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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ec38da42c8d563d639579d77b883e9ed1cbe2582 / . / 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>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
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>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]88 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]89 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]149 </ol>
150 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]158 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
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>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]276 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]277 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]278 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]279 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]280 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]281 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]282 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]283 '<tt>llvm.trap</tt>' Intrinsic</a></li>
284 <li><a href="#int_stackprotector">
285 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]286 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]287 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]288 </ol>
289 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]290</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]291
292<div class="doc_author">
293 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
294 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]295</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]296
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]298<div class="doc_section"> <a name="abstract">Abstract </a></div>
299<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]300
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]301<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]302
303<p>This document is a reference manual for the LLVM assembly language. LLVM is
304 a Static Single Assignment (SSA) based representation that provides type
305 safety, low-level operations, flexibility, and the capability of representing
306 'all' high-level languages cleanly. It is the common code representation
307 used throughout all phases of the LLVM compilation strategy.</p>
308
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]309</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]310
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]311<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]312<div class="doc_section"> <a name="introduction">Introduction</a> </div>
313<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]315<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]317<p>The LLVM code representation is designed to be used in three different forms:
318 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
319 for fast loading by a Just-In-Time compiler), and as a human readable
320 assembly language representation. This allows LLVM to provide a powerful
321 intermediate representation for efficient compiler transformations and
322 analysis, while providing a natural means to debug and visualize the
323 transformations. The three different forms of LLVM are all equivalent. This
324 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]326<p>The LLVM representation aims to be light-weight and low-level while being
327 expressive, typed, and extensible at the same time. It aims to be a
328 "universal IR" of sorts, by being at a low enough level that high-level ideas
329 may be cleanly mapped to it (similar to how microprocessors are "universal
330 IR's", allowing many source languages to be mapped to them). By providing
331 type information, LLVM can be used as the target of optimizations: for
332 example, through pointer analysis, it can be proven that a C automatic
333 variable is never accessed outside of the current function... allowing it to
334 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]336</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]337
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]338<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]339<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]343<p>It is important to note that this document describes 'well formed' LLVM
344 assembly language. There is a difference between what the parser accepts and
345 what is considered 'well formed'. For example, the following instruction is
346 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]347
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]348<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]349<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]350%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]351</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]354<p>...because the definition of <tt>%x</tt> does not dominate all of its
355 uses. The LLVM infrastructure provides a verification pass that may be used
356 to verify that an LLVM module is well formed. This pass is automatically run
357 by the parser after parsing input assembly and by the optimizer before it
358 outputs bitcode. The violations pointed out by the verifier pass indicate
359 bugs in transformation passes or input to the parser.</p>
360
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]361</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]363<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]364
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]365<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]366<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]367<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]368
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]369<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]371<p>LLVM identifiers come in two basic types: global and local. Global
372 identifiers (functions, global variables) begin with the <tt>'@'</tt>
373 character. Local identifiers (register names, types) begin with
374 the <tt>'%'</tt> character. Additionally, there are three different formats
375 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]378 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]379 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
380 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
381 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
382 other characters in their names can be surrounded with quotes. Special
383 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
384 ASCII code for the character in hexadecimal. In this way, any character
385 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]387 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]388 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]389
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]390 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]391 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]392</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]393
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]394<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]395 don't need to worry about name clashes with reserved words, and the set of
396 reserved words may be expanded in the future without penalty. Additionally,
397 unnamed identifiers allow a compiler to quickly come up with a temporary
398 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]399
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]400<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]401 languages. There are keywords for different opcodes
402 ('<tt><a href="#i_add">add</a></tt>',
403 '<tt><a href="#i_bitcast">bitcast</a></tt>',
404 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
405 ('<tt><a href="#t_void">void</a></tt>',
406 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
407 reserved words cannot conflict with variable names, because none of them
408 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]409
410<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]411 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]412
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]413<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]415<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]417%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]419</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]421<p>After strength reduction:</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_shl">shl</a> i32 %X, i8 3
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>And the hard way:</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<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
434<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
435%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]436</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]437</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]439<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
440 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]442<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]444 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
446 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]447 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]449 <li>Unnamed temporaries are numbered sequentially</li>
450</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]452<p>...and it also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]453 demonstrating instructions, we will follow an instruction with a comment that
454 defines the type and name of value produced. Comments are shown in italic
455 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]457</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]458
459<!-- *********************************************************************** -->
460<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
461<!-- *********************************************************************** -->
462
463<!-- ======================================================================= -->
464<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
465</div>
466
467<div class="doc_text">
468
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]469<p>LLVM programs are composed of "Module"s, each of which is a translation unit
470 of the input programs. Each module consists of functions, global variables,
471 and symbol table entries. Modules may be combined together with the LLVM
472 linker, which merges function (and global variable) definitions, resolves
473 forward declarations, and merges symbol table entries. Here is an example of
474 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]476<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]478<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
479 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]480
481<i>; External declaration of the puts function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]482<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]483
484<i>; Definition of main function</i>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]485define i32 @main() { <i>; i32()* </i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]486 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]487 %cast210 = <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]488 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]489
490 <i>; Call puts function to write out the string to stdout...</i>
491 <a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]492 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]493 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]494 href="#i_ret">ret</a> i32 0<br>}<br>
495</pre>
496</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]498<p>This example is made up of a <a href="#globalvars">global variable</a> named
499 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
500 a <a href="#functionstructure">function definition</a> for
501 "<tt>main</tt>".</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]503<p>In general, a module is made up of a list of global values, where both
504 functions and global variables are global values. Global values are
505 represented by a pointer to a memory location (in this case, a pointer to an
506 array of char, and a pointer to a function), and have one of the
507 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]508
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="linkage">Linkage Types</a>
514</div>
515
516<div class="doc_text">
517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518<p>All Global Variables and Functions have one of the following types of
519 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]520
521<dl>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]522 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]523 <dd>Global values with private linkage are only directly accessible by objects
524 in the current module. In particular, linking code into a module with an
525 private global value may cause the private to be renamed as necessary to
526 avoid collisions. Because the symbol is private to the module, all
527 references can be updated. This doesn't show up in any symbol table in the
528 object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]529
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]531 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]551
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]558
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]575
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]576
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]583
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]588
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]598
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]603</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]604
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]608
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]623</dl>
624
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]685</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]717
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<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]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]778
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]797
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]800
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]801<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]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]809
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]810<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]811<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]813</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]814</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]815
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]851<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]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]856
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]859
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]860<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]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]865
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]877</div>
878
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]883
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]890
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]893<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]895</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]896</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]897
898</div>
899
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]900<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]926
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</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 sign-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 Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]990
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]991</div>
992
993<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]994<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
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 simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1130</div>
1131
1132<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1138
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 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]1148 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1153</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1154
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <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]1180 bits with the most significance have the lowest address location.</dd>
1181
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <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]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1204 (double).</dd>
1205
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1213</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1214
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1227 <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]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1235</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1240<ol>
1241 <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]1242 specification is used.</li>
1243
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1244 <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]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252 <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]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1257
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1258</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1259
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1312<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1315
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1316<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1318<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
1326</div>
1327
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1328<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1337 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1338 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1339 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342 </tr>
1343 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1357 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1378 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1379</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]1383 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1385</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1387<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]1398<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1399
1400<div class="doc_text">
1401
1402<h5>Overview:</h5>
1403<p>The integer type is a very simple type that simply specifies an arbitrary
1404 bit width for the integer type desired. Any bit width from 1 bit to
1405 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1406
1407<h5>Syntax:</h5>
1408<pre>
1409 iN
1410</pre>
1411
1412<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1413 value.</p>
1414
1415<h5>Examples:</h5>
1416<table class="layout">
1417 <tr class="layout">
1418 <td class="left"><tt>i1</tt></td>
1419 <td class="left">a single-bit integer.</td>
1420 </tr>
1421 <tr class="layout">
1422 <td class="left"><tt>i32</tt></td>
1423 <td class="left">a 32-bit integer.</td>
1424 </tr>
1425 <tr class="layout">
1426 <td class="left"><tt>i1942652</tt></td>
1427 <td class="left">a really big integer of over 1 million bits.</td>
1428 </tr>
1429</table>
1430
1431<p>Note that the code generator does not yet support large integer types to be
1432 used as function return types. The specific limit on how large a return type
1433 the code generator can currently handle is target-dependent; currently it's
1434 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1435
1436</div>
1437
1438<!-- _______________________________________________________________________ -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1439<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1440
1441<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1442
1443<table>
1444 <tbody>
1445 <tr><th>Type</th><th>Description</th></tr>
1446 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1447 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1448 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1449 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1450 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1451 </tbody>
1452</table>
1453
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1454</div>
1455
1456<!-- _______________________________________________________________________ -->
1457<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1458
1459<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1460
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1461<h5>Overview:</h5>
1462<p>The void type does not represent any value and has no size.</p>
1463
1464<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1465<pre>
1466 void
1467</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1469</div>
1470
1471<!-- _______________________________________________________________________ -->
1472<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1473
1474<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1475
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1476<h5>Overview:</h5>
1477<p>The label type represents code labels.</p>
1478
1479<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1480<pre>
1481 label
1482</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1484</div>
1485
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1486<!-- _______________________________________________________________________ -->
1487<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1488
1489<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1490
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1491<h5>Overview:</h5>
1492<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1493 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1494 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1495
1496<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1497<pre>
1498 metadata
1499</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1500
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1501</div>
1502
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1503
1504<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1505<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1506
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1507<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1508
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1509<p>The real power in LLVM comes from the derived types in the system. This is
1510 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]1511 useful types. Each of these types contain one or more element types which
1512 may be a primitive type, or another derived type. For example, it is
1513 possible to have a two dimensional array, using an array as the element type
1514 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1515
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1516</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1517
1518<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1519<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1520
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1521<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1522
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1523<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1524<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1525 sequentially in memory. The array type requires a size (number of elements)
1526 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1528<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1529<pre>
1530 [&lt;# elements&gt; x &lt;elementtype&gt;]
1531</pre>
1532
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1533<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1534 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1536<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1537<table class="layout">
1538 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1539 <td class="left"><tt>[40 x i32]</tt></td>
1540 <td class="left">Array of 40 32-bit integer values.</td>
1541 </tr>
1542 <tr class="layout">
1543 <td class="left"><tt>[41 x i32]</tt></td>
1544 <td class="left">Array of 41 32-bit integer values.</td>
1545 </tr>
1546 <tr class="layout">
1547 <td class="left"><tt>[4 x i8]</tt></td>
1548 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1549 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1550</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1551<p>Here are some examples of multidimensional arrays:</p>
1552<table class="layout">
1553 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1554 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1555 <td class="left">3x4 array of 32-bit integer values.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1559 <td class="left">12x10 array of single precision floating point values.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1563 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1564 </tr>
1565</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1566
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1567<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1568 length array. Normally, accesses past the end of an array are undefined in
1569 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1570 a special case, however, zero length arrays are recognized to be variable
1571 length. This allows implementation of 'pascal style arrays' with the LLVM
1572 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1573
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1574<p>Note that the code generator does not yet support large aggregate types to be
1575 used as function return types. The specific limit on how large an aggregate
1576 return type the code generator can currently handle is target-dependent, and
1577 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1578
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1579</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1581<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1582<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1584<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1586<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1587<p>The function type can be thought of as a function signature. It consists of
1588 a return type and a list of formal parameter types. The return type of a
1589 function type is a scalar type, a void type, or a struct type. If the return
1590 type is a struct type then all struct elements must be of first class types,
1591 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1592
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1594<pre>
1595 &lt;returntype list&gt; (&lt;parameter list&gt;)
1596</pre>
1597
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1598<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]1599 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1600 which indicates that the function takes a variable number of arguments.
1601 Variable argument functions can access their arguments with
1602 the <a href="#int_varargs">variable argument handling intrinsic</a>
1603 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1604 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1606<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1607<table class="layout">
1608 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1609 <td class="left"><tt>i32 (i32)</tt></td>
1610 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1611 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1612 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1613 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1614 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1615 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1616 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1617 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1618 <tt>float</tt>.
1619 </td>
1620 </tr><tr class="layout">
1621 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1622 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1623 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1624 which returns an integer. This is the signature for <tt>printf</tt> in
1625 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1626 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1627 </tr><tr class="layout">
1628 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanb0a57aa2008-11-27 06:41:20 +0000[diff] [blame]1629 <td class="left">A function taking an <tt>i32</tt>, returning two
1630 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1631 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1632 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1633</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1634
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1635</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1636
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1637<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1643<p>The structure type is used to represent a collection of data members together
1644 in memory. The packing of the field types is defined to match the ABI of the
1645 underlying processor. The elements of a structure may be any type that has a
1646 size.</p>
1647
1648<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1649 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1650 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1651
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1653<pre>
1654 { &lt;type list&gt; }
1655</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1656
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1658<table class="layout">
1659 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1660 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1661 <td class="left">A triple of three <tt>i32</tt> values</td>
1662 </tr><tr class="layout">
1663 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1664 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1665 second element is a <a href="#t_pointer">pointer</a> to a
1666 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1667 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1668 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1669</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1670
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1671<p>Note that the code generator does not yet support large aggregate types to be
1672 used as function return types. The specific limit on how large an aggregate
1673 return type the code generator can currently handle is target-dependent, and
1674 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1675
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1679<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1680</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1681
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1682<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1683
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1684<h5>Overview:</h5>
1685<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1686 together in memory. There is no padding between fields. Further, the
1687 alignment of a packed structure is 1 byte. The elements of a packed
1688 structure may be any type that has a size.</p>
1689
1690<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1691 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1692 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1693
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1694<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1695<pre>
1696 &lt; { &lt;type list&gt; } &gt;
1697</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1699<h5>Examples:</h5>
1700<table class="layout">
1701 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1702 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1703 <td class="left">A triple of three <tt>i32</tt> values</td>
1704 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1705 <td class="left">
1706<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1707 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1708 second element is a <a href="#t_pointer">pointer</a> to a
1709 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1710 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1711 </tr>
1712</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1713
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1714</div>
1715
1716<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1717<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1718
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1719<div class="doc_text">
1720
1721<h5>Overview:</h5>
1722<p>As in many languages, the pointer type represents a pointer or reference to
1723 another object, which must live in memory. Pointer types may have an optional
1724 address space attribute defining the target-specific numbered address space
1725 where the pointed-to object resides. The default address space is zero.</p>
1726
1727<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1728 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1729
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1730<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1731<pre>
1732 &lt;type&gt; *
1733</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1734
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1735<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1736<table class="layout">
1737 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1738 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1739 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1740 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1741 </tr>
1742 <tr class="layout">
1743 <td class="left"><tt>i32 (i32 *) *</tt></td>
1744 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1745 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1746 <tt>i32</tt>.</td>
1747 </tr>
1748 <tr class="layout">
1749 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1750 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1751 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1752 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1756
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1757<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1758<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1759
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1760<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1761
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1762<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1763<p>A vector type is a simple derived type that represents a vector of elements.
