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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 40a0b2c305344898fd4e46e988d16846cd5cd6b2 / . / 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>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_floating">Floating Point Types</a></li>
60 <li><a href="#t_void">Void Type</a></li>
61 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]62 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]63 </ol>
64 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#t_derived">Derived Types</a>
66 <ol>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]67 <li><a href="#t_integer">Integer Type</a></li>
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
532 removed by the linker after evaluation.</dd>
533
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]534 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]535 <dd>Similar to private, but the value shows as a local symbol
536 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
537 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]540 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]541 into the object file corresponding to the LLVM module. They exist to
542 allow inlining and other optimizations to take place given knowledge of
543 the definition of the global, which is known to be somewhere outside the
544 module. Globals with <tt>available_externally</tt> linkage are allowed to
545 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
546 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]547
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]549 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]550 the same name when linkage occurs. This is typically used to implement
551 inline functions, templates, or other code which must be generated in each
552 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
553 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]554
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]555 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]556 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
557 <tt>linkonce</tt> linkage, except that unreferenced globals with
558 <tt>weak</tt> linkage may not be discarded. This is used for globals that
559 are declared "weak" in C source code.</dd>
560
561 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
562 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
563 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
564 global scope.
565 Symbols with "<tt>common</tt>" linkage are merged in the same way as
566 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
567 Further, <tt>common</tt> symbols may not have an explicit section, and
568 must have a zero initializer. Functions and aliases may not have common
569 linkage.</dd>
570
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]571
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]573 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]574 pointer to array type. When two global variables with appending linkage
575 are linked together, the two global arrays are appended together. This is
576 the LLVM, typesafe, equivalent of having the system linker append together
577 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]578
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]580 <dd>The semantics of this linkage follow the ELF object file model: the symbol
581 is weak until linked, if not linked, the symbol becomes null instead of
582 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]583
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]586 <dd>Some languages allow differing globals to be merged, such as two functions
587 with different semantics. Other languages, such as <tt>C++</tt>, ensure
588 that only equivalent globals are ever merged (the "one definition rule" -
589 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
590 and <tt>weak_odr</tt> linkage types to indicate that the global will only
591 be merged with equivalent globals. These linkage types are otherwise the
592 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]593
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]595 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]596 visible, meaning that it participates in linkage and can be used to
597 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]598</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]599
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]600<p>The next two types of linkage are targeted for Microsoft Windows platform
601 only. They are designed to support importing (exporting) symbols from (to)
602 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]603
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]604<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]605 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]606 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]607 or variable via a global pointer to a pointer that is set up by the DLL
608 exporting the symbol. On Microsoft Windows targets, the pointer name is
609 formed by combining <code>__imp_</code> and the function or variable
610 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]611
612 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]613 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]614 pointer to a pointer in a DLL, so that it can be referenced with the
615 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
616 name is formed by combining <code>__imp_</code> and the function or
617 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]618</dl>
619
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
621 another module defined a "<tt>.LC0</tt>" variable and was linked with this
622 one, one of the two would be renamed, preventing a collision. Since
623 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
624 declarations), they are accessible outside of the current module.</p>
625
626<p>It is illegal for a function <i>declaration</i> to have any linkage type
627 other than "externally visible", <tt>dllimport</tt>
628 or <tt>extern_weak</tt>.</p>
629
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]630<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]631 or <tt>weak_odr</tt> linkages.</p>
632
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]633</div>
634
635<!-- ======================================================================= -->
636<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]637 <a name="callingconv">Calling Conventions</a>
638</div>
639
640<div class="doc_text">
641
642<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]643 and <a href="#i_invoke">invokes</a> can all have an optional calling
644 convention specified for the call. The calling convention of any pair of
645 dynamic caller/callee must match, or the behavior of the program is
646 undefined. The following calling conventions are supported by LLVM, and more
647 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]648
649<dl>
650 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]651 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]652 specified) matches the target C calling conventions. This calling
653 convention supports varargs function calls and tolerates some mismatch in
654 the declared prototype and implemented declaration of the function (as
655 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]656
657 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]658 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]659 (e.g. by passing things in registers). This calling convention allows the
660 target to use whatever tricks it wants to produce fast code for the
661 target, without having to conform to an externally specified ABI
662 (Application Binary Interface). Implementations of this convention should
663 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
664 optimization</a> to be supported. This calling convention does not
665 support varargs and requires the prototype of all callees to exactly match
666 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]667
668 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]669 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]670 as possible under the assumption that the call is not commonly executed.
671 As such, these calls often preserve all registers so that the call does
672 not break any live ranges in the caller side. This calling convention
673 does not support varargs and requires the prototype of all callees to
674 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]675
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]676 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]677 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]678 target-specific calling conventions to be used. Target specific calling
679 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]680</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]681
682<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 support Pascal conventions or any other well-known target-independent
684 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
686</div>
687
688<!-- ======================================================================= -->
689<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]690 <a name="visibility">Visibility Styles</a>
691</div>
692
693<div class="doc_text">
694
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]695<p>All Global Variables and Functions have one of the following visibility
696 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]697
698<dl>
699 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]700 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]701 that the declaration is visible to other modules and, in shared libraries,
702 means that the declared entity may be overridden. On Darwin, default
703 visibility means that the declaration is visible to other modules. Default
704 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]705
706 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]707 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]708 object if they are in the same shared object. Usually, hidden visibility
709 indicates that the symbol will not be placed into the dynamic symbol
710 table, so no other module (executable or shared library) can reference it
711 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]712
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]713 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]714 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]715 the dynamic symbol table, but that references within the defining module
716 will bind to the local symbol. That is, the symbol cannot be overridden by
717 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718</dl>
719
720</div>
721
722<!-- ======================================================================= -->
723<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]724 <a name="namedtypes">Named Types</a>
725</div>
726
727<div class="doc_text">
728
729<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]730 it easier to read the IR and make the IR more condensed (particularly when
731 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]732
733<div class="doc_code">
734<pre>
735%mytype = type { %mytype*, i32 }
736</pre>
737</div>
738
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]739<p>You may give a name to any <a href="#typesystem">type</a> except
740 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
741 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]742
743<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744 and that you can therefore specify multiple names for the same type. This
745 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
746 uses structural typing, the name is not part of the type. When printing out
747 LLVM IR, the printer will pick <em>one name</em> to render all types of a
748 particular shape. This means that if you have code where two different
749 source types end up having the same LLVM type, that the dumper will sometimes
750 print the "wrong" or unexpected type. This is an important design point and
751 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]752
753</div>
754
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]755<!-- ======================================================================= -->
756<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]757 <a name="globalvars">Global Variables</a>
758</div>
759
760<div class="doc_text">
761
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]762<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]763 instead of run-time. Global variables may optionally be initialized, may
764 have an explicit section to be placed in, and may have an optional explicit
765 alignment specified. A variable may be defined as "thread_local", which
766 means that it will not be shared by threads (each thread will have a
767 separated copy of the variable). A variable may be defined as a global
768 "constant," which indicates that the contents of the variable
769 will <b>never</b> be modified (enabling better optimization, allowing the
770 global data to be placed in the read-only section of an executable, etc).
771 Note that variables that need runtime initialization cannot be marked
772 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]773
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
775 constant, even if the final definition of the global is not. This capability
776 can be used to enable slightly better optimization of the program, but
777 requires the language definition to guarantee that optimizations based on the
778 'constantness' are valid for the translation units that do not include the
779 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]780
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]781<p>As SSA values, global variables define pointer values that are in scope
782 (i.e. they dominate) all basic blocks in the program. Global variables
783 always define a pointer to their "content" type because they describe a
784 region of memory, and all memory objects in LLVM are accessed through
785 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]786
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]787<p>A global variable may be declared to reside in a target-specific numbered
788 address space. For targets that support them, address spaces may affect how
789 optimizations are performed and/or what target instructions are used to
790 access the variable. The default address space is zero. The address space
791 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]792
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]793<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]794 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]795
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]796<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]797 the alignment is set to zero, the alignment of the global is set by the
798 target to whatever it feels convenient. If an explicit alignment is
799 specified, the global is forced to have at least that much alignment. All
800 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]801
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802<p>For example, the following defines a global in a numbered address space with
803 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]804
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]805<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]806<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]807@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]808</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]809</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]810
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]811</div>
812
813
814<!-- ======================================================================= -->
815<div class="doc_subsection">
816 <a name="functionstructure">Functions</a>
817</div>
818
819<div class="doc_text">
820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]821<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
822 optional <a href="#linkage">linkage type</a>, an optional
823 <a href="#visibility">visibility style</a>, an optional
824 <a href="#callingconv">calling convention</a>, a return type, an optional
825 <a href="#paramattrs">parameter attribute</a> for the return type, a function
826 name, a (possibly empty) argument list (each with optional
827 <a href="#paramattrs">parameter attributes</a>), optional
828 <a href="#fnattrs">function attributes</a>, an optional section, an optional
829 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
830 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]831
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
833 optional <a href="#linkage">linkage type</a>, an optional
834 <a href="#visibility">visibility style</a>, an optional
835 <a href="#callingconv">calling convention</a>, a return type, an optional
836 <a href="#paramattrs">parameter attribute</a> for the return type, a function
837 name, a possibly empty list of arguments, an optional alignment, and an
838 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]839
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]840<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]841 (Control Flow Graph) for the function. Each basic block may optionally start
842 with a label (giving the basic block a symbol table entry), contains a list
843 of instructions, and ends with a <a href="#terminators">terminator</a>
844 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]845
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]846<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]847 executed on entrance to the function, and it is not allowed to have
848 predecessor basic blocks (i.e. there can not be any branches to the entry
849 block of a function). Because the block can have no predecessors, it also
850 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]851
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]852<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]853 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]854
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]855<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]856 the alignment is set to zero, the alignment of the function is set by the
857 target to whatever it feels convenient. If an explicit alignment is
858 specified, the function is forced to have at least that much alignment. All
859 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]860
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]861<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]862<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]863<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]864define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]865 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
866 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
867 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
868 [<a href="#gc">gc</a>] { ... }
869</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]870</div>
871
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]872</div>
873
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]874<!-- ======================================================================= -->
875<div class="doc_subsection">
876 <a name="aliasstructure">Aliases</a>
877</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]878
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]879<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]880
881<p>Aliases act as "second name" for the aliasee value (which can be either
882 function, global variable, another alias or bitcast of global value). Aliases
883 may have an optional <a href="#linkage">linkage type</a>, and an
884 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]885
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]886<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]887<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]888<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]889@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]890</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]891</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]892
893</div>
894
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]895<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]896<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]898<div class="doc_text">
899
900<p>The return type and each parameter of a function type may have a set of
901 <i>parameter attributes</i> associated with them. Parameter attributes are
902 used to communicate additional information about the result or parameters of
903 a function. Parameter attributes are considered to be part of the function,
904 not of the function type, so functions with different parameter attributes
905 can have the same function type.</p>
906
907<p>Parameter attributes are simple keywords that follow the type specified. If
908 multiple parameter attributes are needed, they are space separated. For
909 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]910
911<div class="doc_code">
912<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]913declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]914declare i32 @atoi(i8 zeroext)
915declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]916</pre>
917</div>
918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]919<p>Note that any attributes for the function result (<tt>nounwind</tt>,
920 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]921
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]922<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]924<dl>
925 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]926 <dd>This indicates to the code generator that the parameter or return value
927 should be zero-extended to a 32-bit value by the caller (for a parameter)
928 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]929
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]930 <dt><tt>signext</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 sign-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>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates that this parameter or return value should be treated in a
937 special target-dependent fashion during while emitting code for a function
938 call or return (usually, by putting it in a register as opposed to memory,
939 though some targets use it to distinguish between two different kinds of
940 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]941
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]943 <dd>This indicates that the pointer parameter should really be passed by value
944 to the function. The attribute implies that a hidden copy of the pointee
945 is made between the caller and the callee, so the callee is unable to
946 modify the value in the callee. This attribute is only valid on LLVM
947 pointer arguments. It is generally used to pass structs and arrays by
948 value, but is also valid on pointers to scalars. The copy is considered
949 to belong to the caller not the callee (for example,
950 <tt><a href="#readonly">readonly</a></tt> functions should not write to
951 <tt>byval</tt> parameters). This is not a valid attribute for return
952 values. The byval attribute also supports specifying an alignment with
953 the align attribute. This has a target-specific effect on the code
954 generator that usually indicates a desired alignment for the synthesized
955 stack slot.</dd>
956
957 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]958 <dd>This indicates that the pointer parameter specifies the address of a
959 structure that is the return value of the function in the source program.
960 This pointer must be guaranteed by the caller to be valid: loads and
961 stores to the structure may be assumed by the callee to not to trap. This
962 may only be applied to the first parameter. This is not a valid attribute
963 for return values. </dd>
964
965 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]966 <dd>This indicates that the pointer does not alias any global or any other
967 parameter. The caller is responsible for ensuring that this is the
968 case. On a function return value, <tt>noalias</tt> additionally indicates
969 that the pointer does not alias any other pointers visible to the
970 caller. For further details, please see the discussion of the NoAlias
971 response in
972 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
973 analysis</a>.</dd>
974
975 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]976 <dd>This indicates that the callee does not make any copies of the pointer
977 that outlive the callee itself. This is not a valid attribute for return
978 values.</dd>
979
980 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the pointer parameter can be excised using the
982 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
983 attribute for return values.</dd>
984</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]985
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]986</div>
987
988<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]989<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]990 <a name="gc">Garbage Collector Names</a>
991</div>
992
993<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]994
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]995<p>Each function may specify a garbage collector name, which is simply a
996 string:</p>
997
998<div class="doc_code">
999<pre>
1000define void @f() gc "name" { ...
1001</pre>
1002</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1003
1004<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1005 collector which will cause the compiler to alter its output in order to
1006 support the named garbage collection algorithm.</p>
1007
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1008</div>
1009
1010<!-- ======================================================================= -->
1011<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1012 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1013</div>
1014
1015<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1016
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1017<p>Function attributes are set to communicate additional information about a
1018 function. Function attributes are considered to be part of the function, not
1019 of the function type, so functions with different parameter attributes can
1020 have the same function type.</p>
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 simple keywords that follow the type specified. If
1023 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1024
1025<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1026<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1027define void @f() noinline { ... }
1028define void @f() alwaysinline { ... }
1029define void @f() alwaysinline optsize { ... }
1030define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1031</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1032</div>
1033
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1034<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1036 <dd>This attribute indicates that the inliner should attempt to inline this
1037 function into callers whenever possible, ignoring any active inlining size
1038 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should never inline this
1042 function in any situation. This attribute may not be used together with
1043 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1044
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1045 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This attribute suggests that optimization passes and code generator passes
1047 make choices that keep the code size of this function low, and otherwise
1048 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1049
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This function attribute indicates that the function never returns
1052 normally. This produces undefined behavior at runtime if the function
1053 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This function attribute indicates that the function never returns with an
1057 unwind or exceptional control flow. If the function does unwind, its
1058 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This attribute indicates that the function computes its result (or decides
1062 to unwind an exception) based strictly on its arguments, without
1063 dereferencing any pointer arguments or otherwise accessing any mutable
1064 state (e.g. memory, control registers, etc) visible to caller functions.
1065 It does not write through any pointer arguments
1066 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1067 changes any state visible to callers. This means that it cannot unwind
1068 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1069 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1070
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1072 <dd>This attribute indicates that the function does not write through any
1073 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1074 arguments) or otherwise modify any state (e.g. memory, control registers,
1075 etc) visible to caller functions. It may dereference pointer arguments
1076 and read state that may be set in the caller. A readonly function always
1077 returns the same value (or unwinds an exception identically) when called
1078 with the same set of arguments and global state. It cannot unwind an
1079 exception by calling the <tt>C++</tt> exception throwing methods, but may
1080 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1082 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1083 <dd>This attribute indicates that the function should emit a stack smashing
1084 protector. It is in the form of a "canary"&mdash;a random value placed on
1085 the stack before the local variables that's checked upon return from the
1086 function to see if it has been overwritten. A heuristic is used to
1087 determine if a function needs stack protectors or not.<br>
1088<br>
1089 If a function that has an <tt>ssp</tt> attribute is inlined into a
1090 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1091 function will have an <tt>ssp</tt> attribute.</dd>
1092
1093 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This attribute indicates that the function should <em>always</em> emit a
1095 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1096 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1097<br>
1098 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1099 function that doesn't have an <tt>sspreq</tt> attribute or which has
1100 an <tt>ssp</tt> attribute, then the resulting function will have
1101 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1102
1103 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the code generator should not use a red
1105 zone, even if the target-specific ABI normally permits it.</dd>
1106
1107 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1108 <dd>This attributes disables implicit floating point instructions.</dd>
1109
1110 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1111 <dd>This attribute disables prologue / epilogue emission for the function.
