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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / d40d14e98c271068d17585e81d45ee9eca147393 / . / 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
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]341 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]362<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
363 LLVM infrastructure provides a verification pass that may be used to verify
364 that an LLVM module is well formed. This pass is automatically run by the
365 parser after parsing input assembly and by the optimizer before it outputs
366 bitcode. The violations pointed out by the verifier pass indicate bugs in
367 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]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
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]460<p>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">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]485<pre>
486<i>; Declare the string constant as a global constant.</i>
487<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
489<i>; External declaration of the puts function</i>
Bill Wendlingf82d40a2009-11-02 00:24:16 +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 Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
494 <i>; Convert [13 x i8]* to i8 *...</i>
495 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]497 <i>; Call puts function to write out the string to stdout.</i>
498 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
499 <a href="#i_ret">ret</a> i32 0<br>}<br>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]500</pre>
501</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]503<p>This example is made up of a <a href="#globalvars">global variable</a> named
504 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
505 a <a href="#functionstructure">function definition</a> for
506 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]508<p>In general, a module is made up of a list of global values, where both
509 functions and global variables are global values. Global values are
510 represented by a pointer to a memory location (in this case, a pointer to an
511 array of char, and a pointer to a function), and have one of the
512 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]513
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]514</div>
515
516<!-- ======================================================================= -->
517<div class="doc_subsection">
518 <a name="linkage">Linkage Types</a>
519</div>
520
521<div class="doc_text">
522
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523<p>All Global Variables and Functions have one of the following types of
524 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]525
526<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]527 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]528 <dd>Global values with private linkage are only directly accessible by objects
529 in the current module. In particular, linking code into a module with an
530 private global value may cause the private to be renamed as necessary to
531 avoid collisions. Because the symbol is private to the module, all
532 references can be updated. This doesn't show up in any symbol table in the
533 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]534
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]535 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]536 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]537 removed by the linker after evaluation. Note that (unlike private
538 symbols) linker_private symbols are subject to coalescing by the linker:
539 weak symbols get merged and redefinitions are rejected. However, unlike
540 normal strong symbols, they are removed by the linker from the final
541 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]542
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]544 <dd>Similar to private, but the value shows as a local symbol
545 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
546 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]547
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]549 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]550 into the object file corresponding to the LLVM module. They exist to
551 allow inlining and other optimizations to take place given knowledge of
552 the definition of the global, which is known to be somewhere outside the
553 module. Globals with <tt>available_externally</tt> linkage are allowed to
554 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
555 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]556
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]558 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]559 the same name when linkage occurs. This is typically used to implement
560 inline functions, templates, or other code which must be generated in each
561 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
562 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]563
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]565 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
566 <tt>linkonce</tt> linkage, except that unreferenced globals with
567 <tt>weak</tt> linkage may not be discarded. This is used for globals that
568 are declared "weak" in C source code.</dd>
569
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]571 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
572 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
573 global scope.
574 Symbols with "<tt>common</tt>" linkage are merged in the same way as
575 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]576 <tt>common</tt> symbols may not have an explicit section,
577 must have a zero initializer, and may not be marked '<a
578 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
579 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]580
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]581
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]583 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]584 pointer to array type. When two global variables with appending linkage
585 are linked together, the two global arrays are appended together. This is
586 the LLVM, typesafe, equivalent of having the system linker append together
587 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]588
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]590 <dd>The semantics of this linkage follow the ELF object file model: the symbol
591 is weak until linked, if not linked, the symbol becomes null instead of
592 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]593
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
595 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]596 <dd>Some languages allow differing globals to be merged, such as two functions
597 with different semantics. Other languages, such as <tt>C++</tt>, ensure
598 that only equivalent globals are ever merged (the "one definition rule" -
599 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
600 and <tt>weak_odr</tt> linkage types to indicate that the global will only
601 be merged with equivalent globals. These linkage types are otherwise the
602 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]603
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]605 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]606 visible, meaning that it participates in linkage and can be used to
607 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]608</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]609
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]610<p>The next two types of linkage are targeted for Microsoft Windows platform
611 only. They are designed to support importing (exporting) symbols from (to)
612 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]613
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]614<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]617 or variable via a global pointer to a pointer that is set up by the DLL
618 exporting the symbol. On Microsoft Windows targets, the pointer name is
619 formed by combining <code>__imp_</code> and the function or variable
620 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]621
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]623 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]624 pointer to a pointer in a DLL, so that it can be referenced with the
625 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
626 name is formed by combining <code>__imp_</code> and the function or
627 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]628</dl>
629
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]630<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
631 another module defined a "<tt>.LC0</tt>" variable and was linked with this
632 one, one of the two would be renamed, preventing a collision. Since
633 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
634 declarations), they are accessible outside of the current module.</p>
635
636<p>It is illegal for a function <i>declaration</i> to have any linkage type
637 other than "externally visible", <tt>dllimport</tt>
638 or <tt>extern_weak</tt>.</p>
639
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]640<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]641 or <tt>weak_odr</tt> linkages.</p>
642
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]643</div>
644
645<!-- ======================================================================= -->
646<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]647 <a name="callingconv">Calling Conventions</a>
648</div>
649
650<div class="doc_text">
651
652<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653 and <a href="#i_invoke">invokes</a> can all have an optional calling
654 convention specified for the call. The calling convention of any pair of
655 dynamic caller/callee must match, or the behavior of the program is
656 undefined. The following calling conventions are supported by LLVM, and more
657 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]658
659<dl>
660 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]662 specified) matches the target C calling conventions. This calling
663 convention supports varargs function calls and tolerates some mismatch in
664 the declared prototype and implemented declaration of the function (as
665 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]666
667 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]668 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]669 (e.g. by passing things in registers). This calling convention allows the
670 target to use whatever tricks it wants to produce fast code for the
671 target, without having to conform to an externally specified ABI
672 (Application Binary Interface). Implementations of this convention should
673 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
674 optimization</a> to be supported. This calling convention does not
675 support varargs and requires the prototype of all callees to exactly match
676 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]677
678 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]679 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]680 as possible under the assumption that the call is not commonly executed.
681 As such, these calls often preserve all registers so that the call does
682 not break any live ranges in the caller side. This calling convention
683 does not support varargs and requires the prototype of all callees to
684 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]686 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]688 target-specific calling conventions to be used. Target specific calling
689 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]690</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]691
692<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]693 support Pascal conventions or any other well-known target-independent
694 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]695
696</div>
697
698<!-- ======================================================================= -->
699<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]700 <a name="visibility">Visibility Styles</a>
701</div>
702
703<div class="doc_text">
704
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705<p>All Global Variables and Functions have one of the following visibility
706 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]710 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]711 that the declaration is visible to other modules and, in shared libraries,
712 means that the declared entity may be overridden. On Darwin, default
713 visibility means that the declaration is visible to other modules. Default
714 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]715
716 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]717 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]718 object if they are in the same shared object. Usually, hidden visibility
719 indicates that the symbol will not be placed into the dynamic symbol
720 table, so no other module (executable or shared library) can reference it
721 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]722
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]723 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]724 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]725 the dynamic symbol table, but that references within the defining module
726 will bind to the local symbol. That is, the symbol cannot be overridden by
727 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]728</dl>
729
730</div>
731
732<!-- ======================================================================= -->
733<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]734 <a name="namedtypes">Named Types</a>
735</div>
736
737<div class="doc_text">
738
739<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]740 it easier to read the IR and make the IR more condensed (particularly when
741 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]742
743<div class="doc_code">
744<pre>
745%mytype = type { %mytype*, i32 }
746</pre>
747</div>
748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749<p>You may give a name to any <a href="#typesystem">type</a> except
750 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
751 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]752
753<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]754 and that you can therefore specify multiple names for the same type. This
755 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
756 uses structural typing, the name is not part of the type. When printing out
757 LLVM IR, the printer will pick <em>one name</em> to render all types of a
758 particular shape. This means that if you have code where two different
759 source types end up having the same LLVM type, that the dumper will sometimes
760 print the "wrong" or unexpected type. This is an important design point and
761 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]762
763</div>
764
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]765<!-- ======================================================================= -->
766<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]767 <a name="globalvars">Global Variables</a>
768</div>
769
770<div class="doc_text">
771
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]772<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]773 instead of run-time. Global variables may optionally be initialized, may
774 have an explicit section to be placed in, and may have an optional explicit
775 alignment specified. A variable may be defined as "thread_local", which
776 means that it will not be shared by threads (each thread will have a
777 separated copy of the variable). A variable may be defined as a global
778 "constant," which indicates that the contents of the variable
779 will <b>never</b> be modified (enabling better optimization, allowing the
780 global data to be placed in the read-only section of an executable, etc).
781 Note that variables that need runtime initialization cannot be marked
782 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]783
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]784<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
785 constant, even if the final definition of the global is not. This capability
786 can be used to enable slightly better optimization of the program, but
787 requires the language definition to guarantee that optimizations based on the
788 'constantness' are valid for the translation units that do not include the
789 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]790
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]791<p>As SSA values, global variables define pointer values that are in scope
792 (i.e. they dominate) all basic blocks in the program. Global variables
793 always define a pointer to their "content" type because they describe a
794 region of memory, and all memory objects in LLVM are accessed through
795 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]797<p>A global variable may be declared to reside in a target-specific numbered
798 address space. For targets that support them, address spaces may affect how
799 optimizations are performed and/or what target instructions are used to
800 access the variable. The default address space is zero. The address space
801 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]802
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]803<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]804 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]805
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]806<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]807 the alignment is set to zero, the alignment of the global is set by the
808 target to whatever it feels convenient. If an explicit alignment is
809 specified, the global is forced to have at least that much alignment. All
810 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]811
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]812<p>For example, the following defines a global in a numbered address space with
813 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]814
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]815<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]816<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]817@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]818</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]819</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]820
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821</div>
822
823
824<!-- ======================================================================= -->
825<div class="doc_subsection">
826 <a name="functionstructure">Functions</a>
827</div>
828
829<div class="doc_text">
830
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
832 optional <a href="#linkage">linkage type</a>, an optional
833 <a href="#visibility">visibility style</a>, an optional
834 <a href="#callingconv">calling convention</a>, a return type, an optional
835 <a href="#paramattrs">parameter attribute</a> for the return type, a function
836 name, a (possibly empty) argument list (each with optional
837 <a href="#paramattrs">parameter attributes</a>), optional
838 <a href="#fnattrs">function attributes</a>, an optional section, an optional
839 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
840 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]841
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]842<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
843 optional <a href="#linkage">linkage type</a>, an optional
844 <a href="#visibility">visibility style</a>, an optional
845 <a href="#callingconv">calling convention</a>, a return type, an optional
846 <a href="#paramattrs">parameter attribute</a> for the return type, a function
847 name, a possibly empty list of arguments, an optional alignment, and an
848 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]849
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]850<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]851 (Control Flow Graph) for the function. Each basic block may optionally start
852 with a label (giving the basic block a symbol table entry), contains a list
853 of instructions, and ends with a <a href="#terminators">terminator</a>
854 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]855
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]856<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]857 executed on entrance to the function, and it is not allowed to have
858 predecessor basic blocks (i.e. there can not be any branches to the entry
859 block of a function). Because the block can have no predecessors, it also
860 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]861
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]862<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]865<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]866 the alignment is set to zero, the alignment of the function is set by the
867 target to whatever it feels convenient. If an explicit alignment is
868 specified, the function is forced to have at least that much alignment. All
869 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]870
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]871<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]872<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]873<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]874define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]875 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
876 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
877 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
878 [<a href="#gc">gc</a>] { ... }
879</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]880</div>
881
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]882</div>
883
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]884<!-- ======================================================================= -->
885<div class="doc_subsection">
886 <a name="aliasstructure">Aliases</a>
887</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]888
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]889<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]890
891<p>Aliases act as "second name" for the aliasee value (which can be either
892 function, global variable, another alias or bitcast of global value). Aliases
893 may have an optional <a href="#linkage">linkage type</a>, and an
894 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]895
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]896<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]897<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]898<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]899@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]900</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]901</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]902
903</div>
904
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]905<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]907
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]908<div class="doc_text">
909
910<p>The return type and each parameter of a function type may have a set of
911 <i>parameter attributes</i> associated with them. Parameter attributes are
912 used to communicate additional information about the result or parameters of
913 a function. Parameter attributes are considered to be part of the function,
914 not of the function type, so functions with different parameter attributes
915 can have the same function type.</p>
916
917<p>Parameter attributes are simple keywords that follow the type specified. If
918 multiple parameter attributes are needed, they are space separated. For
919 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]920
921<div class="doc_code">
922<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]923declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]924declare i32 @atoi(i8 zeroext)
925declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]926</pre>
927</div>
928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929<p>Note that any attributes for the function result (<tt>nounwind</tt>,
930 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]931
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]932<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]933
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]934<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]935 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be zero-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]940 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates to the code generator that the parameter or return value
942 should be sign-extended to a 32-bit value by the caller (for a parameter)
943 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]944
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]945 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]946 <dd>This indicates that this parameter or return value should be treated in a
947 special target-dependent fashion during while emitting code for a function
948 call or return (usually, by putting it in a register as opposed to memory,
949 though some targets use it to distinguish between two different kinds of
950 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]951
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]952 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]953 <dd>This indicates that the pointer parameter should really be passed by value
954 to the function. The attribute implies that a hidden copy of the pointee
955 is made between the caller and the callee, so the callee is unable to
956 modify the value in the callee. This attribute is only valid on LLVM
957 pointer arguments. It is generally used to pass structs and arrays by
958 value, but is also valid on pointers to scalars. The copy is considered
959 to belong to the caller not the callee (for example,
960 <tt><a href="#readonly">readonly</a></tt> functions should not write to
961 <tt>byval</tt> parameters). This is not a valid attribute for return
962 values. The byval attribute also supports specifying an alignment with
963 the align attribute. This has a target-specific effect on the code
964 generator that usually indicates a desired alignment for the synthesized
965 stack slot.</dd>
966
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]967 <dt><tt><b>sret</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]968 <dd>This indicates that the pointer parameter specifies the address of a
969 structure that is the return value of the function in the source program.
970 This pointer must be guaranteed by the caller to be valid: loads and
971 stores to the structure may be assumed by the callee to not to trap. This
972 may only be applied to the first parameter. This is not a valid attribute
973 for return values. </dd>
974
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]975 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]976 <dd>This indicates that the pointer does not alias any global or any other
977 parameter. The caller is responsible for ensuring that this is the
978 case. On a function return value, <tt>noalias</tt> additionally indicates
979 that the pointer does not alias any other pointers visible to the
980 caller. For further details, please see the discussion of the NoAlias
981 response in
982 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
983 analysis</a>.</dd>
984
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]985 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the callee does not make any copies of the pointer
987 that outlive the callee itself. This is not a valid attribute for return
988 values.</dd>
989
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]990 <dt><tt><b>nest</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]991 <dd>This indicates that the pointer parameter can be excised using the
992 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
993 attribute for return values.</dd>
994</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]995
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996</div>
997
998<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]999<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1000 <a name="gc">Garbage Collector Names</a>
1001</div>
1002
1003<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1004
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Each function may specify a garbage collector name, which is simply a
1006 string:</p>
1007
1008<div class="doc_code">
1009<pre>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1010define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1011</pre>
1012</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1013
1014<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1015 collector which will cause the compiler to alter its output in order to
1016 support the named garbage collection algorithm.</p>
1017
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1022 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1023</div>
1024
1025<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are set to communicate additional information about a
1028 function. Function attributes are considered to be part of the function, not
1029 of the function type, so functions with different parameter attributes can
1030 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1031
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1032<p>Function attributes are simple keywords that follow the type specified. If
1033 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1034
1035<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1036<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1037define void @f() noinline { ... }
1038define void @f() alwaysinline { ... }
1039define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1040define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1041</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1042</div>
1043
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This attribute indicates that the inliner should attempt to inline this
1047 function into callers whenever possible, ignoring any active inlining size
1048 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1049
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1050 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1051 <dd>This attribute indicates that the source code contained a hint that inlining
1052 this function is desirable (such as the "inline" keyword in C/C++). It
1053 is just a hint; it imposes no requirements on the inliner.</dd>
1054
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1055 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute indicates that the inliner should never inline this
1057 function in any situation. This attribute may not be used together with
1058 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1060 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This attribute suggests that optimization passes and code generator passes
1062 make choices that keep the code size of this function low, and otherwise
1063 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1064
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns
1067 normally. This produces undefined behavior at runtime if the function
1068 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1069
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1070 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This function attribute indicates that the function never returns with an
1072 unwind or exceptional control flow. If the function does unwind, its
1073 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1074
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1075 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This attribute indicates that the function computes its result (or decides
1077 to unwind an exception) based strictly on its arguments, without
1078 dereferencing any pointer arguments or otherwise accessing any mutable
1079 state (e.g. memory, control registers, etc) visible to caller functions.