1764 Vector types are used when multiple primitive data are operated in parallel
1765 using a single instruction (SIMD). A vector type requires a size (number of
1766 elements) and an underlying primitive data type. Vectors must have a power
1767 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1768 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1771<pre>
1772 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1773</pre>
1774
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1775<p>The number of elements is a constant integer value; elementtype may be any
1776 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1777
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1778<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779<table class="layout">
1780 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1781 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1782 <td class="left">Vector of 4 32-bit integer values.</td>
1783 </tr>
1784 <tr class="layout">
1785 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1786 <td class="left">Vector of 8 32-bit floating-point values.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1790 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1791 </tr>
1792</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1793
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1794<p>Note that the code generator does not yet support large vector types to be
1795 used as function return types. The specific limit on how large a vector
1796 return type codegen can currently handle is target-dependent; currently it's
1797 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799</div>
1800
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
1802<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1803<div class="doc_text">
1804
1805<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1806<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1807 corresponds (for example) to the C notion of a forward declared structure
1808 type. In LLVM, opaque types can eventually be resolved to any type (not just
1809 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1810
1811<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1812<pre>
1813 opaque
1814</pre>
1815
1816<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1817<table class="layout">
1818 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1819 <td class="left"><tt>opaque</tt></td>
1820 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1823
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1824</div>
1825
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1826<!-- ======================================================================= -->
1827<div class="doc_subsection">
1828 <a name="t_uprefs">Type Up-references</a>
1829</div>
1830
1831<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1832
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1833<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1834<p>An "up reference" allows you to refer to a lexically enclosing type without
1835 requiring it to have a name. For instance, a structure declaration may
1836 contain a pointer to any of the types it is lexically a member of. Example
1837 of up references (with their equivalent as named type declarations)
1838 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1839
1840<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1841 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1842 { \2 }* %y = type { %y }*
1843 \1* %z = type %z*
1844</pre>
1845
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1846<p>An up reference is needed by the asmprinter for printing out cyclic types
1847 when there is no declared name for a type in the cycle. Because the
1848 asmprinter does not want to print out an infinite type string, it needs a
1849 syntax to handle recursive types that have no names (all names are optional
1850 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1851
1852<h5>Syntax:</h5>
1853<pre>
1854 \&lt;level&gt;
1855</pre>
1856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1857<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]1858
1859<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1860<table class="layout">
1861 <tr class="layout">
1862 <td class="left"><tt>\1*</tt></td>
1863 <td class="left">Self-referential pointer.</td>
1864 </tr>
1865 <tr class="layout">
1866 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1867 <td class="left">Recursive structure where the upref refers to the out-most
1868 structure.</td>
1869 </tr>
1870</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1871
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1872</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1873
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1874<!-- *********************************************************************** -->
1875<div class="doc_section"> <a name="constants">Constants</a> </div>
1876<!-- *********************************************************************** -->
1877
1878<div class="doc_text">
1879
1880<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882
1883</div>
1884
1885<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1886<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1887
1888<div class="doc_text">
1889
1890<dl>
1891 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1892 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]1893 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1894
1895 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1896 <dd>Standard integers (such as '4') are constants of
1897 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1898 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899
1900 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1901 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1902 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1903 notation (see below). The assembler requires the exact decimal value of a
1904 floating-point constant. For example, the assembler accepts 1.25 but
1905 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1906 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1909 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1910 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1911</dl>
1912
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1913<p>The one non-intuitive notation for constants is the hexadecimal form of
1914 floating point constants. For example, the form '<tt>double
1915 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1916 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1917 constants are required (and the only time that they are generated by the
1918 disassembler) is when a floating point constant must be emitted but it cannot
1919 be represented as a decimal floating point number in a reasonable number of
1920 digits. For example, NaN's, infinities, and other special values are
1921 represented in their IEEE hexadecimal format so that assembly and disassembly
1922 do not cause any bits to change in the constants.</p>
1923
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1924<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1925 represented using the 16-digit form shown above (which matches the IEEE754
1926 representation for double); float values must, however, be exactly
1927 representable as IEE754 single precision. Hexadecimal format is always used
1928 for long double, and there are three forms of long double. The 80-bit format
1929 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1930 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1931 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1932 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1933 currently supported target uses this format. Long doubles will only work if
1934 they match the long double format on your target. All hexadecimal formats
1935 are big-endian (sign bit at the left).</p>
1936
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1937</div>
1938
1939<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1940<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1941<a name="aggregateconstants"></a> <!-- old anchor -->
1942<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1943</div>
1944
1945<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1946
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1947<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1948 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1949
1950<dl>
1951 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1952 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1953 type definitions (a comma separated list of elements, surrounded by braces
1954 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1955 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1956 Structure constants must have <a href="#t_struct">structure type</a>, and
1957 the number and types of elements must match those specified by the
1958 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1959
1960 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1961 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1962 definitions (a comma separated list of elements, surrounded by square
1963 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1964 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1967
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1968 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1969 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by
1971 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1972 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1973 have <a href="#t_vector">vector type</a>, and the number and types of
1974 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975
1976 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1977 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1978 value to zero of <em>any</em> type, including scalar and aggregate types.
1979 This is often used to avoid having to print large zero initializers
1980 (e.g. for large arrays) and is always exactly equivalent to using explicit
1981 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1982
1983 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1984 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1985 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1986 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1987 be interpreted as part of the instruction stream, metadata is a place to
1988 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1989</dl>
1990
1991</div>
1992
1993<!-- ======================================================================= -->
1994<div class="doc_subsection">
1995 <a name="globalconstants">Global Variable and Function Addresses</a>
1996</div>
1997
1998<div class="doc_text">
1999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2000<p>The addresses of <a href="#globalvars">global variables</a>
2001 and <a href="#functionstructure">functions</a> are always implicitly valid
2002 (link-time) constants. These constants are explicitly referenced when
2003 the <a href="#identifiers">identifier for the global</a> is used and always
2004 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2005 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2006
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2007<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2008<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2009@X = global i32 17
2010@Y = global i32 42
2011@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2012</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2013</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2014
2015</div>
2016
2017<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2018<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2019<div class="doc_text">
2020
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2021<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2022 indicates that the user of the value may recieve an unspecified bit-pattern.
2023 Undefined values may be of any type (other than label or void) and be used
2024 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2025
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2026<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2027 program is well defined no matter what value is used. This gives the
2028 compiler more freedom to optimize. Here are some examples of (potentially
2029 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2030
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2031
2032<div class="doc_code">
2033<pre>
2034 %A = add %X, undef
2035 %B = sub %X, undef
2036 %C = xor %X, undef
2037Safe:
2038 %A = undef
2039 %B = undef
2040 %C = undef
2041</pre>
2042</div>
2043
2044<p>This is safe because all of the output bits are affected by the undef bits.
2045Any output bit can have a zero or one depending on the input bits.</p>
2046
2047<div class="doc_code">
2048<pre>
2049 %A = or %X, undef
2050 %B = and %X, undef
2051Safe:
2052 %A = -1
2053 %B = 0
2054Unsafe:
2055 %A = undef
2056 %B = undef
2057</pre>
2058</div>
2059
2060<p>These logical operations have bits that are not always affected by the input.
2061For example, if "%X" has a zero bit, then the output of the 'and' operation will
2062always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2063such, it is unsafe to optimize or assume that the result of the and is undef.
2064However, it is safe to assume that all bits of the undef could be 0, and
2065optimize the and to 0. Likewise, it is safe to assume that all the bits of
2066the undef operand to the or could be set, allowing the or to be folded to
2067-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2068
2069<div class="doc_code">
2070<pre>
2071 %A = select undef, %X, %Y
2072 %B = select undef, 42, %Y
2073 %C = select %X, %Y, undef
2074Safe:
2075 %A = %X (or %Y)
2076 %B = 42 (or %Y)
2077 %C = %Y
2078Unsafe:
2079 %A = undef
2080 %B = undef
2081 %C = undef
2082</pre>
2083</div>
2084
2085<p>This set of examples show that undefined select (and conditional branch)
2086conditions can go "either way" but they have to come from one of the two
2087operands. In the %A example, if %X and %Y were both known to have a clear low
2088bit, then %A would have to have a cleared low bit. However, in the %C example,
2089the optimizer is allowed to assume that the undef operand could be the same as
2090%Y, allowing the whole select to be eliminated.</p>
2091
2092
2093<div class="doc_code">
2094<pre>
2095 %A = xor undef, undef
2096
2097 %B = undef
2098 %C = xor %B, %B
2099
2100 %D = undef
2101 %E = icmp lt %D, 4
2102 %F = icmp gte %D, 4
2103
2104Safe:
2105 %A = undef
2106 %B = undef
2107 %C = undef
2108 %D = undef
2109 %E = undef
2110 %F = undef
2111</pre>
2112</div>
2113
2114<p>This example points out that two undef operands are not necessarily the same.
2115This can be surprising to people (and also matches C semantics) where they
2116assume that "X^X" is always zero, even if X is undef. This isn't true for a
2117number of reasons, but the short answer is that an undef "variable" can
2118arbitrarily change its value over its "live range". This is true because the
2119"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2120logically read from arbitrary registers that happen to be around when needed,
2121so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2122to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2123would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2124
2125<div class="doc_code">
2126<pre>
2127 %A = fdiv undef, %X
2128 %B = fdiv %X, undef
2129Safe:
2130 %A = undef
2131b: unreachable
2132</pre>
2133</div>
2134
2135<p>These examples show the crucial difference between an <em>undefined
2136value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2137allowed to have an arbitrary bit-pattern. This means that the %A operation
2138can be constant folded to undef because the undef could be an SNaN, and fdiv is
2139not (currently) defined on SNaN's. However, in the second example, we can make
2140a more aggressive assumption: because the undef is allowed to be an arbitrary
2141value, 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]2142has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2143does not execute at all. This allows us to delete the divide and all code after
2144it: since the undefined operation "can't happen", the optimizer can assume that
2145it occurs in dead code.
2146</p>
2147
2148<div class="doc_code">
2149<pre>
2150a: store undef -> %X
2151b: store %X -> undef
2152Safe:
2153a: &lt;deleted&gt;
2154b: unreachable
2155</pre>
2156</div>
2157
2158<p>These examples reiterate the fdiv example: a store "of" an undefined value
2159can be assumed to not have any effect: we can assume that the value is
2160overwritten with bits that happen to match what was already there. However, a
2161store "to" an undefined location could clobber arbitrary memory, therefore, it
2162has undefined behavior.</p>
2163
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2164</div>
2165
2166<!-- ======================================================================= -->
2167<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2168</div>
2169
2170<div class="doc_text">
2171
2172<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2173 to be used as constants. Constant expressions may be of
2174 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2175 operation that does not have side effects (e.g. load and call are not
2176 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2177
2178<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2179 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2180 <dd>Truncate a constant to another type. The bit size of CST must be larger
2181 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2182
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2183 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2184 <dd>Zero extend a constant to another type. The bit size of CST must be
2185 smaller or equal to the bit size of TYPE. Both types must be
2186 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2187
2188 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2189 <dd>Sign extend a constant to another type. The bit size of CST must be
2190 smaller or equal to the bit size of TYPE. Both types must be
2191 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2192
2193 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2194 <dd>Truncate a floating point constant to another floating point type. The
2195 size of CST must be larger than the size of TYPE. Both types must be
2196 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2197
2198 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2199 <dd>Floating point extend a constant to another type. The size of CST must be
2200 smaller or equal to the size of TYPE. Both types must be floating
2201 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2202
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2203 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2204 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2205 constant. TYPE must be a scalar or vector integer type. CST must be of
2206 scalar or vector floating point type. Both CST and TYPE must be scalars,
2207 or vectors of the same number of elements. If the value won't fit in the
2208 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2209
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2210 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2211 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2212 constant. TYPE must be a scalar or vector integer type. CST must be of
2213 scalar or vector floating point type. Both CST and TYPE must be scalars,
2214 or vectors of the same number of elements. If the value won't fit in the
2215 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2216
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2217 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2218 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2219 constant. TYPE must be a scalar or vector floating point type. CST must be
2220 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2221 vectors of the same number of elements. If the value won't fit in the
2222 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2223
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2224 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2225 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2226 constant. TYPE must be a scalar or vector floating point type. CST must be
2227 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2228 vectors of the same number of elements. If the value won't fit in the
2229 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2230
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2231 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2232 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2233 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2234 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2235 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2236
2237 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2238 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2239 type. CST must be of integer type. The CST value is zero extended,
2240 truncated, or unchanged to make it fit in a pointer size. This one is
2241 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2242
2243 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2244 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2245 are the same as those for the <a href="#i_bitcast">bitcast
2246 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2247
2248 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2249 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2250 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2251 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2252 instruction, the index list may have zero or more indexes, which are
2253 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2254
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2255 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2256 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2257
2258 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2259 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2260
2261 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2262 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2263
2264 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2265 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2266 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2267
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2268 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2269 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2270 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2271
2272 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2273 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2274 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2275
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2276 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2278 be any of the <a href="#binaryops">binary</a>
2279 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2280 on operands are the same as those for the corresponding instruction
2281 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2282</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2283
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2284</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2285
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2286<!-- ======================================================================= -->
2287<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2288</div>
2289
2290<div class="doc_text">
2291
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2292<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2293 stream without affecting the behaviour of the program. There are two
2294 metadata primitives, strings and nodes. All metadata has the
2295 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2296 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2297
2298<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2299 any character by escaping non-printable characters with "\xx" where "xx" is
2300 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2301
2302<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303 (a comma separated list of elements, surrounded by braces and preceeded by an
2304 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2305 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2306
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2307<p>A metadata node will attempt to track changes to the values it holds. In the
2308 event that a value is deleted, it will be replaced with a typeless
2309 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2310
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2311<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 the program that isn't available in the instructions, or that isn't easily
2313 computable. Similarly, the code generator may expect a certain metadata
2314 format to be used to express debugging information.</p>
2315
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2316</div>
2317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2318<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2319<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2320<!-- *********************************************************************** -->
2321
2322<!-- ======================================================================= -->
2323<div class="doc_subsection">
2324<a name="inlineasm">Inline Assembler Expressions</a>
2325</div>
2326
2327<div class="doc_text">
2328
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2329<p>LLVM supports inline assembler expressions (as opposed
2330 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2331 a special value. This value represents the inline assembler as a string
2332 (containing the instructions to emit), a list of operand constraints (stored
2333 as a string), and a flag that indicates whether or not the inline asm
2334 expression has side effects. An example inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2335
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2336<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2337<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2338i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2339</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2340</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2342<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2343 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2344 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2345
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2346<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2347<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2348%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]2349</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2350</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2351
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2352<p>Inline asms with side effects not visible in the constraint list must be
2353 marked as having side effects. This is done through the use of the
2354 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2355
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2356<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2358call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2359</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2360</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2361
2362<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2363 documented here. Constraints on what can be done (e.g. duplication, moving,
2364 etc need to be documented). This is probably best done by reference to
2365 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2366
2367</div>
2368
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2369
2370<!-- *********************************************************************** -->
2371<div class="doc_section">
2372 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2373</div>
2374<!-- *********************************************************************** -->
2375
2376<p>LLVM has a number of "magic" global variables that contain data that affect
2377code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2378of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2379section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2380by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2381
2382<!-- ======================================================================= -->
2383<div class="doc_subsection">
2384<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2385</div>
2386
2387<div class="doc_text">
2388
2389<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2390href="#linkage_appending">appending linkage</a>. This array contains a list of
2391pointers to global variables and functions which may optionally have a pointer
2392cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2393
2394<pre>
2395 @X = global i8 4
2396 @Y = global i32 123
2397
2398 @llvm.used = appending global [2 x i8*] [
2399 i8* @X,
2400 i8* bitcast (i32* @Y to i8*)
2401 ], section "llvm.metadata"
2402</pre>
2403
2404<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2405compiler, assembler, and linker are required to treat the symbol as if there is
2406a reference to the global that it cannot see. For example, if a variable has
2407internal linkage and no references other than that from the <tt>@llvm.used</tt>
2408list, it cannot be deleted. This is commonly used to represent references from
2409inline asms and other things the compiler cannot "see", and corresponds to
2410"attribute((used))" in GNU C.</p>
2411
2412<p>On some targets, the code generator must emit a directive to the assembler or
2413object file to prevent the assembler and linker from molesting the symbol.</p>
2414
2415</div>
2416
2417<!-- ======================================================================= -->
2418<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2419<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2420</div>
2421
2422<div class="doc_text">
2423
2424<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2425<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2426touching the symbol. On targets that support it, this allows an intelligent
2427linker to optimize references to the symbol without being impeded as it would be
2428by <tt>@llvm.used</tt>.</p>
2429
2430<p>This is a rare construct that should only be used in rare circumstances, and
2431should not be exposed to source languages.</p>
2432
2433</div>
2434
2435<!-- ======================================================================= -->
2436<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2437<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2438</div>
2439
2440<div class="doc_text">
2441
2442<p>TODO: Describe this.</p>
2443
2444</div>
2445
2446<!-- ======================================================================= -->
2447<div class="doc_subsection">
2448<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2449</div>
2450
2451<div class="doc_text">
2452
2453<p>TODO: Describe this.</p>
2454
2455</div>
2456
2457
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2458<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2459<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2460<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2461
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2462<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2464<p>The LLVM instruction set consists of several different classifications of
2465 instructions: <a href="#terminators">terminator
2466 instructions</a>, <a href="#binaryops">binary instructions</a>,
2467 <a href="#bitwiseops">bitwise binary instructions</a>,
2468 <a href="#memoryops">memory instructions</a>, and
2469 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2470
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2471</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2472
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2473<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2474<div class="doc_subsection"> <a name="terminators">Terminator
2475Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2477<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2478
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2480 in a program ends with a "Terminator" instruction, which indicates which
2481 block should be executed after the current block is finished. These
2482 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2483 control flow, not values (the one exception being the
2484 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2485
2486<p>There are six different terminator instructions: the
2487 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2488 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2489 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2490 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2491 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2492 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2493
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2494</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2496<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2497<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2498Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2500<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2501
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2502<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2503<pre>
2504 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]2505 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2506</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2507
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2508<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2509<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2510 a value) from a function back to the caller.</p>
2511
2512<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2513 value and then causes control flow, and one that just causes control flow to
2514 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2516<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2517<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2518 return value. The type of the return value must be a
2519 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2521<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2522 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2523 value or a return value with a type that does not match its type, or if it
2524 has a void return type and contains a '<tt>ret</tt>' instruction with a
2525 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2528<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2529 the calling function's context. If the caller is a
2530 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2531 instruction after the call. If the caller was an
2532 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2533 the beginning of the "normal" destination block. If the instruction returns
2534 a value, that value shall set the call or invoke instruction's return
2535 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2536
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2537<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2538<pre>
2539 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2540 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2541 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]2542</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2543
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2544<p>Note that the code generator does not yet fully support large
2545 return values. The specific sizes that are currently supported are
2546 dependent on the target. For integers, on 32-bit targets the limit
2547 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2548 For aggregate types, the current limits are dependent on the element
2549 types; for example targets are often limited to 2 total integer
2550 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2551
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2552</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2553<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2554<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2556<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2559<pre>