1112 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1113</dl>
1114
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1115</div>
1116
1117<!-- ======================================================================= -->
1118<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1119 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1120</div>
1121
1122<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1123
1124<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1125 the GCC "file scope inline asm" blocks. These blocks are internally
1126 concatenated by LLVM and treated as a single unit, but may be separated in
1127 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1128
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1129<div class="doc_code">
1130<pre>
1131module asm "inline asm code goes here"
1132module asm "more can go here"
1133</pre>
1134</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1135
1136<p>The strings can contain any character by escaping non-printable characters.
1137 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]1138 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1139
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1140<p>The inline asm code is simply printed to the machine code .s file when
1141 assembly code is generated.</p>
1142
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1143</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1144
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1145<!-- ======================================================================= -->
1146<div class="doc_subsection">
1147 <a name="datalayout">Data Layout</a>
1148</div>
1149
1150<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1151
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1152<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1153 data is to be laid out in memory. The syntax for the data layout is
1154 simply:</p>
1155
1156<div class="doc_code">
1157<pre>
1158target datalayout = "<i>layout specification</i>"
1159</pre>
1160</div>
1161
1162<p>The <i>layout specification</i> consists of a list of specifications
1163 separated by the minus sign character ('-'). Each specification starts with
1164 a letter and may include other information after the letter to define some
1165 aspect of the data layout. The specifications accepted are as follows:</p>
1166
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1167<dl>
1168 <dt><tt>E</tt></dt>
1169 <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]1170 bits with the most significance have the lowest address location.</dd>
1171
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1172 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1173 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1174 the bits with the least significance have the lowest address
1175 location.</dd>
1176
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1177 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1178 <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]1179 <i>preferred</i> alignments. All sizes are in bits. Specifying
1180 the <i>pref</i> alignment is optional. If omitted, the
1181 preceding <tt>:</tt> should be omitted too.</dd>
1182
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1183 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1184 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1185 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1186
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1189 <i>size</i>.</dd>
1190
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1191 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1192 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1193 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1194 (double).</dd>
1195
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1196 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1197 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 <i>size</i>.</dd>
1199
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1200 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1201 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1202 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1203</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1204
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1205<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1206 default set of specifications which are then (possibly) overriden by the
1207 specifications in the <tt>datalayout</tt> keyword. The default specifications
1208 are given in this list:</p>
1209
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1210<ul>
1211 <li><tt>E</tt> - big endian</li>
1212 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1213 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1214 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1215 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1216 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1217 <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]1218 alignment of 64-bits</li>
1219 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1220 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1221 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1222 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1223 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1224 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1225</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226
1227<p>When LLVM is determining the alignment for a given type, it uses the
1228 following rules:</p>
1229
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1230<ol>
1231 <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]1232 specification is used.</li>
1233
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1234 <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]1235 smallest integer type that is larger than the bitwidth of the sought type
1236 is used. If none of the specifications are larger than the bitwidth then
1237 the the largest integer type is used. For example, given the default
1238 specifications above, the i7 type will use the alignment of i8 (next
1239 largest) while both i65 and i256 will use the alignment of i64 (largest
1240 specified).</li>
1241
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1242 <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]1243 largest vector type that is smaller than the sought vector type will be
1244 used as a fall back. This happens because &lt;128 x double&gt; can be
1245 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1246</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1247
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1248</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1249
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1250<!-- ======================================================================= -->
1251<div class="doc_subsection">
1252 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1253</div>
1254
1255<div class="doc_text">
1256
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1257<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1258with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1259is undefined. Pointer values are associated with address ranges
1260according to the following rules:</p>
1261
1262<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1263 <li>A pointer value formed from a
1264 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1265 is associated with the addresses associated with the first operand
1266 of the <tt>getelementptr</tt>.</li>
1267 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1268 range of the variable's storage.</li>
1269 <li>The result value of an allocation instruction is associated with
1270 the address range of the allocated storage.</li>
1271 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1272 no address.</li>
1273 <li>A pointer value formed by an
1274 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1275 address ranges of all pointer values that contribute (directly or
1276 indirectly) to the computation of the pointer's value.</li>
1277 <li>The result value of a
1278 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1279 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1280 <li>An integer constant other than zero or a pointer value returned
1281 from a function not defined within LLVM may be associated with address
1282 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1283 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1284 allocated by mechanisms provided by LLVM.</li>
1285 </ul>
1286
1287<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1288<tt><a href="#i_load">load</a></tt> merely indicates the size and
1289alignment of the memory from which to load, as well as the
1290interpretation of the value. The first operand of a
1291<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1292and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1293
1294<p>Consequently, type-based alias analysis, aka TBAA, aka
1295<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1296LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1297additional information which specialized optimization passes may use
1298to implement type-based alias analysis.</p>
1299
1300</div>
1301
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1302<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1303<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1304<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1306<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1307
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1308<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1309 intermediate representation. Being typed enables a number of optimizations
1310 to be performed on the intermediate representation directly, without having
1311 to do extra analyses on the side before the transformation. A strong type
1312 system makes it easier to read the generated code and enables novel analyses
1313 and transformations that are not feasible to perform on normal three address
1314 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1315
1316</div>
1317
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1318<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1319<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1320Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1321
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1322<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1323
1324<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1325
1326<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1327 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1328 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1329 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1330 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1331 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1332 </tr>
1333 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1334 <td><a href="#t_floating">floating point</a></td>
1335 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1336 </tr>
1337 <tr>
1338 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1339 <td><a href="#t_integer">integer</a>,
1340 <a href="#t_floating">floating point</a>,
1341 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1342 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1343 <a href="#t_struct">structure</a>,
1344 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1345 <a href="#t_label">label</a>,
1346 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1347 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1348 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1349 <tr>
1350 <td><a href="#t_primitive">primitive</a></td>
1351 <td><a href="#t_label">label</a>,
1352 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1353 <a href="#t_floating">floating point</a>,
1354 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1355 </tr>
1356 <tr>
1357 <td><a href="#t_derived">derived</a></td>
1358 <td><a href="#t_integer">integer</a>,
1359 <a href="#t_array">array</a>,
1360 <a href="#t_function">function</a>,
1361 <a href="#t_pointer">pointer</a>,
1362 <a href="#t_struct">structure</a>,
1363 <a href="#t_pstruct">packed structure</a>,
1364 <a href="#t_vector">vector</a>,
1365 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1366 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1367 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1368 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1369</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1370
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1371<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1372 important. Values of these types are the only ones which can be produced by
1373 instructions, passed as arguments, or used as operands to instructions.</p>
1374
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1375</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1377<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1378<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1379
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1380<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1381
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1382<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1383 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1384
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1385</div>
1386
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1387<!-- _______________________________________________________________________ -->
1388<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1389
1390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1391
1392<table>
1393 <tbody>
1394 <tr><th>Type</th><th>Description</th></tr>
1395 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1396 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1397 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1398 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1399 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1400 </tbody>
1401</table>
1402
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1403</div>
1404
1405<!-- _______________________________________________________________________ -->
1406<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1407
1408<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1409
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1410<h5>Overview:</h5>
1411<p>The void type does not represent any value and has no size.</p>
1412
1413<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1414<pre>
1415 void
1416</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1417
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1418</div>
1419
1420<!-- _______________________________________________________________________ -->
1421<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1422
1423<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1424
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1425<h5>Overview:</h5>
1426<p>The label type represents code labels.</p>
1427
1428<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1429<pre>
1430 label
1431</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1432
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1433</div>
1434
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1435<!-- _______________________________________________________________________ -->
1436<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1437
1438<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1439
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1440<h5>Overview:</h5>
1441<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1442 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1443 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1444
1445<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1446<pre>
1447 metadata
1448</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1449
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1450</div>
1451
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1452
1453<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1454<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1455
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1456<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1457
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1458<p>The real power in LLVM comes from the derived types in the system. This is
1459 what allows a programmer to represent arrays, functions, pointers, and other
1460 useful types. Note that these derived types may be recursive: For example,
1461 it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1463</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1464
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1465<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1466<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1467
1468<div class="doc_text">
1469
1470<h5>Overview:</h5>
1471<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1472 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1473 2^23-1 (about 8 million) can be specified.</p>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1474
1475<h5>Syntax:</h5>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1476<pre>
1477 iN
1478</pre>
1479
1480<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1481 value.</p>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1482
1483<h5>Examples:</h5>
1484<table class="layout">
Nick Lewycky86c48642009-05-24 02:46:06 +0000[diff] [blame]1485 <tr class="layout">
1486 <td class="left"><tt>i1</tt></td>
1487 <td class="left">a single-bit integer.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1488 </tr>
Nick Lewycky86c48642009-05-24 02:46:06 +0000[diff] [blame]1489 <tr class="layout">
1490 <td class="left"><tt>i32</tt></td>
1491 <td class="left">a 32-bit integer.</td>
1492 </tr>
1493 <tr class="layout">
1494 <td class="left"><tt>i1942652</tt></td>
1495 <td class="left">a really big integer of over 1 million bits.</td>
1496 </tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1497</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1498
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1499<p>Note that the code generator does not yet support large integer types to be
1500 used as function return types. The specific limit on how large a return type
1501 the code generator can currently handle is target-dependent; currently it's
1502 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1503
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1504</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1505
1506<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1507<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1508
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1509<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1510
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1511<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1512<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1513 sequentially in memory. The array type requires a size (number of elements)
1514 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1515
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1516<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1517<pre>
1518 [&lt;# elements&gt; x &lt;elementtype&gt;]
1519</pre>
1520
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1521<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1522 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1523
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1524<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1525<table class="layout">
1526 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1527 <td class="left"><tt>[40 x i32]</tt></td>
1528 <td class="left">Array of 40 32-bit integer values.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>[41 x i32]</tt></td>
1532 <td class="left">Array of 41 32-bit integer values.</td>
1533 </tr>
1534 <tr class="layout">
1535 <td class="left"><tt>[4 x i8]</tt></td>
1536 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1537 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1539<p>Here are some examples of multidimensional arrays:</p>
1540<table class="layout">
1541 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1542 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1543 <td class="left">3x4 array of 32-bit integer values.</td>
1544 </tr>
1545 <tr class="layout">
1546 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1547 <td class="left">12x10 array of single precision floating point values.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1551 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1552 </tr>
1553</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1554
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1555<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1556 length array. Normally, accesses past the end of an array are undefined in
1557 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1558 a special case, however, zero length arrays are recognized to be variable
1559 length. This allows implementation of 'pascal style arrays' with the LLVM
1560 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1561
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1562<p>Note that the code generator does not yet support large aggregate types to be
1563 used as function return types. The specific limit on how large an aggregate
1564 return type the code generator can currently handle is target-dependent, and
1565 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1566
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1568
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1569<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1570<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1571
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1572<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1575<p>The function type can be thought of as a function signature. It consists of
1576 a return type and a list of formal parameter types. The return type of a
1577 function type is a scalar type, a void type, or a struct type. If the return
1578 type is a struct type then all struct elements must be of first class types,
1579 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1580
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1581<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1582<pre>
1583 &lt;returntype list&gt; (&lt;parameter list&gt;)
1584</pre>
1585
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1586<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]1587 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1588 which indicates that the function takes a variable number of arguments.
1589 Variable argument functions can access their arguments with
1590 the <a href="#int_varargs">variable argument handling intrinsic</a>
1591 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1592 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1595<table class="layout">
1596 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1597 <td class="left"><tt>i32 (i32)</tt></td>
1598 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1599 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1600 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1601 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1602 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1603 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1604 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1605 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1606 <tt>float</tt>.
1607 </td>
1608 </tr><tr class="layout">
1609 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1610 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1611 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1612 which returns an integer. This is the signature for <tt>printf</tt> in
1613 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1614 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1615 </tr><tr class="layout">
1616 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanb0a57aa2008-11-27 06:41:20 +0000[diff] [blame]1617 <td class="left">A function taking an <tt>i32</tt>, returning two
1618 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1619 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1620 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1621</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1623</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1626<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1627
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1628<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1629
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1630<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1631<p>The structure type is used to represent a collection of data members together
1632 in memory. The packing of the field types is defined to match the ABI of the
1633 underlying processor. The elements of a structure may be any type that has a
1634 size.</p>
1635
1636<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1637 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1638 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1639
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1641<pre>
1642 { &lt;type list&gt; }
1643</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1646<table class="layout">
1647 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1648 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1649 <td class="left">A triple of three <tt>i32</tt> values</td>
1650 </tr><tr class="layout">
1651 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1652 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1653 second element is a <a href="#t_pointer">pointer</a> to a
1654 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1655 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1656 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1657</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1658
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1659<p>Note that the code generator does not yet support large aggregate types to be
1660 used as function return types. The specific limit on how large an aggregate
1661 return type the code generator can currently handle is target-dependent, and
1662 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1663
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1664</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1666<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1667<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1668</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1669
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1670<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1671
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1672<h5>Overview:</h5>
1673<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1674 together in memory. There is no padding between fields. Further, the
1675 alignment of a packed structure is 1 byte. The elements of a packed
1676 structure may be any type that has a size.</p>
1677
1678<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1679 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1680 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1681
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1682<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1683<pre>
1684 &lt; { &lt;type list&gt; } &gt;
1685</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1686
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1687<h5>Examples:</h5>
1688<table class="layout">
1689 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1690 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1691 <td class="left">A triple of three <tt>i32</tt> values</td>
1692 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1693 <td class="left">
1694<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1695 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1696 second element is a <a href="#t_pointer">pointer</a> to a
1697 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1698 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1699 </tr>
1700</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1701
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1702</div>
1703
1704<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1705<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1706
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1707<div class="doc_text">
1708
1709<h5>Overview:</h5>
1710<p>As in many languages, the pointer type represents a pointer or reference to
1711 another object, which must live in memory. Pointer types may have an optional
1712 address space attribute defining the target-specific numbered address space
1713 where the pointed-to object resides. The default address space is zero.</p>
1714
1715<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1716 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1717
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1718<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1719<pre>
1720 &lt;type&gt; *
1721</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1722
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1723<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1724<table class="layout">
1725 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1726 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1727 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1728 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1729 </tr>
1730 <tr class="layout">
1731 <td class="left"><tt>i32 (i32 *) *</tt></td>
1732 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1733 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1734 <tt>i32</tt>.</td>
1735 </tr>
1736 <tr class="layout">
1737 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1738 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1739 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1740 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1741</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1742
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1743</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1744
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1745<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1746<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1749
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1750<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751<p>A vector type is a simple derived type that represents a vector of elements.