1080 It does not write through any pointer arguments
1081 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1082 changes any state visible to callers. This means that it cannot unwind
1083 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1084 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1085
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1086 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This attribute indicates that the function does not write through any
1088 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1089 arguments) or otherwise modify any state (e.g. memory, control registers,
1090 etc) visible to caller functions. It may dereference pointer arguments
1091 and read state that may be set in the caller. A readonly function always
1092 returns the same value (or unwinds an exception identically) when called
1093 with the same set of arguments and global state. It cannot unwind an
1094 exception by calling the <tt>C++</tt> exception throwing methods, but may
1095 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1096
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1097 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1098 <dd>This attribute indicates that the function should emit a stack smashing
1099 protector. It is in the form of a "canary"&mdash;a random value placed on
1100 the stack before the local variables that's checked upon return from the
1101 function to see if it has been overwritten. A heuristic is used to
1102 determine if a function needs stack protectors or not.<br>
1103<br>
1104 If a function that has an <tt>ssp</tt> attribute is inlined into a
1105 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1106 function will have an <tt>ssp</tt> attribute.</dd>
1107
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1108 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1109 <dd>This attribute indicates that the function should <em>always</em> emit a
1110 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1111 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1112<br>
1113 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1114 function that doesn't have an <tt>sspreq</tt> attribute or which has
1115 an <tt>ssp</tt> attribute, then the resulting function will have
1116 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1117
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the code generator should not use a red
1120 zone, even if the target-specific ABI normally permits it.</dd>
1121
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1122 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1123 <dd>This attributes disables implicit floating point instructions.</dd>
1124
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1125 <dt><tt><b>naked</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attribute disables prologue / epilogue emission for the function.
1127 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1128</dl>
1129
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1130</div>
1131
1132<!-- ======================================================================= -->
1133<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1134 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1135</div>
1136
1137<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1138
1139<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1140 the GCC "file scope inline asm" blocks. These blocks are internally
1141 concatenated by LLVM and treated as a single unit, but may be separated in
1142 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1143
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1144<div class="doc_code">
1145<pre>
1146module asm "inline asm code goes here"
1147module asm "more can go here"
1148</pre>
1149</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1150
1151<p>The strings can contain any character by escaping non-printable characters.
1152 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]1153 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1154
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1155<p>The inline asm code is simply printed to the machine code .s file when
1156 assembly code is generated.</p>
1157
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1158</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1159
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1160<!-- ======================================================================= -->
1161<div class="doc_subsection">
1162 <a name="datalayout">Data Layout</a>
1163</div>
1164
1165<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1166
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1167<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1168 data is to be laid out in memory. The syntax for the data layout is
1169 simply:</p>
1170
1171<div class="doc_code">
1172<pre>
1173target datalayout = "<i>layout specification</i>"
1174</pre>
1175</div>
1176
1177<p>The <i>layout specification</i> consists of a list of specifications
1178 separated by the minus sign character ('-'). Each specification starts with
1179 a letter and may include other information after the letter to define some
1180 aspect of the data layout. The specifications accepted are as follows:</p>
1181
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1182<dl>
1183 <dt><tt>E</tt></dt>
1184 <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]1185 bits with the most significance have the lowest address location.</dd>
1186
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1188 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1189 the bits with the least significance have the lowest address
1190 location.</dd>
1191
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1192 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <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]1194 <i>preferred</i> alignments. All sizes are in bits. Specifying
1195 the <i>pref</i> alignment is optional. If omitted, the
1196 preceding <tt>:</tt> should be omitted too.</dd>
1197
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1198 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1199 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1200 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1201
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1202 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1203 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204 <i>size</i>.</dd>
1205
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1209 (double).</dd>
1210
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1211 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1212 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1215 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1216 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1218
1219 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1220 <dd>This specifies a set of native integer widths for the target CPU
1221 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1222 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
1223 this set are considered to support most general arithmetic
1224 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1225</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1227<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1228 default set of specifications which are then (possibly) overriden by the
1229 specifications in the <tt>datalayout</tt> keyword. The default specifications
1230 are given in this list:</p>
1231
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1232<ul>
1233 <li><tt>E</tt> - big endian</li>
1234 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1235 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1236 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1237 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1238 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1239 <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]1240 alignment of 64-bits</li>
1241 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1242 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1243 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1244 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1245 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1246 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1247</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>When LLVM is determining the alignment for a given type, it uses the
1250 following rules:</p>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252<ol>
1253 <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]1254 specification is used.</li>
1255
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256 <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]1257 smallest integer type that is larger than the bitwidth of the sought type
1258 is used. If none of the specifications are larger than the bitwidth then
1259 the the largest integer type is used. For example, given the default
1260 specifications above, the i7 type will use the alignment of i8 (next
1261 largest) while both i65 and i256 will use the alignment of i64 (largest
1262 specified).</li>
1263
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1264 <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]1265 largest vector type that is smaller than the sought vector type will be
1266 used as a fall back. This happens because &lt;128 x double&gt; can be
1267 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1268</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1269
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1270</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1271
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1272<!-- ======================================================================= -->
1273<div class="doc_subsection">
1274 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1275</div>
1276
1277<div class="doc_text">
1278
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1279<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1280with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1281is undefined. Pointer values are associated with address ranges
1282according to the following rules:</p>
1283
1284<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1285 <li>A pointer value formed from a
1286 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1287 is associated with the addresses associated with the first operand
1288 of the <tt>getelementptr</tt>.</li>
1289 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1290 range of the variable's storage.</li>
1291 <li>The result value of an allocation instruction is associated with
1292 the address range of the allocated storage.</li>
1293 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1294 no address.</li>
1295 <li>A pointer value formed by an
1296 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1297 address ranges of all pointer values that contribute (directly or
1298 indirectly) to the computation of the pointer's value.</li>
1299 <li>The result value of a
1300 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1301 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1302 <li>An integer constant other than zero or a pointer value returned
1303 from a function not defined within LLVM may be associated with address
1304 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1305 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1306 allocated by mechanisms provided by LLVM.</li>
1307 </ul>
1308
1309<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1310<tt><a href="#i_load">load</a></tt> merely indicates the size and
1311alignment of the memory from which to load, as well as the
1312interpretation of the value. The first operand of a
1313<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1314and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1315
1316<p>Consequently, type-based alias analysis, aka TBAA, aka
1317<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1318LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1319additional information which specialized optimization passes may use
1320to implement type-based alias analysis.</p>
1321
1322</div>
1323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1324<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1326<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1327
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1328<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1329
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1330<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331 intermediate representation. Being typed enables a number of optimizations
1332 to be performed on the intermediate representation directly, without having
1333 to do extra analyses on the side before the transformation. A strong type
1334 system makes it easier to read the generated code and enables novel analyses
1335 and transformations that are not feasible to perform on normal three address
1336 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1337
1338</div>
1339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1340<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1341<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1344<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1347
1348<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1349 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1350 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1351 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1353 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1354 </tr>
1355 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1356 <td><a href="#t_floating">floating point</a></td>
1357 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
1359 <tr>
1360 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a>,
1362 <a href="#t_floating">floating point</a>,
1363 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1364 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1365 <a href="#t_struct">structure</a>,
1366 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1367 <a href="#t_label">label</a>,
1368 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1369 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1370 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1371 <tr>
1372 <td><a href="#t_primitive">primitive</a></td>
1373 <td><a href="#t_label">label</a>,
1374 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1375 <a href="#t_floating">floating point</a>,
1376 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
1378 <tr>
1379 <td><a href="#t_derived">derived</a></td>
1380 <td><a href="#t_integer">integer</a>,
1381 <a href="#t_array">array</a>,
1382 <a href="#t_function">function</a>,
1383 <a href="#t_pointer">pointer</a>,
1384 <a href="#t_struct">structure</a>,
1385 <a href="#t_pstruct">packed structure</a>,
1386 <a href="#t_vector">vector</a>,
1387 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1388 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1389 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1390 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1391</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1392
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1393<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1394 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1395 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1396
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1397</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1399<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1400<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1401
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1402<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1404<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1405 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1406
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1407</div>
1408
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1409<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1410<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1411
1412<div class="doc_text">
1413
1414<h5>Overview:</h5>
1415<p>The integer type is a very simple type that simply specifies an arbitrary
1416 bit width for the integer type desired. Any bit width from 1 bit to
1417 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1418
1419<h5>Syntax:</h5>
1420<pre>
1421 iN
1422</pre>
1423
1424<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1425 value.</p>
1426
1427<h5>Examples:</h5>
1428<table class="layout">
1429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i32</tt></td>
1435 <td class="left">a 32-bit integer.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>i1942652</tt></td>
1439 <td class="left">a really big integer of over 1 million bits.</td>
1440 </tr>
1441</table>
1442
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1443</div>
1444
1445<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1447
1448<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1449
1450<table>
1451 <tbody>
1452 <tr><th>Type</th><th>Description</th></tr>
1453 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1454 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1455 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1456 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1457 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1458 </tbody>
1459</table>
1460
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461</div>
1462
1463<!-- _______________________________________________________________________ -->
1464<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1465
1466<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1467
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1468<h5>Overview:</h5>
1469<p>The void type does not represent any value and has no size.</p>
1470
1471<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1472<pre>
1473 void
1474</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1475
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476</div>
1477
1478<!-- _______________________________________________________________________ -->
1479<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1480
1481<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1482
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1483<h5>Overview:</h5>
1484<p>The label type represents code labels.</p>
1485
1486<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1487<pre>
1488 label
1489</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1490
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1491</div>
1492
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1493<!-- _______________________________________________________________________ -->
1494<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1495
1496<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1497
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1498<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1499<p>The metadata type represents embedded metadata. No derived types may be
1500 created from metadata except for <a href="#t_function">function</a>
1501 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1502
1503<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1504<pre>
1505 metadata
1506</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1507
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1508</div>
1509
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1510
1511<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1512<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1514<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1516<p>The real power in LLVM comes from the derived types in the system. This is
1517 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1518 useful types. Each of these types contain one or more element types which
1519 may be a primitive type, or another derived type. For example, it is
1520 possible to have a two dimensional array, using an array as the element type
1521 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1522
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1523</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1524
1525<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1526<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1530<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1531<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1532 sequentially in memory. The array type requires a size (number of elements)
1533 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1534
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1535<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536<pre>
1537 [&lt;# elements&gt; x &lt;elementtype&gt;]
1538</pre>
1539
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1540<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1541 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1543<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1544<table class="layout">
1545 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1546 <td class="left"><tt>[40 x i32]</tt></td>
1547 <td class="left">Array of 40 32-bit integer values.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>[41 x i32]</tt></td>
1551 <td class="left">Array of 41 32-bit integer values.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>[4 x i8]</tt></td>
1555 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1556 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1557</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1558<p>Here are some examples of multidimensional arrays:</p>
1559<table class="layout">
1560 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1561 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1562 <td class="left">3x4 array of 32-bit integer values.</td>
1563 </tr>
1564 <tr class="layout">
1565 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1566 <td class="left">12x10 array of single precision floating point values.</td>
1567 </tr>
1568 <tr class="layout">
1569 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1570 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1571 </tr>
1572</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1573
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1574<p>There is no restriction on indexing beyond the end of the array implied by
1575 a static type (though there are restrictions on indexing beyond the bounds
1576 of an allocated object in some cases). This means that single-dimension
1577 'variable sized array' addressing can be implemented in LLVM with a zero
1578 length array type. An implementation of 'pascal style arrays' in LLVM could
1579 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1580
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1581</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1582
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1583<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1586<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1589<p>The function type can be thought of as a function signature. It consists of
1590 a return type and a list of formal parameter types. The return type of a
1591 function type is a scalar type, a void type, or a struct type. If the return
1592 type is a struct type then all struct elements must be of first class types,
1593 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1595<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1596<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1597 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1598</pre>
1599
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1600<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]1601 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1602 which indicates that the function takes a variable number of arguments.
1603 Variable argument functions can access their arguments with
1604 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1605 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1606 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1607
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1609<table class="layout">
1610 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1611 <td class="left"><tt>i32 (i32)</tt></td>
1612 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1613 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1614 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1615 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1616 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1617 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1618 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1619 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1620 <tt>float</tt>.
1621 </td>
1622 </tr><tr class="layout">
1623 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1624 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1625 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1626 which returns an integer. This is the signature for <tt>printf</tt> in
1627 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1628 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1629 </tr><tr class="layout">
1630 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1631 <td class="left">A function taking an <tt>i32</tt>, returning a
1632 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1633 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1634 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1635</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1636
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1637</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1639<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1640<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1643
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1644<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1645<p>The structure type is used to represent a collection of data members together
1646 in memory. The packing of the field types is defined to match the ABI of the
1647 underlying processor. The elements of a structure may be any type that has a
1648 size.</p>
1649
1650<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1651 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1652 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1653
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1655<pre>
1656 { &lt;type list&gt; }
1657</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1660<table class="layout">
1661 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1662 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1663 <td class="left">A triple of three <tt>i32</tt> values</td>
1664 </tr><tr class="layout">
1665 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1666 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1667 second element is a <a href="#t_pointer">pointer</a> to a
1668 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1669 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1670 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1671</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1673</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1674
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1676<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1677</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1678
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1679<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1680
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1681<h5>Overview:</h5>
1682<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1683 together in memory. There is no padding between fields. Further, the
1684 alignment of a packed structure is 1 byte. The elements of a packed
1685 structure may be any type that has a size.</p>
1686
1687<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1688 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1689 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1690
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1691<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1692<pre>
1693 &lt; { &lt;type list&gt; } &gt;
1694</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1695
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1696<h5>Examples:</h5>
1697<table class="layout">
1698 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1699 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1700 <td class="left">A triple of three <tt>i32</tt> values</td>
1701 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1702 <td class="left">
1703<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1704 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1705 second element is a <a href="#t_pointer">pointer</a> to a
1706 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1707 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1708 </tr>
1709</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1710
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1711</div>
1712
1713<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1716<div class="doc_text">
1717
1718<h5>Overview:</h5>
1719<p>As in many languages, the pointer type represents a pointer or reference to
1720 another object, which must live in memory. Pointer types may have an optional
1721 address space attribute defining the target-specific numbered address space
1722 where the pointed-to object resides. The default address space is zero.</p>
1723
1724<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1725 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1726
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1727<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1728<pre>
1729 &lt;type&gt; *
1730</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1731
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1732<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1733<table class="layout">
1734 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1735 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1736 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1737 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1738 </tr>
1739 <tr class="layout">
1740 <td class="left"><tt>i32 (i32 *) *</tt></td>
1741 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1742 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1743 <tt>i32</tt>.</td>
1744 </tr>
1745 <tr class="layout">
1746 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1747 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1748 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1749 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1750</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1753
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1758
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760<p>A vector type is a simple derived type that represents a vector of elements.
1761 Vector types are used when multiple primitive data are operated in parallel
1762 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame^]1763 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1764 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1765
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1766<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1767<pre>
1768 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1769</pre>
1770
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1771<p>The number of elements is a constant integer value; elementtype may be any
1772 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1773
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1774<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1775<table class="layout">
1776 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1777 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1778 <td class="left">Vector of 4 32-bit integer values.</td>
1779 </tr>
1780 <tr class="layout">
1781 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1782 <td class="left">Vector of 8 32-bit floating-point values.</td>
1783 </tr>
1784 <tr class="layout">
1785 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1786 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1787 </tr>
1788</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1789
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1790</div>
1791
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1792<!-- _______________________________________________________________________ -->
1793<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1794<div class="doc_text">
1795
1796<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1797<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1798 corresponds (for example) to the C notion of a forward declared structure
1799 type. In LLVM, opaque types can eventually be resolved to any type (not just
1800 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1801
1802<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1803<pre>
1804 opaque
1805</pre>
1806
1807<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1808<table class="layout">
1809 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1810 <td class="left"><tt>opaque</tt></td>
1811 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1812 </tr>
1813</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1814
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1815</div>
1816
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1817<!-- ======================================================================= -->
1818<div class="doc_subsection">
1819 <a name="t_uprefs">Type Up-references</a>
1820</div>
1821
1822<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1824<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1825<p>An "up reference" allows you to refer to a lexically enclosing type without
1826 requiring it to have a name. For instance, a structure declaration may
1827 contain a pointer to any of the types it is lexically a member of. Example
1828 of up references (with their equivalent as named type declarations)
1829 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1830
1831<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1832 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1833 { \2 }* %y = type { %y }*
1834 \1* %z = type %z*
1835</pre>
1836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1837<p>An up reference is needed by the asmprinter for printing out cyclic types
1838 when there is no declared name for a type in the cycle. Because the
1839 asmprinter does not want to print out an infinite type string, it needs a
1840 syntax to handle recursive types that have no names (all names are optional
1841 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1842
1843<h5>Syntax:</h5>
1844<pre>
1845 \&lt;level&gt;
1846</pre>
1847
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1848<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]1849
1850<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1851<table class="layout">
1852 <tr class="layout">
1853 <td class="left"><tt>\1*</tt></td>
1854 <td class="left">Self-referential pointer.</td>
1855 </tr>
1856 <tr class="layout">
1857 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1858 <td class="left">Recursive structure where the upref refers to the out-most
1859 structure.</td>
1860 </tr>
1861</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1862
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1863</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1864
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1865<!-- *********************************************************************** -->
1866<div class="doc_section"> <a name="constants">Constants</a> </div>
1867<!-- *********************************************************************** -->
1868
1869<div class="doc_text">
1870
1871<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1872 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1873
1874</div>
1875
1876<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1877<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1878
1879<div class="doc_text">
1880
1881<dl>
1882 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1883 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1884 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1885
1886 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1887 <dd>Standard integers (such as '4') are constants of
1888 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1889 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890
1891 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1892 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1893 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1894 notation (see below). The assembler requires the exact decimal value of a
1895 floating-point constant. For example, the assembler accepts 1.25 but
1896 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1897 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1898
1899 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1900 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1902</dl>
1903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1904<p>The one non-intuitive notation for constants is the hexadecimal form of
1905 floating point constants. For example, the form '<tt>double
1906 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1907 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1908 constants are required (and the only time that they are generated by the
1909 disassembler) is when a floating point constant must be emitted but it cannot
1910 be represented as a decimal floating point number in a reasonable number of
1911 digits. For example, NaN's, infinities, and other special values are
1912 represented in their IEEE hexadecimal format so that assembly and disassembly
1913 do not cause any bits to change in the constants.</p>
1914
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1915<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1916 represented using the 16-digit form shown above (which matches the IEEE754
1917 representation for double); float values must, however, be exactly
1918 representable as IEE754 single precision. Hexadecimal format is always used
1919 for long double, and there are three forms of long double. The 80-bit format
1920 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1921 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1922 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1923 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1924 currently supported target uses this format. Long doubles will only work if
1925 they match the long double format on your target. All hexadecimal formats
1926 are big-endian (sign bit at the left).</p>
1927
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1928</div>
1929
1930<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1931<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1932<a name="aggregateconstants"></a> <!-- old anchor -->
1933<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934</div>
1935
1936<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1937
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1938<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1939 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1940
1941<dl>
1942 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1944 type definitions (a comma separated list of elements, surrounded by braces
1945 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1946 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1947 Structure constants must have <a href="#t_struct">structure type</a>, and
1948 the number and types of elements must match those specified by the
1949 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1950
1951 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1952 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1953 definitions (a comma separated list of elements, surrounded by square
1954 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1955 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1956 the number and types of elements must match those specified by the
1957 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1958
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1959 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1960 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1961 definitions (a comma separated list of elements, surrounded by
1962 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1963 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1964 have <a href="#t_vector">vector type</a>, and the number and types of
1965 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1966
1967 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1968 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1969 value to zero of <em>any</em> type, including scalar and aggregate types.