2560 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]2561</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2563<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2564<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2565 different basic block in the current function. There are two forms of this
2566 instruction, corresponding to a conditional branch and an unconditional
2567 branch.</p>
2568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2569<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2571 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2572 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2573 target.</p>
2574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2576<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2577 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2578 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2579 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2581<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2582<pre>
2583Test:
2584 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2585 br i1 %cond, label %IfEqual, label %IfUnequal
2586IfEqual:
2587 <a href="#i_ret">ret</a> i32 1
2588IfUnequal:
2589 <a href="#i_ret">ret</a> i32 0
2590</pre>
2591
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2592</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2594<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2595<div class="doc_subsubsection">
2596 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2597</div>
2598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2599<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2600
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2601<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2602<pre>
2603 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2604</pre>
2605
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2607<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]2608 several different places. It is a generalization of the '<tt>br</tt>'
2609 instruction, allowing a branch to occur to one of many possible
2610 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2612<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2613<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2614 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2615 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2616 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2617
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2618<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2619<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2620 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2621 is searched for the given value. If the value is found, control flow is
2622 transfered to the corresponding destination; otherwise, control flow is
2623 transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2624
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2625<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2626<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2627 <tt>switch</tt> instruction, this instruction may be code generated in
2628 different ways. For example, it could be generated as a series of chained
2629 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2630
2631<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2632<pre>
2633 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2634 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2635 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2636
2637 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2638 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2639
2640 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2641 switch i32 %val, label %otherwise [ i32 0, label %onzero
2642 i32 1, label %onone
2643 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2644</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2645
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2646</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2647
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2648<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2649<div class="doc_subsubsection">
2650 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2651</div>
2652
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2653<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2655<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2656<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2657 &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]2658 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2659</pre>
2660
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2661<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2662<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2663 function, with the possibility of control flow transfer to either the
2664 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2665 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2666 control flow will return to the "normal" label. If the callee (or any
2667 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2668 instruction, control is interrupted and continued at the dynamically nearest
2669 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2671<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2672<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2675 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2676 convention</a> the call should use. If none is specified, the call
2677 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2678
2679 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2680 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2681 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2682
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2683 <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]2684 function value being invoked. In most cases, this is a direct function
2685 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2686 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2687
2688 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2689 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2690
2691 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692 signature argument types. If the function signature indicates the
2693 function accepts a variable number of arguments, the extra arguments can
2694 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2695
2696 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2697 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2698
2699 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2700 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2701
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2702 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2703 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2704 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2705</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2707<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2708<p>This instruction is designed to operate as a standard
2709 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2710 primary difference is that it establishes an association with a label, which
2711 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2712
2713<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2714 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2715 exception. Additionally, this is important for implementation of
2716 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2717
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2718<p>For the purposes of the SSA form, the definition of the value returned by the
2719 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2720 block to the "normal" label. If the callee unwinds then no return value is
2721 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2722
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2723<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2724<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2725 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2726 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2727 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2728 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2729</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2730
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2731</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2732
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2733<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2734
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2735<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2736Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2738<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2739
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2740<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2741<pre>
2742 unwind
2743</pre>
2744
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2745<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2746<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2747 at the first callee in the dynamic call stack which used
2748 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2749 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2750
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2751<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2752<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753 immediately halt. The dynamic call stack is then searched for the
2754 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2755 Once found, execution continues at the "exceptional" destination block
2756 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2757 instruction in the dynamic call chain, undefined behavior results.</p>
2758
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2759</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2760
2761<!-- _______________________________________________________________________ -->
2762
2763<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2764Instruction</a> </div>
2765
2766<div class="doc_text">
2767
2768<h5>Syntax:</h5>
2769<pre>
2770 unreachable
2771</pre>
2772
2773<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2774<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2775 instruction is used to inform the optimizer that a particular portion of the
2776 code is not reachable. This can be used to indicate that the code after a
2777 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2778
2779<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2780<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2781
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2782</div>
2783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2784<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2785<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2787<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2788
2789<p>Binary operators are used to do most of the computation in a program. They
2790 require two operands of the same type, execute an operation on them, and
2791 produce a single value. The operands might represent multiple data, as is
2792 the case with the <a href="#t_vector">vector</a> data type. The result value
2793 has the same type as its operands.</p>
2794
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2795<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2797</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2799<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2800<div class="doc_subsubsection">
2801 <a name="i_add">'<tt>add</tt>' Instruction</a>
2802</div>
2803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2804<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2805
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2806<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2807<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2808 &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]2809 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2810 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2811 &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]2812</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2815<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2816
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2817<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2818<p>The two arguments to the '<tt>add</tt>' instruction must
2819 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2820 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2822<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2823<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2824
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2825<p>If the sum has unsigned overflow, the result returned is the mathematical
2826 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]2827
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2828<p>Because LLVM integers use a two's complement representation, this instruction
2829 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2830
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2831<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2832 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2833 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2834 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2837<pre>
2838 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2841</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2843<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2844<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2845 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2846</div>
2847
2848<div class="doc_text">
2849
2850<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2851<pre>
2852 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2853</pre>
2854
2855<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2856<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2857
2858<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2859<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2860 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2861 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2862
2863<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2864<p>The value produced is the floating point sum of the two operands.</p>
2865
2866<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2867<pre>
2868 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2869</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2871</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2872
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2873<!-- _______________________________________________________________________ -->
2874<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2875 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2876</div>
2877
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2878<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2879
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2880<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2881<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2882 &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]2883 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2884 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2885 &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]2886</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2887
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2888<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2889<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2890 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2891
2892<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2893 '<tt>neg</tt>' instruction present in most other intermediate
2894 representations.</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>sub</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 difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2903
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2904<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2905 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2906 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2907
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2908<p>Because LLVM integers use a two's complement representation, this instruction
2909 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2910
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2911<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2912 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2913 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2914 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2916<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2917<pre>
2918 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2919 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2920</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2924<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2925<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2926 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2927</div>
2928
2929<div class="doc_text">
2930
2931<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2932<pre>
2933 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2934</pre>
2935
2936<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2937<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2939
2940<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2941 '<tt>fneg</tt>' instruction present in most other intermediate
2942 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2943
2944<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2945<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2946 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2947 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2948
2949<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2950<p>The value produced is the floating point difference of the two operands.</p>
2951
2952<h5>Example:</h5>
2953<pre>
2954 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2955 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2956</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2957
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2958</div>
2959
2960<!-- _______________________________________________________________________ -->
2961<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2962 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2963</div>
2964
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2965<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2966
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2967<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2968<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2969 &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]2970 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2971 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2972 &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]2973</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2975<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2976<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2978<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2979<p>The two arguments to the '<tt>mul</tt>' instruction must
2980 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2981 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2984<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2985
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2986<p>If the result of the multiplication has unsigned overflow, the result
2987 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2988 width of the result.</p>
2989
2990<p>Because LLVM integers use a two's complement representation, and the result
2991 is the same width as the operands, this instruction returns the correct
2992 result for both signed and unsigned integers. If a full product
2993 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2994 be sign-extended or zero-extended as appropriate to the width of the full
2995 product.</p>
2996
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2997<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2998 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2999 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3000 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3002<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3003<pre>
3004 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3005</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3006
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3007</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3008
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3009<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3010<div class="doc_subsubsection">
3011 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3012</div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3017<pre>
3018 &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]3019</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3020
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3021<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3022<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3023
3024<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3025<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3026 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3027 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3028
3029<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3030<p>The value produced is the floating point product of the two operands.</p>
3031
3032<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3033<pre>
3034 &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]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<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3040<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3041</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3043<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3045<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3046<pre>
3047 &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]3048</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3049
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3050<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3051<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3052
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3053<h5>Arguments:</h5>
3054<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3055 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3056 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3057
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3058<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3059<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3060
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3061<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3063
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3064<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3066<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067<pre>
3068 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3069</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3071</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3072
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3073<!-- _______________________________________________________________________ -->
3074<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3075</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3076
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3077<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3078
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3079<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3080<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3081 &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]3082 &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]3083</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3084
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3085<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3086<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3087
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3088<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3089<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3090 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3091 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3092
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3093<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3094<p>The value produced is the signed integer quotient of the two operands rounded
3095 towards zero.</p>
3096
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3097<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3099
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3100<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3101 undefined behavior; this is a rare case, but can occur, for example, by doing
3102 a 32-bit division of -2147483648 by -1.</p>
3103
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3104<p>If the <tt>exact</tt> keyword is present, the result value of the
3105 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3106 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3107
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3108<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109<pre>
3110 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3111</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3113</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3114
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3115<!-- _______________________________________________________________________ -->
3116<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3117Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3119<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3120
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3121<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3122<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3123 &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]3124</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3125
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3126<h5>Overview:</h5>
3127<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3128
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3129<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3130<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3132 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3133
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3134<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3135<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3136
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3137<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3138<pre>
3139 &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]3140</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3141
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3142</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3143
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3144<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3145<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3146</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3147
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3148<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3150<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151<pre>
3152 &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]3153</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3154
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3155<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3157 division of its two arguments.</p>
3158
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3159<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3160<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3161 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3162 values. Both arguments must have identical types.</p>
3163
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3164<h5>Semantics:</h5>
3165<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166 This instruction always performs an unsigned division to get the
3167 remainder.</p>
3168
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3169<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3171
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3172<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3174<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3175<pre>
3176 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3177</pre>
3178
3179</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3180
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3181<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3182<div class="doc_subsubsection">
3183 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3184</div>
3185
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3186<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3187
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3188<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3189<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3190 &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]3191</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3192
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3193<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3194<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3195 division of its two operands. This instruction can also take
3196 <a href="#t_vector">vector</a> versions of the values in which case the
3197 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3198
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3199<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3200<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3201 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3202 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3203
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3204<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3205<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3206 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3207 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3208 a value. For more information about the difference,
3209 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3210 Math Forum</a>. For a table of how this is implemented in various languages,
3211 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3212 Wikipedia: modulo operation</a>.</p>
3213
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3214<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3216
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3217<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3218 Overflow also leads to undefined behavior; this is a rare case, but can
3219 occur, for example, by taking the remainder of a 32-bit division of
3220 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3221 lets srem be implemented using instructions that return both the result of
3222 the division and the remainder.)</p>
3223
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3224<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3225<pre>
3226 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3227</pre>
3228
3229</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3230
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3231<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3232<div class="doc_subsubsection">
3233 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3234
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3235<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3236
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3237<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3238<pre>
3239 &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]3240</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3242<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3243<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3244 its two operands.</p>
3245
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3246<h5>Arguments:</h5>
3247<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3248 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3249 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3250
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3251<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3252<p>This instruction returns the <i>remainder</i> of a division. The remainder
3253 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3255<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3256<pre>
3257 &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]3258</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3259
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3260</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3261
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3262<!-- ======================================================================= -->
3263<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3264Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3266<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3267
3268<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3269 program. They are generally very efficient instructions and can commonly be
3270 strength reduced from other instructions. They require two operands of the
3271 same type, execute an operation on them, and produce a single value. The
3272 resulting value is the same type as its operands.</p>
3273
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3274</div>
3275
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3276<!-- _______________________________________________________________________ -->
3277<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3278Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3280<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3282<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3283<pre>
3284 &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]3285</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3286
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3287<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3288<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3289 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3290
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3291<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3292<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3293 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3294 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3295
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3296<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3298 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3299 is (statically or dynamically) negative or equal to or larger than the number
3300 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3301 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3302 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3303
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3304<h5>Example:</h5>
3305<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3306 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3307 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3308 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3309 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3310 &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]3311</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3312
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3313</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3314
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3315<!-- _______________________________________________________________________ -->
3316<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3317Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3318
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3319<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3321<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3322<pre>
3323 &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]3324</pre>
3325
3326<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3327<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3328 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3329
3330<h5>Arguments:</h5>
3331<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3332 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3333 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3334
3335<h5>Semantics:</h5>
3336<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3337 significant bits of the result will be filled with zero bits after the shift.