1752 Vector types are used when multiple primitive data are operated in parallel
1753 using a single instruction (SIMD). A vector type requires a size (number of
1754 elements) and an underlying primitive data type. Vectors must have a power
1755 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1756 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1757
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1758<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1759<pre>
1760 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1761</pre>
1762
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1763<p>The number of elements is a constant integer value; elementtype may be any
1764 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1765
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1766<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1767<table class="layout">
1768 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1769 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1770 <td class="left">Vector of 4 32-bit integer values.</td>
1771 </tr>
1772 <tr class="layout">
1773 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1774 <td class="left">Vector of 8 32-bit floating-point values.</td>
1775 </tr>
1776 <tr class="layout">
1777 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1778 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
1780</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1781
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1782<p>Note that the code generator does not yet support large vector types to be
1783 used as function return types. The specific limit on how large a vector
1784 return type codegen can currently handle is target-dependent; currently it's
1785 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787</div>
1788
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1789<!-- _______________________________________________________________________ -->
1790<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1791<div class="doc_text">
1792
1793<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1794<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1795 corresponds (for example) to the C notion of a forward declared structure
1796 type. In LLVM, opaque types can eventually be resolved to any type (not just
1797 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1798
1799<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1800<pre>
1801 opaque
1802</pre>
1803
1804<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1805<table class="layout">
1806 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1807 <td class="left"><tt>opaque</tt></td>
1808 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1809 </tr>
1810</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1811
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1812</div>
1813
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1814<!-- ======================================================================= -->
1815<div class="doc_subsection">
1816 <a name="t_uprefs">Type Up-references</a>
1817</div>
1818
1819<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1820
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1821<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1822<p>An "up reference" allows you to refer to a lexically enclosing type without
1823 requiring it to have a name. For instance, a structure declaration may
1824 contain a pointer to any of the types it is lexically a member of. Example
1825 of up references (with their equivalent as named type declarations)
1826 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1827
1828<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1829 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1830 { \2 }* %y = type { %y }*
1831 \1* %z = type %z*
1832</pre>
1833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1834<p>An up reference is needed by the asmprinter for printing out cyclic types
1835 when there is no declared name for a type in the cycle. Because the
1836 asmprinter does not want to print out an infinite type string, it needs a
1837 syntax to handle recursive types that have no names (all names are optional
1838 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1839
1840<h5>Syntax:</h5>
1841<pre>
1842 \&lt;level&gt;
1843</pre>
1844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1845<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]1846
1847<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1848<table class="layout">
1849 <tr class="layout">
1850 <td class="left"><tt>\1*</tt></td>
1851 <td class="left">Self-referential pointer.</td>
1852 </tr>
1853 <tr class="layout">
1854 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1855 <td class="left">Recursive structure where the upref refers to the out-most
1856 structure.</td>
1857 </tr>
1858</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1859
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1860</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1861
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1862<!-- *********************************************************************** -->
1863<div class="doc_section"> <a name="constants">Constants</a> </div>
1864<!-- *********************************************************************** -->
1865
1866<div class="doc_text">
1867
1868<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1869 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1870
1871</div>
1872
1873<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1874<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1875
1876<div class="doc_text">
1877
1878<dl>
1879 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1880 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1881 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1882
1883 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1884 <dd>Standard integers (such as '4') are constants of
1885 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1886 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1887
1888 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1889 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1890 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1891 notation (see below). The assembler requires the exact decimal value of a
1892 floating-point constant. For example, the assembler accepts 1.25 but
1893 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1894 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1895
1896 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1897 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1898 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899</dl>
1900
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1901<p>The one non-intuitive notation for constants is the hexadecimal form of
1902 floating point constants. For example, the form '<tt>double
1903 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1904 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1905 constants are required (and the only time that they are generated by the
1906 disassembler) is when a floating point constant must be emitted but it cannot
1907 be represented as a decimal floating point number in a reasonable number of
1908 digits. For example, NaN's, infinities, and other special values are
1909 represented in their IEEE hexadecimal format so that assembly and disassembly
1910 do not cause any bits to change in the constants.</p>
1911
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1912<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1913 represented using the 16-digit form shown above (which matches the IEEE754
1914 representation for double); float values must, however, be exactly
1915 representable as IEE754 single precision. Hexadecimal format is always used
1916 for long double, and there are three forms of long double. The 80-bit format
1917 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1918 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1919 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1920 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1921 currently supported target uses this format. Long doubles will only work if
1922 they match the long double format on your target. All hexadecimal formats
1923 are big-endian (sign bit at the left).</p>
1924
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1925</div>
1926
1927<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1928<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1929<a name="aggregateconstants"></a> <!-- old anchor -->
1930<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1931</div>
1932
1933<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1934
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1935<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1936 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1937
1938<dl>
1939 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1940 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1941 type definitions (a comma separated list of elements, surrounded by braces
1942 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1943 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1944 Structure constants must have <a href="#t_struct">structure type</a>, and
1945 the number and types of elements must match those specified by the
1946 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1947
1948 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1949 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1950 definitions (a comma separated list of elements, surrounded by square
1951 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1952 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1953 the number and types of elements must match those specified by the
1954 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1955
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1956 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1957 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1958 definitions (a comma separated list of elements, surrounded by
1959 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1960 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1961 have <a href="#t_vector">vector type</a>, and the number and types of
1962 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1963
1964 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1965 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1966 value to zero of <em>any</em> type, including scalar and aggregate types.
1967 This is often used to avoid having to print large zero initializers
1968 (e.g. for large arrays) and is always exactly equivalent to using explicit
1969 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1970
1971 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1972 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1973 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1974 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1975 be interpreted as part of the instruction stream, metadata is a place to
1976 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1977</dl>
1978
1979</div>
1980
1981<!-- ======================================================================= -->
1982<div class="doc_subsection">
1983 <a name="globalconstants">Global Variable and Function Addresses</a>
1984</div>
1985
1986<div class="doc_text">
1987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1988<p>The addresses of <a href="#globalvars">global variables</a>
1989 and <a href="#functionstructure">functions</a> are always implicitly valid
1990 (link-time) constants. These constants are explicitly referenced when
1991 the <a href="#identifiers">identifier for the global</a> is used and always
1992 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1993 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1994
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1995<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1996<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1997@X = global i32 17
1998@Y = global i32 42
1999@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2000</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2001</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2002
2003</div>
2004
2005<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2006<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2007<div class="doc_text">
2008
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2009<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has no
2010 specific value. Undefined values may be of any type and be used anywhere a
2011 constant is permitted.</p>
2012
2013<p>Undefined values indicate to the compiler that the program is well defined no
2014 matter what value is used, giving the compiler more freedom to optimize.</p>
2015
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2016</div>
2017
2018<!-- ======================================================================= -->
2019<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2020</div>
2021
2022<div class="doc_text">
2023
2024<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2025 to be used as constants. Constant expressions may be of
2026 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2027 operation that does not have side effects (e.g. load and call are not
2028 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2029
2030<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2031 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2032 <dd>Truncate a constant to another type. The bit size of CST must be larger
2033 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2034
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2035 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2036 <dd>Zero extend a constant to another type. The bit size of CST must be
2037 smaller or equal to the bit size of TYPE. Both types must be
2038 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2039
2040 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2041 <dd>Sign extend a constant to another type. The bit size of CST must be
2042 smaller or equal to the bit size of TYPE. Both types must be
2043 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2044
2045 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2046 <dd>Truncate a floating point constant to another floating point type. The
2047 size of CST must be larger than the size of TYPE. Both types must be
2048 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2049
2050 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2051 <dd>Floating point extend a constant to another type. The size of CST must be
2052 smaller or equal to the size of TYPE. Both types must be floating
2053 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2054
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2055 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2056 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2057 constant. TYPE must be a scalar or vector integer type. CST must be of
2058 scalar or vector floating point type. Both CST and TYPE must be scalars,
2059 or vectors of the same number of elements. If the value won't fit in the
2060 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2061
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2062 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2063 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2064 constant. TYPE must be a scalar or vector integer type. CST must be of
2065 scalar or vector floating point type. Both CST and TYPE must be scalars,
2066 or vectors of the same number of elements. If the value won't fit in the
2067 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2068
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2069 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2070 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2071 constant. TYPE must be a scalar or vector floating point type. CST must be
2072 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2073 vectors of the same number of elements. If the value won't fit in the
2074 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2075
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2076 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2077 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2078 constant. TYPE must be a scalar or vector floating point type. CST must be
2079 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2080 vectors of the same number of elements. If the value won't fit in the
2081 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2082
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2083 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2084 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2085 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2086 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2087 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2088
2089 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2090 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2091 type. CST must be of integer type. The CST value is zero extended,
2092 truncated, or unchanged to make it fit in a pointer size. This one is
2093 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2094
2095 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2096 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2097 are the same as those for the <a href="#i_bitcast">bitcast
2098 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2099
2100 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2101 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2102 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2103 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2104 instruction, the index list may have zero or more indexes, which are
2105 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2106
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2107 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2109
2110 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2111 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2112
2113 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2114 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2115
2116 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2117 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2118 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2119
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2120 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2121 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2122 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2123
2124 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2125 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2126 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2127
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2128 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2129 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2130 be any of the <a href="#binaryops">binary</a>
2131 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2132 on operands are the same as those for the corresponding instruction
2133 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2134</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2135
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2136</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2137
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2138<!-- ======================================================================= -->
2139<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2140</div>
2141
2142<div class="doc_text">
2143
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2144<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2145 stream without affecting the behaviour of the program. There are two
2146 metadata primitives, strings and nodes. All metadata has the
2147 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2148 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2149
2150<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2151 any character by escaping non-printable characters with "\xx" where "xx" is
2152 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2153
2154<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2155 (a comma separated list of elements, surrounded by braces and preceeded by an
2156 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2157 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2158
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2159<p>A metadata node will attempt to track changes to the values it holds. In the
2160 event that a value is deleted, it will be replaced with a typeless
2161 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2162
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2163<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2164 the program that isn't available in the instructions, or that isn't easily
2165 computable. Similarly, the code generator may expect a certain metadata
2166 format to be used to express debugging information.</p>
2167
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2168</div>
2169
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2170<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2171<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2172<!-- *********************************************************************** -->
2173
2174<!-- ======================================================================= -->
2175<div class="doc_subsection">
2176<a name="inlineasm">Inline Assembler Expressions</a>
2177</div>
2178
2179<div class="doc_text">
2180
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181<p>LLVM supports inline assembler expressions (as opposed
2182 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2183 a special value. This value represents the inline assembler as a string
2184 (containing the instructions to emit), a list of operand constraints (stored
2185 as a string), and a flag that indicates whether or not the inline asm
2186 expression has side effects. An example inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2187
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2188<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2189<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2190i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2191</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2192</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2193
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2194<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2195 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2196 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2197
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2198<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2199<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2200%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]2201</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2202</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2203
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2204<p>Inline asms with side effects not visible in the constraint list must be
2205 marked as having side effects. This is done through the use of the
2206 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2207
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2208<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2209<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2210call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2211</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2212</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2213
2214<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2215 documented here. Constraints on what can be done (e.g. duplication, moving,
2216 etc need to be documented). This is probably best done by reference to
2217 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2218
2219</div>
2220
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2221
2222<!-- *********************************************************************** -->
2223<div class="doc_section">
2224 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2225</div>
2226<!-- *********************************************************************** -->
2227
2228<p>LLVM has a number of "magic" global variables that contain data that affect
2229code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2230of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2231section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2232by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2233
2234<!-- ======================================================================= -->
2235<div class="doc_subsection">
2236<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2237</div>
2238
2239<div class="doc_text">
2240
2241<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2242href="#linkage_appending">appending linkage</a>. This array contains a list of
2243pointers to global variables and functions which may optionally have a pointer
2244cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2245
2246<pre>
2247 @X = global i8 4
2248 @Y = global i32 123
2249
2250 @llvm.used = appending global [2 x i8*] [
2251 i8* @X,
2252 i8* bitcast (i32* @Y to i8*)
2253 ], section "llvm.metadata"
2254</pre>
2255
2256<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2257compiler, assembler, and linker are required to treat the symbol as if there is
2258a reference to the global that it cannot see. For example, if a variable has
2259internal linkage and no references other than that from the <tt>@llvm.used</tt>
2260list, it cannot be deleted. This is commonly used to represent references from
2261inline asms and other things the compiler cannot "see", and corresponds to
2262"attribute((used))" in GNU C.</p>
2263
2264<p>On some targets, the code generator must emit a directive to the assembler or
2265object file to prevent the assembler and linker from molesting the symbol.</p>
2266
2267</div>
2268
2269<!-- ======================================================================= -->
2270<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2271<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2272</div>
2273
2274<div class="doc_text">
2275
2276<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2277<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2278touching the symbol. On targets that support it, this allows an intelligent
2279linker to optimize references to the symbol without being impeded as it would be
2280by <tt>@llvm.used</tt>.</p>
2281
2282<p>This is a rare construct that should only be used in rare circumstances, and
2283should not be exposed to source languages.</p>
2284
2285</div>
2286
2287<!-- ======================================================================= -->
2288<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2289<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2290</div>
2291
2292<div class="doc_text">
2293
2294<p>TODO: Describe this.</p>
2295
2296</div>
2297
2298<!-- ======================================================================= -->
2299<div class="doc_subsection">
2300<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2301</div>
2302
2303<div class="doc_text">
2304
2305<p>TODO: Describe this.</p>
2306
2307</div>
2308
2309
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2310<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2311<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2312<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2314<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2315
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2316<p>The LLVM instruction set consists of several different classifications of
2317 instructions: <a href="#terminators">terminator
2318 instructions</a>, <a href="#binaryops">binary instructions</a>,
2319 <a href="#bitwiseops">bitwise binary instructions</a>,
2320 <a href="#memoryops">memory instructions</a>, and
2321 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2323</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2324
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2325<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2326<div class="doc_subsection"> <a name="terminators">Terminator
2327Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2328
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2329<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2330
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2331<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2332 in a program ends with a "Terminator" instruction, which indicates which
2333 block should be executed after the current block is finished. These
2334 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2335 control flow, not values (the one exception being the
2336 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2337
2338<p>There are six different terminator instructions: the
2339 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2340 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2341 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2342 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2343 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2344 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2346</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2347
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2348<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2349<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2350Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2351
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2352<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2354<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2355<pre>
2356 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]2357 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2358</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2359
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2360<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2361<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2362 a value) from a function back to the caller.</p>
2363
2364<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2365 value and then causes control flow, and one that just causes control flow to
2366 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2368<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2369<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2370 return value. The type of the return value must be a
2371 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2372
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2373<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2374 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2375 value or a return value with a type that does not match its type, or if it
2376 has a void return type and contains a '<tt>ret</tt>' instruction with a
2377 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2378
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2379<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2380<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2381 the calling function's context. If the caller is a
2382 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2383 instruction after the call. If the caller was an
2384 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2385 the beginning of the "normal" destination block. If the instruction returns
2386 a value, that value shall set the call or invoke instruction's return
2387 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2389<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2390<pre>
2391 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2392 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2393 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]2394</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2395
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2396<p>Note that the code generator does not yet fully support large
2397 return values. The specific sizes that are currently supported are
2398 dependent on the target. For integers, on 32-bit targets the limit
2399 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2400 For aggregate types, the current limits are dependent on the element
2401 types; for example targets are often limited to 2 total integer
2402 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2403
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2404</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2405<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2406<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2407
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2408<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2409
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2410<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2411<pre>
2412 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]2413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2414
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2415<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2416<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2417 different basic block in the current function. There are two forms of this
2418 instruction, corresponding to a conditional branch and an unconditional
2419 branch.</p>
2420
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2421<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2422<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2423 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2424 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2425 target.</p>
2426
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2428<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2429 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2430 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2431 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2432
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2433<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2434<pre>
2435Test:
2436 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2437 br i1 %cond, label %IfEqual, label %IfUnequal
2438IfEqual:
2439 <a href="#i_ret">ret</a> i32 1
2440IfUnequal:
2441 <a href="#i_ret">ret</a> i32 0
2442</pre>
2443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2444</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2445
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2446<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2447<div class="doc_subsubsection">
2448 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2449</div>
2450
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2451<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2453<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2454<pre>
2455 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2456</pre>
2457
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2458<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2459<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]2460 several different places. It is a generalization of the '<tt>br</tt>'
2461 instruction, allowing a branch to occur to one of many possible
2462 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2463
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2464<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2465<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2466 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2467 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2468 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2470<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2471<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2472 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2473 is searched for the given value. If the value is found, control flow is
2474 transfered to the corresponding destination; otherwise, control flow is
2475 transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2476
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2477<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2478<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2479 <tt>switch</tt> instruction, this instruction may be code generated in
2480 different ways. For example, it could be generated as a series of chained
2481 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2482
2483<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2484<pre>
2485 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2486 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2487 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2488
2489 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2490 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2491
2492 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2493 switch i32 %val, label %otherwise [ i32 0, label %onzero
2494 i32 1, label %onone
2495 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2496</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2498</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2500<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2501<div class="doc_subsubsection">
2502 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2503</div>
2504
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2505<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2506
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2507<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2508<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2509 &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]2510 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2511</pre>
2512
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2513<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2514<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2515 function, with the possibility of control flow transfer to either the
2516 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2517 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2518 control flow will return to the "normal" label. If the callee (or any
2519 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2520 instruction, control is interrupted and continued at the dynamically nearest
2521 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2522
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2523<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2524<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2525
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2526<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2527 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2528 convention</a> the call should use. If none is specified, the call
2529 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2530
2531 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2532 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2533 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2534
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2535 <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]2536 function value being invoked. In most cases, this is a direct function
2537 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2538 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2539
2540 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2541 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2542
2543 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2544 signature argument types. If the function signature indicates the
2545 function accepts a variable number of arguments, the extra arguments can
2546 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2547
2548 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2549 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2550
2551 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2553
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2554 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2556 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2557</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2559<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2560<p>This instruction is designed to operate as a standard
2561 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2562 primary difference is that it establishes an association with a label, which
2563 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2564
2565<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2566 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2567 exception. Additionally, this is important for implementation of
2568 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2569
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2570<p>For the purposes of the SSA form, the definition of the value returned by the
2571 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2572 block to the "normal" label. If the callee unwinds then no return value is
2573 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2574
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2576<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2577 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2578 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2579 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2580 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2581</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2582