1970 This is often used to avoid having to print large zero initializers
1971 (e.g. for large arrays) and is always exactly equivalent to using explicit
1972 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1973
1974 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1975 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1977 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1978 be interpreted as part of the instruction stream, metadata is a place to
1979 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1980</dl>
1981
1982</div>
1983
1984<!-- ======================================================================= -->
1985<div class="doc_subsection">
1986 <a name="globalconstants">Global Variable and Function Addresses</a>
1987</div>
1988
1989<div class="doc_text">
1990
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1991<p>The addresses of <a href="#globalvars">global variables</a>
1992 and <a href="#functionstructure">functions</a> are always implicitly valid
1993 (link-time) constants. These constants are explicitly referenced when
1994 the <a href="#identifiers">identifier for the global</a> is used and always
1995 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1996 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1997
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1998<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1999<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2000@X = global i32 17
2001@Y = global i32 42
2002@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2003</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2004</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2005
2006</div>
2007
2008<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2009<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2010<div class="doc_text">
2011
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2012<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]2013 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2014 Undefined values may be of any type (other than label or void) and be used
2015 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2016
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2017<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2018 program is well defined no matter what value is used. This gives the
2019 compiler more freedom to optimize. Here are some examples of (potentially
2020 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2021
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2022
2023<div class="doc_code">
2024<pre>
2025 %A = add %X, undef
2026 %B = sub %X, undef
2027 %C = xor %X, undef
2028Safe:
2029 %A = undef
2030 %B = undef
2031 %C = undef
2032</pre>
2033</div>
2034
2035<p>This is safe because all of the output bits are affected by the undef bits.
2036Any output bit can have a zero or one depending on the input bits.</p>
2037
2038<div class="doc_code">
2039<pre>
2040 %A = or %X, undef
2041 %B = and %X, undef
2042Safe:
2043 %A = -1
2044 %B = 0
2045Unsafe:
2046 %A = undef
2047 %B = undef
2048</pre>
2049</div>
2050
2051<p>These logical operations have bits that are not always affected by the input.
2052For example, if "%X" has a zero bit, then the output of the 'and' operation will
2053always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2054such, it is unsafe to optimize or assume that the result of the and is undef.
2055However, it is safe to assume that all bits of the undef could be 0, and
2056optimize the and to 0. Likewise, it is safe to assume that all the bits of
2057the undef operand to the or could be set, allowing the or to be folded to
2058-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2059
2060<div class="doc_code">
2061<pre>
2062 %A = select undef, %X, %Y
2063 %B = select undef, 42, %Y
2064 %C = select %X, %Y, undef
2065Safe:
2066 %A = %X (or %Y)
2067 %B = 42 (or %Y)
2068 %C = %Y
2069Unsafe:
2070 %A = undef
2071 %B = undef
2072 %C = undef
2073</pre>
2074</div>
2075
2076<p>This set of examples show that undefined select (and conditional branch)
2077conditions can go "either way" but they have to come from one of the two
2078operands. In the %A example, if %X and %Y were both known to have a clear low
2079bit, then %A would have to have a cleared low bit. However, in the %C example,
2080the optimizer is allowed to assume that the undef operand could be the same as
2081%Y, allowing the whole select to be eliminated.</p>
2082
2083
2084<div class="doc_code">
2085<pre>
2086 %A = xor undef, undef
2087
2088 %B = undef
2089 %C = xor %B, %B
2090
2091 %D = undef
2092 %E = icmp lt %D, 4
2093 %F = icmp gte %D, 4
2094
2095Safe:
2096 %A = undef
2097 %B = undef
2098 %C = undef
2099 %D = undef
2100 %E = undef
2101 %F = undef
2102</pre>
2103</div>
2104
2105<p>This example points out that two undef operands are not necessarily the same.
2106This can be surprising to people (and also matches C semantics) where they
2107assume that "X^X" is always zero, even if X is undef. This isn't true for a
2108number of reasons, but the short answer is that an undef "variable" can
2109arbitrarily change its value over its "live range". This is true because the
2110"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2111logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2112so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2113to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2114would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2115
2116<div class="doc_code">
2117<pre>
2118 %A = fdiv undef, %X
2119 %B = fdiv %X, undef
2120Safe:
2121 %A = undef
2122b: unreachable
2123</pre>
2124</div>
2125
2126<p>These examples show the crucial difference between an <em>undefined
2127value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2128allowed to have an arbitrary bit-pattern. This means that the %A operation
2129can be constant folded to undef because the undef could be an SNaN, and fdiv is
2130not (currently) defined on SNaN's. However, in the second example, we can make
2131a more aggressive assumption: because the undef is allowed to be an arbitrary
2132value, 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]2133has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2134does not execute at all. This allows us to delete the divide and all code after
2135it: since the undefined operation "can't happen", the optimizer can assume that
2136it occurs in dead code.
2137</p>
2138
2139<div class="doc_code">
2140<pre>
2141a: store undef -> %X
2142b: store %X -> undef
2143Safe:
2144a: &lt;deleted&gt;
2145b: unreachable
2146</pre>
2147</div>
2148
2149<p>These examples reiterate the fdiv example: a store "of" an undefined value
2150can be assumed to not have any effect: we can assume that the value is
2151overwritten with bits that happen to match what was already there. However, a
2152store "to" an undefined location could clobber arbitrary memory, therefore, it
2153has undefined behavior.</p>
2154
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2155</div>
2156
2157<!-- ======================================================================= -->
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2158<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2159 Blocks</a></div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2160<div class="doc_text">
2161
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2162<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2163
2164<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2165 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2166 the address of the entry block is illegal.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2167
2168<p>This value only has defined behavior when used as an operand to the
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2169 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2170 against null. Pointer equality tests between labels addresses is undefined
2171 behavior - though, again, comparison against null is ok, and no label is
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2172 equal to the null pointer. This may also be passed around as an opaque
2173 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner3fd77ce2009-10-27 21:44:20 +0000[diff] [blame]2174 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2175 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]2176
2177<p>Finally, some targets may provide defined semantics when
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2178 using the value as the operand to an inline assembly, but that is target
2179 specific.
2180 </p>
2181
2182</div>
2183
2184
2185<!-- ======================================================================= -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2186<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2187</div>
2188
2189<div class="doc_text">
2190
2191<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2192 to be used as constants. Constant expressions may be of
2193 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2194 operation that does not have side effects (e.g. load and call are not
2195 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2196
2197<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2198 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2199 <dd>Truncate a constant to another type. The bit size of CST must be larger
2200 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2201
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2202 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2203 <dd>Zero extend a constant to another type. The bit size of CST must be
2204 smaller or equal to the bit size of TYPE. Both types must be
2205 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2206
2207 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2208 <dd>Sign extend a constant to another type. The bit size of CST must be
2209 smaller or equal to the bit size of TYPE. Both types must be
2210 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2211
2212 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2213 <dd>Truncate a floating point constant to another floating point type. The
2214 size of CST must be larger than the size of TYPE. Both types must be
2215 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2216
2217 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2218 <dd>Floating point extend a constant to another type. The size of CST must be
2219 smaller or equal to the size of TYPE. Both types must be floating
2220 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2221
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2222 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2223 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2224 constant. TYPE must be a scalar or vector integer type. CST must be of
2225 scalar or vector floating point type. Both CST and TYPE must be scalars,
2226 or vectors of the same number of elements. If the value won't fit in the
2227 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2228
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2229 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2230 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2231 constant. TYPE must be a scalar or vector integer type. CST must be of
2232 scalar or vector floating point type. Both CST and TYPE must be scalars,
2233 or vectors of the same number of elements. If the value won't fit in the
2234 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2235
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2236 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2237 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2238 constant. TYPE must be a scalar or vector floating point type. CST must be
2239 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2240 vectors of the same number of elements. If the value won't fit in the
2241 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2242
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2243 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2244 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2245 constant. TYPE must be a scalar or vector floating point type. CST must be
2246 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2247 vectors of the same number of elements. If the value won't fit in the
2248 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2249
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2250 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2251 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2252 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2253 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2254 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2255
2256 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2257 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2258 type. CST must be of integer type. The CST value is zero extended,
2259 truncated, or unchanged to make it fit in a pointer size. This one is
2260 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2261
2262 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2263 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2264 are the same as those for the <a href="#i_bitcast">bitcast
2265 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2266
2267 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2268 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2269 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2270 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2271 instruction, the index list may have zero or more indexes, which are
2272 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2273
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2274 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2275 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2276
2277 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2278 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2279
2280 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2281 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2282
2283 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2284 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2285 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2286
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2287 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2288 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2289 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2290
2291 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2292 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2293 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2294
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2295 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2296 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2297 be any of the <a href="#binaryops">binary</a>
2298 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2299 on operands are the same as those for the corresponding instruction
2300 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2301</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2302
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2303</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2304
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2305<!-- ======================================================================= -->
2306<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2307</div>
2308
2309<div class="doc_text">
2310
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2311<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2312 stream without affecting the behaviour of the program. There are two
2313 metadata primitives, strings and nodes. All metadata has the
2314 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2315 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2316
2317<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2318 any character by escaping non-printable characters with "\xx" where "xx" is
2319 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2320
2321<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2322 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2323 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2324 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2326<p>A metadata node will attempt to track changes to the values it holds. In the
2327 event that a value is deleted, it will be replaced with a typeless
2328 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2329
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2330<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2331 the program that isn't available in the instructions, or that isn't easily
2332 computable. Similarly, the code generator may expect a certain metadata
2333 format to be used to express debugging information.</p>
2334
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2335</div>
2336
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2337<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2338<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2339<!-- *********************************************************************** -->
2340
2341<!-- ======================================================================= -->
2342<div class="doc_subsection">
2343<a name="inlineasm">Inline Assembler Expressions</a>
2344</div>
2345
2346<div class="doc_text">
2347
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2348<p>LLVM supports inline assembler expressions (as opposed
2349 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2350 a special value. This value represents the inline assembler as a string
2351 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2352 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2353 expression has side effects, and a flag indicating whether the function
2354 containing the asm needs to align its stack conservatively. An example
2355 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2356
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2357<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2358<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2359i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2360</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2361</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2362
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2363<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2364 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2365 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2366
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2367<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2368<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2369%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]2370</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2371</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2372
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2373<p>Inline asms with side effects not visible in the constraint list must be
2374 marked as having side effects. This is done through the use of the
2375 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2376
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2377<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2378<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2379call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2380</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2381</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2382
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2383<p>In some cases inline asms will contain code that will not work unless the
2384 stack is aligned in some way, such as calls or SSE instructions on x86,
2385 yet will not contain code that does that alignment within the asm.
2386 The compiler should make conservative assumptions about what the asm might
2387 contain and should generate its usual stack alignment code in the prologue
2388 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2389
2390<div class="doc_code">
2391<pre>
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2392call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2393</pre>
2394</div>
2395
2396<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2397 first.</p>
2398
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2399<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2400 documented here. Constraints on what can be done (e.g. duplication, moving,
2401 etc need to be documented). This is probably best done by reference to
2402 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2403
2404</div>
2405
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2406
2407<!-- *********************************************************************** -->
2408<div class="doc_section">
2409 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2410</div>
2411<!-- *********************************************************************** -->
2412
2413<p>LLVM has a number of "magic" global variables that contain data that affect
2414code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2415of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2416section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2417by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2418
2419<!-- ======================================================================= -->
2420<div class="doc_subsection">
2421<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2422</div>
2423
2424<div class="doc_text">
2425
2426<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2427href="#linkage_appending">appending linkage</a>. This array contains a list of
2428pointers to global variables and functions which may optionally have a pointer
2429cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2430
2431<pre>
2432 @X = global i8 4
2433 @Y = global i32 123
2434
2435 @llvm.used = appending global [2 x i8*] [
2436 i8* @X,
2437 i8* bitcast (i32* @Y to i8*)
2438 ], section "llvm.metadata"
2439</pre>
2440
2441<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2442compiler, assembler, and linker are required to treat the symbol as if there is
2443a reference to the global that it cannot see. For example, if a variable has
2444internal linkage and no references other than that from the <tt>@llvm.used</tt>
2445list, it cannot be deleted. This is commonly used to represent references from
2446inline asms and other things the compiler cannot "see", and corresponds to
2447"attribute((used))" in GNU C.</p>
2448
2449<p>On some targets, the code generator must emit a directive to the assembler or
2450object file to prevent the assembler and linker from molesting the symbol.</p>
2451
2452</div>
2453
2454<!-- ======================================================================= -->
2455<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2456<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2457</div>
2458
2459<div class="doc_text">
2460
2461<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2462<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2463touching the symbol. On targets that support it, this allows an intelligent
2464linker to optimize references to the symbol without being impeded as it would be
2465by <tt>@llvm.used</tt>.</p>
2466
2467<p>This is a rare construct that should only be used in rare circumstances, and
2468should not be exposed to source languages.</p>
2469
2470</div>
2471
2472<!-- ======================================================================= -->
2473<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2474<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2475</div>
2476
2477<div class="doc_text">
2478
2479<p>TODO: Describe this.</p>
2480
2481</div>
2482
2483<!-- ======================================================================= -->
2484<div class="doc_subsection">
2485<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2486</div>
2487
2488<div class="doc_text">
2489
2490<p>TODO: Describe this.</p>
2491
2492</div>
2493
2494
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2495<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2496<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2497<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2498
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2499<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2500
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501<p>The LLVM instruction set consists of several different classifications of
2502 instructions: <a href="#terminators">terminator
2503 instructions</a>, <a href="#binaryops">binary instructions</a>,
2504 <a href="#bitwiseops">bitwise binary instructions</a>,
2505 <a href="#memoryops">memory instructions</a>, and
2506 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2507
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2508</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2509
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2510<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511<div class="doc_subsection"> <a name="terminators">Terminator
2512Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2514<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2515
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2516<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2517 in a program ends with a "Terminator" instruction, which indicates which
2518 block should be executed after the current block is finished. These
2519 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2520 control flow, not values (the one exception being the
2521 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2522
2523<p>There are six different terminator instructions: the
2524 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2525 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2526 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling21c346e2009-11-02 00:25:26 +0000[diff] [blame]2527 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2529 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2530 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2532</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2534<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2535<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2536Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2537
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2538<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2540<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2541<pre>
2542 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]2543 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2544</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2546<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2547<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2548 a value) from a function back to the caller.</p>
2549
2550<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2551 value and then causes control flow, and one that just causes control flow to
2552 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2556 return value. The type of the return value must be a
2557 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2558
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2559<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2560 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2561 value or a return value with a type that does not match its type, or if it
2562 has a void return type and contains a '<tt>ret</tt>' instruction with a
2563 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2565<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2566<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2567 the calling function's context. If the caller is a
2568 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2569 instruction after the call. If the caller was an
2570 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2571 the beginning of the "normal" destination block. If the instruction returns
2572 a value, that value shall set the call or invoke instruction's return
2573 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2576<pre>
2577 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2578 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2579 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]2580</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2582</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2583<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2584<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2586<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2587
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2588<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2589<pre>
2590 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]2591</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2593<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2594<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2595 different basic block in the current function. There are two forms of this
2596 instruction, corresponding to a conditional branch and an unconditional
2597 branch.</p>
2598
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2599<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2600<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2601 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2602 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2603 target.</p>
2604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2606<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2607 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2608 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2609 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2611<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2612<pre>
2613Test:
2614 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2615 br i1 %cond, label %IfEqual, label %IfUnequal
2616IfEqual:
2617 <a href="#i_ret">ret</a> i32 1
2618IfUnequal:
2619 <a href="#i_ret">ret</a> i32 0
2620</pre>
2621
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2622</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2623
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2624<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2625<div class="doc_subsubsection">
2626 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2627</div>
2628
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2629<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2630
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2631<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2632<pre>
2633 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2634</pre>
2635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2636<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2637<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]2638 several different places. It is a generalization of the '<tt>br</tt>'
2639 instruction, allowing a branch to occur to one of many possible
2640 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2642<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2643<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2644 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2645 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2646 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2647
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2648<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2649<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2650 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2651 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2652 transferred to the corresponding destination; otherwise, control flow is
2653 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2654
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2655<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2656<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2657 <tt>switch</tt> instruction, this instruction may be code generated in
2658 different ways. For example, it could be generated as a series of chained
2659 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2660
2661<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2662<pre>
2663 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2664 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2665 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2666
2667 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2668 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2669
2670 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2671 switch i32 %val, label %otherwise [ i32 0, label %onzero
2672 i32 1, label %onone
2673 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2676</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2677
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2678
2679<!-- _______________________________________________________________________ -->
2680<div class="doc_subsubsection">
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2681 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2682</div>
2683
2684<div class="doc_text">
2685
2686<h5>Syntax:</h5>
2687<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2688 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]2689</pre>
2690
2691<h5>Overview:</h5>
2692
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2693<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2694 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2695 "<tt>address</tt>". Address must be derived from a <a
2696 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2697
2698<h5>Arguments:</h5>
2699
2700<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2701 rest of the arguments indicate the full set of possible destinations that the
2702 address may point to. Blocks are allowed to occur multiple times in the
2703 destination list, though this isn't particularly useful.</p>
2704
2705<p>This destination list is required so that dataflow analysis has an accurate
2706 understanding of the CFG.</p>
2707
2708<h5>Semantics:</h5>
2709
2710<p>Control transfers to the block specified in the address argument. All
2711 possible destination blocks must be listed in the label list, otherwise this
2712 instruction has undefined behavior. This implies that jumps to labels
2713 defined in other functions have undefined behavior as well.</p>
2714
2715<h5>Implementation:</h5>
2716
2717<p>This is typically implemented with a jump through a register.</p>
2718
2719<h5>Example:</h5>
2720<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]2721 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]2722</pre>
2723
2724</div>
2725
2726
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2727<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2728<div class="doc_subsubsection">
2729 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2730</div>
2731
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2732<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2733
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2734<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2735<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2736 &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]2737 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2738</pre>
2739
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2740<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2741<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2742 function, with the possibility of control flow transfer to either the
2743 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2744 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2745 control flow will return to the "normal" label. If the callee (or any
2746 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2747 instruction, control is interrupted and continued at the dynamically nearest
2748 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2750<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2751<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2753<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2754 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2755 convention</a> the call should use. If none is specified, the call
2756 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2757
2758 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2759 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2760 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2761
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2762 <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]2763 function value being invoked. In most cases, this is a direct function
2764 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2765 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2766
2767 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2768 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2769
2770 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2771 signature argument types. If the function signature indicates the
2772 function accepts a variable number of arguments, the extra arguments can
2773 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2774
2775 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2776 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2777
2778 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2780
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2781 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2782 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2783 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2784</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2786<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2787<p>This instruction is designed to operate as a standard
2788 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2789 primary difference is that it establishes an association with a label, which
2790 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2791
2792<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2794 exception. Additionally, this is important for implementation of
2795 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2796
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2797<p>For the purposes of the SSA form, the definition of the value returned by the
2798 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2799 block to the "normal" label. If the callee unwinds then no return value is
2800 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2802<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2803<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2804 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2805 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2806 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2807 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2808</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2809
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2810</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2811
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2812<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2813
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2814<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2815Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2817<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2818
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2819<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2820<pre>
2821 unwind
2822</pre>
2823