3338 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3339 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3340 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3341 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3342
3343<h5>Example:</h5>
3344<pre>
3345 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3346 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3347 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3348 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3349 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3350 &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]3351</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3352
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3353</div>
3354
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3355<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3356<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3357Instruction</a> </div>
3358<div class="doc_text">
3359
3360<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3361<pre>
3362 &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]3363</pre>
3364
3365<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3366<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3367 operand shifted to the right a specified number of bits with sign
3368 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3369
3370<h5>Arguments:</h5>
3371<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3372 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3373 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3374
3375<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3376<p>This instruction always performs an arithmetic shift right operation, The
3377 most significant bits of the result will be filled with the sign bit
3378 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3379 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3380 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3381 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3382
3383<h5>Example:</h5>
3384<pre>
3385 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3386 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3387 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3388 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3389 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3390 &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]3391</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3392
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3393</div>
3394
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3395<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3396<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3397Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3398
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3399<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3400
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3401<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3402<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3403 &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]3404</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3405
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3406<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3407<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3408 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3409
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3411<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3412 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3413 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3414
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3415<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3416<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3417
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3418<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3419 <tbody>
3420 <tr>
3421 <td>In0</td>
3422 <td>In1</td>
3423 <td>Out</td>
3424 </tr>
3425 <tr>
3426 <td>0</td>
3427 <td>0</td>
3428 <td>0</td>
3429 </tr>
3430 <tr>
3431 <td>0</td>
3432 <td>1</td>
3433 <td>0</td>
3434 </tr>
3435 <tr>
3436 <td>1</td>
3437 <td>0</td>
3438 <td>0</td>
3439 </tr>
3440 <tr>
3441 <td>1</td>
3442 <td>1</td>
3443 <td>1</td>
3444 </tr>
3445 </tbody>
3446</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3448<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3449<pre>
3450 &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]3451 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3452 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3453</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3454</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3455<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3456<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3457
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458<div class="doc_text">
3459
3460<h5>Syntax:</h5>
3461<pre>
3462 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3463</pre>
3464
3465<h5>Overview:</h5>
3466<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3467 two operands.</p>
3468
3469<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3470<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3471 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3472 values. Both arguments must have identical types.</p>
3473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3474<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3475<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3476
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3477<table border="1" cellspacing="0" cellpadding="4">
3478 <tbody>
3479 <tr>
3480 <td>In0</td>
3481 <td>In1</td>
3482 <td>Out</td>
3483 </tr>
3484 <tr>
3485 <td>0</td>
3486 <td>0</td>
3487 <td>0</td>
3488 </tr>
3489 <tr>
3490 <td>0</td>
3491 <td>1</td>
3492 <td>1</td>
3493 </tr>
3494 <tr>
3495 <td>1</td>
3496 <td>0</td>
3497 <td>1</td>
3498 </tr>
3499 <tr>
3500 <td>1</td>
3501 <td>1</td>
3502 <td>1</td>
3503 </tr>
3504 </tbody>
3505</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508<pre>
3509 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3510 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3511 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3512</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3514</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3515
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3516<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3517<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3518Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3520<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3522<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523<pre>
3524 &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]3525</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3527<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3528<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3529 its two operands. The <tt>xor</tt> is used to implement the "one's
3530 complement" operation, which is the "~" operator in C.</p>
3531
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3533<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3534 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3535 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3536
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3537<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3538<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3539
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3540<table border="1" cellspacing="0" cellpadding="4">
3541 <tbody>
3542 <tr>
3543 <td>In0</td>
3544 <td>In1</td>
3545 <td>Out</td>
3546 </tr>
3547 <tr>
3548 <td>0</td>
3549 <td>0</td>
3550 <td>0</td>
3551 </tr>
3552 <tr>
3553 <td>0</td>
3554 <td>1</td>
3555 <td>1</td>
3556 </tr>
3557 <tr>
3558 <td>1</td>
3559 <td>0</td>
3560 <td>1</td>
3561 </tr>
3562 <tr>
3563 <td>1</td>
3564 <td>1</td>
3565 <td>0</td>
3566 </tr>
3567 </tbody>
3568</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3569
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3570<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3571<pre>
3572 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3573 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3574 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3575 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3576</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3577
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3578</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3580<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3581<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3582 <a name="vectorops">Vector Operations</a>
3583</div>
3584
3585<div class="doc_text">
3586
3587<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3588 target-independent manner. These instructions cover the element-access and
3589 vector-specific operations needed to process vectors effectively. While LLVM
3590 does directly support these vector operations, many sophisticated algorithms
3591 will want to use target-specific intrinsics to take full advantage of a
3592 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3593
3594</div>
3595
3596<!-- _______________________________________________________________________ -->
3597<div class="doc_subsubsection">
3598 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3599</div>
3600
3601<div class="doc_text">
3602
3603<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3604<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3605 &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]3606</pre>
3607
3608<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3609<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3610 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3611
3612
3613<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3614<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3615 of <a href="#t_vector">vector</a> type. The second operand is an index
3616 indicating the position from which to extract the element. The index may be
3617 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3618
3619<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3620<p>The result is a scalar of the same type as the element type of
3621 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3622 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3623 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3624
3625<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3626<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3627 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3628</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3629
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3630</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3631
3632<!-- _______________________________________________________________________ -->
3633<div class="doc_subsubsection">
3634 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3635</div>
3636
3637<div class="doc_text">
3638
3639<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3640<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3641 &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]3642</pre>
3643
3644<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3645<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3646 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3647
3648<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3650 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3651 whose type must equal the element type of the first operand. The third
3652 operand is an index indicating the position at which to insert the value.
3653 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3654
3655<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3656<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3657 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3658 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3659 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3660
3661<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3662<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3663 %result = 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]3664</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3665
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3666</div>
3667
3668<!-- _______________________________________________________________________ -->
3669<div class="doc_subsubsection">
3670 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3671</div>
3672
3673<div class="doc_text">
3674
3675<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3676<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3677 &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]3678</pre>
3679
3680<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3681<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3682 from two input vectors, returning a vector with the same element type as the
3683 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3684
3685<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3687 with types that match each other. The third argument is a shuffle mask whose
3688 element type is always 'i32'. The result of the instruction is a vector
3689 whose length is the same as the shuffle mask and whose element type is the
3690 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3691
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3692<p>The shuffle mask operand is required to be a constant vector with either
3693 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3694
3695<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3696<p>The elements of the two input vectors are numbered from left to right across
3697 both of the vectors. The shuffle mask operand specifies, for each element of
3698 the result vector, which element of the two input vectors the result element
3699 gets. The element selector may be undef (meaning "don't care") and the
3700 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3701
3702<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3703<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3704 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3705 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3706 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3707 &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.
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3708 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3709 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3710 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3711 &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]3712</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3713
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3714</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3715
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3716<!-- ======================================================================= -->
3717<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3718 <a name="aggregateops">Aggregate Operations</a>
3719</div>
3720
3721<div class="doc_text">
3722
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3723<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3724
3725</div>
3726
3727<!-- _______________________________________________________________________ -->
3728<div class="doc_subsubsection">
3729 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3730</div>
3731
3732<div class="doc_text">
3733
3734<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3735<pre>
3736 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3737</pre>
3738
3739<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3741 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3742
3743<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3744<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3745 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3746 operands are constant indices to specify which value to extract in a similar
3747 manner as indices in a
3748 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3749
3750<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3751<p>The result is the value at the position in the aggregate specified by the
3752 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3753
3754<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3755<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3756 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3757</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3758
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3759</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3760
3761<!-- _______________________________________________________________________ -->
3762<div class="doc_subsubsection">
3763 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3764</div>
3765
3766<div class="doc_text">
3767
3768<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3769<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3770 &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]3771</pre>
3772
3773<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3774<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3775 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3776
3777
3778<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3779<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3780 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3781 second operand is a first-class value to insert. The following operands are
3782 constant indices indicating the position at which to insert the value in a
3783 similar manner as indices in a
3784 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3785 value to insert must have the same type as the value identified by the
3786 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3787
3788<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3789<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3790 that of <tt>val</tt> except that the value at the position specified by the
3791 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3792
3793<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3794<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3795 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3798</div>
3799
3800
3801<!-- ======================================================================= -->
3802<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3803 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3804</div>
3805
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3806<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3808<p>A key design point of an SSA-based representation is how it represents
3809 memory. In LLVM, no memory locations are in SSA form, which makes things
3810 very simple. This section describes how to read, write, allocate, and free
3811 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3812
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3813</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3814
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3815<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3816<div class="doc_subsubsection">
3817 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3818</div>
3819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3820<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3822<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3823<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3824 &lt;result&gt; = malloc &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]3825</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3827<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3828<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3829 returns a pointer to it. The object is always allocated in the generic
3830 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3832<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3833<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3835 system and returns a pointer of the appropriate type to the program. If
3836 "NumElements" is specified, it is the number of elements allocated, otherwise
3837 "NumElements" is defaulted to be one. If a constant alignment is specified,
3838 the value result of the allocation is guaranteed to be aligned to at least
3839 that boundary. If not specified, or if zero, the target can choose to align
3840 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3841
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3842<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3844<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3845<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3846 pointer is returned. The result of a zero byte allocation is undefined. The
3847 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3848
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3849<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3850<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3851 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3852
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3853 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3854 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3855 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3856 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3857 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3858</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3859
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3860<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3861
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3862</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3864<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3865<div class="doc_subsubsection">
3866 <a name="i_free">'<tt>free</tt>' Instruction</a>
3867</div>
3868
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3869<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3871<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3872<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3873 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3874</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3876<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3878 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3879
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3880<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3881<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3882 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<p>Access to the memory pointed to by the pointer is no longer defined after
3886 this instruction executes. If the pointer is null, the operation is a
3887 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3888
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3889<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3890<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3891 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3892 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3893</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3894
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3895</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3896
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3897<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3898<div class="doc_subsubsection">
3899 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3900</div>
3901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3902<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3906 &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]3907</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3910<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911 currently executing function, to be automatically released when this function
3912 returns to its caller. The object is always allocated in the generic address
3913 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3914
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3915<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3916<p>The '<tt>alloca</tt>' instruction
3917 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3918 runtime stack, returning a pointer of the appropriate type to the program.