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2583</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2584
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2585<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2586
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2587<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2588Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2590<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2591
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2592<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2593<pre>
2594 unwind
2595</pre>
2596
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2597<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2598<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2599 at the first callee in the dynamic call stack which used
2600 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2601 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2602
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2603<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2604<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2605 immediately halt. The dynamic call stack is then searched for the
2606 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2607 Once found, execution continues at the "exceptional" destination block
2608 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2609 instruction in the dynamic call chain, undefined behavior results.</p>
2610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2611</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2612
2613<!-- _______________________________________________________________________ -->
2614
2615<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2616Instruction</a> </div>
2617
2618<div class="doc_text">
2619
2620<h5>Syntax:</h5>
2621<pre>
2622 unreachable
2623</pre>
2624
2625<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2626<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2627 instruction is used to inform the optimizer that a particular portion of the
2628 code is not reachable. This can be used to indicate that the code after a
2629 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2630
2631<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2632<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2633
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2634</div>
2635
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2636<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2637<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2639<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2640
2641<p>Binary operators are used to do most of the computation in a program. They
2642 require two operands of the same type, execute an operation on them, and
2643 produce a single value. The operands might represent multiple data, as is
2644 the case with the <a href="#t_vector">vector</a> data type. The result value
2645 has the same type as its operands.</p>
2646
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2647<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2648
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2649</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2650
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2651<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2652<div class="doc_subsubsection">
2653 <a name="i_add">'<tt>add</tt>' Instruction</a>
2654</div>
2655
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2656<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2658<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2659<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2660 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2661 &lt;result&gt; = nuw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2662 &lt;result&gt; = nsw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2663 &lt;result&gt; = nuw nsw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2664</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2665
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2666<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2667<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2670<p>The two arguments to the '<tt>add</tt>' instruction must
2671 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2672 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2674<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2675<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2676
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677<p>If the sum has unsigned overflow, the result returned is the mathematical
2678 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]2679
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2680<p>Because LLVM integers use a two's complement representation, this instruction
2681 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2682
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2683<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2684 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2685 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2686 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2687
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2688<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2689<pre>
2690 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2691</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2693</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2695<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2696<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2697 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2698</div>
2699
2700<div class="doc_text">
2701
2702<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2703<pre>
2704 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2705</pre>
2706
2707<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2708<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2709
2710<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2711<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2712 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2713 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2714
2715<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2716<p>The value produced is the floating point sum of the two operands.</p>
2717
2718<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2719<pre>
2720 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2721</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2722
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2723</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2724
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2725<!-- _______________________________________________________________________ -->
2726<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2727 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2728</div>
2729
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2730<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2731
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2732<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2733<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2734 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2735 &lt;result&gt; = nuw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2736 &lt;result&gt; = nsw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2737 &lt;result&gt; = nuw nsw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2738</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2739
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2740<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2741<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2742 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2743
2744<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2745 '<tt>neg</tt>' instruction present in most other intermediate
2746 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2747
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2748<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2749<p>The two arguments to the '<tt>sub</tt>' instruction must
2750 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2751 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2753<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2754<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2755
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2756<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2757 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2758 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2759
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2760<p>Because LLVM integers use a two's complement representation, this instruction
2761 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2762
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2763<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2764 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2765 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2766 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2768<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2769<pre>
2770 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2771 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2772</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2773
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2774</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2775
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2776<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2777<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2778 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2779</div>
2780
2781<div class="doc_text">
2782
2783<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2784<pre>
2785 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2786</pre>
2787
2788<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2789<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2790 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2791
2792<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793 '<tt>fneg</tt>' instruction present in most other intermediate
2794 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2795
2796<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2797<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2798 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2799 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2800
2801<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2802<p>The value produced is the floating point difference of the two operands.</p>
2803
2804<h5>Example:</h5>
2805<pre>
2806 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2807 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2808</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2809
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2810</div>
2811
2812<!-- _______________________________________________________________________ -->
2813<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2814 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2815</div>
2816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2817<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2819<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2820<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2821 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2822 &lt;result&gt; = nuw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2823 &lt;result&gt; = nsw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2824 &lt;result&gt; = nuw nsw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2827<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2828<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2830<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2831<p>The two arguments to the '<tt>mul</tt>' instruction must
2832 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2833 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2835<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2836<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838<p>If the result of the multiplication has unsigned overflow, the result
2839 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2840 width of the result.</p>
2841
2842<p>Because LLVM integers use a two's complement representation, and the result
2843 is the same width as the operands, this instruction returns the correct
2844 result for both signed and unsigned integers. If a full product
2845 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2846 be sign-extended or zero-extended as appropriate to the width of the full
2847 product.</p>
2848
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2849<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2850 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2851 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2852 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2855<pre>
2856 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2857</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2859</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2861<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2862<div class="doc_subsubsection">
2863 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2864</div>
2865
2866<div class="doc_text">
2867
2868<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2869<pre>
2870 &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]2871</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2872
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2873<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2874<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2875
2876<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2877<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2878 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2879 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2880
2881<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2882<p>The value produced is the floating point product of the two operands.</p>
2883
2884<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2885<pre>
2886 &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]2887</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2888
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2889</div>
2890
2891<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2892<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2893</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2895<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2896
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2897<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2898<pre>
2899 &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]2900</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2901
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2902<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2903<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2904
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2905<h5>Arguments:</h5>
2906<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2907 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2908 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2909
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2910<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2911<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2912
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2913<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2914 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2915
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2916<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2917
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2918<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919<pre>
2920 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2921</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2922
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2923</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2924
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2925<!-- _______________________________________________________________________ -->
2926<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2927</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2928
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2929<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2930
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2931<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2932<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2933 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2934 &lt;result&gt; = exact sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2935</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2936
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2939
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2940<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2941<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2942 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2943 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2944
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2945<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2946<p>The value produced is the signed integer quotient of the two operands rounded
2947 towards zero.</p>
2948
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2949<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2950 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2951
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2952<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2953 undefined behavior; this is a rare case, but can occur, for example, by doing
2954 a 32-bit division of -2147483648 by -1.</p>
2955
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]2956<p>If the <tt>exact</tt> keyword is present, the result value of the
2957 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
2958 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2959
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2960<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2961<pre>
2962 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2963</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2964
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2965</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2967<!-- _______________________________________________________________________ -->
2968<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2969Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2971<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2973<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2974<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]2975 &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]2976</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2977
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2978<h5>Overview:</h5>
2979<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2981<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2982<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2983 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2984 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2985
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2986<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2987<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2988
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2989<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2990<pre>
2991 &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]2992</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2993
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2994</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2995
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2996<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2997<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2998</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2999
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3000<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3001
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3002<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3003<pre>
3004 &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]3005</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3006
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3007<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3008<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3009 division of its two arguments.</p>
3010
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3011<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3012<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3013 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3014 values. Both arguments must have identical types.</p>
3015
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3016<h5>Semantics:</h5>
3017<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3018 This instruction always performs an unsigned division to get the
3019 remainder.</p>
3020
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3021<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3022 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3023
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3024<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3025
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3026<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3027<pre>
3028 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3029</pre>
3030
3031</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3032
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3033<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3034<div class="doc_subsubsection">
3035 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3036</div>
3037
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3038<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3039
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3040<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3041<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3042 &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]3043</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3044
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3045<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3046<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3047 division of its two operands. This instruction can also take
3048 <a href="#t_vector">vector</a> versions of the values in which case the
3049 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3050
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3051<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3052<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3053 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3054 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3055
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3056<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3057<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3059 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3060 a value. For more information about the difference,
3061 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3062 Math Forum</a>. For a table of how this is implemented in various languages,
3063 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3064 Wikipedia: modulo operation</a>.</p>
3065
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3066<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3068
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3069<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070 Overflow also leads to undefined behavior; this is a rare case, but can
3071 occur, for example, by taking the remainder of a 32-bit division of
3072 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3073 lets srem be implemented using instructions that return both the result of
3074 the division and the remainder.)</p>
3075
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3076<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3077<pre>
3078 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3079</pre>
3080
3081</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3082
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3083<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3084<div class="doc_subsubsection">
3085 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3086
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3087<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3088
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3089<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3090<pre>
3091 &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]3092</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3093
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3094<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3095<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3096 its two operands.</p>
3097
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3098<h5>Arguments:</h5>
3099<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3100 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3101 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3102
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3103<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3104<p>This instruction returns the <i>remainder</i> of a division. The remainder
3105 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3106
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3107<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3108<pre>
3109 &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]3110</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3111
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3112</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3113
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3114<!-- ======================================================================= -->
3115<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3116Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3118<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3119
3120<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3121 program. They are generally very efficient instructions and can commonly be
3122 strength reduced from other instructions. They require two operands of the
3123 same type, execute an operation on them, and produce a single value. The
3124 resulting value is the same type as its operands.</p>
3125
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3126</div>
3127
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3128<!-- _______________________________________________________________________ -->
3129<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3130Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3131
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3132<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3133
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3134<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3135<pre>
3136 &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]3137</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3138
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3139<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3140<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3141 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3142
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3143<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3145 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3146 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3147
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3148<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3150 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3151 is (statically or dynamically) negative or equal to or larger than the number
3152 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3153 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3154 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3156<h5>Example:</h5>
3157<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3158 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3159 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3160 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3161 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3162 &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]3163</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3164
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3165</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3167<!-- _______________________________________________________________________ -->
3168<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3169Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3171<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3173<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3174<pre>
3175 &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]3176</pre>
3177
3178<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3179<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3180 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3181
3182<h5>Arguments:</h5>
3183<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3184 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3185 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3186
3187<h5>Semantics:</h5>
3188<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189 significant bits of the result will be filled with zero bits after the shift.
3190 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3191 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3192 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3193 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3194
3195<h5>Example:</h5>
3196<pre>
3197 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3198 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3199 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3200 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3201 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3202 &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]3203</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3205</div>
3206
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3207<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3208<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3209Instruction</a> </div>
3210<div class="doc_text">
3211
3212<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3213<pre>
3214 &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]3215</pre>
3216
3217<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3218<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3219 operand shifted to the right a specified number of bits with sign
3220 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3221
3222<h5>Arguments:</h5>
3223<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3224 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3225 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3226
3227<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3228<p>This instruction always performs an arithmetic shift right operation, The
3229 most significant bits of the result will be filled with the sign bit
3230 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3231 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3232 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3233 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3234
3235<h5>Example:</h5>
3236<pre>
3237 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3238 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3239 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3240 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3241 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3242 &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]3243</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3244
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3245</div>
3246
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3247<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3248<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3249Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3250
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3251<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3252
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3253<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3255 &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]3256</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3259<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3260 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3261
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3262<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3263<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3265 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3266
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3267<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3268<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3270<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3271 <tbody>
3272 <tr>
3273 <td>In0</td>
3274 <td>In1</td>
3275 <td>Out</td>
3276 </tr>
3277 <tr>
3278 <td>0</td>
3279 <td>0</td>
3280 <td>0</td>
3281 </tr>
3282 <tr>
3283 <td>0</td>
3284 <td>1</td>
3285 <td>0</td>
3286 </tr>
3287 <tr>
3288 <td>1</td>
3289 <td>0</td>
3290 <td>0</td>
3291 </tr>
3292 <tr>
3293 <td>1</td>
3294 <td>1</td>
3295 <td>1</td>
3296 </tr>
3297 </tbody>
3298</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3299
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3300<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3301<pre>
3302 &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]3303 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3304 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3305</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3306</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3307<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3308<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3309
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310<div class="doc_text">
3311
3312<h5>Syntax:</h5>
3313<pre>
3314 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3315</pre>
3316
3317<h5>Overview:</h5>
3318<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3319 two operands.</p>
3320
3321<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3322<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3323 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3324 values. Both arguments must have identical types.</p>
3325
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3326<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3327<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3328
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3329<table border="1" cellspacing="0" cellpadding="4">
3330 <tbody>
3331 <tr>
3332 <td>In0</td>
3333 <td>In1</td>
3334 <td>Out</td>
3335 </tr>
3336 <tr>
3337 <td>0</td>
3338 <td>0</td>
3339 <td>0</td>
3340 </tr>
3341 <tr>
3342 <td>0</td>
3343 <td>1</td>
3344 <td>1</td>
3345 </tr>
3346 <tr>
3347 <td>1</td>
3348 <td>0</td>
3349 <td>1</td>
3350 </tr>
3351 <tr>
3352 <td>1</td>
3353 <td>1</td>
3354 <td>1</td>
3355 </tr>
3356 </tbody>
3357</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3360<pre>
3361 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3362 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3363 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3364</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3365
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3366</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3368<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3369<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3370Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3371
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3372<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3374<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3375<pre>
3376 &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]3377</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3378
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3380<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3381 its two operands. The <tt>xor</tt> is used to implement the "one's
3382 complement" operation, which is the "~" operator in C.</p>
3383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3385<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3386 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3387 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3388
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3389<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3390<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3391
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3392<table border="1" cellspacing="0" cellpadding="4">
3393 <tbody>
3394 <tr>
3395 <td>In0</td>
3396 <td>In1</td>
3397 <td>Out</td>
3398 </tr>
3399 <tr>
3400 <td>0</td>
3401 <td>0</td>
3402 <td>0</td>
3403 </tr>
3404 <tr>
3405 <td>0</td>
3406 <td>1</td>
3407 <td>1</td>
3408 </tr>
3409 <tr>
3410 <td>1</td>
3411 <td>0</td>
3412 <td>1</td>
3413 </tr>
3414 <tr>
3415 <td>1</td>
3416 <td>1</td>
3417 <td>0</td>
3418 </tr>
3419 </tbody>
3420</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3421
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3422<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3425 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3426 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3427 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3428</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3429
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3430</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3431
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3432<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3433<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3434 <a name="vectorops">Vector Operations</a>
3435</div>
3436
3437<div class="doc_text">
3438
3439<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3440 target-independent manner. These instructions cover the element-access and
3441 vector-specific operations needed to process vectors effectively. While LLVM
3442 does directly support these vector operations, many sophisticated algorithms
3443 will want to use target-specific intrinsics to take full advantage of a
3444 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3445
3446</div>
3447
3448<!-- _______________________________________________________________________ -->
3449<div class="doc_subsubsection">
3450 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3451</div>
3452
3453<div class="doc_text">
3454
3455<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3456<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3457 &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]3458</pre>
3459
3460<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3461<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3462 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3463
3464
3465<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3466<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3467 of <a href="#t_vector">vector</a> type. The second operand is an index
3468 indicating the position from which to extract the element. The index may be
3469 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3470
3471<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3472<p>The result is a scalar of the same type as the element type of
3473 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3474 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3475 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3476
3477<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3478<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3479 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3480</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3481
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3482</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3483
3484<!-- _______________________________________________________________________ -->
3485<div class="doc_subsubsection">
3486 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3487</div>
3488
3489<div class="doc_text">
3490
3491<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3492<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3493 &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]3494</pre>
3495
3496<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3497<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3498 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3499
3500<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3502 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3503 whose type must equal the element type of the first operand. The third
3504 operand is an index indicating the position at which to insert the value.
