument is a pointer to a value, the second is a pointer to a
7170 global string, the third is a pointer to a global string which is the source
7171 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7172
7173<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<p>This intrinsic allows annotation of local variables with arbitrary strings.
7175 This can be useful for special purpose optimizations that want to look for
7176 these annotations. These have no other defined use, they are ignored by code
7177 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7178
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7179</div>
7180
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7181<!-- _______________________________________________________________________ -->
7182<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7183 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7184</div>
7185
7186<div class="doc_text">
7187
7188<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7189<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7190 any integer bit width.</p>
7191
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7192<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7193 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7194 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7195 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7196 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7197 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]7198</pre>
7199
7200<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7201<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7202
7203<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7204<p>The first argument is an integer value (result of some expression), the
7205 second is a pointer to a global string, the third is a pointer to a global
7206 string which is the source file name, and the last argument is the line
7207 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7208
7209<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7210<p>This intrinsic allows annotations to be put on arbitrary expressions with
7211 arbitrary strings. This can be useful for special purpose optimizations that
7212 want to look for these annotations. These have no other defined use, they
7213 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7214
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7215</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7216
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7217<!-- _______________________________________________________________________ -->
7218<div class="doc_subsubsection">
7219 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7220</div>
7221
7222<div class="doc_text">
7223
7224<h5>Syntax:</h5>
7225<pre>
7226 declare void @llvm.trap()
7227</pre>
7228
7229<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7230<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7231
7232<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7233<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7234
7235<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7236<p>This intrinsics is lowered to the target dependent trap instruction. If the
7237 target does not have a trap instruction, this intrinsic will be lowered to
7238 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7239
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7240</div>
7241
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7242<!-- _______________________________________________________________________ -->
7243<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7244 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7245</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7246
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7247<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7248
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7249<h5>Syntax:</h5>
7250<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7251 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7252</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7253
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7254<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7255<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7256 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7257 ensure that it is placed on the stack before local variables.</p>
7258
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7259<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7260<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7261 arguments. The first argument is the value loaded from the stack
7262 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7263 that has enough space to hold the value of the guard.</p>
7264
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7265<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7266<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7267 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7268 stack. This is to ensure that if a local variable on the stack is
7269 overwritten, it will destroy the value of the guard. When the function exits,
7270 the guard on the stack is checked against the original guard. If they're
7271 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7272 function.</p>
7273
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7274</div>
7275
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7276<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7277<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7278<address>
7279 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7280 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7281 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7282 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]7283
7284 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7285 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7286 Last modified: $Date$
7287</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7288
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7289</body>
7290</html>