3919 If "NumElements" is specified, it is the number of elements allocated,
3920 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3921 specified, the value result of the allocation is guaranteed to be aligned to
3922 at least that boundary. If not specified, or if zero, the target can choose
3923 to align the allocation on any convenient boundary compatible with the
3924 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3925
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3926<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3928<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3929<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3930 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3931 memory is automatically released when the function returns. The
3932 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3933 variables that must have an address available. When the function returns
3934 (either with the <tt><a href="#i_ret">ret</a></tt>
3935 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3936 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3937
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3938<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3939<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3940 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3942 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3943 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3944</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3945
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3946</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3947
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3948<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3949<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3950Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3952<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3954<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955<pre>
3956 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3957 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3958</pre>
3959
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3960<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3961<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3963<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3964<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3965 from which to load. The pointer must point to
3966 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3967 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3968 number or order of execution of this <tt>load</tt> with other
3969 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3970 instructions. </p>
3971
3972<p>The optional constant "align" argument specifies the alignment of the
3973 operation (that is, the alignment of the memory address). A value of 0 or an
3974 omitted "align" argument means that the operation has the preferential
3975 alignment for the target. It is the responsibility of the code emitter to
3976 ensure that the alignment information is correct. Overestimating the
3977 alignment results in an undefined behavior. Underestimating the alignment may
3978 produce less efficient code. An alignment of 1 is always safe.</p>
3979
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3980<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981<p>The location of memory pointed to is loaded. If the value being loaded is of
3982 scalar type then the number of bytes read does not exceed the minimum number
3983 of bytes needed to hold all bits of the type. For example, loading an
3984 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3985 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3986 is undefined if the value was not originally written using a store of the
3987 same type.</p>
3988
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3989<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3990<pre>
3991 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3992 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3993 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3994</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3996</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3997
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3998<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3999<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4000Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4002<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4004<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4005<pre>
4006 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]4007 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]4008</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4010<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4011<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4013<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4014<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4015 and an address at which to store it. The type of the
4016 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4017 the <a href="#t_firstclass">first class</a> type of the
4018 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4019 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4020 or order of execution of this <tt>store</tt> with other
4021 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4022 instructions.</p>
4023
4024<p>The optional constant "align" argument specifies the alignment of the
4025 operation (that is, the alignment of the memory address). A value of 0 or an
4026 omitted "align" argument means that the operation has the preferential
4027 alignment for the target. It is the responsibility of the code emitter to
4028 ensure that the alignment information is correct. Overestimating the
4029 alignment results in an undefined behavior. Underestimating the alignment may
4030 produce less efficient code. An alignment of 1 is always safe.</p>
4031
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4032<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4033<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4034 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4035 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4036 does not exceed the minimum number of bytes needed to hold all bits of the
4037 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4038 writing a value of a type like <tt>i20</tt> with a size that is not an
4039 integral number of bytes, it is unspecified what happens to the extra bits
4040 that do not belong to the type, but they will typically be overwritten.</p>
4041
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4042<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4043<pre>
4044 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4045 store i32 3, i32* %ptr <i>; yields {void}</i>
4046 %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]4047</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4048
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4049</div>
4050
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4051<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4052<div class="doc_subsubsection">
4053 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4054</div>
4055
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4056<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4057
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4058<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4059<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4060 &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]4061 &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]4062</pre>
4063
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4064<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4066 subelement of an aggregate data structure. It performs address calculation
4067 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4068
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4069<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4070<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4071 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4072 elements of the aggregate object are indexed. The interpretation of each
4073 index is dependent on the type being indexed into. The first index always
4074 indexes the pointer value given as the first argument, the second index
4075 indexes a value of the type pointed to (not necessarily the value directly
4076 pointed to, since the first index can be non-zero), etc. The first type
4077 indexed into must be a pointer value, subsequent types can be arrays, vectors
4078 and structs. Note that subsequent types being indexed into can never be
4079 pointers, since that would require loading the pointer before continuing
4080 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4081
4082<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]4083 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4085 vector, integers of any width are allowed, and they are not required to be
4086 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4088<p>For example, let's consider a C code fragment and how it gets compiled to
4089 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4090
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4091<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4092<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4093struct RT {
4094 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4095 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4096 char C;
4097};
4098struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4099 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4100 double Y;
4101 struct RT Z;
4102};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4103
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4104int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4105 return &amp;s[1].Z.B[5][13];
4106}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4107</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4108</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4109
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4110<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4111
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4112<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4113<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4114%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4115%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4116
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4117define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4118entry:
4119 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4120 ret i32* %reg
4121}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4122</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4123</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4124
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4125<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4126<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]4127 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4128 }</tt>' type, a structure. The second index indexes into the third element
4129 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4130 i8 }</tt>' type, another structure. The third index indexes into the second
4131 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4132 array. The two dimensions of the array are subscripted into, yielding an
4133 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4134 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4135
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4136<p>Note that it is perfectly legal to index partially through a structure,
4137 returning a pointer to an inner element. Because of this, the LLVM code for
4138 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4139
4140<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4141 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4142 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4143 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4144 %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]4145 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4146 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4147 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4148 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4149</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4150
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4151<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4152 <tt>getelementptr</tt> is undefined if the base pointer is not an
4153 <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]4154 that would be formed by successive addition of the offsets implied by the
4155 indices to the base address with infinitely precise arithmetic are not an
4156 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4157 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4158 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4159
4160<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4161 the base address with silently-wrapping two's complement arithmetic, and
4162 the result value of the <tt>getelementptr</tt> may be outside the object
4163 pointed to by the base pointer. The result value may not necessarily be
4164 used to access memory though, even if it happens to point into allocated
4165 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4166 section for more information.</p>
4167
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4168<p>The getelementptr instruction is often confusing. For some more insight into
4169 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4170
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4171<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4172<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4173 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4174 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4175 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4176 %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]4177 <i>; yields i8*:eptr</i>
4178 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4179 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4180 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4181</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4182
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4183</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4184
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4185<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4186<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4187</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4189<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4190
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4191<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192 which all take a single operand and a type. They perform various bit
4193 conversions on the operand.</p>
4194
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4195</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4196
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4197<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4198<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4199 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4200</div>
4201<div class="doc_text">
4202
4203<h5>Syntax:</h5>
4204<pre>
4205 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4206</pre>
4207
4208<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4209<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4210 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4211
4212<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4213<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4214 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4215 size and type of the result, which must be
4216 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4217 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4218 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4219
4220<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4221<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4222 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4223 source size must be larger than the destination size, <tt>trunc</tt> cannot
4224 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4225
4226<h5>Example:</h5>
4227<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4228 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4229 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4230 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4231</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4232
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4233</div>
4234
4235<!-- _______________________________________________________________________ -->
4236<div class="doc_subsubsection">
4237 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4238</div>
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
4243 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4244</pre>
4245
4246<h5>Overview:</h5>
4247<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4249
4250
4251<h5>Arguments:</h5>
4252<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]4253 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4254 also be of <a href="#t_integer">integer</a> type. The bit size of the
4255 <tt>value</tt> must be smaller than the bit size of the destination type,
4256 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4257
4258<h5>Semantics:</h5>
4259<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]4260 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4261
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4262<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]4263
4264<h5>Example:</h5>
4265<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4266 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4267 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4268</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4269
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4270</div>
4271
4272<!-- _______________________________________________________________________ -->
4273<div class="doc_subsubsection">
4274 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4275</div>
4276<div class="doc_text">
4277
4278<h5>Syntax:</h5>
4279<pre>
4280 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4281</pre>
4282
4283<h5>Overview:</h5>
4284<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4285
4286<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4287<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4288 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4289 also be of <a href="#t_integer">integer</a> type. The bit size of the
4290 <tt>value</tt> must be smaller than the bit size of the destination type,
4291 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4292
4293<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4294<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4295 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4296 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4297
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4298<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]4299
4300<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4301<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4302 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4303 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4304</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4305
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4306</div>
4307
4308<!-- _______________________________________________________________________ -->
4309<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4310 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4311</div>
4312
4313<div class="doc_text">
4314
4315<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4316<pre>
4317 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4318</pre>
4319
4320<h5>Overview:</h5>
4321<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4322 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4323
4324<h5>Arguments:</h5>
4325<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4326 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4327 to cast it to. The size of <tt>value</tt> must be larger than the size of
4328 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4329 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4330
4331<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4332<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4333 <a href="#t_floating">floating point</a> type to a smaller
4334 <a href="#t_floating">floating point</a> type. If the value cannot fit
4335 within the destination type, <tt>ty2</tt>, then the results are
4336 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4337
4338<h5>Example:</h5>
4339<pre>
4340 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4341 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4342</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4343
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4344</div>
4345
4346<!-- _______________________________________________________________________ -->
4347<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4348 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4349</div>
4350<div class="doc_text">
4351
4352<h5>Syntax:</h5>
4353<pre>
4354 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4355</pre>
4356
4357<h5>Overview:</h5>
4358<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]4359 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4360
4361<h5>Arguments:</h5>
4362<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4363 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4364 a <a href="#t_floating">floating point</a> type to cast it to. The source
4365 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4366
4367<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4368<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4369 <a href="#t_floating">floating point</a> type to a larger
4370 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4371 used to make a <i>no-op cast</i> because it always changes bits. Use
4372 <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]4373
4374<h5>Example:</h5>
4375<pre>
4376 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4377 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4378</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4379
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4380</div>
4381
4382<!-- _______________________________________________________________________ -->
4383<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4384 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4385</div>
4386<div class="doc_text">
4387
4388<h5>Syntax:</h5>
4389<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4390 &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]4391</pre>
4392
4393<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4394<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4395 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4396
4397<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4398<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4399 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4400 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4401 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4402 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4403
4404<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<p>The '<tt>fptoui</tt>' instruction converts its
4406 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4407 towards zero) unsigned integer value. If the value cannot fit
4408 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4409
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4410<h5>Example:</h5>
4411<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4412 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4413 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4414 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4415</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4416
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4417</div>
4418
4419<!-- _______________________________________________________________________ -->
4420<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4421 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4422</div>
4423<div class="doc_text">
4424
4425<h5>Syntax:</h5>
4426<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4427 &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]4428</pre>
4429
4430<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4431<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4432 <a href="#t_floating">floating point</a> <tt>value</tt> to
4433 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4434
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4435<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4437 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4438 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4439 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4440 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4441
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4442<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4443<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4444 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4445 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4446 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4447
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4448<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4449<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4450 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4451 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4452 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4453</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4455</div>
4456
4457<!-- _______________________________________________________________________ -->
4458<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4459 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4460</div>
4461<div class="doc_text">
4462
4463<h5>Syntax:</h5>
4464<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4465 &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]4466</pre>
4467
4468<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4469<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4470 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4471
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4472<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4473<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]4474 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4475 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4476 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4477 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4478
4479<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4480<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4481 integer quantity and converts it to the corresponding floating point
4482 value. If the value cannot fit in the floating point value, the results are
4483 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4484
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4485<h5>Example:</h5>
4486<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4487 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4488 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4489</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4491</div>
4492
4493<!-- _______________________________________________________________________ -->
4494<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4495 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4496</div>
4497<div class="doc_text">
4498
4499<h5>Syntax:</h5>
4500<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4501 &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]4502</pre>
4503
4504<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4505<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4506 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4507
4508<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4509<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]4510 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4511 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4512 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4513 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4514
4515<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4516<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4517 quantity and converts it to the corresponding floating point value. If the
4518 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4519
4520<h5>Example:</h5>
4521<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4522 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4523 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4524</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4526</div>
4527
4528<!-- _______________________________________________________________________ -->
4529<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4530 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4531</div>
4532<div class="doc_text">
4533
4534<h5>Syntax:</h5>
4535<pre>
4536 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4537</pre>
4538
4539<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4541 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4542
4543<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4544<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4545 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4546 <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]4547
4548<h5>Semantics:</h5>
4549<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4550 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4551 truncating or zero extending that value to the size of the integer type. If
4552 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4553 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4554 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4555 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4556
4557<h5>Example:</h5>
4558<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4559 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4560 %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]4561</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4562
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4563</div>
4564
4565<!-- _______________________________________________________________________ -->
4566<div class="doc_subsubsection">
4567 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4568</div>
4569<div class="doc_text">
4570
4571<h5>Syntax:</h5>
4572<pre>
4573 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4574</pre>
4575
4576<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4577<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4578 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4579
4580<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4581<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4582 value to cast, and a type to cast it to, which must be a
4583 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4584
4585<h5>Semantics:</h5>
4586<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4587 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4588 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4589 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4590 than the size of a pointer then a zero extension is done. If they are the
4591 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4592
4593<h5>Example:</h5>
4594<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4595 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4596 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4597 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4598</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4599
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4600</div>
4601
4602<!-- _______________________________________________________________________ -->
4603<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4604 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4605</div>
4606<div class="doc_text">
4607
4608<h5>Syntax:</h5>
4609<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4610 &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]4611</pre>
4612
4613<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4614<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4616
4617<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4618<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4619 non-aggregate first class value, and a type to cast it to, which must also be
4620 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4621 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4622 identical. If the source type is a pointer, the destination type must also be
4623 a pointer. This instruction supports bitwise conversion of vectors to
4624 integers and to vectors of other types (as long as they have the same
4625 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4626
4627<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4628<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4629 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4630 this conversion. The conversion is done as if the <tt>value</tt> had been
4631 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4632 be converted to other pointer types with this instruction. To convert
4633 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4634 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4635
4636<h5>Example:</h5>
4637<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4638 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4639 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4640 %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]4641</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4643</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4644
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4645<!-- ======================================================================= -->
4646<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4647
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4648<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4649
4650<p>The instructions in this category are the "miscellaneous" instructions, which
4651 defy better classification.</p>
4652
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4653</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4657</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4659<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4661<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662<pre>
4663 &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]4664</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4666<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4667<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4668 boolean values based on comparison of its two integer, integer vector, or
4669 pointer operands.</p>
4670
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4671<h5>Arguments:</h5>
4672<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4673 the condition code indicating the kind of comparison to perform. It is not a
4674 value, just a keyword. The possible condition code are:</p>
4675
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4676<ol>
4677 <li><tt>eq</tt>: equal</li>
4678 <li><tt>ne</tt>: not equal </li>
4679 <li><tt>ugt</tt>: unsigned greater than</li>
4680 <li><tt>uge</tt>: unsigned greater or equal</li>
4681 <li><tt>ult</tt>: unsigned less than</li>
4682 <li><tt>ule</tt>: unsigned less or equal</li>
4683 <li><tt>sgt</tt>: signed greater than</li>
4684 <li><tt>sge</tt>: signed greater or equal</li>
4685 <li><tt>slt</tt>: signed less than</li>
4686 <li><tt>sle</tt>: signed less or equal</li>
4687</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4689<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4690 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4691 typed. They must also be identical types.</p>
4692
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4693<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4694<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4695 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]4696 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]4697 result, as follows:</p>
4698
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4699<ol>
4700 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4701 <tt>false</tt> otherwise. No sign interpretation is necessary or
4702 performed.</li>
4703
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4704 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4705 <tt>false</tt> otherwise. No sign interpretation is necessary or
4706 performed.</li>
4707
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4708 <li><tt>ugt</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 <tt>op2</tt>.</li>
4710
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4711 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4712 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4713 to <tt>op2</tt>.</li>
4714
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4715 <li><tt>ult</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 <tt>op2</tt>.</li>
4717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4718 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4721 <li><tt>sgt</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 <tt>op2</tt>.</li>
4723
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4724 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4726 to <tt>op2</tt>.</li>
4727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4728 <li><tt>slt</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 <tt>op2</tt>.</li>
4730
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4731 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732 <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]4733</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4735<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4736 values are compared as if they were integers.</p>
4737
4738<p>If the operands are integer vectors, then they are compared element by
4739 element. The result is an <tt>i1</tt> vector with the same number of elements
4740 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4741
4742<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4743<pre>
4744 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4745 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4747 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4748 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4749 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4750</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4751
4752<p>Note that the code generator does not yet support vector types with
4753 the <tt>icmp</tt> instruction.</p>
4754
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4755</div>
4756
4757<!-- _______________________________________________________________________ -->
4758<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4759</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4761<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4763<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764<pre>
4765 &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]4766</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4768<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4769<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4770 values based on comparison of its operands.</p>
4771
4772<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^]4773(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4774
4775<p>If the operands are floating point vectors, then the result type is a vector
4776 of boolean with the same number of elements as the operands being
4777 compared.</p>
4778
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4779<h5>Arguments:</h5>
4780<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4781 the condition code indicating the kind of comparison to perform. It is not a
4782 value, just a keyword. The possible condition code are:</p>
4783
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4784<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4785 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4786 <li><tt>oeq</tt>: ordered and equal</li>
4787 <li><tt>ogt</tt>: ordered and greater than </li>
4788 <li><tt>oge</tt>: ordered and greater than or equal</li>
4789 <li><tt>olt</tt>: ordered and less than </li>
4790 <li><tt>ole</tt>: ordered and less than or equal</li>
4791 <li><tt>one</tt>: ordered and not equal</li>
4792 <li><tt>ord</tt>: ordered (no nans)</li>
4793 <li><tt>ueq</tt>: unordered or equal</li>
4794 <li><tt>ugt</tt>: unordered or greater than </li>
4795 <li><tt>uge</tt>: unordered or greater than or equal</li>
4796 <li><tt>ult</tt>: unordered or less than </li>
4797 <li><tt>ule</tt>: unordered or less than or equal</li>
4798 <li><tt>une</tt>: unordered or not equal</li>
4799 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4800 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4801</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4803<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4804 <i>unordered</i> means that either operand may be a QNAN.</p>
4805
4806<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4807 a <a href="#t_floating">floating point</a> type or
4808 a <a href="#t_vector">vector</a> of floating point type. They must have
4809 identical types.</p>
4810
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4811<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4812<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4813 according to the condition code given as <tt>cond</tt>. If the operands are
4814 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame^]4815 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4816 follows:</p>
4817
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4818<ol>
4819 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4820
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4821 <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]4822 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4823
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4824 <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]4825 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4826
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4827 <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]4828 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4829
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4830 <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]4831 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4832
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4835
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4836 <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]4837 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4838
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4839 <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]4840
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4841 <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]4842 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4843
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4844 <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]4845 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4846
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4849
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4852
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4855
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4858
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4859 <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]4860
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4861 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4862</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4863
4864<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4865<pre>
4866 &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]4867 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4868 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4869 &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]4870</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4871
4872<p>Note that the code generator does not yet support vector types with
4873 the <tt>fcmp</tt> instruction.</p>
4874
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4875</div>
4876
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4877<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4878<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4879 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4880</div>
4881
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4882<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4883
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4884<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4885<pre>
4886 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4887</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4888
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4889<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4890<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4891 SSA graph representing the function.</p>
4892
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4894<p>The type of the incoming values is specified with the first type field. After
4895 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4896 one pair for each predecessor basic block of the current block. Only values
4897 of <a href="#t_firstclass">first class</a> type may be used as the value
4898 arguments to the PHI node. Only labels may be used as the label
4899 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4900
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4901<p>There must be no non-phi instructions between the start of a basic block and
4902 the PHI instructions: i.e. PHI instructions must be first in a basic
4903 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4905<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4906 occur on the edge from the corresponding predecessor block to the current
4907 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4908 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4909
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4910<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4911<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4912 specified by the pair corresponding to the predecessor basic block that
4913 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4914
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4915<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4916<pre>
4917Loop: ; Infinite loop that counts from 0 on up...