3505 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3506
3507<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3508<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3509 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3510 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3511 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3512
3513<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3514<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3515 %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]3516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3518</div>
3519
3520<!-- _______________________________________________________________________ -->
3521<div class="doc_subsubsection">
3522 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3523</div>
3524
3525<div class="doc_text">
3526
3527<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3528<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3529 &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]3530</pre>
3531
3532<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3534 from two input vectors, returning a vector with the same element type as the
3535 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3536
3537<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3538<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3539 with types that match each other. The third argument is a shuffle mask whose
3540 element type is always 'i32'. The result of the instruction is a vector
3541 whose length is the same as the shuffle mask and whose element type is the
3542 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3543
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3544<p>The shuffle mask operand is required to be a constant vector with either
3545 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3546
3547<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3548<p>The elements of the two input vectors are numbered from left to right across
3549 both of the vectors. The shuffle mask operand specifies, for each element of
3550 the result vector, which element of the two input vectors the result element
3551 gets. The element selector may be undef (meaning "don't care") and the
3552 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3553
3554<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3555<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3556 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3557 &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]3558 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3559 &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]3560 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3561 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3562 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3563 &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]3564</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3565
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3567
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3568<!-- ======================================================================= -->
3569<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3570 <a name="aggregateops">Aggregate Operations</a>
3571</div>
3572
3573<div class="doc_text">
3574
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3576
3577</div>
3578
3579<!-- _______________________________________________________________________ -->
3580<div class="doc_subsubsection">
3581 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3582</div>
3583
3584<div class="doc_text">
3585
3586<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3587<pre>
3588 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3589</pre>
3590
3591<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3592<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3593 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3594
3595<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3596<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3597 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3598 operands are constant indices to specify which value to extract in a similar
3599 manner as indices in a
3600 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3601
3602<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3603<p>The result is the value at the position in the aggregate specified by the
3604 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3605
3606<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3607<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3608 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3609</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3610
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3612
3613<!-- _______________________________________________________________________ -->
3614<div class="doc_subsubsection">
3615 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3616</div>
3617
3618<div class="doc_text">
3619
3620<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3621<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3622 &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]3623</pre>
3624
3625<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3626<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3627 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3628
3629
3630<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3632 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3633 second operand is a first-class value to insert. The following operands are
3634 constant indices indicating the position at which to insert the value in a
3635 similar manner as indices in a
3636 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3637 value to insert must have the same type as the value identified by the
3638 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3639
3640<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3641<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3642 that of <tt>val</tt> except that the value at the position specified by the
3643 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3644
3645<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3646<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3647 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3648</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3650</div>
3651
3652
3653<!-- ======================================================================= -->
3654<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3655 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3656</div>
3657
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3658<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3659
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3660<p>A key design point of an SSA-based representation is how it represents
3661 memory. In LLVM, no memory locations are in SSA form, which makes things
3662 very simple. This section describes how to read, write, allocate, and free
3663 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3665</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3666
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3667<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3668<div class="doc_subsubsection">
3669 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3670</div>
3671
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3672<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3673
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3674<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3675<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3676 &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]3677</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3678
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3679<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3680<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3681 returns a pointer to it. The object is always allocated in the generic
3682 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3683
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3684<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3685<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3687 system and returns a pointer of the appropriate type to the program. If
3688 "NumElements" is specified, it is the number of elements allocated, otherwise
3689 "NumElements" is defaulted to be one. If a constant alignment is specified,
3690 the value result of the allocation is guaranteed to be aligned to at least
3691 that boundary. If not specified, or if zero, the target can choose to align
3692 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3693
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3694<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3696<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3698 pointer is returned. The result of a zero byte allocation is undefined. The
3699 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3700
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3701<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3702<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3703 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3704
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3705 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3706 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3707 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3708 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3709 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3710</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3711
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3713
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3714</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3715
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3716<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3717<div class="doc_subsubsection">
3718 <a name="i_free">'<tt>free</tt>' Instruction</a>
3719</div>
3720
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3721<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3722
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3723<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3724<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3725 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3726</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3727
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3728<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3729<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3730 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3731
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3732<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3733<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3734 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3735
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3736<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737<p>Access to the memory pointed to by the pointer is no longer defined after
3738 this instruction executes. If the pointer is null, the operation is a
3739 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3740
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3741<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3742<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3743 %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]3744 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3745</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3746
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3747</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3748
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3749<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3750<div class="doc_subsubsection">
3751 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3752</div>
3753
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3754<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3755
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3756<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3757<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3758 &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]3759</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3762<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3763 currently executing function, to be automatically released when this function
3764 returns to its caller. The object is always allocated in the generic address
3765 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3766
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3767<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3768<p>The '<tt>alloca</tt>' instruction
3769 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3770 runtime stack, returning a pointer of the appropriate type to the program.
3771 If "NumElements" is specified, it is the number of elements allocated,
3772 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3773 specified, the value result of the allocation is guaranteed to be aligned to
3774 at least that boundary. If not specified, or if zero, the target can choose
3775 to align the allocation on any convenient boundary compatible with the
3776 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3777
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3778<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3780<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3781<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3782 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3783 memory is automatically released when the function returns. The
3784 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3785 variables that must have an address available. When the function returns
3786 (either with the <tt><a href="#i_ret">ret</a></tt>
3787 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3788 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3790<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3791<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3792 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3793 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3794 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3795 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3800<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3801<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3802Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3804<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3806<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3807<pre>
3808 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3809 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3810</pre>
3811
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3812<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3813<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3814
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3815<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3816<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3817 from which to load. The pointer must point to
3818 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3819 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3820 number or order of execution of this <tt>load</tt> with other
3821 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3822 instructions. </p>
3823
3824<p>The optional constant "align" argument specifies the alignment of the
3825 operation (that is, the alignment of the memory address). A value of 0 or an
3826 omitted "align" argument means that the operation has the preferential
3827 alignment for the target. It is the responsibility of the code emitter to
3828 ensure that the alignment information is correct. Overestimating the
3829 alignment results in an undefined behavior. Underestimating the alignment may
3830 produce less efficient code. An alignment of 1 is always safe.</p>
3831
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3832<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3833<p>The location of memory pointed to is loaded. If the value being loaded is of
3834 scalar type then the number of bytes read does not exceed the minimum number
3835 of bytes needed to hold all bits of the type. For example, loading an
3836 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3837 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3838 is undefined if the value was not originally written using a store of the
3839 same type.</p>
3840
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3841<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842<pre>
3843 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3844 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3845 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3846</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3847
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3848</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3849
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3850<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3851<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3852Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]3854<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3856<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857<pre>
3858 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]3859 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]3860</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3861
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3862<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3863<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3864
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3865<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3866<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3867 and an address at which to store it. The type of the
3868 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3869 the <a href="#t_firstclass">first class</a> type of the
3870 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3871 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3872 or order of execution of this <tt>store</tt> with other
3873 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3874 instructions.</p>
3875
3876<p>The optional constant "align" argument specifies the alignment of the
3877 operation (that is, the alignment of the memory address). A value of 0 or an
3878 omitted "align" argument means that the operation has the preferential
3879 alignment for the target. It is the responsibility of the code emitter to
3880 ensure that the alignment information is correct. Overestimating the
3881 alignment results in an undefined behavior. Underestimating the alignment may
3882 produce less efficient code. An alignment of 1 is always safe.</p>
3883
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3884<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3886 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3887 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3888 does not exceed the minimum number of bytes needed to hold all bits of the
3889 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3890 writing a value of a type like <tt>i20</tt> with a size that is not an
3891 integral number of bytes, it is unspecified what happens to the extra bits
3892 that do not belong to the type, but they will typically be overwritten.</p>
3893
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3894<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3895<pre>
3896 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]3897 store i32 3, i32* %ptr <i>; yields {void}</i>
3898 %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]3899</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3901</div>
3902
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3903<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3904<div class="doc_subsubsection">
3905 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3906</div>
3907
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3908<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3910<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3911<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]3912 &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]3913 &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]3914</pre>
3915
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3916<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3917<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
3918 subelement of an aggregate data structure. It performs address calculation
3919 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3920
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3921<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]3922<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]3923 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3924 elements of the aggregate object are indexed. The interpretation of each
3925 index is dependent on the type being indexed into. The first index always
3926 indexes the pointer value given as the first argument, the second index
3927 indexes a value of the type pointed to (not necessarily the value directly
3928 pointed to, since the first index can be non-zero), etc. The first type
3929 indexed into must be a pointer value, subsequent types can be arrays, vectors
3930 and structs. Note that subsequent types being indexed into can never be
3931 pointers, since that would require loading the pointer before continuing
3932 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]3933
3934<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]3935 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3936 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]3937 vector, integers of any width are allowed, and they are not required to be
3938 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3940<p>For example, let's consider a C code fragment and how it gets compiled to
3941 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3942
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3943<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3944<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3945struct RT {
3946 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3947 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3948 char C;
3949};
3950struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3951 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3952 double Y;
3953 struct RT Z;
3954};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3955
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3956int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3957 return &amp;s[1].Z.B[5][13];
3958}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3959</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3960</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3962<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3963
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3964<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3965<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]3966%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3967%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3968
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]3969define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3970entry:
3971 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3972 ret i32* %reg
3973}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3974</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3975</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3976
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3977<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3978<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]3979 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3980 }</tt>' type, a structure. The second index indexes into the third element
3981 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3982 i8 }</tt>' type, another structure. The third index indexes into the second
3983 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3984 array. The two dimensions of the array are subscripted into, yielding an
3985 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
3986 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3987
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<p>Note that it is perfectly legal to index partially through a structure,
3989 returning a pointer to an inner element. Because of this, the LLVM code for
3990 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3991
3992<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]3993 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3994 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3995 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3996 %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]3997 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3998 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3999 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4000 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4001</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4002
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4003<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4004 <tt>getelementptr</tt> is undefined if the base pointer is not an
4005 <i>in bounds</i> address of an allocated object, or if any of the addresses
4006 formed by successive addition of the offsets implied by the indices to
4007 the base address are not an <i>in bounds</i> address of that allocated
4008 object.
4009 The <i>in bounds</i> addresses for an allocated object are all the addresses
4010 that point into the object, plus the address one past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4011
4012<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4013 the base address with silently-wrapping two's complement arithmetic, and
4014 the result value of the <tt>getelementptr</tt> may be outside the object
4015 pointed to by the base pointer. The result value may not necessarily be
4016 used to access memory though, even if it happens to point into allocated
4017 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4018 section for more information.</p>
4019
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020<p>The getelementptr instruction is often confusing. For some more insight into
4021 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4022
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4023<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4024<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4025 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4026 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4027 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4028 %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]4029 <i>; yields i8*:eptr</i>
4030 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4031 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4032 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4033</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4034
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4035</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4036
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4037<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4038<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4039</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4041<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4042
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4043<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044 which all take a single operand and a type. They perform various bit
4045 conversions on the operand.</p>
4046
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4047</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4048
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4049<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4050<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4051 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4052</div>
4053<div class="doc_text">
4054
4055<h5>Syntax:</h5>
4056<pre>
4057 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4058</pre>
4059
4060<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4061<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4062 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4063
4064<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4066 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4067 size and type of the result, which must be
4068 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4069 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4070 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4074 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4075 source size must be larger than the destination size, <tt>trunc</tt> cannot
4076 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4077
4078<h5>Example:</h5>
4079<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4080 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4081 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4082 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4083</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4085</div>
4086
4087<!-- _______________________________________________________________________ -->
4088<div class="doc_subsubsection">
4089 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4090</div>
4091<div class="doc_text">
4092
4093<h5>Syntax:</h5>
4094<pre>
4095 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4096</pre>
4097
4098<h5>Overview:</h5>
4099<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4100 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4101
4102
4103<h5>Arguments:</h5>
4104<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]4105 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4106 also be of <a href="#t_integer">integer</a> type. The bit size of the
4107 <tt>value</tt> must be smaller than the bit size of the destination type,
4108 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4109
4110<h5>Semantics:</h5>
4111<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]4112 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4113
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4114<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]4115
4116<h5>Example:</h5>
4117<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4118 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4119 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4120</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4121
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4122</div>
4123
4124<!-- _______________________________________________________________________ -->
4125<div class="doc_subsubsection">
4126 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4127</div>
4128<div class="doc_text">
4129
4130<h5>Syntax:</h5>
4131<pre>
4132 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4133</pre>
4134
4135<h5>Overview:</h5>
4136<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4137
4138<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4140 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4141 also be of <a href="#t_integer">integer</a> type. The bit size of the
4142 <tt>value</tt> must be smaller than the bit size of the destination type,
4143 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4144
4145<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4146<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4147 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4148 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4149
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4150<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]4151
4152<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4153<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4154 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4155 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4156</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4157
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4158</div>
4159
4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4162 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4163</div>
4164
4165<div class="doc_text">
4166
4167<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4168<pre>
4169 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4170</pre>
4171
4172<h5>Overview:</h5>
4173<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4174 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4175
4176<h5>Arguments:</h5>
4177<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4178 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4179 to cast it to. The size of <tt>value</tt> must be larger than the size of
4180 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4181 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4182
4183<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4184<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4185 <a href="#t_floating">floating point</a> type to a smaller
4186 <a href="#t_floating">floating point</a> type. If the value cannot fit
4187 within the destination type, <tt>ty2</tt>, then the results are
4188 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4189
4190<h5>Example:</h5>
4191<pre>
4192 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4193 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4194</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4195
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4196</div>
4197
4198<!-- _______________________________________________________________________ -->
4199<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4200 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4201</div>
4202<div class="doc_text">
4203
4204<h5>Syntax:</h5>
4205<pre>
4206 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4207</pre>
4208
4209<h5>Overview:</h5>
4210<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]4211 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4212
4213<h5>Arguments:</h5>
4214<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4215 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4216 a <a href="#t_floating">floating point</a> type to cast it to. The source
4217 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4218
4219<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4220<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4221 <a href="#t_floating">floating point</a> type to a larger
4222 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4223 used to make a <i>no-op cast</i> because it always changes bits. Use
4224 <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]4225
4226<h5>Example:</h5>
4227<pre>
4228 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4229 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4230</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4231
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4232</div>
4233
4234<!-- _______________________________________________________________________ -->
4235<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4236 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4237</div>
4238<div class="doc_text">
4239
4240<h5>Syntax:</h5>
4241<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4242 &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]4243</pre>
4244
4245<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4246<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4247 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4248
4249<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4251 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4252 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4253 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4254 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4257<p>The '<tt>fptoui</tt>' instruction converts its
4258 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4259 towards zero) unsigned integer value. If the value cannot fit
4260 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4261
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4262<h5>Example:</h5>
4263<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4264 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4265 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4266 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4267</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4268
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4269</div>
4270
4271<!-- _______________________________________________________________________ -->
4272<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4273 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4274</div>
4275<div class="doc_text">
4276
4277<h5>Syntax:</h5>
4278<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4279 &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]4280</pre>
4281
4282<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4283<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284 <a href="#t_floating">floating point</a> <tt>value</tt> to
4285 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4286
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4287<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4288<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4289 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4290 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4291 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4292 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4293
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4294<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4295<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4296 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4297 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4298 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4299
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4300<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4301<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4302 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4303 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4304 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4305</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4306
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4307</div>
4308
4309<!-- _______________________________________________________________________ -->
4310<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4311 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4312</div>
4313<div class="doc_text">
4314
4315<h5>Syntax:</h5>
4316<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4317 &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]4318</pre>
4319
4320<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4321<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4322 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4323
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4324<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4325<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]4326 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4327 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4328 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4329 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4330
4331<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4332<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4333 integer quantity and converts it to the corresponding floating point
4334 value. If the value cannot fit in the floating point value, the results are
4335 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4336
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4337<h5>Example:</h5>
4338<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4339 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4340 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4341</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4342
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4343</div>
4344
4345<!-- _______________________________________________________________________ -->
4346<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4347 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4348</div>
4349<div class="doc_text">
4350
4351<h5>Syntax:</h5>
4352<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4353 &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]4354</pre>
4355
4356<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4358 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4359
4360<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4361<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]4362 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4363 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4364 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4365 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4366
4367<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4369 quantity and converts it to the corresponding floating point value. If the
4370 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4371
4372<h5>Example:</h5>
4373<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4374 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4375 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4378</div>
4379
4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4382 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4383</div>
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
4388 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4389</pre>
4390
4391<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4392<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4393 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4397 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4398 <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]4399
4400<h5>Semantics:</h5>
4401<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4403 truncating or zero extending that value to the size of the integer type. If
4404 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4405 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4406 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4407 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4408
4409<h5>Example:</h5>
4410<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4411 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4412 %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]4413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4414
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4415</div>
4416
4417<!-- _______________________________________________________________________ -->
4418<div class="doc_subsubsection">
4419 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4420</div>
4421<div class="doc_text">
4422
4423<h5>Syntax:</h5>
4424<pre>
4425 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4426</pre>
4427
4428<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4430 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4431
4432<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4433<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4434 value to cast, and a type to cast it to, which must be a
4435 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4436
4437<h5>Semantics:</h5>