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2824<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2825<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2826 at the first callee in the dynamic call stack which used
2827 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2828 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2829
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2830<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2831<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2832 immediately halt. The dynamic call stack is then searched for the
2833 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2834 Once found, execution continues at the "exceptional" destination block
2835 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2836 instruction in the dynamic call chain, undefined behavior results.</p>
2837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2838</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2839
2840<!-- _______________________________________________________________________ -->
2841
2842<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2843Instruction</a> </div>
2844
2845<div class="doc_text">
2846
2847<h5>Syntax:</h5>
2848<pre>
2849 unreachable
2850</pre>
2851
2852<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2853<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2854 instruction is used to inform the optimizer that a particular portion of the
2855 code is not reachable. This can be used to indicate that the code after a
2856 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2857
2858<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2859<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2860
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2861</div>
2862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2863<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2864<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2866<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2867
2868<p>Binary operators are used to do most of the computation in a program. They
2869 require two operands of the same type, execute an operation on them, and
2870 produce a single value. The operands might represent multiple data, as is
2871 the case with the <a href="#t_vector">vector</a> data type. The result value
2872 has the same type as its operands.</p>
2873
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2874<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2875
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2876</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2879<div class="doc_subsubsection">
2880 <a name="i_add">'<tt>add</tt>' Instruction</a>
2881</div>
2882
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2883<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2885<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2886<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2887 &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]2888 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2889 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2890 &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]2891</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2894<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2897<p>The two arguments to the '<tt>add</tt>' instruction must
2898 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2899 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2902<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2903
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2904<p>If the sum has unsigned overflow, the result returned is the mathematical
2905 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]2906
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2907<p>Because LLVM integers use a two's complement representation, this instruction
2908 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2909
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2910<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2911 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2912 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2913 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2914
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2915<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2916<pre>
2917 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2920</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2923<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2924 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2925</div>
2926
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2930<pre>
2931 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2932</pre>
2933
2934<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2935<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2936
2937<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2938<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2939 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2940 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2941
2942<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2943<p>The value produced is the floating point sum of the two operands.</p>
2944
2945<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2946<pre>
2947 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2948</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2949
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2950</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2951
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2952<!-- _______________________________________________________________________ -->
2953<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2954 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2955</div>
2956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2957<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2958
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2959<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2960<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2961 &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]2962 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2963 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2964 &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]2965</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2966
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2967<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2968<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2969 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2970
2971<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972 '<tt>neg</tt>' instruction present in most other intermediate
2973 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2975<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2976<p>The two arguments to the '<tt>sub</tt>' instruction must
2977 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2978 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2980<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2981<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2982
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2983<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2984 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2985 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2986
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2987<p>Because LLVM integers use a two's complement representation, this instruction
2988 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2989
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2990<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2991 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2992 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2993 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2994
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2995<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2996<pre>
2997 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2998 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2999</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3000
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3001</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3002
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3003<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3004<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3005 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3006</div>
3007
3008<div class="doc_text">
3009
3010<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3011<pre>
3012 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3013</pre>
3014
3015<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3016<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3017 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3018
3019<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3020 '<tt>fneg</tt>' instruction present in most other intermediate
3021 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3022
3023<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3024<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3025 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3026 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3027
3028<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3029<p>The value produced is the floating point difference of the two operands.</p>
3030
3031<h5>Example:</h5>
3032<pre>
3033 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3034 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3035</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3036
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3037</div>
3038
3039<!-- _______________________________________________________________________ -->
3040<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3041 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3042</div>
3043
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3044<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3045
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3046<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3048 &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]3049 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3050 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3051 &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]3052</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3053
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3054<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3055<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3056
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3057<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058<p>The two arguments to the '<tt>mul</tt>' instruction must
3059 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3060 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3061
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3062<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3063<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3064
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065<p>If the result of the multiplication has unsigned overflow, the result
3066 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3067 width of the result.</p>
3068
3069<p>Because LLVM integers use a two's complement representation, and the result
3070 is the same width as the operands, this instruction returns the correct
3071 result for both signed and unsigned integers. If a full product
3072 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3073 be sign-extended or zero-extended as appropriate to the width of the full
3074 product.</p>
3075
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3076<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3077 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3078 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3079 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3080
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3081<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082<pre>
3083 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3084</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3085
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3086</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3087
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3088<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3089<div class="doc_subsubsection">
3090 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3091</div>
3092
3093<div class="doc_text">
3094
3095<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3096<pre>
3097 &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]3098</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3099
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3102
3103<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3104<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3105 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3106 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3107
3108<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3109<p>The value produced is the floating point product of the two operands.</p>
3110
3111<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112<pre>
3113 &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]3114</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3116</div>
3117
3118<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3119<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3120</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3121
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3122<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3124<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3125<pre>
3126 &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]3127</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3128
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3129<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3130<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3131
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3132<h5>Arguments:</h5>
3133<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3134 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3135 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3136
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3137<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3138<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3139
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3140<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3141 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3142
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3143<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3145<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146<pre>
3147 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3148</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3150</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3152<!-- _______________________________________________________________________ -->
3153<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3154</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3155
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3156<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3157
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3158<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3159<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3160 &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]3161 &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]3162</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3163
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3164<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3165<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3166
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3167<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3168<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3169 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3170 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3171
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3172<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173<p>The value produced is the signed integer quotient of the two operands rounded
3174 towards zero.</p>
3175
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3176<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3178
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3179<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3180 undefined behavior; this is a rare case, but can occur, for example, by doing
3181 a 32-bit division of -2147483648 by -1.</p>
3182
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3183<p>If the <tt>exact</tt> keyword is present, the result value of the
3184 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3185 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3186
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3187<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3188<pre>
3189 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3190</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3191
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3192</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3193
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3194<!-- _______________________________________________________________________ -->
3195<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3196Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3198<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3200<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3202 &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]3203</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3204
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205<h5>Overview:</h5>
3206<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3207
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3208<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3209<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3210 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3211 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3212
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3213<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3214<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3215
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3216<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3217<pre>
3218 &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]3219</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3220
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3221</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3222
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3223<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3224<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3225</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3226
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3227<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3228
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3229<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3230<pre>
3231 &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]3232</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3233
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3234<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3236 division of its two arguments.</p>
3237
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3238<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3239<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3241 values. Both arguments must have identical types.</p>
3242
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3243<h5>Semantics:</h5>
3244<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245 This instruction always performs an unsigned division to get the
3246 remainder.</p>
3247
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3248<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3249 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3250
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3251<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3253<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3254<pre>
3255 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3256</pre>
3257
3258</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3259
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3260<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261<div class="doc_subsubsection">
3262 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3263</div>
3264
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3265<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3266
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3267<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3268<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3269 &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]3270</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3271
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3272<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3273<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3274 division of its two operands. This instruction can also take
3275 <a href="#t_vector">vector</a> versions of the values in which case the
3276 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3277
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3278<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3279<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3281 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3282
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3283<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3284<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3286 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3287 a value. For more information about the difference,
3288 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3289 Math Forum</a>. For a table of how this is implemented in various languages,
3290 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3291 Wikipedia: modulo operation</a>.</p>
3292
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3293<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3295
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3296<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297 Overflow also leads to undefined behavior; this is a rare case, but can
3298 occur, for example, by taking the remainder of a 32-bit division of
3299 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3300 lets srem be implemented using instructions that return both the result of
3301 the division and the remainder.)</p>
3302
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3303<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3304<pre>
3305 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3306</pre>
3307
3308</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3309
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3310<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3311<div class="doc_subsubsection">
3312 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3313
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3314<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3315
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3316<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317<pre>
3318 &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]3319</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3321<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3323 its two operands.</p>
3324
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3325<h5>Arguments:</h5>
3326<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3327 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3328 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3329
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3330<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3331<p>This instruction returns the <i>remainder</i> of a division. The remainder
3332 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3333
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3334<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3335<pre>
3336 &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]3337</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3339</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3340
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3341<!-- ======================================================================= -->
3342<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3343Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3344
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3345<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3346
3347<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3348 program. They are generally very efficient instructions and can commonly be
3349 strength reduced from other instructions. They require two operands of the
3350 same type, execute an operation on them, and produce a single value. The
3351 resulting value is the same type as its operands.</p>
3352
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3353</div>
3354
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3355<!-- _______________________________________________________________________ -->
3356<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3357Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3359<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3360
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3361<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3362<pre>
3363 &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]3364</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3365
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3366<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3368 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3369
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3370<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3372 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3373 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3374
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3375<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3376<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3377 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3378 is (statically or dynamically) negative or equal to or larger than the number
3379 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3380 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3381 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3382
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3383<h5>Example:</h5>
3384<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3385 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3386 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3387 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3388 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3389 &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]3390</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3391
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3392</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3393
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3394<!-- _______________________________________________________________________ -->
3395<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3396Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3397
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3398<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3399
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3400<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3401<pre>
3402 &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]3403</pre>
3404
3405<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3406<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3407 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3408
3409<h5>Arguments:</h5>
3410<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3411 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3412 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3413
3414<h5>Semantics:</h5>
3415<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3416 significant bits of the result will be filled with zero bits after the shift.
3417 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3418 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3419 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3420 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3421
3422<h5>Example:</h5>
3423<pre>
3424 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3425 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3426 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3427 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3428 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3429 &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]3430</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3431
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3432</div>
3433
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3434<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3435<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3436Instruction</a> </div>
3437<div class="doc_text">
3438
3439<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440<pre>
3441 &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]3442</pre>
3443
3444<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3445<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3446 operand shifted to the right a specified number of bits with sign
3447 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3448
3449<h5>Arguments:</h5>
3450<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3451 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3452 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3453
3454<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455<p>This instruction always performs an arithmetic shift right operation, The
3456 most significant bits of the result will be filled with the sign bit
3457 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3458 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3459 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3460 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3461
3462<h5>Example:</h5>
3463<pre>
3464 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3465 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3466 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3467 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3468 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3469 &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]3470</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3471
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3472</div>
3473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3474<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3475<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3476Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3477
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3478<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3479
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3480<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3481<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3482 &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]3483</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3485<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3486<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3487 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3488
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3489<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3490<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3491 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3492 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3494<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3495<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3497<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3498 <tbody>
3499 <tr>
3500 <td>In0</td>
3501 <td>In1</td>
3502 <td>Out</td>
3503 </tr>
3504 <tr>
3505 <td>0</td>
3506 <td>0</td>
3507 <td>0</td>
3508 </tr>
3509 <tr>
3510 <td>0</td>
3511 <td>1</td>
3512 <td>0</td>
3513 </tr>
3514 <tr>
3515 <td>1</td>
3516 <td>0</td>
3517 <td>0</td>
3518 </tr>
3519 <tr>
3520 <td>1</td>
3521 <td>1</td>
3522 <td>1</td>
3523 </tr>
3524 </tbody>
3525</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3527<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3528<pre>
3529 &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]3530 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3531 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3533</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3535<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3536
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537<div class="doc_text">
3538
3539<h5>Syntax:</h5>
3540<pre>
3541 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3542</pre>
3543
3544<h5>Overview:</h5>
3545<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3546 two operands.</p>
3547
3548<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3549<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3550 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3551 values. Both arguments must have identical types.</p>
3552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3554<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3555
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3556<table border="1" cellspacing="0" cellpadding="4">
3557 <tbody>
3558 <tr>
3559 <td>In0</td>
3560 <td>In1</td>
3561 <td>Out</td>
3562 </tr>
3563 <tr>
3564 <td>0</td>
3565 <td>0</td>
3566 <td>0</td>
3567 </tr>
3568 <tr>
3569 <td>0</td>
3570 <td>1</td>
3571 <td>1</td>
3572 </tr>
3573 <tr>
3574 <td>1</td>
3575 <td>0</td>
3576 <td>1</td>
3577 </tr>
3578 <tr>
3579 <td>1</td>
3580 <td>1</td>
3581 <td>1</td>
3582 </tr>
3583 </tbody>
3584</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3587<pre>
3588 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3589 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3590 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3591</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3593</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3595<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3596<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3597Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3599<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3600
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3601<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3602<pre>
3603 &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]3604</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3606<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3608 its two operands. The <tt>xor</tt> is used to implement the "one's
3609 complement" operation, which is the "~" operator in C.</p>
3610
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3611<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3614 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3615
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3616<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3617<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3619<table border="1" cellspacing="0" cellpadding="4">
3620 <tbody>
3621 <tr>
3622 <td>In0</td>
3623 <td>In1</td>
3624 <td>Out</td>
3625 </tr>
3626 <tr>
3627 <td>0</td>
3628 <td>0</td>
3629 <td>0</td>
3630 </tr>
3631 <tr>
3632 <td>0</td>
3633 <td>1</td>
3634 <td>1</td>
3635 </tr>
3636 <tr>
3637 <td>1</td>
3638 <td>0</td>
3639 <td>1</td>
3640 </tr>
3641 <tr>
3642 <td>1</td>
3643 <td>1</td>
3644 <td>0</td>
3645 </tr>
3646 </tbody>
3647</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3649<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3650<pre>
3651 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3652 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3653 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3654 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3655</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3657</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3659<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3660<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3661 <a name="vectorops">Vector Operations</a>
3662</div>
3663
3664<div class="doc_text">
3665
3666<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3667 target-independent manner. These instructions cover the element-access and
3668 vector-specific operations needed to process vectors effectively. While LLVM
3669 does directly support these vector operations, many sophisticated algorithms
3670 will want to use target-specific intrinsics to take full advantage of a
3671 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3672
3673</div>
3674
3675<!-- _______________________________________________________________________ -->
3676<div class="doc_subsubsection">
3677 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3678</div>
3679
3680<div class="doc_text">
3681
3682<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3683<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3684 &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]3685</pre>
3686
3687<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3688<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3689 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3690
3691
3692<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3694 of <a href="#t_vector">vector</a> type. The second operand is an index
3695 indicating the position from which to extract the element. The index may be
3696 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3697
3698<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3699<p>The result is a scalar of the same type as the element type of
3700 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3701 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3702 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3703
3704<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3705<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3706 &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]3707</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3708
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3709</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3710
3711<!-- _______________________________________________________________________ -->
3712<div class="doc_subsubsection">
3713 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3714</div>
3715
3716<div class="doc_text">
3717
3718<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3719<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3720 &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]3721</pre>
3722
3723<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3725 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3726
3727<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3729 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3730 whose type must equal the element type of the first operand. The third
3731 operand is an index indicating the position at which to insert the value.