4918 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4919 %nextindvar = add i32 %indvar, 1
4920 br label %Loop
4921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4922
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4923</div>
4924
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4925<!-- _______________________________________________________________________ -->
4926<div class="doc_subsubsection">
4927 <a name="i_select">'<tt>select</tt>' Instruction</a>
4928</div>
4929
4930<div class="doc_text">
4931
4932<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4933<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4934 &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>
4935
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4936 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4937</pre>
4938
4939<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4940<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4941 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4942
4943
4944<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4945<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4946 values indicating the condition, and two values of the
4947 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4948 vectors and the condition is a scalar, then entire vectors are selected, not
4949 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4950
4951<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4952<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4953 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4954
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4955<p>If the condition is a vector of i1, then the value arguments must be vectors
4956 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4957
4958<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4960 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4961</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4962
4963<p>Note that the code generator does not yet support conditions
4964 with vector type.</p>
4965
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4966</div>
4967
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4968<!-- _______________________________________________________________________ -->
4969<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4970 <a name="i_call">'<tt>call</tt>' Instruction</a>
4971</div>
4972
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4973<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4975<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4976<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4977 &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]4978</pre>
4979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4981<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4983<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4984<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4985
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4986<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4987 <li>The optional "tail" marker indicates whether the callee function accesses
4988 any allocas or varargs in the caller. If the "tail" marker is present,
4989 the function call is eligible for tail call optimization. Note that calls
4990 may be marked "tail" even if they do not occur before
4991 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4992
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4993 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4994 convention</a> the call should use. If none is specified, the call
4995 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4996
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4997 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4998 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4999 '<tt>inreg</tt>' attributes are valid here.</li>
5000
5001 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5002 type of the return value. Functions that return no value are marked
5003 <tt><a href="#t_void">void</a></tt>.</li>
5004
5005 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5006 being invoked. The argument types must match the types implied by this
5007 signature. This type can be omitted if the function is not varargs and if
5008 the function type does not return a pointer to a function.</li>
5009
5010 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5011 be invoked. In most cases, this is a direct function invocation, but
5012 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5013 to function value.</li>
5014
5015 <li>'<tt>function args</tt>': argument list whose types match the function
5016 signature argument types. All arguments must be of
5017 <a href="#t_firstclass">first class</a> type. If the function signature
5018 indicates the function accepts a variable number of arguments, the extra
5019 arguments can be specified.</li>
5020
5021 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5022 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5023 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5024</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5025
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5026<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5027<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5028 a specified function, with its incoming arguments bound to the specified
5029 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5030 function, control flow continues with the instruction after the function
5031 call, and the return value of the function is bound to the result
5032 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5033
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5034<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5035<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5036 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5037 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5038 %X = tail call i32 @foo() <i>; yields i32</i>
5039 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5040 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5041
5042 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5043 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5044 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5045 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5046 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5047 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5048</pre>
5049
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5050<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]5051standard C99 library as being the C99 library functions, and may perform
5052optimizations or generate code for them under that assumption. This is
5053something we'd like to change in the future to provide better support for
5054freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5055
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5056</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5057
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5058<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5059<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5060 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5061</div>
5062
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5063<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5064
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5065<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5066<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5067 &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]5068</pre>
5069
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5070<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5071<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5072 the "variable argument" area of a function call. It is used to implement the
5073 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5074
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5075<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5076<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5077 argument. It returns a value of the specified argument type and increments
5078 the <tt>va_list</tt> to point to the next argument. The actual type
5079 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5080
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5081<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5083 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5084 to the next argument. For more information, see the variable argument
5085 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5086
5087<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]5088 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5089 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5090
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5091<p><tt>va_arg</tt> is an LLVM instruction instead of
5092 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5093 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5094
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5095<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5096<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5097
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5098<p>Note that the code generator does not yet fully support va_arg on many
5099 targets. Also, it does not currently support va_arg with aggregate types on
5100 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5101
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5102</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5103
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5104<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5105<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5106<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5108<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5109
5110<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5111 well known names and semantics and are required to follow certain
5112 restrictions. Overall, these intrinsics represent an extension mechanism for
5113 the LLVM language that does not require changing all of the transformations
5114 in LLVM when adding to the language (or the bitcode reader/writer, the
5115 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5116
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5117<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5118 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5119 begin with this prefix. Intrinsic functions must always be external
5120 functions: you cannot define the body of intrinsic functions. Intrinsic
5121 functions may only be used in call or invoke instructions: it is illegal to
5122 take the address of an intrinsic function. Additionally, because intrinsic
5123 functions are part of the LLVM language, it is required if any are added that
5124 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5125
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5126<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5127 family of functions that perform the same operation but on different data
5128 types. Because LLVM can represent over 8 million different integer types,
5129 overloading is used commonly to allow an intrinsic function to operate on any
5130 integer type. One or more of the argument types or the result type can be
5131 overloaded to accept any integer type. Argument types may also be defined as
5132 exactly matching a previous argument's type or the result type. This allows
5133 an intrinsic function which accepts multiple arguments, but needs all of them
5134 to be of the same type, to only be overloaded with respect to a single
5135 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5136
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5137<p>Overloaded intrinsics will have the names of its overloaded argument types
5138 encoded into its function name, each preceded by a period. Only those types
5139 which are overloaded result in a name suffix. Arguments whose type is matched
5140 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5141 can take an integer of any width and returns an integer of exactly the same
5142 integer width. This leads to a family of functions such as
5143 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5144 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5145 suffix is required. Because the argument's type is matched against the return
5146 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5147
5148<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5149 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5150
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5151</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5152
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5153<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5154<div class="doc_subsection">
5155 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5156</div>
5157
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5158<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5160<p>Variable argument support is defined in LLVM with
5161 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5162 intrinsic functions. These functions are related to the similarly named
5163 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5165<p>All of these functions operate on arguments that use a target-specific value
5166 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5167 not define what this type is, so all transformations should be prepared to
5168 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5169
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5170<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]5171 instruction and the variable argument handling intrinsic functions are
5172 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5173
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5174<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5175<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5176define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5177 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5178 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5179 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5180 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5181
5182 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5183 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5184
5185 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5186 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5187 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5188 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5189 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5190
5191 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5192 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5193 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5194}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5195
5196declare void @llvm.va_start(i8*)
5197declare void @llvm.va_copy(i8*, i8*)
5198declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5199</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5200</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5201
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5202</div>
5203
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5204<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5205<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5206 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5207</div>
5208
5209
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5210<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5212<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5213<pre>
5214 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5215</pre>
5216
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5217<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5218<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5219 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]5220
5221<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5222<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]5223
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5224<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5225<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]5226 macro available in C. In a target-dependent way, it initializes
5227 the <tt>va_list</tt> element to which the argument points, so that the next
5228 call to <tt>va_arg</tt> will produce the first variable argument passed to
5229 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5230 need to know the last argument of the function as the compiler can figure
5231 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5232
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5233</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5234
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5235<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5236<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5237 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5238</div>
5239
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5240<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5241
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5242<h5>Syntax:</h5>
5243<pre>
5244 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5245</pre>
5246
5247<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5248<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5249 which has been initialized previously
5250 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5251 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5252
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5253<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5254<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]5255
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5256<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5257<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]5258 macro available in C. In a target-dependent way, it destroys
5259 the <tt>va_list</tt> element to which the argument points. Calls
5260 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5261 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5262 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5263
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5264</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5265
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5266<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5267<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5268 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5269</div>
5270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5271<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5272
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5273<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5274<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5275 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5276</pre>
5277
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5278<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5279<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5280 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5281
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5282<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5283<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]5284 The second argument is a pointer to a <tt>va_list</tt> element to copy
5285 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5286
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5287<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5288<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]5289 macro available in C. In a target-dependent way, it copies the
5290 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5291 element. This intrinsic is necessary because
5292 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5293 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5294
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5295</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5296
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5297<!-- ======================================================================= -->
5298<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5299 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5300</div>
5301
5302<div class="doc_text">
5303
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5304<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5305Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5306intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5307roots on the stack</a>, as well as garbage collector implementations that
5308require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5309barriers. Front-ends for type-safe garbage collected languages should generate
5310these intrinsics to make use of the LLVM garbage collectors. For more details,
5311see <a href="GarbageCollection.html">Accurate Garbage Collection with
5312LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5313
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5314<p>The garbage collection intrinsics only operate on objects in the generic
5315 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5316
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5317</div>
5318
5319<!-- _______________________________________________________________________ -->
5320<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5321 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5322</div>
5323
5324<div class="doc_text">
5325
5326<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5327<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5328 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5329</pre>
5330
5331<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5332<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]5333 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5334
5335<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5336<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5337 root pointer. The second pointer (which must be either a constant or a
5338 global value address) contains the meta-data to be associated with the
5339 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5340
5341<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5342<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]5343 location. At compile-time, the code generator generates information to allow
5344 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5345 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5346 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5347
5348</div>
5349
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5352 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5358<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5359 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5360</pre>
5361
5362<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5363<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5364 locations, allowing garbage collector implementations that require read
5365 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5366
5367<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5368<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]5369 allocated from the garbage collector. The first object is a pointer to the
5370 start of the referenced object, if needed by the language runtime (otherwise
5371 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372
5373<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5374<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5375 instruction, but may be replaced with substantially more complex code by the
5376 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5377 may only be used in a function which <a href="#gc">specifies a GC
5378 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5379
5380</div>
5381
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5382<!-- _______________________________________________________________________ -->
5383<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5384 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5385</div>
5386
5387<div class="doc_text">
5388
5389<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5390<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5391 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5392</pre>
5393
5394<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5395<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5396 locations, allowing garbage collector implementations that require write
5397 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5398
5399<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5400<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]5401 object to store it to, and the third is the address of the field of Obj to
5402 store to. If the runtime does not require a pointer to the object, Obj may
5403 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404
5405<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5406<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5407 instruction, but may be replaced with substantially more complex code by the
5408 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5409 may only be used in a function which <a href="#gc">specifies a GC
5410 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5411
5412</div>
5413
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5414<!-- ======================================================================= -->
5415<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5416 <a name="int_codegen">Code Generator Intrinsics</a>
5417</div>
5418
5419<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5420
5421<p>These intrinsics are provided by LLVM to expose special features that may
5422 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5423
5424</div>
5425
5426<!-- _______________________________________________________________________ -->
5427<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5428 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5429</div>
5430
5431<div class="doc_text">
5432
5433<h5>Syntax:</h5>
5434<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5435 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5436</pre>
5437
5438<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5439<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5440 target-specific value indicating the return address of the current function
5441 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5442
5443<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5444<p>The argument to this intrinsic indicates which function to return the address
5445 for. Zero indicates the calling function, one indicates its caller, etc.
5446 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5447
5448<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5449<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5450 indicating the return address of the specified call frame, or zero if it
5451 cannot be identified. The value returned by this intrinsic is likely to be
5452 incorrect or 0 for arguments other than zero, so it should only be used for
5453 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5454
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5455<p>Note that calling this intrinsic does not prevent function inlining or other
5456 aggressive transformations, so the value returned may not be that of the
5457 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5458
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5459</div>
5460
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5461<!-- _______________________________________________________________________ -->
5462<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5463 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5464</div>
5465
5466<div class="doc_text">
5467
5468<h5>Syntax:</h5>
5469<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5470 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5471</pre>
5472
5473<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5475 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5476
5477<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5478<p>The argument to this intrinsic indicates which function to return the frame
5479 pointer for. Zero indicates the calling function, one indicates its caller,
5480 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5481
5482<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5483<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5484 indicating the frame address of the specified call frame, or zero if it
5485 cannot be identified. The value returned by this intrinsic is likely to be
5486 incorrect or 0 for arguments other than zero, so it should only be used for
5487 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5489<p>Note that calling this intrinsic does not prevent function inlining or other
5490 aggressive transformations, so the value returned may not be that of the
5491 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5492
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5493</div>
5494
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5495<!-- _______________________________________________________________________ -->
5496<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5497 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5498</div>
5499
5500<div class="doc_text">
5501
5502<h5>Syntax:</h5>
5503<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5504 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5505</pre>
5506
5507<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5509 of the function stack, for use
5510 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5511 useful for implementing language features like scoped automatic variable
5512 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5513
5514<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5515<p>This intrinsic returns a opaque pointer value that can be passed
5516 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5517 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5518 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5519 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5520 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5521 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5522
5523</div>
5524
5525<!-- _______________________________________________________________________ -->
5526<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5527 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5528</div>
5529
5530<div class="doc_text">
5531
5532<h5>Syntax:</h5>
5533<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5534 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5535</pre>
5536
5537<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5538<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5539 the function stack to the state it was in when the
5540 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5541 executed. This is useful for implementing language features like scoped
5542 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5543
5544<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5545<p>See the description
5546 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5547
5548</div>
5549
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5550<!-- _______________________________________________________________________ -->
5551<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5552 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5553</div>
5554
5555<div class="doc_text">
5556
5557<h5>Syntax:</h5>
5558<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5559 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]5560</pre>
5561
5562<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5563<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5564 insert a prefetch instruction if supported; otherwise, it is a noop.
5565 Prefetches have no effect on the behavior of the program but can change its
5566 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5567
5568<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5569<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5570 specifier determining if the fetch should be for a read (0) or write (1),
5571 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5572 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5573 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5574
5575<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5576<p>This intrinsic does not modify the behavior of the program. In particular,
5577 prefetches cannot trap and do not produce a value. On targets that support
5578 this intrinsic, the prefetch can provide hints to the processor cache for
5579 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5580
5581</div>
5582
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5583<!-- _______________________________________________________________________ -->
5584<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5585 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5586</div>
5587
5588<div class="doc_text">
5589
5590<h5>Syntax:</h5>
5591<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5592 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5593</pre>
5594
5595<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5596<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5597 Counter (PC) in a region of code to simulators and other tools. The method
5598 is target specific, but it is expected that the marker will use exported
5599 symbols to transmit the PC of the marker. The marker makes no guarantees
5600 that it will remain with any specific instruction after optimizations. It is
5601 possible that the presence of a marker will inhibit optimizations. The
5602 intended use is to be inserted after optimizations to allow correlations of
5603 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5604
5605<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5606<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5607
5608<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5609<p>This intrinsic does not modify the behavior of the program. Backends that do
5610 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5611
5612</div>
5613
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5614<!-- _______________________________________________________________________ -->
5615<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5616 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5617</div>
5618
5619<div class="doc_text">
5620
5621<h5>Syntax:</h5>
5622<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5623 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5624</pre>
5625
5626<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5628 counter register (or similar low latency, high accuracy clocks) on those
5629 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5630 should map to RPCC. As the backing counters overflow quickly (on the order
5631 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5632
5633<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634<p>When directly supported, reading the cycle counter should not modify any
5635 memory. Implementations are allowed to either return a application specific
5636 value or a system wide value. On backends without support, this is lowered
5637 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5638
5639</div>
5640
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5641<!-- ======================================================================= -->
5642<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5643 <a name="int_libc">Standard C Library Intrinsics</a>
5644</div>
5645
5646<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5647
5648<p>LLVM provides intrinsics for a few important standard C library functions.