4438<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4439 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4440 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4441 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4442 than the size of a pointer then a zero extension is done. If they are the
4443 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4444
4445<h5>Example:</h5>
4446<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4447 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4448 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4449 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4450</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4456 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4457</div>
4458<div class="doc_text">
4459
4460<h5>Syntax:</h5>
4461<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4462 &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]4463</pre>
4464
4465<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4466<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4467 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4468
4469<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4470<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4471 non-aggregate first class value, and a type to cast it to, which must also be
4472 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4473 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4474 identical. If the source type is a pointer, the destination type must also be
4475 a pointer. This instruction supports bitwise conversion of vectors to
4476 integers and to vectors of other types (as long as they have the same
4477 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4478
4479<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4480<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4481 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4482 this conversion. The conversion is done as if the <tt>value</tt> had been
4483 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4484 be converted to other pointer types with this instruction. To convert
4485 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4486 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4487
4488<h5>Example:</h5>
4489<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4490 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4491 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4492 %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]4493</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4494
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4495</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4496
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4497<!-- ======================================================================= -->
4498<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4500<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4501
4502<p>The instructions in this category are the "miscellaneous" instructions, which
4503 defy better classification.</p>
4504
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4505</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4506
4507<!-- _______________________________________________________________________ -->
4508<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4509</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4510
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4511<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4512
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4513<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514<pre>
4515 &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]4516</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4517
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4518<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4519<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4520 boolean values based on comparison of its two integer, integer vector, or
4521 pointer operands.</p>
4522
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4523<h5>Arguments:</h5>
4524<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4525 the condition code indicating the kind of comparison to perform. It is not a
4526 value, just a keyword. The possible condition code are:</p>
4527
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4528<ol>
4529 <li><tt>eq</tt>: equal</li>
4530 <li><tt>ne</tt>: not equal </li>
4531 <li><tt>ugt</tt>: unsigned greater than</li>
4532 <li><tt>uge</tt>: unsigned greater or equal</li>
4533 <li><tt>ult</tt>: unsigned less than</li>
4534 <li><tt>ule</tt>: unsigned less or equal</li>
4535 <li><tt>sgt</tt>: signed greater than</li>
4536 <li><tt>sge</tt>: signed greater or equal</li>
4537 <li><tt>slt</tt>: signed less than</li>
4538 <li><tt>sle</tt>: signed less or equal</li>
4539</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4540
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4541<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4543 typed. They must also be identical types.</p>
4544
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4545<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4546<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4547 condition code given as <tt>cond</tt>. The comparison performed always yields
4548 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4549 result, as follows:</p>
4550
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4551<ol>
4552 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4553 <tt>false</tt> otherwise. No sign interpretation is necessary or
4554 performed.</li>
4555
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4556 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4557 <tt>false</tt> otherwise. No sign interpretation is necessary or
4558 performed.</li>
4559
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4560 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4561 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4562
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4563 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4564 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4565 to <tt>op2</tt>.</li>
4566
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4567 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4568 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4569
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4570 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4571 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4572
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4573 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4575
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4576 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4577 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4578 to <tt>op2</tt>.</li>
4579
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4580 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4581 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4582
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4583 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584 <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]4585</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4586
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4587<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4588 values are compared as if they were integers.</p>
4589
4590<p>If the operands are integer vectors, then they are compared element by
4591 element. The result is an <tt>i1</tt> vector with the same number of elements
4592 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4593
4594<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4595<pre>
4596 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4597 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4598 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4599 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4600 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4601 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4602</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4603
4604<p>Note that the code generator does not yet support vector types with
4605 the <tt>icmp</tt> instruction.</p>
4606
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4607</div>
4608
4609<!-- _______________________________________________________________________ -->
4610<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4611</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4613<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4614
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4615<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4616<pre>
4617 &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]4618</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4619
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4620<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4622 values based on comparison of its operands.</p>
4623
4624<p>If the operands are floating point scalars, then the result type is a boolean
4625(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4626
4627<p>If the operands are floating point vectors, then the result type is a vector
4628 of boolean with the same number of elements as the operands being
4629 compared.</p>
4630
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4631<h5>Arguments:</h5>
4632<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4633 the condition code indicating the kind of comparison to perform. It is not a
4634 value, just a keyword. The possible condition code are:</p>
4635
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4636<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4637 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4638 <li><tt>oeq</tt>: ordered and equal</li>
4639 <li><tt>ogt</tt>: ordered and greater than </li>
4640 <li><tt>oge</tt>: ordered and greater than or equal</li>
4641 <li><tt>olt</tt>: ordered and less than </li>
4642 <li><tt>ole</tt>: ordered and less than or equal</li>
4643 <li><tt>one</tt>: ordered and not equal</li>
4644 <li><tt>ord</tt>: ordered (no nans)</li>
4645 <li><tt>ueq</tt>: unordered or equal</li>
4646 <li><tt>ugt</tt>: unordered or greater than </li>
4647 <li><tt>uge</tt>: unordered or greater than or equal</li>
4648 <li><tt>ult</tt>: unordered or less than </li>
4649 <li><tt>ule</tt>: unordered or less than or equal</li>
4650 <li><tt>une</tt>: unordered or not equal</li>
4651 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4652 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4653</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4654
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4655<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656 <i>unordered</i> means that either operand may be a QNAN.</p>
4657
4658<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4659 a <a href="#t_floating">floating point</a> type or
4660 a <a href="#t_vector">vector</a> of floating point type. They must have
4661 identical types.</p>
4662
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4663<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4664<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665 according to the condition code given as <tt>cond</tt>. If the operands are
4666 vectors, then the vectors are compared element by element. Each comparison
4667 performed always yields an <a href="#t_primitive">i1</a> result, as
4668 follows:</p>
4669
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4670<ol>
4671 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4673 <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]4674 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4675
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4676 <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]4677 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4678
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4679 <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]4680 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4681
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4682 <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]4683 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4684
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4685 <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]4686 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4687
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4688 <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]4689 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4690
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4691 <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]4692
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4693 <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]4694 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4695
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4696 <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]4697 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4698
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4699 <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]4700 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4701
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4702 <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]4703 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4704
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4705 <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]4706 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4707
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4708 <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]4709 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4710
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4711 <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]4712
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4713 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4714</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4715
4716<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717<pre>
4718 &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]4719 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4720 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4721 &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]4722</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4723
4724<p>Note that the code generator does not yet support vector types with
4725 the <tt>fcmp</tt> instruction.</p>
4726
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4727</div>
4728
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4729<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4730<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4731 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4732</div>
4733
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4734<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4735
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4736<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4737<pre>
4738 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4739</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4740
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4741<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4742<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4743 SSA graph representing the function.</p>
4744
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4745<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4746<p>The type of the incoming values is specified with the first type field. After
4747 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4748 one pair for each predecessor basic block of the current block. Only values
4749 of <a href="#t_firstclass">first class</a> type may be used as the value
4750 arguments to the PHI node. Only labels may be used as the label
4751 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4752
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753<p>There must be no non-phi instructions between the start of a basic block and
4754 the PHI instructions: i.e. PHI instructions must be first in a basic
4755 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4756
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4757<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4758 occur on the edge from the corresponding predecessor block to the current
4759 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4760 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4761
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4762<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4763<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764 specified by the pair corresponding to the predecessor basic block that
4765 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4766
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4767<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4768<pre>
4769Loop: ; Infinite loop that counts from 0 on up...
4770 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4771 %nextindvar = add i32 %indvar, 1
4772 br label %Loop
4773</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4774
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4775</div>
4776
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4777<!-- _______________________________________________________________________ -->
4778<div class="doc_subsubsection">
4779 <a name="i_select">'<tt>select</tt>' Instruction</a>
4780</div>
4781
4782<div class="doc_text">
4783
4784<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4785<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4786 &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>
4787
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4788 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4789</pre>
4790
4791<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4792<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4793 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4794
4795
4796<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4797<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4798 values indicating the condition, and two values of the
4799 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4800 vectors and the condition is a scalar, then entire vectors are selected, not
4801 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4802
4803<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4804<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4805 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4807<p>If the condition is a vector of i1, then the value arguments must be vectors
4808 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4809
4810<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4811<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4812 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4813</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4814
4815<p>Note that the code generator does not yet support conditions
4816 with vector type.</p>
4817
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4818</div>
4819
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4820<!-- _______________________________________________________________________ -->
4821<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4822 <a name="i_call">'<tt>call</tt>' Instruction</a>
4823</div>
4824
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4825<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4827<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4828<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4829 &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]4830</pre>
4831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4832<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4833<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4835<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4836<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4837
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4838<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4839 <li>The optional "tail" marker indicates whether the callee function accesses
4840 any allocas or varargs in the caller. If the "tail" marker is present,
4841 the function call is eligible for tail call optimization. Note that calls
4842 may be marked "tail" even if they do not occur before
4843 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4845 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4846 convention</a> the call should use. If none is specified, the call
4847 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4848
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4849 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4850 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4851 '<tt>inreg</tt>' attributes are valid here.</li>
4852
4853 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4854 type of the return value. Functions that return no value are marked
4855 <tt><a href="#t_void">void</a></tt>.</li>
4856
4857 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4858 being invoked. The argument types must match the types implied by this
4859 signature. This type can be omitted if the function is not varargs and if
4860 the function type does not return a pointer to a function.</li>
4861
4862 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4863 be invoked. In most cases, this is a direct function invocation, but
4864 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4865 to function value.</li>
4866
4867 <li>'<tt>function args</tt>': argument list whose types match the function
4868 signature argument types. All arguments must be of
4869 <a href="#t_firstclass">first class</a> type. If the function signature
4870 indicates the function accepts a variable number of arguments, the extra
4871 arguments can be specified.</li>
4872
4873 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4874 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4875 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4876</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4878<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4879<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4880 a specified function, with its incoming arguments bound to the specified
4881 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4882 function, control flow continues with the instruction after the function
4883 call, and the return value of the function is bound to the result
4884 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4886<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4887<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]4888 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]4889 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4890 %X = tail call i32 @foo() <i>; yields i32</i>
4891 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4892 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]4893
4894 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4895 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]4896 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4897 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]4898 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]4899 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4900</pre>
4901
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4902</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4903
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4904<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4905<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]4906 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4907</div>
4908
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4909<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4910
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]4911<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4912<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4913 &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]4914</pre>
4915
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]4916<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4917<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4918 the "variable argument" area of a function call. It is used to implement the
4919 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4920
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]4921<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4922<p>This instruction takes a <tt>va_list*</tt> value and the type of the
4923 argument. It returns a value of the specified argument type and increments
4924 the <tt>va_list</tt> to point to the next argument. The actual type
4925 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4926
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]4927<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4928<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
4929 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
4930 to the next argument. For more information, see the variable argument
4931 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4932
4933<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]4934 take a variable number of arguments, for example, the <tt>vfprintf</tt>
4935 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4936
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937<p><tt>va_arg</tt> is an LLVM instruction instead of
4938 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
4939 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4940
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]4941<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]4942<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4943
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4944<p>Note that the code generator does not yet fully support va_arg on many
4945 targets. Also, it does not currently support va_arg with aggregate types on
4946 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]4947
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4948</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4949
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4950<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4951<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4952<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4953
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4954<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4955
4956<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4957 well known names and semantics and are required to follow certain
4958 restrictions. Overall, these intrinsics represent an extension mechanism for
4959 the LLVM language that does not require changing all of the transformations
4960 in LLVM when adding to the language (or the bitcode reader/writer, the
4961 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4962
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4963<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4964 prefix is reserved in LLVM for intrinsic names; thus, function names may not
4965 begin with this prefix. Intrinsic functions must always be external
4966 functions: you cannot define the body of intrinsic functions. Intrinsic
4967 functions may only be used in call or invoke instructions: it is illegal to
4968 take the address of an intrinsic function. Additionally, because intrinsic
4969 functions are part of the LLVM language, it is required if any are added that
4970 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4971
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4972<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
4973 family of functions that perform the same operation but on different data
4974 types. Because LLVM can represent over 8 million different integer types,
4975 overloading is used commonly to allow an intrinsic function to operate on any
4976 integer type. One or more of the argument types or the result type can be
4977 overloaded to accept any integer type. Argument types may also be defined as
4978 exactly matching a previous argument's type or the result type. This allows
4979 an intrinsic function which accepts multiple arguments, but needs all of them
4980 to be of the same type, to only be overloaded with respect to a single
4981 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4982
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4983<p>Overloaded intrinsics will have the names of its overloaded argument types
4984 encoded into its function name, each preceded by a period. Only those types
4985 which are overloaded result in a name suffix. Arguments whose type is matched
4986 against another type do not. For example, the <tt>llvm.ctpop</tt> function
4987 can take an integer of any width and returns an integer of exactly the same
4988 integer width. This leads to a family of functions such as
4989 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
4990 %val)</tt>. Only one type, the return type, is overloaded, and only one type
4991 suffix is required. Because the argument's type is matched against the return
4992 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4993
4994<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4997</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4998
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4999<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5000<div class="doc_subsection">
5001 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5002</div>
5003
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5004<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5005
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5006<p>Variable argument support is defined in LLVM with
5007 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5008 intrinsic functions. These functions are related to the similarly named
5009 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5010
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5011<p>All of these functions operate on arguments that use a target-specific value
5012 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5013 not define what this type is, so all transformations should be prepared to
5014 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5015
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5016<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]5017 instruction and the variable argument handling intrinsic functions are
5018 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5019
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5020<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5021<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5022define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5023 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5024 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5025 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5026 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5027
5028 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5029 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5030
5031 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5032 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5033 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5034 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5035 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5036
5037 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5038 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5039 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5040}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5041
5042declare void @llvm.va_start(i8*)
5043declare void @llvm.va_copy(i8*, i8*)
5044declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5045</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5046</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5047
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5048</div>
5049
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5050<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5051<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5052 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5053</div>
5054
5055
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5056<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5057
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5058<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5059<pre>
5060 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5061</pre>
5062
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5063<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5064<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5065 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]5066
5067<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5068<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]5069
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5070<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5071<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]5072 macro available in C. In a target-dependent way, it initializes
5073 the <tt>va_list</tt> element to which the argument points, so that the next
5074 call to <tt>va_arg</tt> will produce the first variable argument passed to
5075 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5076 need to know the last argument of the function as the compiler can figure
5077 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5078
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5079</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5080
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5081<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5082<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5083 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5084</div>
5085
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5086<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5087
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088<h5>Syntax:</h5>
5089<pre>
5090 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5091</pre>
5092
5093<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5094<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5095 which has been initialized previously
5096 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5097 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5098
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5099<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5100<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]5101
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5102<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5103<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]5104 macro available in C. In a target-dependent way, it destroys
5105 the <tt>va_list</tt> element to which the argument points. Calls
5106 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5107 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5108 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5109
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5110</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5111
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5112<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5113<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5114 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5115</div>
5116
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5117<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5118
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5119<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5120<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5121 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5122</pre>
5123
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5124<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5125<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5126 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5127
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5128<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5129<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]5130 The second argument is a pointer to a <tt>va_list</tt> element to copy
5131 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5132
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5133<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5134<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]5135 macro available in C. In a target-dependent way, it copies the
5136 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5137 element. This intrinsic is necessary because
5138 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5139 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5140
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5141</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5142
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5143<!-- ======================================================================= -->
5144<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5145 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5146</div>
5147
5148<div class="doc_text">
5149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5150<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5151Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5152intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5153roots on the stack</a>, as well as garbage collector implementations that
5154require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5155barriers. Front-ends for type-safe garbage collected languages should generate
5156these intrinsics to make use of the LLVM garbage collectors. For more details,
5157see <a href="GarbageCollection.html">Accurate Garbage Collection with
5158LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5160<p>The garbage collection intrinsics only operate on objects in the generic
5161 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5162
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5163</div>
5164
5165<!-- _______________________________________________________________________ -->
5166<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5167 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5168</div>
5169
5170<div class="doc_text">
5171
5172<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5173<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5174 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5175</pre>
5176
5177<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5178<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]5179 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5180
5181<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5182<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5183 root pointer. The second pointer (which must be either a constant or a
5184 global value address) contains the meta-data to be associated with the
5185 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5186
5187<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5188<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]5189 location. At compile-time, the code generator generates information to allow
5190 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5191 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5192 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5193
5194</div>
5195
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5196<!-- _______________________________________________________________________ -->
5197<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5198 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5199</div>
5200
5201<div class="doc_text">
5202
5203<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5204<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5205 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5206</pre>
5207
5208<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5209<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5210 locations, allowing garbage collector implementations that require read
5211 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5212
5213<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5214<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]5215 allocated from the garbage collector. The first object is a pointer to the
5216 start of the referenced object, if needed by the language runtime (otherwise
5217 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5218
5219<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5220<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5221 instruction, but may be replaced with substantially more complex code by the
5222 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5223 may only be used in a function which <a href="#gc">specifies a GC
5224 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5225
5226</div>
5227
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5228<!-- _______________________________________________________________________ -->
5229<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5230 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5231</div>
5232
5233<div class="doc_text">
5234
5235<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5236<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5237 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5238</pre>
5239
5240<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5241<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5242 locations, allowing garbage collector implementations that require write
5243 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5244
5245<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5246<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]5247 object to store it to, and the third is the address of the field of Obj to
5248 store to. If the runtime does not require a pointer to the object, Obj may
5249 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5250
5251<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5252<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5253 instruction, but may be replaced with substantially more complex code by the
5254 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5255 may only be used in a function which <a href="#gc">specifies a GC
5256 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5257
5258</div>
5259
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5260<!-- ======================================================================= -->
5261<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5262 <a name="int_codegen">Code Generator Intrinsics</a>
5263</div>
5264
5265<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5266
5267<p>These intrinsics are provided by LLVM to expose special features that may
5268 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5269
5270</div>
5271
5272<!-- _______________________________________________________________________ -->
5273<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5274 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5275</div>
5276
5277<div class="doc_text">
5278
5279<h5>Syntax:</h5>
5280<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5281 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5282</pre>
5283
5284<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5285<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5286 target-specific value indicating the return address of the current function
5287 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5288
5289<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5290<p>The argument to this intrinsic indicates which function to return the address
5291 for. Zero indicates the calling function, one indicates its caller, etc.