3732 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3733
3734<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3735<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3736 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3737 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3738 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3739
3740<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3741<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3742 &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]3743</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3745</div>
3746
3747<!-- _______________________________________________________________________ -->
3748<div class="doc_subsubsection">
3749 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3750</div>
3751
3752<div class="doc_text">
3753
3754<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3755<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3756 &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]3757</pre>
3758
3759<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3760<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3761 from two input vectors, returning a vector with the same element type as the
3762 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3763
3764<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3765<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3766 with types that match each other. The third argument is a shuffle mask whose
3767 element type is always 'i32'. The result of the instruction is a vector
3768 whose length is the same as the shuffle mask and whose element type is the
3769 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3770
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771<p>The shuffle mask operand is required to be a constant vector with either
3772 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3773
3774<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3775<p>The elements of the two input vectors are numbered from left to right across
3776 both of the vectors. The shuffle mask operand specifies, for each element of
3777 the result vector, which element of the two input vectors the result element
3778 gets. The element selector may be undef (meaning "don't care") and the
3779 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3780
3781<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3782<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3783 &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]3784 &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]3785 &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]3786 &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]3787 &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]3788 &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]3789 &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]3790 &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]3791</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3792
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3793</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3794
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3795<!-- ======================================================================= -->
3796<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3797 <a name="aggregateops">Aggregate Operations</a>
3798</div>
3799
3800<div class="doc_text">
3801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3802<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3803
3804</div>
3805
3806<!-- _______________________________________________________________________ -->
3807<div class="doc_subsubsection">
3808 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3809</div>
3810
3811<div class="doc_text">
3812
3813<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3814<pre>
3815 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3816</pre>
3817
3818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3819<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3820 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3821
3822<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3823<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3824 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3825 operands are constant indices to specify which value to extract in a similar
3826 manner as indices in a
3827 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3828
3829<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3830<p>The result is the value at the position in the aggregate specified by the
3831 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3832
3833<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3834<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3835 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3836</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3839
3840<!-- _______________________________________________________________________ -->
3841<div class="doc_subsubsection">
3842 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3843</div>
3844
3845<div class="doc_text">
3846
3847<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3848<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3849 &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]3850</pre>
3851
3852<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3854 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3855
3856
3857<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3859 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3860 second operand is a first-class value to insert. The following operands are
3861 constant indices indicating the position at which to insert the value in a
3862 similar manner as indices in a
3863 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3864 value to insert must have the same type as the value identified by the
3865 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3866
3867<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3869 that of <tt>val</tt> except that the value at the position specified by the
3870 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3871
3872<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3873<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]3874 &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]3875</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3876
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3877</div>
3878
3879
3880<!-- ======================================================================= -->
3881<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3882 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3883</div>
3884
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3885<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3886
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3887<p>A key design point of an SSA-based representation is how it represents
3888 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]3889 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3890 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3891
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3892</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3894<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3895<div class="doc_subsubsection">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3896 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3897</div>
3898
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3899<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3902<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3903 &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]3904</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3907<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908 currently executing function, to be automatically released when this function
3909 returns to its caller. The object is always allocated in the generic address
3910 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3912<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913<p>The '<tt>alloca</tt>' instruction
3914 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3915 runtime stack, returning a pointer of the appropriate type to the program.
3916 If "NumElements" is specified, it is the number of elements allocated,
3917 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3918 specified, the value result of the allocation is guaranteed to be aligned to
3919 at least that boundary. If not specified, or if zero, the target can choose
3920 to align the allocation on any convenient boundary compatible with the
3921 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3923<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3925<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3926<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3927 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3928 memory is automatically released when the function returns. The
3929 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3930 variables that must have an address available. When the function returns
3931 (either with the <tt><a href="#i_ret">ret</a></tt>
3932 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3933 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3936<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3937 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3938 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3941</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3943</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3945<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3946<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3947Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3949<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3951<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952<pre>
3953 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3954 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955</pre>
3956
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3957<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3958<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3960<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3962 from which to load. The pointer must point to
3963 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3964 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3965 number or order of execution of this <tt>load</tt> with other
3966 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3967 instructions. </p>
3968
3969<p>The optional constant "align" argument specifies the alignment of the
3970 operation (that is, the alignment of the memory address). A value of 0 or an
3971 omitted "align" argument means that the operation has the preferential
3972 alignment for the target. It is the responsibility of the code emitter to
3973 ensure that the alignment information is correct. Overestimating the
3974 alignment results in an undefined behavior. Underestimating the alignment may
3975 produce less efficient code. An alignment of 1 is always safe.</p>
3976
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3978<p>The location of memory pointed to is loaded. If the value being loaded is of
3979 scalar type then the number of bytes read does not exceed the minimum number
3980 of bytes needed to hold all bits of the type. For example, loading an
3981 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3982 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3983 is undefined if the value was not originally written using a store of the
3984 same type.</p>
3985
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3986<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987<pre>
3988 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3989 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3990 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3991</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3992
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3993</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3994
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3995<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3996<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3997Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]3999<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4001<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 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]4004 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]4005</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4007<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4008<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4010<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4012 and an address at which to store it. The type of the
4013 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4014 the <a href="#t_firstclass">first class</a> type of the
4015 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4016 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4017 or order of execution of this <tt>store</tt> with other
4018 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4019 instructions.</p>
4020
4021<p>The optional constant "align" argument specifies the alignment of the
4022 operation (that is, the alignment of the memory address). A value of 0 or an
4023 omitted "align" argument means that the operation has the preferential
4024 alignment for the target. It is the responsibility of the code emitter to
4025 ensure that the alignment information is correct. Overestimating the
4026 alignment results in an undefined behavior. Underestimating the alignment may
4027 produce less efficient code. An alignment of 1 is always safe.</p>
4028
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4031 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4032 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4033 does not exceed the minimum number of bytes needed to hold all bits of the
4034 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4035 writing a value of a type like <tt>i20</tt> with a size that is not an
4036 integral number of bytes, it is unspecified what happens to the extra bits
4037 that do not belong to the type, but they will typically be overwritten.</p>
4038
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4039<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040<pre>
4041 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4042 store i32 3, i32* %ptr <i>; yields {void}</i>
4043 %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]4044</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4046</div>
4047
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4048<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4049<div class="doc_subsubsection">
4050 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4051</div>
4052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4053<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4054
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4055<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4056<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4057 &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]4058 &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]4059</pre>
4060
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4063 subelement of an aggregate data structure. It performs address calculation
4064 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4065
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4066<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4067<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4068 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069 elements of the aggregate object are indexed. The interpretation of each
4070 index is dependent on the type being indexed into. The first index always
4071 indexes the pointer value given as the first argument, the second index
4072 indexes a value of the type pointed to (not necessarily the value directly
4073 pointed to, since the first index can be non-zero), etc. The first type
4074 indexed into must be a pointer value, subsequent types can be arrays, vectors
4075 and structs. Note that subsequent types being indexed into can never be
4076 pointers, since that would require loading the pointer before continuing
4077 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4078
4079<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]4080 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4082 vector, integers of any width are allowed, and they are not required to be
4083 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085<p>For example, let's consider a C code fragment and how it gets compiled to
4086 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4087
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4088<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4089<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4090struct RT {
4091 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4092 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4093 char C;
4094};
4095struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4096 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4097 double Y;
4098 struct RT Z;
4099};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4100
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4101int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4102 return &amp;s[1].Z.B[5][13];
4103}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4104</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4105</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4106
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4107<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4108
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4109<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4110<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4111%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4112%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4113
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4114define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4115entry:
4116 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4117 ret i32* %reg
4118}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4119</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4120</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4121
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4122<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4123<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]4124 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4125 }</tt>' type, a structure. The second index indexes into the third element
4126 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4127 i8 }</tt>' type, another structure. The third index indexes into the second
4128 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4129 array. The two dimensions of the array are subscripted into, yielding an
4130 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4131 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133<p>Note that it is perfectly legal to index partially through a structure,
4134 returning a pointer to an inner element. Because of this, the LLVM code for
4135 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4136
4137<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4138 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4139 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4140 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4141 %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]4142 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4143 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4144 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4145 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4146</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4147
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4148<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4149 <tt>getelementptr</tt> is undefined if the base pointer is not an
4150 <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]4151 that would be formed by successive addition of the offsets implied by the
4152 indices to the base address with infinitely precise arithmetic are not an
4153 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4154 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4155 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4156
4157<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4158 the base address with silently-wrapping two's complement arithmetic, and
4159 the result value of the <tt>getelementptr</tt> may be outside the object
4160 pointed to by the base pointer. The result value may not necessarily be
4161 used to access memory though, even if it happens to point into allocated
4162 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4163 section for more information.</p>
4164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The getelementptr instruction is often confusing. For some more insight into
4166 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4167
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4168<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4169<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4170 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4171 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4172 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4173 %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]4174 <i>; yields i8*:eptr</i>
4175 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4176 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4177 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4178</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4180</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4181
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4182<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4183<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4184</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4186<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4187
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4188<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189 which all take a single operand and a type. They perform various bit
4190 conversions on the operand.</p>
4191
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4192</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4193
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4194<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4195<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4196 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4197</div>
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
4201<pre>
4202 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4203</pre>
4204
4205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4207 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4208
4209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4211 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4212 size and type of the result, which must be
4213 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4214 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4215 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4216
4217<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4219 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4220 source size must be larger than the destination size, <tt>trunc</tt> cannot
4221 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4222
4223<h5>Example:</h5>
4224<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4225 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4226 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4227 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4228</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4229
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4230</div>
4231
4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
4234 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4235</div>
4236<div class="doc_text">
4237
4238<h5>Syntax:</h5>
4239<pre>
4240 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4241</pre>
4242
4243<h5>Overview:</h5>
4244<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4246
4247
4248<h5>Arguments:</h5>
4249<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]4250 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4251 also be of <a href="#t_integer">integer</a> type. The bit size of the
4252 <tt>value</tt> must be smaller than the bit size of the destination type,
4253 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4254
4255<h5>Semantics:</h5>
4256<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]4257 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4258
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4259<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]4260
4261<h5>Example:</h5>
4262<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4263 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4264 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4265</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4267</div>
4268
4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
4271 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4272</div>
4273<div class="doc_text">
4274
4275<h5>Syntax:</h5>
4276<pre>
4277 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4278</pre>
4279
4280<h5>Overview:</h5>
4281<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4282
4283<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4285 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4286 also be of <a href="#t_integer">integer</a> type. The bit size of the
4287 <tt>value</tt> must be smaller than the bit size of the destination type,
4288 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4289
4290<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4292 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4293 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4294
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4295<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]4296
4297<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4298<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4299 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4300 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4301</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4303</div>
4304
4305<!-- _______________________________________________________________________ -->
4306<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4307 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4308</div>
4309
4310<div class="doc_text">
4311
4312<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4313<pre>
4314 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4315</pre>
4316
4317<h5>Overview:</h5>
4318<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4320
4321<h5>Arguments:</h5>
4322<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4324 to cast it to. The size of <tt>value</tt> must be larger than the size of
4325 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4326 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4327
4328<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4330 <a href="#t_floating">floating point</a> type to a smaller
4331 <a href="#t_floating">floating point</a> type. If the value cannot fit
4332 within the destination type, <tt>ty2</tt>, then the results are
4333 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4334
4335<h5>Example:</h5>
4336<pre>
4337 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4338 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4339</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4341</div>
4342
4343<!-- _______________________________________________________________________ -->
4344<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4345 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4346</div>
4347<div class="doc_text">
4348
4349<h5>Syntax:</h5>
4350<pre>
4351 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4352</pre>
4353
4354<h5>Overview:</h5>
4355<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]4356 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4357
4358<h5>Arguments:</h5>
4359<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4361 a <a href="#t_floating">floating point</a> type to cast it to. The source
4362 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4363
4364<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4365<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366 <a href="#t_floating">floating point</a> type to a larger
4367 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4368 used to make a <i>no-op cast</i> because it always changes bits. Use
4369 <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]4370
4371<h5>Example:</h5>
4372<pre>
4373 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4374 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4375</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4376
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4377</div>
4378
4379<!-- _______________________________________________________________________ -->
4380<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4381 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4382</div>
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4387 &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]4388</pre>
4389
4390<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4391<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4392 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4393
4394<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4395<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4396 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4397 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4398 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4399 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4400
4401<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>The '<tt>fptoui</tt>' instruction converts its
4403 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4404 towards zero) unsigned integer value. If the value cannot fit
4405 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4406
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4407<h5>Example:</h5>
4408<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4409 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4410 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4411 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4413
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4414</div>
4415
4416<!-- _______________________________________________________________________ -->
4417<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4418 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4419</div>
4420<div class="doc_text">
4421
4422<h5>Syntax:</h5>
4423<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4424 &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]4425</pre>
4426
4427<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4428<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429 <a href="#t_floating">floating point</a> <tt>value</tt> to
4430 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4431
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4432<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4434 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4435 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4436 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4437 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4438
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4439<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4440<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4442 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4443 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4444
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4445<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4446<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4447 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4448 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]4449 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4450</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4456 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4457</div>
4458<div class="doc_text">
4459
4460<h5>Syntax:</h5>
4461<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4462 &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]4463</pre>
4464
4465<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4466<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4467 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4468
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4469<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4470<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]4471 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4472 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4473 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4474 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4475
4476<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4477<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4478 integer quantity and converts it to the corresponding floating point
4479 value. If the value cannot fit in the floating point value, the results are
4480 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4481
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4482<h5>Example:</h5>
4483<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4484 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4485 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4486</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4487
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4488</div>
4489
4490<!-- _______________________________________________________________________ -->
4491<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4492 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4493</div>
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
4497<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4498 &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]4499</pre>
4500
4501<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4502<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4503 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4504
4505<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4506<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]4507 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4508 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4509 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4510 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4511
4512<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4513<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4514 quantity and converts it to the corresponding floating point value. If the
4515 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4516
4517<h5>Example:</h5>
4518<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4519 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4520 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4521</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4522
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4523</div>
4524
4525<!-- _______________________________________________________________________ -->
4526<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4527 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4528</div>
4529<div class="doc_text">
4530
4531<h5>Syntax:</h5>
4532<pre>
4533 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4534</pre>
4535
4536<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4538 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4539
4540<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4541<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4542 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4543 <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]4544
4545<h5>Semantics:</h5>
4546<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4548 truncating or zero extending that value to the size of the integer type. If
4549 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4550 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4551 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4552 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4553
4554<h5>Example:</h5>
4555<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4556 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4557 %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]4558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4560</div>
4561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
4564 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4565</div>
4566<div class="doc_text">
4567
4568<h5>Syntax:</h5>
4569<pre>
4570 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4571</pre>
4572
4573<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4575 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4576
4577<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4578<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579 value to cast, and a type to cast it to, which must be a
4580 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4581
4582<h5>Semantics:</h5>
4583<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4585 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4586 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4587 than the size of a pointer then a zero extension is done. If they are the
4588 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4589
4590<h5>Example:</h5>
4591<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4592 %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]4593 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4594 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4595</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4597</div>
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4601 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4602</div>
4603<div class="doc_text">
4604
4605<h5>Syntax:</h5>
4606<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4607 &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]4608</pre>
4609
4610<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4611<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4613
4614<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4616 non-aggregate first class value, and a type to cast it to, which must also be
4617 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4618 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4619 identical. If the source type is a pointer, the destination type must also be
4620 a pointer. This instruction supports bitwise conversion of vectors to
4621 integers and to vectors of other types (as long as they have the same
4622 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4625<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4627 this conversion. The conversion is done as if the <tt>value</tt> had been
4628 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4629 be converted to other pointer types with this instruction. To convert
4630 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4631 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4632
4633<h5>Example:</h5>
4634<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4635 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4636 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4637 %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]4638</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4640</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4641
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4642<!-- ======================================================================= -->
4643<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4645<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4646
4647<p>The instructions in this category are the "miscellaneous" instructions, which
4648 defy better classification.</p>
4649
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4650</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4651
4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4654</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4655
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4656<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4657
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4658<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659<pre>
4660 &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]4661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4663<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4665 boolean values based on comparison of its two integer, integer vector, or
4666 pointer operands.</p>
4667
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4668<h5>Arguments:</h5>
4669<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4670 the condition code indicating the kind of comparison to perform. It is not a
4671 value, just a keyword. The possible condition code are:</p>
4672
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4673<ol>
4674 <li><tt>eq</tt>: equal</li>
4675 <li><tt>ne</tt>: not equal </li>
4676 <li><tt>ugt</tt>: unsigned greater than</li>
4677 <li><tt>uge</tt>: unsigned greater or equal</li>
4678 <li><tt>ult</tt>: unsigned less than</li>
4679 <li><tt>ule</tt>: unsigned less or equal</li>
4680 <li><tt>sgt</tt>: signed greater than</li>
4681 <li><tt>sge</tt>: signed greater or equal</li>
4682 <li><tt>slt</tt>: signed less than</li>
4683 <li><tt>sle</tt>: signed less or equal</li>
4684</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4685
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4686<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4688 typed. They must also be identical types.</p>
4689
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4692 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4693 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]4694 result, as follows:</p>
4695
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4696<ol>
4697 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4698 <tt>false</tt> otherwise. No sign interpretation is necessary or
4699 performed.</li>
4700
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4701 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4702 <tt>false</tt> otherwise. No sign interpretation is necessary or
4703 performed.</li>
4704
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4705 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4707
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4708 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4710 to <tt>op2</tt>.</li>
4711
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4712 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4714
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4715 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4718 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4721 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4722 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4723 to <tt>op2</tt>.</li>
4724
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4725 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4726 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4728 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729 <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]4730</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4732<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733 values are compared as if they were integers.</p>
4734
4735<p>If the operands are integer vectors, then they are compared element by
4736 element. The result is an <tt>i1</tt> vector with the same number of elements
4737 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4738
4739<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740<pre>
4741 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4742 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4743 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4744 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4745 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4747</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4748
4749<p>Note that the code generator does not yet support vector types with
4750 the <tt>icmp</tt> instruction.</p>
4751
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
4755<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4756</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4757
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4758<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4759
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4760<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4761<pre>
4762 &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]4763</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4766<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4767 values based on comparison of its operands.</p>
4768
4769<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]4770(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4771
4772<p>If the operands are floating point vectors, then the result type is a vector
4773 of boolean with the same number of elements as the operands being
4774 compared.</p>
4775
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4776<h5>Arguments:</h5>
4777<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 the condition code indicating the kind of comparison to perform. It is not a
4779 value, just a keyword. The possible condition code are:</p>
4780
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4781<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4782 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4783 <li><tt>oeq</tt>: ordered and equal</li>
4784 <li><tt>ogt</tt>: ordered and greater than </li>
4785 <li><tt>oge</tt>: ordered and greater than or equal</li>
4786 <li><tt>olt</tt>: ordered and less than </li>
4787 <li><tt>ole</tt>: ordered and less than or equal</li>
4788 <li><tt>one</tt>: ordered and not equal</li>
4789 <li><tt>ord</tt>: ordered (no nans)</li>
4790 <li><tt>ueq</tt>: unordered or equal</li>
4791 <li><tt>ugt</tt>: unordered or greater than </li>
4792 <li><tt>uge</tt>: unordered or greater than or equal</li>
4793 <li><tt>ult</tt>: unordered or less than </li>
4794 <li><tt>ule</tt>: unordered or less than or equal</li>
4795 <li><tt>une</tt>: unordered or not equal</li>
4796 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4797 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4798</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4800<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4801 <i>unordered</i> means that either operand may be a QNAN.</p>
4802
4803<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4804 a <a href="#t_floating">floating point</a> type or
4805 a <a href="#t_vector">vector</a> of floating point type. They must have
4806 identical types.</p>
4807
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4808<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4809<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4810 according to the condition code given as <tt>cond</tt>. If the operands are
4811 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]4812 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813 follows:</p>
4814
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4815<ol>
4816 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4817
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4818 <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]4819 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4820
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4821 <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]4822 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4823
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4824 <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]4825 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4826
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4827 <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]4828 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4829
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4830 <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]4831 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4832
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4835
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4836 <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]4837
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4838 <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]4839 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4840
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4841 <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]4842 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4843
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4844 <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]4845 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4846
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4849
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4852
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4855
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4856 <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]4857
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4858 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4859</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4860
4861<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862<pre>
4863 &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]4864 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4865 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4866 &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]4867</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4868
4869<p>Note that the code generator does not yet support vector types with
4870 the <tt>fcmp</tt> instruction.</p>
4871
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4872</div>
4873
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4874<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4875<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4876 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4877</div>
4878
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4879<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4880
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4881<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882<pre>
4883 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4884</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4885
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4886<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4888 SSA graph representing the function.</p>
4889
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4890<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4891<p>The type of the incoming values is specified with the first type field. After
4892 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4893 one pair for each predecessor basic block of the current block. Only values
4894 of <a href="#t_firstclass">first class</a> type may be used as the value
4895 arguments to the PHI node. Only labels may be used as the label
4896 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898<p>There must be no non-phi instructions between the start of a basic block and
4899 the PHI instructions: i.e. PHI instructions must be first in a basic
4900 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4901
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4902<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4903 occur on the edge from the corresponding predecessor block to the current
4904 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4905 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4906
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4907<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4908<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4909 specified by the pair corresponding to the predecessor basic block that
4910 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4911
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4912<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4913<pre>
4914Loop: ; Infinite loop that counts from 0 on up...