5649 These intrinsics allow source-language front-ends to pass information about
5650 the alignment of the pointer arguments to the code generator, providing
5651 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5652
5653</div>
5654
5655<!-- _______________________________________________________________________ -->
5656<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5657 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5658</div>
5659
5660<div class="doc_text">
5661
5662<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5663<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5664 integer bit width. Not all targets support all bit widths however.</p>
5665
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5666<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5668 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5669 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5670 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5671 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5672 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5673 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5674 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5675</pre>
5676
5677<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5678<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5679 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5680
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5681<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5682 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5685<p>The first argument is a pointer to the destination, the second is a pointer
5686 to the source. The third argument is an integer argument specifying the
5687 number of bytes to copy, and the fourth argument is the alignment of the
5688 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5689
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5690<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5691 then the caller guarantees that both the source and destination pointers are
5692 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5693
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5694<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5695<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5696 source location to the destination location, which are not allowed to
5697 overlap. It copies "len" bytes of memory over. If the argument is known to
5698 be aligned to some boundary, this can be specified as the fourth argument,
5699 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5700
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5701</div>
5702
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5703<!-- _______________________________________________________________________ -->
5704<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5705 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5706</div>
5707
5708<div class="doc_text">
5709
5710<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5711<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]5712 width. Not all targets support all bit widths however.</p>
5713
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5714<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5715 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5716 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5717 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5718 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5719 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5720 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5721 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5722 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5723</pre>
5724
5725<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5726<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5727 source location to the destination location. It is similar to the
5728 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5729 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5730
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5731<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5732 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5733
5734<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5735<p>The first argument is a pointer to the destination, the second is a pointer
5736 to the source. The third argument is an integer argument specifying the
5737 number of bytes to copy, and the fourth argument is the alignment of the
5738 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5739
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5740<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5741 then the caller guarantees that the source and destination pointers are
5742 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5743
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5744<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5746 source location to the destination location, which may overlap. It copies
5747 "len" bytes of memory over. If the argument is known to be aligned to some
5748 boundary, this can be specified as the fourth argument, otherwise it should
5749 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5750
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5751</div>
5752
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5753<!-- _______________________________________________________________________ -->
5754<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5755 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5756</div>
5757
5758<div class="doc_text">
5759
5760<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5761<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]5762 width. Not all targets support all bit widths however.</p>
5763
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5764<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5765 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5766 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5767 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5768 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5769 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5770 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5771 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5772 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5773</pre>
5774
5775<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5776<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5777 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5779<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5780 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5781
5782<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5783<p>The first argument is a pointer to the destination to fill, the second is the
5784 byte value to fill it with, the third argument is an integer argument
5785 specifying the number of bytes to fill, and the fourth argument is the known
5786 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5787
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5788<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5789 then the caller guarantees that the destination pointer is aligned to that
5790 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5791
5792<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5793<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5794 at the destination location. If the argument is known to be aligned to some
5795 boundary, this can be specified as the fourth argument, otherwise it should
5796 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5797
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5798</div>
5799
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5800<!-- _______________________________________________________________________ -->
5801<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5802 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5803</div>
5804
5805<div class="doc_text">
5806
5807<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5808<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5809 floating point or vector of floating point type. Not all targets support all
5810 types however.</p>
5811
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5812<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5813 declare float @llvm.sqrt.f32(float %Val)
5814 declare double @llvm.sqrt.f64(double %Val)
5815 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5816 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5817 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5818</pre>
5819
5820<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5821<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5822 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5823 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5824 behavior for negative numbers other than -0.0 (which allows for better
5825 optimization, because there is no need to worry about errno being
5826 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]5827
5828<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5829<p>The argument and return value are floating point numbers of the same
5830 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5831
5832<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5833<p>This function returns the sqrt of the specified operand if it is a
5834 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5835
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5836</div>
5837
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5838<!-- _______________________________________________________________________ -->
5839<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5840 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5841</div>
5842
5843<div class="doc_text">
5844
5845<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5846<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5847 floating point or vector of floating point type. Not all targets support all
5848 types however.</p>
5849
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5850<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5851 declare float @llvm.powi.f32(float %Val, i32 %power)
5852 declare double @llvm.powi.f64(double %Val, i32 %power)
5853 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5854 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5855 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5856</pre>
5857
5858<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5859<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5860 specified (positive or negative) power. The order of evaluation of
5861 multiplications is not defined. When a vector of floating point type is
5862 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5863
5864<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5865<p>The second argument is an integer power, and the first is a value to raise to
5866 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5867
5868<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869<p>This function returns the first value raised to the second power with an
5870 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5871
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5872</div>
5873
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5874<!-- _______________________________________________________________________ -->
5875<div class="doc_subsubsection">
5876 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5877</div>
5878
5879<div class="doc_text">
5880
5881<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5882<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5883 floating point or vector of floating point type. Not all targets support all
5884 types however.</p>
5885
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5886<pre>
5887 declare float @llvm.sin.f32(float %Val)
5888 declare double @llvm.sin.f64(double %Val)
5889 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5890 declare fp128 @llvm.sin.f128(fp128 %Val)
5891 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5892</pre>
5893
5894<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5896
5897<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5898<p>The argument and return value are floating point numbers of the same
5899 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5900
5901<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5902<p>This function returns the sine of the specified operand, returning the same
5903 values as the libm <tt>sin</tt> functions would, and handles error conditions
5904 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5905
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5906</div>
5907
5908<!-- _______________________________________________________________________ -->
5909<div class="doc_subsubsection">
5910 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5911</div>
5912
5913<div class="doc_text">
5914
5915<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5916<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5917 floating point or vector of floating point type. Not all targets support all
5918 types however.</p>
5919
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5920<pre>
5921 declare float @llvm.cos.f32(float %Val)
5922 declare double @llvm.cos.f64(double %Val)
5923 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5924 declare fp128 @llvm.cos.f128(fp128 %Val)
5925 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5926</pre>
5927
5928<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5930
5931<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5932<p>The argument and return value are floating point numbers of the same
5933 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5934
5935<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5936<p>This function returns the cosine of the specified operand, returning the same
5937 values as the libm <tt>cos</tt> functions would, and handles error conditions
5938 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5939
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5940</div>
5941
5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
5944 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5950<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5951 floating point or vector of floating point type. Not all targets support all
5952 types however.</p>
5953
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5954<pre>
5955 declare float @llvm.pow.f32(float %Val, float %Power)
5956 declare double @llvm.pow.f64(double %Val, double %Power)
5957 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5958 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5959 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5960</pre>
5961
5962<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5963<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5964 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5965
5966<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5967<p>The second argument is a floating point power, and the first is a value to
5968 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5971<p>This function returns the first value raised to the second power, returning
5972 the same values as the libm <tt>pow</tt> functions would, and handles error
5973 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5974
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5975</div>
5976
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5977<!-- ======================================================================= -->
5978<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5979 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5980</div>
5981
5982<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5983
5984<p>LLVM provides intrinsics for a few important bit manipulation operations.
5985 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5986
5987</div>
5988
5989<!-- _______________________________________________________________________ -->
5990<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5991 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5992</div>
5993
5994<div class="doc_text">
5995
5996<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5997<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5998 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5999
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6000<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6001 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6002 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6003 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6004</pre>
6005
6006<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6007<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6008 values with an even number of bytes (positive multiple of 16 bits). These
6009 are useful for performing operations on data that is not in the target's
6010 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6011
6012<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6013<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6014 and low byte of the input i16 swapped. Similarly,
6015 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6016 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6017 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6018 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6019 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6020 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6021
6022</div>
6023
6024<!-- _______________________________________________________________________ -->
6025<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6026 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6027</div>
6028
6029<div class="doc_text">
6030
6031<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6032<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]6033 width. Not all targets support all bit widths however.</p>
6034
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6035<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6036 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6037 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6038 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6039 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6040 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6041</pre>
6042
6043<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6044<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6045 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6046
6047<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6048<p>The only argument is the value to be counted. The argument may be of any
6049 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6050
6051<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6052<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]6053
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6054</div>
6055
6056<!-- _______________________________________________________________________ -->
6057<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6058 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6059</div>
6060
6061<div class="doc_text">
6062
6063<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6064<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6065 integer bit width. Not all targets support all bit widths however.</p>
6066
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6067<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6068 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6069 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6070 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6071 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6072 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6073</pre>
6074
6075<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6077 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6078
6079<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6080<p>The only argument is the value to be counted. The argument may be of any
6081 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6082
6083<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6085 zeros in a variable. If the src == 0 then the result is the size in bits of
6086 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6087
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6088</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6089
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6090<!-- _______________________________________________________________________ -->
6091<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6092 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6093</div>
6094
6095<div class="doc_text">
6096
6097<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6098<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6099 integer bit width. Not all targets support all bit widths however.</p>
6100
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6101<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6102 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6103 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6104 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6105 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6106 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6107</pre>
6108
6109<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6111 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6112
6113<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6114<p>The only argument is the value to be counted. The argument may be of any
6115 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6116
6117<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6119 zeros in a variable. If the src == 0 then the result is the size in bits of
6120 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6121
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6122</div>
6123
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6124<!-- ======================================================================= -->
6125<div class="doc_subsection">
6126 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6127</div>
6128
6129<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6130
6131<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6132
6133</div>
6134
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6135<!-- _______________________________________________________________________ -->
6136<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6137 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6138</div>
6139
6140<div class="doc_text">
6141
6142<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6143<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]6144 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6145
6146<pre>
6147 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6148 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6149 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6150</pre>
6151
6152<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6153<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6154 a signed addition of the two arguments, and indicate whether an overflow
6155 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6156
6157<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6158<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]6159 be of integer types of any bit width, but they must have the same bit
6160 width. The second element of the result structure must be of
6161 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6162 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6163
6164<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6165<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6166 a signed addition of the two variables. They return a structure &mdash; the
6167 first element of which is the signed summation, and the second element of
6168 which is a bit specifying if the signed summation resulted in an
6169 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6170
6171<h5>Examples:</h5>
6172<pre>
6173 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6174 %sum = extractvalue {i32, i1} %res, 0
6175 %obit = extractvalue {i32, i1} %res, 1
6176 br i1 %obit, label %overflow, label %normal
6177</pre>
6178
6179</div>
6180
6181<!-- _______________________________________________________________________ -->
6182<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6183 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6184</div>
6185
6186<div class="doc_text">
6187
6188<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189<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]6190 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6191
6192<pre>
6193 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6194 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6195 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6199<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6200 an unsigned addition of the two arguments, and indicate whether a carry
6201 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6202
6203<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6204<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]6205 be of integer types of any bit width, but they must have the same bit
6206 width. The second element of the result structure must be of
6207 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6208 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6209
6210<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6211<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6212 an unsigned addition of the two arguments. They return a structure &mdash;
6213 the first element of which is the sum, and the second element of which is a
6214 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6215
6216<h5>Examples:</h5>
6217<pre>
6218 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6219 %sum = extractvalue {i32, i1} %res, 0
6220 %obit = extractvalue {i32, i1} %res, 1
6221 br i1 %obit, label %carry, label %normal
6222</pre>
6223
6224</div>
6225
6226<!-- _______________________________________________________________________ -->
6227<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6228 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6229</div>
6230
6231<div class="doc_text">
6232
6233<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6234<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]6235 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6236
6237<pre>
6238 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6239 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6240 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6241</pre>
6242
6243<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6244<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6245 a signed subtraction of the two arguments, and indicate whether an overflow
6246 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6247
6248<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6249<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]6250 be of integer types of any bit width, but they must have the same bit
6251 width. The second element of the result structure must be of
6252 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6253 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6254
6255<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6256<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6257 a signed subtraction of the two arguments. They return a structure &mdash;
6258 the first element of which is the subtraction, and the second element of
6259 which is a bit specifying if the signed subtraction resulted in an
6260 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6261
6262<h5>Examples:</h5>
6263<pre>
6264 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6265 %sum = extractvalue {i32, i1} %res, 0
6266 %obit = extractvalue {i32, i1} %res, 1
6267 br i1 %obit, label %overflow, label %normal
6268</pre>
6269
6270</div>
6271
6272<!-- _______________________________________________________________________ -->
6273<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6274 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6275</div>
6276
6277<div class="doc_text">
6278
6279<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280<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]6281 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6282
6283<pre>
6284 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6285 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6286 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6287</pre>
6288
6289<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6290<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291 an unsigned subtraction of the two arguments, and indicate whether an
6292 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6293
6294<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6295<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]6296 be of integer types of any bit width, but they must have the same bit
6297 width. The second element of the result structure must be of
6298 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6299 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6300
6301<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6302<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303 an unsigned subtraction of the two arguments. They return a structure &mdash;
6304 the first element of which is the subtraction, and the second element of
6305 which is a bit specifying if the unsigned subtraction resulted in an
6306 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6307
6308<h5>Examples:</h5>
6309<pre>
6310 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6311 %sum = extractvalue {i32, i1} %res, 0
6312 %obit = extractvalue {i32, i1} %res, 1
6313 br i1 %obit, label %overflow, label %normal
6314</pre>
6315
6316</div>
6317
6318<!-- _______________________________________________________________________ -->
6319<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6320 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6321</div>
6322
6323<div class="doc_text">
6324
6325<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326<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]6327 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6328
6329<pre>
6330 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6331 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6332 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6333</pre>
6334
6335<h5>Overview:</h5>
6336
6337<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6338 a signed multiplication of the two arguments, and indicate whether an
6339 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6340
6341<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6342<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]6343 be of integer types of any bit width, but they must have the same bit
6344 width. The second element of the result structure must be of
6345 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6346 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6347
6348<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6349<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6350 a signed multiplication of the two arguments. They return a structure &mdash;
6351 the first element of which is the multiplication, and the second element of
6352 which is a bit specifying if the signed multiplication resulted in an
6353 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6354
6355<h5>Examples:</h5>
6356<pre>
6357 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6358 %sum = extractvalue {i32, i1} %res, 0
6359 %obit = extractvalue {i32, i1} %res, 1
6360 br i1 %obit, label %overflow, label %normal
6361</pre>
6362
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6363</div>
6364
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6365<!-- _______________________________________________________________________ -->
6366<div class="doc_subsubsection">
6367 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6368</div>
6369
6370<div class="doc_text">
6371
6372<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6373<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]6374 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6375
6376<pre>
6377 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6378 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6379 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6380</pre>
6381
6382<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6383<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6384 a unsigned multiplication of the two arguments, and indicate whether an
6385 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6386
6387<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6388<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]6389 be of integer types of any bit width, but they must have the same bit
6390 width. The second element of the result structure must be of
6391 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6392 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6393
6394<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6395<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6396 an unsigned multiplication of the two arguments. They return a structure
6397 &mdash; the first element of which is the multiplication, and the second
6398 element of which is a bit specifying if the unsigned multiplication resulted
6399 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6400
6401<h5>Examples:</h5>
6402<pre>
6403 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6404 %sum = extractvalue {i32, i1} %res, 0
6405 %obit = extractvalue {i32, i1} %res, 1
6406 br i1 %obit, label %overflow, label %normal
6407</pre>
6408
6409</div>
6410
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6411<!-- ======================================================================= -->
6412<div class="doc_subsection">
6413 <a name="int_debugger">Debugger Intrinsics</a>
6414</div>
6415
6416<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6417
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6418<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6419 prefix), are described in
6420 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6421 Level Debugging</a> document.</p>
6422
6423</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6424
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6425<!-- ======================================================================= -->
6426<div class="doc_subsection">
6427 <a name="int_eh">Exception Handling Intrinsics</a>
6428</div>
6429
6430<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6431
6432<p>The LLVM exception handling intrinsics (which all start with
6433 <tt>llvm.eh.</tt> prefix), are described in
6434 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6435 Handling</a> document.</p>
6436
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6437</div>
6438
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6439<!-- ======================================================================= -->
6440<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6441 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6442</div>
6443
6444<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6445
6446<p>This intrinsic makes it possible to excise one parameter, marked with
6447 the <tt>nest</tt> attribute, from a function. The result is a callable
6448 function pointer lacking the nest parameter - the caller does not need to
6449 provide a value for it. Instead, the value to use is stored in advance in a
6450 "trampoline", a block of memory usually allocated on the stack, which also
6451 contains code to splice the nest value into the argument list. This is used
6452 to implement the GCC nested function address extension.</p>
6453
6454<p>For example, if the function is
6455 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6456 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6457 follows:</p>
6458
6459<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6460<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6461 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6462 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6463 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6464 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6465</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466</div>
6467
6468<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6469 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6470
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6471</div>
6472
6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
6475 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6476</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6477
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6478<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6479
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6480<h5>Syntax:</h5>
6481<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482 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]6483</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6485<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6486<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6487 function pointer suitable for executing it.</p>
6488
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6489<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6490<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6491 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6492 sufficiently aligned block of memory; this memory is written to by the
6493 intrinsic. Note that the size and the alignment are target-specific - LLVM
6494 currently provides no portable way of determining them, so a front-end that
6495 generates this intrinsic needs to have some target-specific knowledge.