5292 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5293
5294<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5296 indicating the return address of the specified call frame, or zero if it
5297 cannot be identified. The value returned by this intrinsic is likely to be
5298 incorrect or 0 for arguments other than zero, so it should only be used for
5299 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5300
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5301<p>Note that calling this intrinsic does not prevent function inlining or other
5302 aggressive transformations, so the value returned may not be that of the
5303 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5304
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5305</div>
5306
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5307<!-- _______________________________________________________________________ -->
5308<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5309 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5310</div>
5311
5312<div class="doc_text">
5313
5314<h5>Syntax:</h5>
5315<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5316 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5317</pre>
5318
5319<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5320<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5321 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5322
5323<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5324<p>The argument to this intrinsic indicates which function to return the frame
5325 pointer for. Zero indicates the calling function, one indicates its caller,
5326 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5327
5328<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5329<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5330 indicating the frame address of the specified call frame, or zero if it
5331 cannot be identified. The value returned by this intrinsic is likely to be
5332 incorrect or 0 for arguments other than zero, so it should only be used for
5333 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5334
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5335<p>Note that calling this intrinsic does not prevent function inlining or other
5336 aggressive transformations, so the value returned may not be that of the
5337 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5338
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5339</div>
5340
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5341<!-- _______________________________________________________________________ -->
5342<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5343 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5344</div>
5345
5346<div class="doc_text">
5347
5348<h5>Syntax:</h5>
5349<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5350 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5351</pre>
5352
5353<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5354<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5355 of the function stack, for use
5356 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5357 useful for implementing language features like scoped automatic variable
5358 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5359
5360<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5361<p>This intrinsic returns a opaque pointer value that can be passed
5362 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5363 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5364 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5365 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5366 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5367 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5368
5369</div>
5370
5371<!-- _______________________________________________________________________ -->
5372<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5373 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5374</div>
5375
5376<div class="doc_text">
5377
5378<h5>Syntax:</h5>
5379<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5380 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5381</pre>
5382
5383<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5384<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5385 the function stack to the state it was in when the
5386 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5387 executed. This is useful for implementing language features like scoped
5388 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5389
5390<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5391<p>See the description
5392 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5393
5394</div>
5395
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5396<!-- _______________________________________________________________________ -->
5397<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5398 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5399</div>
5400
5401<div class="doc_text">
5402
5403<h5>Syntax:</h5>
5404<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5405 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]5406</pre>
5407
5408<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5409<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5410 insert a prefetch instruction if supported; otherwise, it is a noop.
5411 Prefetches have no effect on the behavior of the program but can change its
5412 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5413
5414<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5415<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5416 specifier determining if the fetch should be for a read (0) or write (1),
5417 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5418 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5419 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5420
5421<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5422<p>This intrinsic does not modify the behavior of the program. In particular,
5423 prefetches cannot trap and do not produce a value. On targets that support
5424 this intrinsic, the prefetch can provide hints to the processor cache for
5425 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5426
5427</div>
5428
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5429<!-- _______________________________________________________________________ -->
5430<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5431 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5432</div>
5433
5434<div class="doc_text">
5435
5436<h5>Syntax:</h5>
5437<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5438 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5439</pre>
5440
5441<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5443 Counter (PC) in a region of code to simulators and other tools. The method
5444 is target specific, but it is expected that the marker will use exported
5445 symbols to transmit the PC of the marker. The marker makes no guarantees
5446 that it will remain with any specific instruction after optimizations. It is
5447 possible that the presence of a marker will inhibit optimizations. The
5448 intended use is to be inserted after optimizations to allow correlations of
5449 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5450
5451<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5452<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5453
5454<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5455<p>This intrinsic does not modify the behavior of the program. Backends that do
5456 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5457
5458</div>
5459
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5460<!-- _______________________________________________________________________ -->
5461<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5462 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5463</div>
5464
5465<div class="doc_text">
5466
5467<h5>Syntax:</h5>
5468<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5469 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5470</pre>
5471
5472<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5474 counter register (or similar low latency, high accuracy clocks) on those
5475 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5476 should map to RPCC. As the backing counters overflow quickly (on the order
5477 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5478
5479<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480<p>When directly supported, reading the cycle counter should not modify any
5481 memory. Implementations are allowed to either return a application specific
5482 value or a system wide value. On backends without support, this is lowered
5483 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5484
5485</div>
5486
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5487<!-- ======================================================================= -->
5488<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5489 <a name="int_libc">Standard C Library Intrinsics</a>
5490</div>
5491
5492<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5493
5494<p>LLVM provides intrinsics for a few important standard C library functions.
5495 These intrinsics allow source-language front-ends to pass information about
5496 the alignment of the pointer arguments to the code generator, providing
5497 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5498
5499</div>
5500
5501<!-- _______________________________________________________________________ -->
5502<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5503 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5504</div>
5505
5506<div class="doc_text">
5507
5508<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5509<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5510 integer bit width. Not all targets support all bit widths however.</p>
5511
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5512<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5513 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5514 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5515 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5516 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5517 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5518 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5519 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5520 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5521</pre>
5522
5523<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5524<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5525 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5526
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5527<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5528 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5529
5530<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5531<p>The first argument is a pointer to the destination, the second is a pointer
5532 to the source. The third argument is an integer argument specifying the
5533 number of bytes to copy, and the fourth argument is the alignment of the
5534 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5535
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5537 then the caller guarantees that both the source and destination pointers are
5538 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5539
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5540<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5541<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5542 source location to the destination location, which are not allowed to
5543 overlap. It copies "len" bytes of memory over. If the argument is known to
5544 be aligned to some boundary, this can be specified as the fourth argument,
5545 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5546
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5547</div>
5548
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5549<!-- _______________________________________________________________________ -->
5550<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5551 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5552</div>
5553
5554<div class="doc_text">
5555
5556<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5557<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]5558 width. Not all targets support all bit widths however.</p>
5559
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5560<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5561 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5562 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5563 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5564 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5565 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5566 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5567 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5568 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5569</pre>
5570
5571<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5572<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5573 source location to the destination location. It is similar to the
5574 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5575 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5576
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5577<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5578 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5579
5580<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5581<p>The first argument is a pointer to the destination, the second is a pointer
5582 to the source. The third argument is an integer argument specifying the
5583 number of bytes to copy, and the fourth argument is the alignment of the
5584 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5585
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5586<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5587 then the caller guarantees that the source and destination pointers are
5588 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5589
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5590<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5591<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5592 source location to the destination location, which may overlap. It copies
5593 "len" bytes of memory over. If the argument is known to be aligned to some
5594 boundary, this can be specified as the fourth argument, otherwise it should
5595 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5596
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5597</div>
5598
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5599<!-- _______________________________________________________________________ -->
5600<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5601 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5602</div>
5603
5604<div class="doc_text">
5605
5606<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5607<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]5608 width. Not all targets support all bit widths however.</p>
5609
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5610<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5611 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5612 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5613 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5614 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5615 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5616 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5617 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5618 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5619</pre>
5620
5621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5623 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5624
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5626 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5627
5628<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5629<p>The first argument is a pointer to the destination to fill, the second is the
5630 byte value to fill it with, the third argument is an integer argument
5631 specifying the number of bytes to fill, and the fourth argument is the known
5632 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5633
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5634<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5635 then the caller guarantees that the destination pointer is aligned to that
5636 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5637
5638<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5639<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5640 at the destination location. If the argument is known to be aligned to some
5641 boundary, this can be specified as the fourth argument, otherwise it should
5642 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5643
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5644</div>
5645
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5646<!-- _______________________________________________________________________ -->
5647<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5648 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5649</div>
5650
5651<div class="doc_text">
5652
5653<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5654<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5655 floating point or vector of floating point type. Not all targets support all
5656 types however.</p>
5657
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5658<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5659 declare float @llvm.sqrt.f32(float %Val)
5660 declare double @llvm.sqrt.f64(double %Val)
5661 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5662 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5663 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5664</pre>
5665
5666<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5667<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5668 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5669 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5670 behavior for negative numbers other than -0.0 (which allows for better
5671 optimization, because there is no need to worry about errno being
5672 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]5673
5674<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5675<p>The argument and return value are floating point numbers of the same
5676 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5677
5678<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679<p>This function returns the sqrt of the specified operand if it is a
5680 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5681
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5682</div>
5683
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5684<!-- _______________________________________________________________________ -->
5685<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5686 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5687</div>
5688
5689<div class="doc_text">
5690
5691<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5692<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5693 floating point or vector of floating point type. Not all targets support all
5694 types however.</p>
5695
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5696<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5697 declare float @llvm.powi.f32(float %Val, i32 %power)
5698 declare double @llvm.powi.f64(double %Val, i32 %power)
5699 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5700 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5701 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5702</pre>
5703
5704<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5705<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5706 specified (positive or negative) power. The order of evaluation of
5707 multiplications is not defined. When a vector of floating point type is
5708 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5709
5710<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5711<p>The second argument is an integer power, and the first is a value to raise to
5712 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5713
5714<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5715<p>This function returns the first value raised to the second power with an
5716 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5717
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5718</div>
5719
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5720<!-- _______________________________________________________________________ -->
5721<div class="doc_subsubsection">
5722 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5723</div>
5724
5725<div class="doc_text">
5726
5727<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5728<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5729 floating point or vector of floating point type. Not all targets support all
5730 types however.</p>
5731
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5732<pre>
5733 declare float @llvm.sin.f32(float %Val)
5734 declare double @llvm.sin.f64(double %Val)
5735 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5736 declare fp128 @llvm.sin.f128(fp128 %Val)
5737 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5738</pre>
5739
5740<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5741<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5742
5743<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5744<p>The argument and return value are floating point numbers of the same
5745 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5746
5747<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5748<p>This function returns the sine of the specified operand, returning the same
5749 values as the libm <tt>sin</tt> functions would, and handles error conditions
5750 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5751
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5752</div>
5753
5754<!-- _______________________________________________________________________ -->
5755<div class="doc_subsubsection">
5756 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5757</div>
5758
5759<div class="doc_text">
5760
5761<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5762<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5763 floating point or vector of floating point type. Not all targets support all
5764 types however.</p>
5765
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5766<pre>
5767 declare float @llvm.cos.f32(float %Val)
5768 declare double @llvm.cos.f64(double %Val)
5769 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5770 declare fp128 @llvm.cos.f128(fp128 %Val)
5771 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5772</pre>
5773
5774<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5776
5777<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5778<p>The argument and return value are floating point numbers of the same
5779 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5780
5781<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5782<p>This function returns the cosine of the specified operand, returning the same
5783 values as the libm <tt>cos</tt> functions would, and handles error conditions
5784 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5785
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5786</div>
5787
5788<!-- _______________________________________________________________________ -->
5789<div class="doc_subsubsection">
5790 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5791</div>
5792
5793<div class="doc_text">
5794
5795<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5796<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5797 floating point or vector of floating point type. Not all targets support all
5798 types however.</p>
5799
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5800<pre>
5801 declare float @llvm.pow.f32(float %Val, float %Power)
5802 declare double @llvm.pow.f64(double %Val, double %Power)
5803 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5804 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5805 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5806</pre>
5807
5808<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5809<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5810 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5811
5812<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5813<p>The second argument is a floating point power, and the first is a value to
5814 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5815
5816<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817<p>This function returns the first value raised to the second power, returning
5818 the same values as the libm <tt>pow</tt> functions would, and handles error
5819 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5820
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5821</div>
5822
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5823<!-- ======================================================================= -->
5824<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5825 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5826</div>
5827
5828<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5829
5830<p>LLVM provides intrinsics for a few important bit manipulation operations.