4915 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4916 %nextindvar = add i32 %indvar, 1
4917 br label %Loop
4918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4919
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4920</div>
4921
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4922<!-- _______________________________________________________________________ -->
4923<div class="doc_subsubsection">
4924 <a name="i_select">'<tt>select</tt>' Instruction</a>
4925</div>
4926
4927<div class="doc_text">
4928
4929<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4930<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4931 &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>
4932
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4933 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4934</pre>
4935
4936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4938 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4939
4940
4941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4943 values indicating the condition, and two values of the
4944 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4945 vectors and the condition is a scalar, then entire vectors are selected, not
4946 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4947
4948<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4949<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4950 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4952<p>If the condition is a vector of i1, then the value arguments must be vectors
4953 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4954
4955<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4956<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4957 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4958</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4959
4960<p>Note that the code generator does not yet support conditions
4961 with vector type.</p>
4962
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4963</div>
4964
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4965<!-- _______________________________________________________________________ -->
4966<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4967 <a name="i_call">'<tt>call</tt>' Instruction</a>
4968</div>
4969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4970<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4972<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4973<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4974 &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]4975</pre>
4976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4977<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4978<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4981<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4982
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4983<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984 <li>The optional "tail" marker indicates whether the callee function accesses
4985 any allocas or varargs in the caller. If the "tail" marker is present,
4986 the function call is eligible for tail call optimization. Note that calls
4987 may be marked "tail" even if they do not occur before
4988 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4989
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4990 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4991 convention</a> the call should use. If none is specified, the call
4992 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4993
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4994 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4995 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4996 '<tt>inreg</tt>' attributes are valid here.</li>
4997
4998 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4999 type of the return value. Functions that return no value are marked
5000 <tt><a href="#t_void">void</a></tt>.</li>
5001
5002 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5003 being invoked. The argument types must match the types implied by this
5004 signature. This type can be omitted if the function is not varargs and if
5005 the function type does not return a pointer to a function.</li>
5006
5007 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5008 be invoked. In most cases, this is a direct function invocation, but
5009 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5010 to function value.</li>
5011
5012 <li>'<tt>function args</tt>': argument list whose types match the function
5013 signature argument types. All arguments must be of
5014 <a href="#t_firstclass">first class</a> type. If the function signature
5015 indicates the function accepts a variable number of arguments, the extra
5016 arguments can be specified.</li>
5017
5018 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5019 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5020 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5021</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5022
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5023<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5024<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5025 a specified function, with its incoming arguments bound to the specified
5026 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5027 function, control flow continues with the instruction after the function
5028 call, and the return value of the function is bound to the result
5029 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5030
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5031<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5032<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5033 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5034 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5035 %X = tail call i32 @foo() <i>; yields i32</i>
5036 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5037 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5038
5039 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5040 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5041 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5042 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5043 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5044 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5045</pre>
5046
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5047<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5048standard C99 library as being the C99 library functions, and may perform
5049optimizations or generate code for them under that assumption. This is
5050something we'd like to change in the future to provide better support for
5051freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5053</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5054
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5055<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5056<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5057 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5058</div>
5059
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5060<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5061
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5062<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5063<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5064 &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]5065</pre>
5066
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5067<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5068<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5069 the "variable argument" area of a function call. It is used to implement the
5070 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5071
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5072<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5074 argument. It returns a value of the specified argument type and increments
5075 the <tt>va_list</tt> to point to the next argument. The actual type
5076 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5077
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5078<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5079<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5080 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5081 to the next argument. For more information, see the variable argument
5082 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5083
5084<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]5085 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5086 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088<p><tt>va_arg</tt> is an LLVM instruction instead of
5089 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5090 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5091
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5092<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5093<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5094
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5095<p>Note that the code generator does not yet fully support va_arg on many
5096 targets. Also, it does not currently support va_arg with aggregate types on
5097 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5098
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5099</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5100
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5101<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5102<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5103<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5104
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5105<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5106
5107<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5108 well known names and semantics and are required to follow certain
5109 restrictions. Overall, these intrinsics represent an extension mechanism for
5110 the LLVM language that does not require changing all of the transformations
5111 in LLVM when adding to the language (or the bitcode reader/writer, the
5112 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5113
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5114<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5115 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5116 begin with this prefix. Intrinsic functions must always be external
5117 functions: you cannot define the body of intrinsic functions. Intrinsic
5118 functions may only be used in call or invoke instructions: it is illegal to
5119 take the address of an intrinsic function. Additionally, because intrinsic
5120 functions are part of the LLVM language, it is required if any are added that
5121 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5123<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5124 family of functions that perform the same operation but on different data
5125 types. Because LLVM can represent over 8 million different integer types,
5126 overloading is used commonly to allow an intrinsic function to operate on any
5127 integer type. One or more of the argument types or the result type can be
5128 overloaded to accept any integer type. Argument types may also be defined as
5129 exactly matching a previous argument's type or the result type. This allows
5130 an intrinsic function which accepts multiple arguments, but needs all of them
5131 to be of the same type, to only be overloaded with respect to a single
5132 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5134<p>Overloaded intrinsics will have the names of its overloaded argument types
5135 encoded into its function name, each preceded by a period. Only those types
5136 which are overloaded result in a name suffix. Arguments whose type is matched
5137 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5138 can take an integer of any width and returns an integer of exactly the same
5139 integer width. This leads to a family of functions such as
5140 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5141 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5142 suffix is required. Because the argument's type is matched against the return
5143 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5144
5145<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5146 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5147
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5148</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5149
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5150<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5151<div class="doc_subsection">
5152 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5153</div>
5154
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5155<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5156
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5157<p>Variable argument support is defined in LLVM with
5158 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5159 intrinsic functions. These functions are related to the similarly named
5160 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5161
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5162<p>All of these functions operate on arguments that use a target-specific value
5163 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5164 not define what this type is, so all transformations should be prepared to
5165 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5166
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5167<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]5168 instruction and the variable argument handling intrinsic functions are
5169 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5170
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5171<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5172<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5173define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5174 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5175 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5176 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5177 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5178
5179 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5180 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5181
5182 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5183 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5184 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5185 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5186 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5187
5188 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5189 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5190 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5191}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5192
5193declare void @llvm.va_start(i8*)
5194declare void @llvm.va_copy(i8*, i8*)
5195declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5196</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5197</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5198
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5199</div>
5200
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5201<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5202<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5203 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5204</div>
5205
5206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5207<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5208
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5209<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5210<pre>
5211 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5212</pre>
5213
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5214<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5215<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5216 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]5217
5218<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5219<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]5220
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5221<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5222<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]5223 macro available in C. In a target-dependent way, it initializes
5224 the <tt>va_list</tt> element to which the argument points, so that the next
5225 call to <tt>va_arg</tt> will produce the first variable argument passed to
5226 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5227 need to know the last argument of the function as the compiler can figure
5228 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5229
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5230</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5231
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5232<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5233<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5234 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5235</div>
5236
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5237<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5238
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5239<h5>Syntax:</h5>
5240<pre>
5241 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5242</pre>
5243
5244<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5245<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5246 which has been initialized previously
5247 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5248 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5249
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5250<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5251<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]5252
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5253<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5254<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]5255 macro available in C. In a target-dependent way, it destroys
5256 the <tt>va_list</tt> element to which the argument points. Calls
5257 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5258 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5259 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5260
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5261</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5262
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5263<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5264<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5265 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5266</div>
5267
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5268<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5269
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5270<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5271<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5272 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5273</pre>
5274
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5275<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5276<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5278
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5279<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5280<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]5281 The second argument is a pointer to a <tt>va_list</tt> element to copy
5282 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5283
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5284<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5285<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]5286 macro available in C. In a target-dependent way, it copies the
5287 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5288 element. This intrinsic is necessary because
5289 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5290 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5291
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5292</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5293
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5294<!-- ======================================================================= -->
5295<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5296 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5297</div>
5298
5299<div class="doc_text">
5300
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5301<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5302Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5303intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5304roots on the stack</a>, as well as garbage collector implementations that
5305require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5306barriers. Front-ends for type-safe garbage collected languages should generate
5307these intrinsics to make use of the LLVM garbage collectors. For more details,
5308see <a href="GarbageCollection.html">Accurate Garbage Collection with
5309LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5310
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5311<p>The garbage collection intrinsics only operate on objects in the generic
5312 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5313
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5314</div>
5315
5316<!-- _______________________________________________________________________ -->
5317<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5318 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5319</div>
5320
5321<div class="doc_text">
5322
5323<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5324<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5325 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5326</pre>
5327
5328<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5329<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]5330 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5331
5332<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5333<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5334 root pointer. The second pointer (which must be either a constant or a
5335 global value address) contains the meta-data to be associated with the
5336 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5337
5338<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5339<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]5340 location. At compile-time, the code generator generates information to allow
5341 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5342 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5343 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5344
5345</div>
5346
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5347<!-- _______________________________________________________________________ -->
5348<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5349 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5350</div>
5351
5352<div class="doc_text">
5353
5354<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5355<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5356 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5357</pre>
5358
5359<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5360<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5361 locations, allowing garbage collector implementations that require read
5362 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5363
5364<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5365<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]5366 allocated from the garbage collector. The first object is a pointer to the
5367 start of the referenced object, if needed by the language runtime (otherwise
5368 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5369
5370<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5371<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5372 instruction, but may be replaced with substantially more complex code by the
5373 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5374 may only be used in a function which <a href="#gc">specifies a GC
5375 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5376
5377</div>
5378
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5379<!-- _______________________________________________________________________ -->
5380<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5381 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5382</div>
5383
5384<div class="doc_text">
5385
5386<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5387<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5388 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5389</pre>
5390
5391<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5392<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5393 locations, allowing garbage collector implementations that require write
5394 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5395
5396<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5397<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]5398 object to store it to, and the third is the address of the field of Obj to
5399 store to. If the runtime does not require a pointer to the object, Obj may
5400 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5401
5402<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5403<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5404 instruction, but may be replaced with substantially more complex code by the
5405 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5406 may only be used in a function which <a href="#gc">specifies a GC
5407 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5408
5409</div>
5410
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5411<!-- ======================================================================= -->
5412<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5413 <a name="int_codegen">Code Generator Intrinsics</a>
5414</div>
5415
5416<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5417
5418<p>These intrinsics are provided by LLVM to expose special features that may
5419 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5420
5421</div>
5422
5423<!-- _______________________________________________________________________ -->
5424<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5425 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5426</div>
5427
5428<div class="doc_text">
5429
5430<h5>Syntax:</h5>
5431<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5432 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5433</pre>
5434
5435<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5436<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5437 target-specific value indicating the return address of the current function
5438 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5439
5440<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The argument to this intrinsic indicates which function to return the address
5442 for. Zero indicates the calling function, one indicates its caller, etc.
5443 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5444
5445<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5447 indicating the return address of the specified call frame, or zero if it
5448 cannot be identified. The value returned by this intrinsic is likely to be
5449 incorrect or 0 for arguments other than zero, so it should only be used for
5450 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5451
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5452<p>Note that calling this intrinsic does not prevent function inlining or other
5453 aggressive transformations, so the value returned may not be that of the
5454 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5455
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5456</div>
5457
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5458<!-- _______________________________________________________________________ -->
5459<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5460 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5461</div>
5462
5463<div class="doc_text">
5464
5465<h5>Syntax:</h5>
5466<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5467 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5468</pre>
5469
5470<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5471<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5472 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5473
5474<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5475<p>The argument to this intrinsic indicates which function to return the frame
5476 pointer for. Zero indicates the calling function, one indicates its caller,
5477 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5478
5479<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5481 indicating the frame address of the specified call frame, or zero if it
5482 cannot be identified. The value returned by this intrinsic is likely to be
5483 incorrect or 0 for arguments other than zero, so it should only be used for
5484 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5485
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5486<p>Note that calling this intrinsic does not prevent function inlining or other
5487 aggressive transformations, so the value returned may not be that of the
5488 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5489
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5490</div>
5491
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5492<!-- _______________________________________________________________________ -->
5493<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5494 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5495</div>
5496
5497<div class="doc_text">
5498
5499<h5>Syntax:</h5>
5500<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5501 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5502</pre>
5503
5504<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5505<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5506 of the function stack, for use
5507 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5508 useful for implementing language features like scoped automatic variable
5509 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5510
5511<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5512<p>This intrinsic returns a opaque pointer value that can be passed
5513 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5514 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5515 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5516 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5517 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5518 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5519
5520</div>
5521
5522<!-- _______________________________________________________________________ -->
5523<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5524 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5525</div>
5526
5527<div class="doc_text">
5528
5529<h5>Syntax:</h5>
5530<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5531 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5532</pre>
5533
5534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5535<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5536 the function stack to the state it was in when the
5537 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5538 executed. This is useful for implementing language features like scoped
5539 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5540
5541<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5542<p>See the description
5543 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5544
5545</div>
5546
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5547<!-- _______________________________________________________________________ -->
5548<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5549 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5550</div>
5551
5552<div class="doc_text">
5553
5554<h5>Syntax:</h5>
5555<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5556 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]5557</pre>
5558
5559<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5560<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5561 insert a prefetch instruction if supported; otherwise, it is a noop.
5562 Prefetches have no effect on the behavior of the program but can change its
5563 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5564
5565<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5566<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5567 specifier determining if the fetch should be for a read (0) or write (1),
5568 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5569 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5570 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5571
5572<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5573<p>This intrinsic does not modify the behavior of the program. In particular,
5574 prefetches cannot trap and do not produce a value. On targets that support
5575 this intrinsic, the prefetch can provide hints to the processor cache for
5576 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5577
5578</div>
5579
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5580<!-- _______________________________________________________________________ -->
5581<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5582 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5583</div>
5584
5585<div class="doc_text">
5586
5587<h5>Syntax:</h5>
5588<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5589 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5590</pre>
5591
5592<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5593<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5594 Counter (PC) in a region of code to simulators and other tools. The method
5595 is target specific, but it is expected that the marker will use exported
5596 symbols to transmit the PC of the marker. The marker makes no guarantees
5597 that it will remain with any specific instruction after optimizations. It is
5598 possible that the presence of a marker will inhibit optimizations. The
5599 intended use is to be inserted after optimizations to allow correlations of
5600 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5601
5602<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5603<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5604
5605<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5606<p>This intrinsic does not modify the behavior of the program. Backends that do
5607 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5608
5609</div>
5610
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5611<!-- _______________________________________________________________________ -->
5612<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5613 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5614</div>
5615
5616<div class="doc_text">
5617
5618<h5>Syntax:</h5>
5619<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5620 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5621</pre>
5622
5623<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5624<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5625 counter register (or similar low latency, high accuracy clocks) on those
5626 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5627 should map to RPCC. As the backing counters overflow quickly (on the order
5628 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5629
5630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5631<p>When directly supported, reading the cycle counter should not modify any
5632 memory. Implementations are allowed to either return a application specific
5633 value or a system wide value. On backends without support, this is lowered
5634 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5635
5636</div>
5637
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5638<!-- ======================================================================= -->
5639<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5640 <a name="int_libc">Standard C Library Intrinsics</a>
5641</div>
5642
5643<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5644
5645<p>LLVM provides intrinsics for a few important standard C library functions.