6496 The <tt>func</tt> argument must hold a function bitcast to
6497 an <tt>i8*</tt>.</p>
6498
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6499<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6500<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6501 dependent code, turning it into a function. A pointer to this function is
6502 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6503 function pointer type</a> before being called. The new function's signature
6504 is the same as that of <tt>func</tt> with any arguments marked with
6505 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6506 is allowed, and it must be of pointer type. Calling the new function is
6507 equivalent to calling <tt>func</tt> with the same argument list, but
6508 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6509 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6510 by <tt>tramp</tt> is modified, then the effect of any later call to the
6511 returned function pointer is undefined.</p>
6512
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6513</div>
6514
6515<!-- ======================================================================= -->
6516<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6517 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6518</div>
6519
6520<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6521
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6522<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6523 hardware constructs for atomic operations and memory synchronization. This
6524 provides an interface to the hardware, not an interface to the programmer. It
6525 is aimed at a low enough level to allow any programming models or APIs
6526 (Application Programming Interfaces) which need atomic behaviors to map
6527 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6528 hardware provides a "universal IR" for source languages, it also provides a
6529 starting point for developing a "universal" atomic operation and
6530 synchronization IR.</p>
6531
6532<p>These do <em>not</em> form an API such as high-level threading libraries,
6533 software transaction memory systems, atomic primitives, and intrinsic
6534 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6535 application libraries. The hardware interface provided by LLVM should allow
6536 a clean implementation of all of these APIs and parallel programming models.
6537 No one model or paradigm should be selected above others unless the hardware
6538 itself ubiquitously does so.</p>
6539
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6540</div>
6541
6542<!-- _______________________________________________________________________ -->
6543<div class="doc_subsubsection">
6544 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6545</div>
6546<div class="doc_text">
6547<h5>Syntax:</h5>
6548<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6549 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]6550</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6551
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6552<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6553<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6554 specific pairs of memory access types.</p>
6555
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6556<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6557<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6558 The first four arguments enables a specific barrier as listed below. The
6559 fith argument specifies that the barrier applies to io or device or uncached
6560 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6561
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6562<ul>
6563 <li><tt>ll</tt>: load-load barrier</li>
6564 <li><tt>ls</tt>: load-store barrier</li>
6565 <li><tt>sl</tt>: store-load barrier</li>
6566 <li><tt>ss</tt>: store-store barrier</li>
6567 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6568</ul>
6569
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6570<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571<p>This intrinsic causes the system to enforce some ordering constraints upon
6572 the loads and stores of the program. This barrier does not
6573 indicate <em>when</em> any events will occur, it only enforces
6574 an <em>order</em> in which they occur. For any of the specified pairs of load
6575 and store operations (f.ex. load-load, or store-load), all of the first
6576 operations preceding the barrier will complete before any of the second
6577 operations succeeding the barrier begin. Specifically the semantics for each
6578 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6579
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6580<ul>
6581 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6582 after the barrier begins.</li>
6583 <li><tt>ls</tt>: All loads before the barrier must complete before any
6584 store after the barrier begins.</li>
6585 <li><tt>ss</tt>: All stores before the barrier must complete before any
6586 store after the barrier begins.</li>
6587 <li><tt>sl</tt>: All stores before the barrier must complete before any
6588 load after the barrier begins.</li>
6589</ul>
6590
6591<p>These semantics are applied with a logical "and" behavior when more than one
6592 is enabled in a single memory barrier intrinsic.</p>
6593
6594<p>Backends may implement stronger barriers than those requested when they do
6595 not support as fine grained a barrier as requested. Some architectures do
6596 not need all types of barriers and on such architectures, these become
6597 noops.</p>
6598
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6599<h5>Example:</h5>
6600<pre>
6601%ptr = malloc i32
6602 store i32 4, %ptr
6603
6604%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6605 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6606 <i>; guarantee the above finishes</i>
6607 store i32 8, %ptr <i>; before this begins</i>
6608</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6610</div>
6611
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6612<!-- _______________________________________________________________________ -->
6613<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6614 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6615</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6617<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6619<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6620<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6621 any integer bit width and for different address spaces. Not all targets
6622 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6623
6624<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6625 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6626 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6627 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6628 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]6629</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6631<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6632<p>This loads a value in memory and compares it to a given value. If they are
6633 equal, it stores a new value into the memory.</p>
6634
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6635<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6636<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6637 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6638 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6639 this integer type. While any bit width integer may be used, targets may only
6640 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6641
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6642<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6643<p>This entire intrinsic must be executed atomically. It first loads the value
6644 in memory pointed to by <tt>ptr</tt> and compares it with the
6645 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6646 memory. The loaded value is yielded in all cases. This provides the
6647 equivalent of an atomic compare-and-swap operation within the SSA
6648 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6649
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6650<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6651<pre>
6652%ptr = malloc i32
6653 store i32 4, %ptr
6654
6655%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6656%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6657 <i>; yields {i32}:result1 = 4</i>
6658%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6659%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6660
6661%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6662%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6663 <i>; yields {i32}:result2 = 8</i>
6664%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6665
6666%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6667</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6668
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6669</div>
6670
6671<!-- _______________________________________________________________________ -->
6672<div class="doc_subsubsection">
6673 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6674</div>
6675<div class="doc_text">
6676<h5>Syntax:</h5>
6677
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6679 integer bit width. Not all targets support all bit widths however.</p>
6680
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6681<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6682 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6683 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6684 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6685 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]6686</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6688<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6689<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6690 the value from memory. It then stores the value in <tt>val</tt> in the memory
6691 at <tt>ptr</tt>.</p>
6692
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6693<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6694<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6695 the <tt>val</tt> argument and the result must be integers of the same bit
6696 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6697 integer type. The targets may only lower integer representations they
6698 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6699
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6700<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6701<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6702 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6703 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6704
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6705<h5>Examples:</h5>
6706<pre>
6707%ptr = malloc i32
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>
6762%ptr = malloc i32
6763 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6764%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6766%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6767 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6768%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6769 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6770%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6771</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6772
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6773</div>
6774
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6775<!-- _______________________________________________________________________ -->
6776<div class="doc_subsubsection">
6777 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6778
6779</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6780
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6781<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6783<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6785 any integer bit width and for different address spaces. Not all targets
6786 support all bit widths however.</p>
6787
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6788<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6789 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6790 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6791 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6792 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]6793</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6794
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6795<h5>Overview:</h5>
6796<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6797 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6798
6799<h5>Arguments:</h5>
6800<p>The intrinsic takes two arguments, the first a pointer to an integer value
6801 and the second an integer value. The result is also an integer value. These
6802 integer types can have any bit width, but they must all have the same bit
6803 width. The targets may only lower integer representations they support.</p>
6804
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6805<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6806<p>This intrinsic does a series of operations atomically. It first loads the
6807 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6808 result to <tt>ptr</tt>. It yields the original value stored
6809 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813%ptr = malloc i32
6814 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6815%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6816 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6817%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6818 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6819%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6820 <i>; yields {i32}:result3 = 2</i>
6821%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6822</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6823
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6824</div>
6825
6826<!-- _______________________________________________________________________ -->
6827<div class="doc_subsubsection">
6828 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6829 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6830 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6831 <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]6832</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6833
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6834<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6836<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6837<p>These are overloaded intrinsics. You can
6838 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6839 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6840 bit width and for different address spaces. Not all targets support all bit
6841 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6842
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6843<pre>
6844 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6845 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6846 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6847 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]6848</pre>
6849
6850<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6851 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6852 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6853 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6854 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]6855</pre>
6856
6857<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6858 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6859 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6860 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6861 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]6862</pre>
6863
6864<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6865 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6866 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6867 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6868 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]6869</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6871<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6872<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6873 the value stored in memory at <tt>ptr</tt>. It yields the original value
6874 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6875
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6876<h5>Arguments:</h5>
6877<p>These intrinsics take two arguments, the first a pointer to an integer value
6878 and the second an integer value. The result is also an integer value. These
6879 integer types can have any bit width, but they must all have the same bit
6880 width. The targets may only lower integer representations they support.</p>
6881
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6882<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6883<p>These intrinsics does a series of operations atomically. They first load the
6884 value stored at <tt>ptr</tt>. They then do the bitwise
6885 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6886 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6887
6888<h5>Examples:</h5>
6889<pre>
6890%ptr = malloc i32
6891 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6892%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6893 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6894%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6895 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6896%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6898%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6899 <i>; yields {i32}:result3 = FF</i>
6900%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6901</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6903</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6904
6905<!-- _______________________________________________________________________ -->
6906<div class="doc_subsubsection">
6907 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6908 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6909 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6910 <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]6911</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6913<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6914
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6915<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6916<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6917 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6918 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6919 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6920
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6921<pre>
6922 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6923 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6924 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6925 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]6926</pre>
6927
6928<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6929 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6930 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6931 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6932 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]6933</pre>
6934
6935<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6936 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6937 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6938 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6939 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]6940</pre>
6941
6942<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6944 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6945 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6946 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]6947</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6948
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6949<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6950<p>These intrinsics takes the signed or unsigned minimum or maximum of
6951 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6952 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6953
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<h5>Arguments:</h5>
6955<p>These intrinsics take two arguments, the first a pointer to an integer value
6956 and the second an integer value. The result is also an integer value. These
6957 integer types can have any bit width, but they must all have the same bit
6958 width. The targets may only lower integer representations they support.</p>
6959
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6960<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6961<p>These intrinsics does a series of operations atomically. They first load the
6962 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6963 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6964 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6965
6966<h5>Examples:</h5>
6967<pre>
6968%ptr = malloc i32
6969 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6970%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6971 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6972%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6973 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6974%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6975 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6976%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6977 <i>; yields {i32}:result3 = 8</i>
6978%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6979</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6981</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6982
6983<!-- ======================================================================= -->
6984<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6985 <a name="int_general">General Intrinsics</a>
6986</div>
6987
6988<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6989
6990<p>This class of intrinsics is designed to be generic and has no specific
6991 purpose.</p>
6992
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6993</div>
6994
6995<!-- _______________________________________________________________________ -->
6996<div class="doc_subsubsection">
6997 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6998</div>
6999
7000<div class="doc_text">
7001
7002<h5>Syntax:</h5>
7003<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7004 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]7005</pre>
7006
7007<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7008<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7009
7010<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<p>The first argument is a pointer to a value, the second is a pointer to a
7012 global string, the third is a pointer to a global string which is the source
7013 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7014
7015<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7016<p>This intrinsic allows annotation of local variables with arbitrary strings.
7017 This can be useful for special purpose optimizations that want to look for
7018 these annotations. These have no other defined use, they are ignored by code
7019 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7020
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7021</div>
7022
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7023<!-- _______________________________________________________________________ -->
7024<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7025 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7026</div>
7027
7028<div class="doc_text">
7029
7030<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7031<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7032 any integer bit width.</p>
7033
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7034<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7035 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7036 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7037 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7038 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7039 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]7040</pre>
7041
7042<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7044
7045<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7046<p>The first argument is an integer value (result of some expression), the
7047 second is a pointer to a global string, the third is a pointer to a global
7048 string which is the source file name, and the last argument is the line
7049 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7052<p>This intrinsic allows annotations to be put on arbitrary expressions with
7053 arbitrary strings. This can be useful for special purpose optimizations that
7054 want to look for these annotations. These have no other defined use, they
7055 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7056
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7057</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7058
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7059<!-- _______________________________________________________________________ -->
7060<div class="doc_subsubsection">
7061 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7062</div>
7063
7064<div class="doc_text">
7065
7066<h5>Syntax:</h5>
7067<pre>
7068 declare void @llvm.trap()
7069</pre>
7070
7071<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7072<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7073
7074<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7075<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7076
7077<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7078<p>This intrinsics is lowered to the target dependent trap instruction. If the
7079 target does not have a trap instruction, this intrinsic will be lowered to
7080 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7081
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7082</div>
7083
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
7085<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7086 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7087</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7088
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7089<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7090
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7091<h5>Syntax:</h5>
7092<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7093 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7094</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7095
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7096<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7098 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7099 ensure that it is placed on the stack before local variables.</p>
7100
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7101<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7102<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7103 arguments. The first argument is the value loaded from the stack
7104 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7105 that has enough space to hold the value of the guard.</p>
7106
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7107<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7108<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7109 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7110 stack. This is to ensure that if a local variable on the stack is
7111 overwritten, it will destroy the value of the guard. When the function exits,
7112 the guard on the stack is checked against the original guard. If they're
7113 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7114 function.</p>
7115
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7116</div>
7117
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7118<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7119<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7120<address>
7121 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7122 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7123 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7124 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]7125
7126 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7127 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7128 Last modified: $Date$
7129</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7130
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7131</body>
7132</html>