5646 These intrinsics allow source-language front-ends to pass information about
5647 the alignment of the pointer arguments to the code generator, providing
5648 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5649
5650</div>
5651
5652<!-- _______________________________________________________________________ -->
5653<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5654 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5655</div>
5656
5657<div class="doc_text">
5658
5659<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5660<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5661 integer bit width. Not all targets support all bit widths however.</p>
5662
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5663<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5664 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5666 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5667 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5668 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5669 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5670 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5671 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5672</pre>
5673
5674<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5675<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5676 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5678<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5679 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5680
5681<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5682<p>The first argument is a pointer to the destination, the second is a pointer
5683 to the source. The third argument is an integer argument specifying the
5684 number of bytes to copy, and the fourth argument is the alignment of the
5685 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5686
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5687<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5688 then the caller guarantees that both the source and destination pointers are
5689 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5690
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5691<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5693 source location to the destination location, which are not allowed to
5694 overlap. It copies "len" bytes of memory over. If the argument is known to
5695 be aligned to some boundary, this can be specified as the fourth argument,
5696 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5697
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5698</div>
5699
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5700<!-- _______________________________________________________________________ -->
5701<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5702 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5703</div>
5704
5705<div class="doc_text">
5706
5707<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5708<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]5709 width. Not all targets support all bit widths however.</p>
5710
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5711<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5712 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5713 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5714 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5715 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5716 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5717 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5718 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5719 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5723<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5724 source location to the destination location. It is similar to the
5725 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5726 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5727
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5728<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5729 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5730
5731<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5732<p>The first argument is a pointer to the destination, the second is a pointer
5733 to the source. The third argument is an integer argument specifying the
5734 number of bytes to copy, and the fourth argument is the alignment of the
5735 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5736
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5737<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5738 then the caller guarantees that the source and destination pointers are
5739 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5740
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5741<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5742<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5743 source location to the destination location, which may overlap. It copies
5744 "len" bytes of memory over. If the argument is known to be aligned to some
5745 boundary, this can be specified as the fourth argument, otherwise it should
5746 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5747
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5748</div>
5749
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5750<!-- _______________________________________________________________________ -->
5751<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5752 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5753</div>
5754
5755<div class="doc_text">
5756
5757<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5758<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]5759 width. Not all targets support all bit widths however.</p>
5760
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5761<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5762 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5763 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5764 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5765 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5766 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5767 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5768 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5769 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5770</pre>
5771
5772<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5773<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5774 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5775
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5776<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5777 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778
5779<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5780<p>The first argument is a pointer to the destination to fill, the second is the
5781 byte value to fill it with, the third argument is an integer argument
5782 specifying the number of bytes to fill, and the fourth argument is the known
5783 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5784
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5785<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5786 then the caller guarantees that the destination pointer is aligned to that
5787 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788
5789<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5790<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5791 at the destination location. If the argument is known to be aligned to some
5792 boundary, this can be specified as the fourth argument, otherwise it should
5793 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5794
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795</div>
5796
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5797<!-- _______________________________________________________________________ -->
5798<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5799 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5800</div>
5801
5802<div class="doc_text">
5803
5804<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5805<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5806 floating point or vector of floating point type. Not all targets support all
5807 types however.</p>
5808
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5809<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5810 declare float @llvm.sqrt.f32(float %Val)
5811 declare double @llvm.sqrt.f64(double %Val)
5812 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5813 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5814 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5815</pre>
5816
5817<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5818<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5819 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5820 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5821 behavior for negative numbers other than -0.0 (which allows for better
5822 optimization, because there is no need to worry about errno being
5823 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]5824
5825<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5826<p>The argument and return value are floating point numbers of the same
5827 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5828
5829<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5830<p>This function returns the sqrt of the specified operand if it is a
5831 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5832
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5833</div>
5834
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5835<!-- _______________________________________________________________________ -->
5836<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5837 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5838</div>
5839
5840<div class="doc_text">
5841
5842<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5843<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5844 floating point or vector of floating point type. Not all targets support all
5845 types however.</p>
5846
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5847<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5848 declare float @llvm.powi.f32(float %Val, i32 %power)
5849 declare double @llvm.powi.f64(double %Val, i32 %power)
5850 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5851 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5852 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5853</pre>
5854
5855<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5857 specified (positive or negative) power. The order of evaluation of
5858 multiplications is not defined. When a vector of floating point type is
5859 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5860
5861<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5862<p>The second argument is an integer power, and the first is a value to raise to
5863 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5864
5865<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5866<p>This function returns the first value raised to the second power with an
5867 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5868
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5869</div>
5870
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5871<!-- _______________________________________________________________________ -->
5872<div class="doc_subsubsection">
5873 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5874</div>
5875
5876<div class="doc_text">
5877
5878<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5879<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5880 floating point or vector of floating point type. Not all targets support all
5881 types however.</p>
5882
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5883<pre>
5884 declare float @llvm.sin.f32(float %Val)
5885 declare double @llvm.sin.f64(double %Val)
5886 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5887 declare fp128 @llvm.sin.f128(fp128 %Val)
5888 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5889</pre>
5890
5891<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5892<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5893
5894<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<p>The argument and return value are floating point numbers of the same
5896 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5899<p>This function returns the sine of the specified operand, returning the same
5900 values as the libm <tt>sin</tt> functions would, and handles error conditions
5901 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5902
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5903</div>
5904
5905<!-- _______________________________________________________________________ -->
5906<div class="doc_subsubsection">
5907 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5908</div>
5909
5910<div class="doc_text">
5911
5912<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5914 floating point or vector of floating point type. Not all targets support all
5915 types however.</p>
5916
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5917<pre>
5918 declare float @llvm.cos.f32(float %Val)
5919 declare double @llvm.cos.f64(double %Val)
5920 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5921 declare fp128 @llvm.cos.f128(fp128 %Val)
5922 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5923</pre>
5924
5925<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5926<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5927
5928<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p>The argument and return value are floating point numbers of the same
5930 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5931
5932<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5933<p>This function returns the cosine of the specified operand, returning the same
5934 values as the libm <tt>cos</tt> functions would, and handles error conditions
5935 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5936
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5937</div>
5938
5939<!-- _______________________________________________________________________ -->
5940<div class="doc_subsubsection">
5941 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5942</div>
5943
5944<div class="doc_text">
5945
5946<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5947<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5948 floating point or vector of floating point type. Not all targets support all
5949 types however.</p>
5950
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5951<pre>
5952 declare float @llvm.pow.f32(float %Val, float %Power)
5953 declare double @llvm.pow.f64(double %Val, double %Power)
5954 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5955 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5956 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5957</pre>
5958
5959<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5961 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5962
5963<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964<p>The second argument is a floating point power, and the first is a value to
5965 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5966
5967<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5968<p>This function returns the first value raised to the second power, returning
5969 the same values as the libm <tt>pow</tt> functions would, and handles error
5970 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5971
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5972</div>
5973
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5974<!-- ======================================================================= -->
5975<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5976 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5977</div>
5978
5979<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5980
5981<p>LLVM provides intrinsics for a few important bit manipulation operations.
5982 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5983
5984</div>
5985
5986<!-- _______________________________________________________________________ -->
5987<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5988 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5989</div>
5990
5991<div class="doc_text">
5992
5993<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5994<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5995 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5996
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5997<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5998 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5999 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6000 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6001</pre>
6002
6003<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6005 values with an even number of bytes (positive multiple of 16 bits). These
6006 are useful for performing operations on data that is not in the target's
6007 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6008
6009<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6010<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6011 and low byte of the input i16 swapped. Similarly,
6012 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6013 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6014 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6015 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6016 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6017 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6018
6019</div>
6020
6021<!-- _______________________________________________________________________ -->
6022<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6023 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6024</div>
6025
6026<div class="doc_text">
6027
6028<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6029<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]6030 width. Not all targets support all bit widths however.</p>
6031
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6032<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6033 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6034 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6035 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6036 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6037 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6038</pre>
6039
6040<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6041<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6042 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6043
6044<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6045<p>The only argument is the value to be counted. The argument may be of any
6046 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6047
6048<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6049<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]6050
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6051</div>
6052
6053<!-- _______________________________________________________________________ -->
6054<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6055 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6056</div>
6057
6058<div class="doc_text">
6059
6060<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6061<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6062 integer bit width. Not all targets support all bit widths however.</p>
6063
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6064<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6065 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6066 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6067 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6068 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6069 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6070</pre>
6071
6072<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6073<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6074 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6075
6076<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6077<p>The only argument is the value to be counted. The argument may be of any
6078 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6079
6080<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6081<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6082 zeros in a variable. If the src == 0 then the result is the size in bits of
6083 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6084
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6085</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6086
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6087<!-- _______________________________________________________________________ -->
6088<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6089 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6090</div>
6091
6092<div class="doc_text">
6093
6094<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6095<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6096 integer bit width. Not all targets support all bit widths however.</p>
6097
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6098<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6099 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6100 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6101 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6102 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6103 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6104</pre>
6105
6106<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6107<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6108 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6109
6110<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6111<p>The only argument is the value to be counted. The argument may be of any
6112 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6113
6114<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6115<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6116 zeros in a variable. If the src == 0 then the result is the size in bits of
6117 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6118
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6119</div>
6120
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6121<!-- ======================================================================= -->
6122<div class="doc_subsection">
6123 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6124</div>
6125
6126<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6127
6128<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6129
6130</div>
6131
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6132<!-- _______________________________________________________________________ -->
6133<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6134 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6135</div>
6136
6137<div class="doc_text">
6138
6139<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6140<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]6141 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6142
6143<pre>
6144 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6145 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6146 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6147</pre>
6148
6149<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6150<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6151 a signed addition of the two arguments, and indicate whether an overflow
6152 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6153
6154<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6155<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]6156 be of integer types of any bit width, but they must have the same bit
6157 width. The second element of the result structure must be of
6158 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6159 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6160
6161<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6162<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6163 a signed addition of the two variables. They return a structure &mdash; the
6164 first element of which is the signed summation, and the second element of
6165 which is a bit specifying if the signed summation resulted in an
6166 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6167
6168<h5>Examples:</h5>
6169<pre>
6170 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6171 %sum = extractvalue {i32, i1} %res, 0
6172 %obit = extractvalue {i32, i1} %res, 1
6173 br i1 %obit, label %overflow, label %normal
6174</pre>
6175
6176</div>
6177
6178<!-- _______________________________________________________________________ -->
6179<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6180 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6181</div>
6182
6183<div class="doc_text">
6184
6185<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6186<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]6187 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6188
6189<pre>
6190 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6191 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6192 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6193</pre>
6194
6195<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6196<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6197 an unsigned addition of the two arguments, and indicate whether a carry
6198 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6199
6200<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6201<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]6202 be of integer types of any bit width, but they must have the same bit
6203 width. The second element of the result structure must be of
6204 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6205 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6206
6207<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6208<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6209 an unsigned addition of the two arguments. They return a structure &mdash;
6210 the first element of which is the sum, and the second element of which is a
6211 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6212
6213<h5>Examples:</h5>
6214<pre>
6215 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6216 %sum = extractvalue {i32, i1} %res, 0
6217 %obit = extractvalue {i32, i1} %res, 1
6218 br i1 %obit, label %carry, label %normal
6219</pre>
6220
6221</div>
6222
6223<!-- _______________________________________________________________________ -->
6224<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6225 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6226</div>
6227
6228<div class="doc_text">
6229
6230<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6231<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]6232 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6233
6234<pre>
6235 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6236 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6237 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6238</pre>
6239
6240<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6241<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6242 a signed subtraction of the two arguments, and indicate whether an overflow
6243 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6244
6245<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6246<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]6247 be of integer types of any bit width, but they must have the same bit
6248 width. The second element of the result structure must be of
6249 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6250 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6251
6252<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6253<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6254 a signed subtraction of the two arguments. They return a structure &mdash;
6255 the first element of which is the subtraction, and the second element of
6256 which is a bit specifying if the signed subtraction resulted in an
6257 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6258
6259<h5>Examples:</h5>
6260<pre>
6261 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6262 %sum = extractvalue {i32, i1} %res, 0
6263 %obit = extractvalue {i32, i1} %res, 1
6264 br i1 %obit, label %overflow, label %normal
6265</pre>
6266
6267</div>
6268
6269<!-- _______________________________________________________________________ -->
6270<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6271 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6272</div>
6273
6274<div class="doc_text">
6275
6276<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6277<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]6278 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6279
6280<pre>
6281 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6282 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6283 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6284</pre>
6285
6286<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6287<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6288 an unsigned subtraction of the two arguments, and indicate whether an
6289 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6290
6291<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6292<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]6293 be of integer types of any bit width, but they must have the same bit
6294 width. The second element of the result structure must be of
6295 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6296 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6297
6298<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6299<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6300 an unsigned subtraction of the two arguments. They return a structure &mdash;
6301 the first element of which is the subtraction, and the second element of
6302 which is a bit specifying if the unsigned subtraction resulted in an
6303 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6304
6305<h5>Examples:</h5>
6306<pre>
6307 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6308 %sum = extractvalue {i32, i1} %res, 0
6309 %obit = extractvalue {i32, i1} %res, 1
6310 br i1 %obit, label %overflow, label %normal
6311</pre>
6312
6313</div>
6314
6315<!-- _______________________________________________________________________ -->
6316<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6317 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6318</div>
6319
6320<div class="doc_text">
6321
6322<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6323<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]6324 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6325
6326<pre>
6327 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6328 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6329 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6330</pre>
6331
6332<h5>Overview:</h5>
6333
6334<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6335 a signed multiplication of the two arguments, and indicate whether an
6336 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6337
6338<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6339<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]6340 be of integer types of any bit width, but they must have the same bit
6341 width. The second element of the result structure must be of
6342 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6343 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6344
6345<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6346<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6347 a signed multiplication of the two arguments. They return a structure &mdash;
6348 the first element of which is the multiplication, and the second element of
6349 which is a bit specifying if the signed multiplication resulted in an
6350 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6351
6352<h5>Examples:</h5>
6353<pre>
6354 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6355 %sum = extractvalue {i32, i1} %res, 0
6356 %obit = extractvalue {i32, i1} %res, 1
6357 br i1 %obit, label %overflow, label %normal
6358</pre>
6359
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6360</div>
6361
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6362<!-- _______________________________________________________________________ -->
6363<div class="doc_subsubsection">
6364 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6365</div>
6366
6367<div class="doc_text">
6368
6369<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6370<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]6371 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6372
6373<pre>
6374 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6375 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6376 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6377</pre>
6378
6379<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6380<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6381 a unsigned multiplication of the two arguments, and indicate whether an
6382 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6383
6384<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6385<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]6386 be of integer types of any bit width, but they must have the same bit
6387 width. The second element of the result structure must be of
6388 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6389 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6390
6391<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6392<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6393 an unsigned multiplication of the two arguments. They return a structure
6394 &mdash; the first element of which is the multiplication, and the second
6395 element of which is a bit specifying if the unsigned multiplication resulted
6396 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6397
6398<h5>Examples:</h5>
6399<pre>
6400 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6401 %sum = extractvalue {i32, i1} %res, 0
6402 %obit = extractvalue {i32, i1} %res, 1
6403 br i1 %obit, label %overflow, label %normal
6404</pre>
6405
6406</div>
6407
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6408<!-- ======================================================================= -->
6409<div class="doc_subsection">
6410 <a name="int_debugger">Debugger Intrinsics</a>
6411</div>
6412
6413<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6414
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6415<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6416 prefix), are described in
6417 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6418 Level Debugging</a> document.</p>
6419
6420</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6421
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6422<!-- ======================================================================= -->
6423<div class="doc_subsection">
6424 <a name="int_eh">Exception Handling Intrinsics</a>
6425</div>
6426
6427<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428
6429<p>The LLVM exception handling intrinsics (which all start with
6430 <tt>llvm.eh.</tt> prefix), are described in
6431 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6432 Handling</a> document.</p>
6433
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6434</div>
6435
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6436<!-- ======================================================================= -->
6437<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6438 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6439</div>
6440
6441<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6442
6443<p>This intrinsic makes it possible to excise one parameter, marked with
6444 the <tt>nest</tt> attribute, from a function. The result is a callable
6445 function pointer lacking the nest parameter - the caller does not need to
6446 provide a value for it. Instead, the value to use is stored in advance in a
6447 "trampoline", a block of memory usually allocated on the stack, which also
6448 contains code to splice the nest value into the argument list. This is used
6449 to implement the GCC nested function address extension.</p>
6450
6451<p>For example, if the function is
6452 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6453 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6454 follows:</p>
6455
6456<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6457<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6458 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6459 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6460 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6461 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6462</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6463</div>
6464
6465<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6466 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6467
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6468</div>
6469
6470<!-- _______________________________________________________________________ -->
6471<div class="doc_subsubsection">
6472 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6473</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6474
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6475<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6476
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6477<h5>Syntax:</h5>
6478<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6479 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]6480</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6481
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6482<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6483<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6484 function pointer suitable for executing it.</p>
6485
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6486<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6487<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6488 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6489 sufficiently aligned block of memory; this memory is written to by the
6490 intrinsic. Note that the size and the alignment are target-specific - LLVM
6491 currently provides no portable way of determining them, so a front-end that
6492 generates this intrinsic needs to have some target-specific knowledge.
6493 The <tt>func</tt> argument must hold a function bitcast to
6494 an <tt>i8*</tt>.</p>
6495
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6496<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6497<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6498 dependent code, turning it into a function. A pointer to this function is
6499 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6500 function pointer type</a> before being called. The new function's signature
6501 is the same as that of <tt>func</tt> with any arguments marked with
6502 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6503 is allowed, and it must be of pointer type. Calling the new function is
6504 equivalent to calling <tt>func</tt> with the same argument list, but
6505 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6506 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6507 by <tt>tramp</tt> is modified, then the effect of any later call to the
6508 returned function pointer is undefined.</p>
6509
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6510</div>
6511
6512<!-- ======================================================================= -->
6513<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6514 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6515</div>
6516
6517<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6518
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6519<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6520 hardware constructs for atomic operations and memory synchronization. This
6521 provides an interface to the hardware, not an interface to the programmer. It
6522 is aimed at a low enough level to allow any programming models or APIs
6523 (Application Programming Interfaces) which need atomic behaviors to map
6524 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6525 hardware provides a "universal IR" for source languages, it also provides a
6526 starting point for developing a "universal" atomic operation and
6527 synchronization IR.</p>
6528
6529<p>These do <em>not</em> form an API such as high-level threading libraries,
6530 software transaction memory systems, atomic primitives, and intrinsic
6531 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6532 application libraries. The hardware interface provided by LLVM should allow
6533 a clean implementation of all of these APIs and parallel programming models.
6534 No one model or paradigm should be selected above others unless the hardware
6535 itself ubiquitously does so.</p>
6536
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6537</div>
6538
6539<!-- _______________________________________________________________________ -->
6540<div class="doc_subsubsection">
6541 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6542</div>
6543<div class="doc_text">
6544<h5>Syntax:</h5>
6545<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6546 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]6547</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6549<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6550<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6551 specific pairs of memory access types.</p>
6552
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6553<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6554<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6555 The first four arguments enables a specific barrier as listed below. The
6556 fith argument specifies that the barrier applies to io or device or uncached
6557 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6558
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6559<ul>
6560 <li><tt>ll</tt>: load-load barrier</li>
6561 <li><tt>ls</tt>: load-store barrier</li>
6562 <li><tt>sl</tt>: store-load barrier</li>
6563 <li><tt>ss</tt>: store-store barrier</li>
6564 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6565</ul>
6566
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6567<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6568<p>This intrinsic causes the system to enforce some ordering constraints upon
6569 the loads and stores of the program. This barrier does not
6570 indicate <em>when</em> any events will occur, it only enforces
6571 an <em>order</em> in which they occur. For any of the specified pairs of load
6572 and store operations (f.ex. load-load, or store-load), all of the first
6573 operations preceding the barrier will complete before any of the second
6574 operations succeeding the barrier begin. Specifically the semantics for each
6575 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6576
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6577<ul>
6578 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6579 after the barrier begins.</li>
6580 <li><tt>ls</tt>: All loads before the barrier must complete before any
6581 store after the barrier begins.</li>
6582 <li><tt>ss</tt>: All stores before the barrier must complete before any
6583 store after the barrier begins.</li>
6584 <li><tt>sl</tt>: All stores before the barrier must complete before any
6585 load after the barrier begins.</li>
6586</ul>
6587
6588<p>These semantics are applied with a logical "and" behavior when more than one
6589 is enabled in a single memory barrier intrinsic.</p>
6590
6591<p>Backends may implement stronger barriers than those requested when they do
6592 not support as fine grained a barrier as requested. Some architectures do
6593 not need all types of barriers and on such architectures, these become
6594 noops.</p>
6595
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6596<h5>Example:</h5>
6597<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6598%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6599%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6600 store i32 4, %ptr
6601
6602%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6603 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6604 <i>; guarantee the above finishes</i>
6605 store i32 8, %ptr <i>; before this begins</i>
6606</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6607
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6608</div>
6609
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6610<!-- _______________________________________________________________________ -->
6611<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6612 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6613</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6614
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6615<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6617<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6619 any integer bit width and for different address spaces. Not all targets
6620 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6621
6622<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6623 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6624 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6625 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6626 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]6627</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6628
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6629<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630<p>This loads a value in memory and compares it to a given value. If they are
6631 equal, it stores a new value into the memory.</p>
6632
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6633<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6635 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6636 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6637 this integer type. While any bit width integer may be used, targets may only
6638 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6639
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6640<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641<p>This entire intrinsic must be executed atomically. It first loads the value
6642 in memory pointed to by <tt>ptr</tt> and compares it with the
6643 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6644 memory. The loaded value is yielded in all cases. This provides the
6645 equivalent of an atomic compare-and-swap operation within the SSA
6646 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6648<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6649<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6650%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6651%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6652 store i32 4, %ptr
6653
6654%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6655%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6656 <i>; yields {i32}:result1 = 4</i>
6657%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6658%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6659
6660%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6661%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6662 <i>; yields {i32}:result2 = 8</i>
6663%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6664
6665%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6666</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6667
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6668</div>
6669
6670<!-- _______________________________________________________________________ -->
6671<div class="doc_subsubsection">
6672 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6673</div>
6674<div class="doc_text">
6675<h5>Syntax:</h5>
6676
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6677<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6678 integer bit width. Not all targets support all bit widths however.</p>
6679
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6680<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6681 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6682 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6683 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6684 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]6685</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6686
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6687<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6688<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6689 the value from memory. It then stores the value in <tt>val</tt> in the memory
6690 at <tt>ptr</tt>.</p>
6691
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6692<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6693<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6694 the <tt>val</tt> argument and the result must be integers of the same bit
6695 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6696 integer type. The targets may only lower integer representations they
6697 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6698
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6699<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6700<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6701 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6702 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6703
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6704<h5>Examples:</h5>
6705<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6706%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6707%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6708 store i32 4, %ptr
6709
6710%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6711%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6712 <i>; yields {i32}:result1 = 4</i>
6713%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6714%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6715
6716%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6717%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6718 <i>; yields {i32}:result2 = 8</i>
6719
6720%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6721%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6722</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6723
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6724</div>
6725
6726<!-- _______________________________________________________________________ -->
6727<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6728 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6729
6730</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6731
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6732<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6733
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6734<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6735<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6736 any integer bit width. Not all targets support all bit widths however.</p>
6737
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6738<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6739 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6740 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6741 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6742 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]6743</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6744
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6745<h5>Overview:</h5>
6746<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6747 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6748
6749<h5>Arguments:</h5>
6750<p>The intrinsic takes two arguments, the first a pointer to an integer value
6751 and the second an integer value. The result is also an integer value. These
6752 integer types can have any bit width, but they must all have the same bit
6753 width. The targets may only lower integer representations they support.</p>
6754
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6755<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6756<p>This intrinsic does a series of operations atomically. It first loads the
6757 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6758 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]6759
6760<h5>Examples:</h5>
6761<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6762%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6763%ptr = bitcast i8* %mallocP to i32*
6764 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6765%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6766 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6767%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6768 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6769%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6770 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6771%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6772</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6773
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6774</div>
6775
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6776<!-- _______________________________________________________________________ -->
6777<div class="doc_subsubsection">
6778 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6779
6780</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6781
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6782<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6783
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6784<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6785<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6786 any integer bit width and for different address spaces. Not all targets
6787 support all bit widths however.</p>
6788
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6789<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6790 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6791 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6792 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6793 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]6794</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6795
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6796<h5>Overview:</h5>
6797<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6798 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6799
6800<h5>Arguments:</h5>
6801<p>The intrinsic takes two arguments, the first a pointer to an integer value
6802 and the second an integer value. The result is also an integer value. These
6803 integer types can have any bit width, but they must all have the same bit
6804 width. The targets may only lower integer representations they support.</p>
6805
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6806<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6807<p>This intrinsic does a series of operations atomically. It first loads the
6808 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6809 result to <tt>ptr</tt>. It yields the original value stored
6810 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6811
6812<h5>Examples:</h5>
6813<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6814%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6815%ptr = bitcast i8* %mallocP to i32*
6816 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6817%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6818 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6819%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6820 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6821%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6822 <i>; yields {i32}:result3 = 2</i>
6823%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6824</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6825
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6826</div>
6827
6828<!-- _______________________________________________________________________ -->
6829<div class="doc_subsubsection">
6830 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6831 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6832 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6833 <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]6834</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6836<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6837
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6838<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6839<p>These are overloaded intrinsics. You can
6840 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6841 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6842 bit width and for different address spaces. Not all targets support all bit
6843 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6845<pre>
6846 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6847 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6848 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6849 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]6850</pre>
6851
6852<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6853 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6854 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6855 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6856 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]6857</pre>
6858
6859<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6860 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6861 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6862 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6863 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]6864</pre>
6865
6866<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6867 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6868 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6869 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6870 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]6871</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6872
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6873<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6874<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6875 the value stored in memory at <tt>ptr</tt>. It yields the original value
6876 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6877
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6878<h5>Arguments:</h5>
6879<p>These intrinsics take two arguments, the first a pointer to an integer value
6880 and the second an integer value. The result is also an integer value. These
6881 integer types can have any bit width, but they must all have the same bit
6882 width. The targets may only lower integer representations they support.</p>
6883
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6884<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6885<p>These intrinsics does a series of operations atomically. They first load the
6886 value stored at <tt>ptr</tt>. They then do the bitwise
6887 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6888 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6889
6890<h5>Examples:</h5>
6891<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6892%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6893%ptr = bitcast i8* %mallocP to i32*
6894 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6895%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6896 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6897%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6898 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6899%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6900 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6901%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6902 <i>; yields {i32}:result3 = FF</i>
6903%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6904</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6906</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6907
6908<!-- _______________________________________________________________________ -->
6909<div class="doc_subsubsection">
6910 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6911 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6912 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6913 <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]6914</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6915
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6916<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6917
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6918<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6919<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6920 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6921 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6922 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<pre>
6925 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6926 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6927 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6928 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]6929</pre>
6930
6931<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6932 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6933 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6934 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6935 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]6936</pre>
6937
6938<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6940 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6941 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6942 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]6943</pre>
6944
6945<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6947 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6948 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6949 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]6950</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6951
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6952<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6953<p>These intrinsics takes the signed or unsigned minimum or maximum of
6954 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6955 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6956
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6957<h5>Arguments:</h5>
6958<p>These intrinsics take two arguments, the first a pointer to an integer value
6959 and the second an integer value. The result is also an integer value. These
6960 integer types can have any bit width, but they must all have the same bit
6961 width. The targets may only lower integer representations they support.</p>
6962
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6963<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6964<p>These intrinsics does a series of operations atomically. They first load the
6965 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6966 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6967 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6968
6969<h5>Examples:</h5>
6970<pre>
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]6971%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6972%ptr = bitcast i8* %mallocP to i32*
6973 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6974%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6975 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6976%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6977 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6978%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6979 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6980%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6981 <i>; yields {i32}:result3 = 8</i>
6982%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6983</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6984
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6985</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6986
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]6987
6988<!-- ======================================================================= -->
6989<div class="doc_subsection">
6990 <a name="int_memorymarkers">Memory Use Markers</a>
6991</div>
6992
6993<div class="doc_text">
6994
6995<p>This class of intrinsics exists to information about the lifetime of memory
6996 objects and ranges where variables are immutable.</p>
6997
6998</div>
6999
7000<!-- _______________________________________________________________________ -->
7001<div class="doc_subsubsection">
7002 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7003</div>
7004
7005<div class="doc_text">
7006
7007<h5>Syntax:</h5>
7008<pre>
7009 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7010</pre>
7011
7012<h5>Overview:</h5>
7013<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7014 object's lifetime.</p>
7015
7016<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7017<p>The first argument is a constant integer representing the size of the
7018 object, or -1 if it is variable sized. The second argument is a pointer to
7019 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7020
7021<h5>Semantics:</h5>
7022<p>This intrinsic indicates that before this point in the code, the value of the
7023 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]7024 never be used and has an undefined value. A load from the pointer that
7025 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7026 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7027
7028</div>
7029
7030<!-- _______________________________________________________________________ -->
7031<div class="doc_subsubsection">
7032 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7033</div>
7034
7035<div class="doc_text">
7036
7037<h5>Syntax:</h5>
7038<pre>
7039 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7040</pre>
7041
7042<h5>Overview:</h5>
7043<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7044 object's lifetime.</p>
7045
7046<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7047<p>The first argument is a constant integer representing the size of the
7048 object, or -1 if it is variable sized. The second argument is a pointer to
7049 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
7052<p>This intrinsic indicates that after this point in the code, the value of the
7053 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7054 never be used and has an undefined value. Any stores into the memory object
7055 following this intrinsic may be removed as dead.
7056
7057</div>
7058
7059<!-- _______________________________________________________________________ -->
7060<div class="doc_subsubsection">
7061 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7062</div>
7063
7064<div class="doc_text">
7065
7066<h5>Syntax:</h5>
7067<pre>
7068 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7069</pre>
7070
7071<h5>Overview:</h5>
7072<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7073 a memory object will not change.</p>
7074
7075<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7076<p>The first argument is a constant integer representing the size of the
7077 object, or -1 if it is variable sized. The second argument is a pointer to
7078 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7079
7080<h5>Semantics:</h5>
7081<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7082 the return value, the referenced memory location is constant and
7083 unchanging.</p>
7084
7085</div>
7086
7087<!-- _______________________________________________________________________ -->
7088<div class="doc_subsubsection">
7089 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7090</div>
7091
7092<div class="doc_text">
7093
7094<h5>Syntax:</h5>
7095<pre>
7096 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7097</pre>
7098
7099<h5>Overview:</h5>
7100<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7101 a memory object are mutable.</p>
7102
7103<h5>Arguments:</h5>
7104<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7105 The second argument is a constant integer representing the size of the
7106 object, or -1 if it is variable sized and the third argument is a pointer
7107 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7108
7109<h5>Semantics:</h5>
7110<p>This intrinsic indicates that the memory is mutable again.</p>
7111
7112</div>
7113
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]7114<!-- ======================================================================= -->
7115<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7116 <a name="int_general">General Intrinsics</a>
7117</div>
7118
7119<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7120
7121<p>This class of intrinsics is designed to be generic and has no specific
7122 purpose.</p>
7123
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7124</div>
7125
7126<!-- _______________________________________________________________________ -->
7127<div class="doc_subsubsection">
7128 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7129</div>
7130
7131<div class="doc_text">
7132
7133<h5>Syntax:</h5>
7134<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7135 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]7136</pre>
7137
7138<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7139<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7140
7141<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7142<p>The first argument is a pointer to a value, the second is a pointer to a
7143 global string, the third is a pointer to a global string which is the source
7144 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7145
7146<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7147<p>This intrinsic allows annotation of local variables with arbitrary strings.
7148 This can be useful for special purpose optimizations that want to look for
7149 these annotations. These have no other defined use, they are ignored by code
7150 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7151
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7152</div>
7153
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7154<!-- _______________________________________________________________________ -->
7155<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7156 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7157</div>
7158
7159<div class="doc_text">
7160
7161<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7162<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7163 any integer bit width.</p>
7164
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7165<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7166 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7167 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7168 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7169 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7170 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]7171</pre>
7172
7173<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7174<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7175
7176<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7177<p>The first argument is an integer value (result of some expression), the
7178 second is a pointer to a global string, the third is a pointer to a global
7179 string which is the source file name, and the last argument is the line
7180 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7181
7182<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7183<p>This intrinsic allows annotations to be put on arbitrary expressions with
7184 arbitrary strings. This can be useful for special purpose optimizations that
7185 want to look for these annotations. These have no other defined use, they
7186 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7187
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7188</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7189
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7190<!-- _______________________________________________________________________ -->
7191<div class="doc_subsubsection">
7192 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7193</div>
7194
7195<div class="doc_text">
7196
7197<h5>Syntax:</h5>
7198<pre>
7199 declare void @llvm.trap()
7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7204
7205<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7206<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7207
7208<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7209<p>This intrinsics is lowered to the target dependent trap instruction. If the
7210 target does not have a trap instruction, this intrinsic will be lowered to
7211 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7212
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7213</div>
7214
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7215<!-- _______________________________________________________________________ -->
7216<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7217 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7218</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7219
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7220<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7221
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7222<h5>Syntax:</h5>
7223<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7224 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7225</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7226
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7227<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7228<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7229 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7230 ensure that it is placed on the stack before local variables.</p>
7231
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7232<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7233<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7234 arguments. The first argument is the value loaded from the stack
7235 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7236 that has enough space to hold the value of the guard.</p>
7237
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7238<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7239<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7240 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7241 stack. This is to ensure that if a local variable on the stack is
7242 overwritten, it will destroy the value of the guard. When the function exits,
7243 the guard on the stack is checked against the original guard. If they're
7244 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7245 function.</p>
7246
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7247</div>
7248
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7249<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7250<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7251<address>
7252 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7253 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7254 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7255 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]7256
7257 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7258 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7259 Last modified: $Date$
7260</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7262</body>
7263</html>