5831 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5832
5833</div>
5834
5835<!-- _______________________________________________________________________ -->
5836<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5837 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5838</div>
5839
5840<div class="doc_text">
5841
5842<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5843<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5845
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5846<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5847 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5848 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5849 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5850</pre>
5851
5852<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5853<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5854 values with an even number of bytes (positive multiple of 16 bits). These
5855 are useful for performing operations on data that is not in the target's
5856 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5857
5858<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5859<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5860 and low byte of the input i16 swapped. Similarly,
5861 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5862 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5863 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5864 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5865 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5866 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5867
5868</div>
5869
5870<!-- _______________________________________________________________________ -->
5871<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5872 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5873</div>
5874
5875<div class="doc_text">
5876
5877<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5878<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]5879 width. Not all targets support all bit widths however.</p>
5880
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5881<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5882 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5883 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5884 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5885 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5886 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5887</pre>
5888
5889<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5891 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5892
5893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5894<p>The only argument is the value to be counted. The argument may be of any
5895 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5896
5897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5898<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]5899
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5900</div>
5901
5902<!-- _______________________________________________________________________ -->
5903<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5904 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5905</div>
5906
5907<div class="doc_text">
5908
5909<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5910<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5911 integer bit width. Not all targets support all bit widths however.</p>
5912
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5913<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5914 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5915 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5916 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5917 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5918 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5923 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5924
5925<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5926<p>The only argument is the value to be counted. The argument may be of any
5927 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5928
5929<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
5931 zeros in a variable. If the src == 0 then the result is the size in bits of
5932 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5933
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5934</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5935
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5936<!-- _______________________________________________________________________ -->
5937<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5938 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5939</div>
5940
5941<div class="doc_text">
5942
5943<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5944<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5945 integer bit width. Not all targets support all bit widths however.</p>
5946
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5947<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5948 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5949 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5950 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5951 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5952 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5953</pre>
5954
5955<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5957 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5958
5959<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5960<p>The only argument is the value to be counted. The argument may be of any
5961 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5962
5963<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5964<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
5965 zeros in a variable. If the src == 0 then the result is the size in bits of
5966 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5967
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5968</div>
5969
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]5970<!-- ======================================================================= -->
5971<div class="doc_subsection">
5972 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5973</div>
5974
5975<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5976
5977<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]5978
5979</div>
5980
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5981<!-- _______________________________________________________________________ -->
5982<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]5983 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5984</div>
5985
5986<div class="doc_text">
5987
5988<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5989<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]5990 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5991
5992<pre>
5993 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5994 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5995 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5996</pre>
5997
5998<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]5999<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6000 a signed addition of the two arguments, and indicate whether an overflow
6001 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6002
6003<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6004<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]6005 be of integer types of any bit width, but they must have the same bit
6006 width. The second element of the result structure must be of
6007 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6008 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6009
6010<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6011<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6012 a signed addition of the two variables. They return a structure &mdash; the
6013 first element of which is the signed summation, and the second element of
6014 which is a bit specifying if the signed summation resulted in an
6015 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6016
6017<h5>Examples:</h5>
6018<pre>
6019 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6020 %sum = extractvalue {i32, i1} %res, 0
6021 %obit = extractvalue {i32, i1} %res, 1
6022 br i1 %obit, label %overflow, label %normal
6023</pre>
6024
6025</div>
6026
6027<!-- _______________________________________________________________________ -->
6028<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6029 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6030</div>
6031
6032<div class="doc_text">
6033
6034<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6035<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]6036 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6037
6038<pre>
6039 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6040 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6041 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6042</pre>
6043
6044<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6045<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6046 an unsigned addition of the two arguments, and indicate whether a carry
6047 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6048
6049<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6050<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]6051 be of integer types of any bit width, but they must have the same bit
6052 width. The second element of the result structure must be of
6053 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6054 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6055
6056<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6057<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6058 an unsigned addition of the two arguments. They return a structure &mdash;
6059 the first element of which is the sum, and the second element of which is a
6060 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6061
6062<h5>Examples:</h5>
6063<pre>
6064 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6065 %sum = extractvalue {i32, i1} %res, 0
6066 %obit = extractvalue {i32, i1} %res, 1
6067 br i1 %obit, label %carry, label %normal
6068</pre>
6069
6070</div>
6071
6072<!-- _______________________________________________________________________ -->
6073<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6074 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6075</div>
6076
6077<div class="doc_text">
6078
6079<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6080<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]6081 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6082
6083<pre>
6084 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6085 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6086 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6087</pre>
6088
6089<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6090<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6091 a signed subtraction of the two arguments, and indicate whether an overflow
6092 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6093
6094<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6095<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]6096 be of integer types of any bit width, but they must have the same bit
6097 width. The second element of the result structure must be of
6098 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6099 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6100
6101<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6102<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6103 a signed subtraction of the two arguments. They return a structure &mdash;
6104 the first element of which is the subtraction, and the second element of
6105 which is a bit specifying if the signed subtraction resulted in an
6106 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6107
6108<h5>Examples:</h5>
6109<pre>
6110 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6111 %sum = extractvalue {i32, i1} %res, 0
6112 %obit = extractvalue {i32, i1} %res, 1
6113 br i1 %obit, label %overflow, label %normal
6114</pre>
6115
6116</div>
6117
6118<!-- _______________________________________________________________________ -->
6119<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6120 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6121</div>
6122
6123<div class="doc_text">
6124
6125<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6126<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]6127 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6128
6129<pre>
6130 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6131 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6132 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6133</pre>
6134
6135<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6136<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6137 an unsigned subtraction of the two arguments, and indicate whether an
6138 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6139
6140<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6141<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]6142 be of integer types of any bit width, but they must have the same bit
6143 width. The second element of the result structure must be of
6144 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6145 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6146
6147<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6148<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6149 an unsigned subtraction of the two arguments. They return a structure &mdash;
6150 the first element of which is the subtraction, and the second element of
6151 which is a bit specifying if the unsigned subtraction resulted in an
6152 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6153
6154<h5>Examples:</h5>
6155<pre>
6156 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6157 %sum = extractvalue {i32, i1} %res, 0
6158 %obit = extractvalue {i32, i1} %res, 1
6159 br i1 %obit, label %overflow, label %normal
6160</pre>
6161
6162</div>
6163
6164<!-- _______________________________________________________________________ -->
6165<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6166 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6167</div>
6168
6169<div class="doc_text">
6170
6171<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6172<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]6173 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6174
6175<pre>
6176 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6177 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6178 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6179</pre>
6180
6181<h5>Overview:</h5>
6182
6183<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6184 a signed multiplication of the two arguments, and indicate whether an
6185 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6186
6187<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6188<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]6189 be of integer types of any bit width, but they must have the same bit
6190 width. The second element of the result structure must be of
6191 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6192 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6193
6194<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6195<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6196 a signed multiplication of the two arguments. They return a structure &mdash;
6197 the first element of which is the multiplication, and the second element of
6198 which is a bit specifying if the signed multiplication resulted in an
6199 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Examples:</h5>
6202<pre>
6203 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6204 %sum = extractvalue {i32, i1} %res, 0
6205 %obit = extractvalue {i32, i1} %res, 1
6206 br i1 %obit, label %overflow, label %normal
6207</pre>
6208
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6209</div>
6210
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6211<!-- _______________________________________________________________________ -->
6212<div class="doc_subsubsection">
6213 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6214</div>
6215
6216<div class="doc_text">
6217
6218<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6219<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]6220 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6221
6222<pre>
6223 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6224 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6225 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6226</pre>
6227
6228<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6229<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6230 a unsigned multiplication of the two arguments, and indicate whether an
6231 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6232
6233<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6234<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]6235 be of integer types of any bit width, but they must have the same bit
6236 width. The second element of the result structure must be of
6237 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6238 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6239
6240<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6241<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6242 an unsigned multiplication of the two arguments. They return a structure
6243 &mdash; the first element of which is the multiplication, and the second
6244 element of which is a bit specifying if the unsigned multiplication resulted
6245 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6246
6247<h5>Examples:</h5>
6248<pre>
6249 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6250 %sum = extractvalue {i32, i1} %res, 0
6251 %obit = extractvalue {i32, i1} %res, 1
6252 br i1 %obit, label %overflow, label %normal
6253</pre>
6254
6255</div>
6256
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6257<!-- ======================================================================= -->
6258<div class="doc_subsection">
6259 <a name="int_debugger">Debugger Intrinsics</a>
6260</div>
6261
6262<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6263
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6264<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6265 prefix), are described in
6266 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6267 Level Debugging</a> document.</p>
6268
6269</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6270
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6271<!-- ======================================================================= -->
6272<div class="doc_subsection">
6273 <a name="int_eh">Exception Handling Intrinsics</a>
6274</div>
6275
6276<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6277
6278<p>The LLVM exception handling intrinsics (which all start with
6279 <tt>llvm.eh.</tt> prefix), are described in
6280 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6281 Handling</a> document.</p>
6282
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6283</div>
6284
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6285<!-- ======================================================================= -->
6286<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6287 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6288</div>
6289
6290<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291
6292<p>This intrinsic makes it possible to excise one parameter, marked with
6293 the <tt>nest</tt> attribute, from a function. The result is a callable
6294 function pointer lacking the nest parameter - the caller does not need to
6295 provide a value for it. Instead, the value to use is stored in advance in a
6296 "trampoline", a block of memory usually allocated on the stack, which also
6297 contains code to splice the nest value into the argument list. This is used
6298 to implement the GCC nested function address extension.</p>
6299
6300<p>For example, if the function is
6301 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6302 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6303 follows:</p>
6304
6305<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6306<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6307 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6308 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6309 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6310 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6311</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312</div>
6313
6314<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6315 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6316
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6317</div>
6318
6319<!-- _______________________________________________________________________ -->
6320<div class="doc_subsubsection">
6321 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6322</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6324<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6325
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6326<h5>Syntax:</h5>
6327<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6328 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]6329</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6330
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6331<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6332<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6333 function pointer suitable for executing it.</p>
6334
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6335<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6336<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6337 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6338 sufficiently aligned block of memory; this memory is written to by the
6339 intrinsic. Note that the size and the alignment are target-specific - LLVM
6340 currently provides no portable way of determining them, so a front-end that
6341 generates this intrinsic needs to have some target-specific knowledge.
6342 The <tt>func</tt> argument must hold a function bitcast to
6343 an <tt>i8*</tt>.</p>
6344
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6345<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6346<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6347 dependent code, turning it into a function. A pointer to this function is
6348 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6349 function pointer type</a> before being called. The new function's signature
6350 is the same as that of <tt>func</tt> with any arguments marked with
6351 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6352 is allowed, and it must be of pointer type. Calling the new function is
6353 equivalent to calling <tt>func</tt> with the same argument list, but
6354 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6355 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6356 by <tt>tramp</tt> is modified, then the effect of any later call to the
6357 returned function pointer is undefined.</p>
6358
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6359</div>
6360
6361<!-- ======================================================================= -->
6362<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6363 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6364</div>
6365
6366<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6368<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6369 hardware constructs for atomic operations and memory synchronization. This
6370 provides an interface to the hardware, not an interface to the programmer. It
6371 is aimed at a low enough level to allow any programming models or APIs
6372 (Application Programming Interfaces) which need atomic behaviors to map
6373 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6374 hardware provides a "universal IR" for source languages, it also provides a
6375 starting point for developing a "universal" atomic operation and
6376 synchronization IR.</p>
6377
6378<p>These do <em>not</em> form an API such as high-level threading libraries,
6379 software transaction memory systems, atomic primitives, and intrinsic
6380 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6381 application libraries. The hardware interface provided by LLVM should allow
6382 a clean implementation of all of these APIs and parallel programming models.
6383 No one model or paradigm should be selected above others unless the hardware
6384 itself ubiquitously does so.</p>
6385
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6386</div>
6387
6388<!-- _______________________________________________________________________ -->
6389<div class="doc_subsubsection">
6390 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6391</div>
6392<div class="doc_text">
6393<h5>Syntax:</h5>
6394<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6395 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]6396</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6397
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6398<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6399<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6400 specific pairs of memory access types.</p>
6401
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6402<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6403<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6404 The first four arguments enables a specific barrier as listed below. The
6405 fith argument specifies that the barrier applies to io or device or uncached
6406 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6407
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6408<ul>
6409 <li><tt>ll</tt>: load-load barrier</li>
6410 <li><tt>ls</tt>: load-store barrier</li>
6411 <li><tt>sl</tt>: store-load barrier</li>
6412 <li><tt>ss</tt>: store-store barrier</li>
6413 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6414</ul>
6415
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6416<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6417<p>This intrinsic causes the system to enforce some ordering constraints upon
6418 the loads and stores of the program. This barrier does not
6419 indicate <em>when</em> any events will occur, it only enforces
6420 an <em>order</em> in which they occur. For any of the specified pairs of load
6421 and store operations (f.ex. load-load, or store-load), all of the first
6422 operations preceding the barrier will complete before any of the second
6423 operations succeeding the barrier begin. Specifically the semantics for each
6424 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6425
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6426<ul>
6427 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6428 after the barrier begins.</li>
6429 <li><tt>ls</tt>: All loads before the barrier must complete before any
6430 store after the barrier begins.</li>
6431 <li><tt>ss</tt>: All stores before the barrier must complete before any
6432 store after the barrier begins.</li>
6433 <li><tt>sl</tt>: All stores before the barrier must complete before any
6434 load after the barrier begins.</li>
6435</ul>
6436
6437<p>These semantics are applied with a logical "and" behavior when more than one
6438 is enabled in a single memory barrier intrinsic.</p>
6439
6440<p>Backends may implement stronger barriers than those requested when they do
6441 not support as fine grained a barrier as requested. Some architectures do
6442 not need all types of barriers and on such architectures, these become
6443 noops.</p>
6444
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6445<h5>Example:</h5>
6446<pre>
6447%ptr = malloc i32
6448 store i32 4, %ptr
6449
6450%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6451 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6452 <i>; guarantee the above finishes</i>
6453 store i32 8, %ptr <i>; before this begins</i>
6454</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6455
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6456</div>
6457
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6458<!-- _______________________________________________________________________ -->
6459<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6460 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6461</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6462
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6463<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6465<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6466<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6467 any integer bit width and for different address spaces. Not all targets
6468 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6469
6470<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6471 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6472 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6473 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6474 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]6475</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6476
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6477<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6478<p>This loads a value in memory and compares it to a given value. If they are
6479 equal, it stores a new value into the memory.</p>
6480
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6481<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6483 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6484 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6485 this integer type. While any bit width integer may be used, targets may only
6486 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6487
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6488<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6489<p>This entire intrinsic must be executed atomically. It first loads the value
6490 in memory pointed to by <tt>ptr</tt> and compares it with the
6491 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6492 memory. The loaded value is yielded in all cases. This provides the
6493 equivalent of an atomic compare-and-swap operation within the SSA
6494 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6495
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6496<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6497<pre>
6498%ptr = malloc i32
6499 store i32 4, %ptr
6500
6501%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6502%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6503 <i>; yields {i32}:result1 = 4</i>
6504%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6505%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6506
6507%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6508%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6509 <i>; yields {i32}:result2 = 8</i>
6510%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6511
6512%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6513</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6514
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6515</div>
6516
6517<!-- _______________________________________________________________________ -->
6518<div class="doc_subsubsection">
6519 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6520</div>
6521<div class="doc_text">
6522<h5>Syntax:</h5>
6523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6524<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6525 integer bit width. Not all targets support all bit widths however.</p>
6526
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6527<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6528 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6529 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6530 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6531 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]6532</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6533
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6534<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6535<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6536 the value from memory. It then stores the value in <tt>val</tt> in the memory
6537 at <tt>ptr</tt>.</p>
6538
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6539<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6541 the <tt>val</tt> argument and the result must be integers of the same bit
6542 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6543 integer type. The targets may only lower integer representations they
6544 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6545
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6546<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6548 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6549 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6550
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6551<h5>Examples:</h5>
6552<pre>
6553%ptr = malloc i32
6554 store i32 4, %ptr
6555
6556%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6557%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6558 <i>; yields {i32}:result1 = 4</i>
6559%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6560%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6561
6562%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6563%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6564 <i>; yields {i32}:result2 = 8</i>
6565
6566%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6567%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6568</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6570</div>
6571
6572<!-- _______________________________________________________________________ -->
6573<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6574 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6575
6576</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6577
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6578<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6579
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6580<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6581<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6582 any integer bit width. Not all targets support all bit widths however.</p>
6583
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6584<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6585 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6586 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6587 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6588 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]6589</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6590
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6591<h5>Overview:</h5>
6592<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6593 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6594
6595<h5>Arguments:</h5>
6596<p>The intrinsic takes two arguments, the first a pointer to an integer value
6597 and the second an integer value. The result is also an integer value. These
6598 integer types can have any bit width, but they must all have the same bit
6599 width. The targets may only lower integer representations they support.</p>
6600
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6601<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6602<p>This intrinsic does a series of operations atomically. It first loads the
6603 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6604 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]6605
6606<h5>Examples:</h5>
6607<pre>
6608%ptr = malloc i32
6609 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6610%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6611 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6612%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6613 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6614%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6615 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6616%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6617</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6619</div>
6620
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6621<!-- _______________________________________________________________________ -->
6622<div class="doc_subsubsection">
6623 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6624
6625</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6626
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6627<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6628
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6629<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6631 any integer bit width and for different address spaces. Not all targets
6632 support all bit widths however.</p>
6633
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6634<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6635 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6636 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6637 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6638 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]6639</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6640
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641<h5>Overview:</h5>
6642<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6643 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6644
6645<h5>Arguments:</h5>
6646<p>The intrinsic takes two arguments, the first a pointer to an integer value
6647 and the second an integer value. The result is also an integer value. These
6648 integer types can have any bit width, but they must all have the same bit
6649 width. The targets may only lower integer representations they support.</p>
6650
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6651<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6652<p>This intrinsic does a series of operations atomically. It first loads the
6653 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6654 result to <tt>ptr</tt>. It yields the original value stored
6655 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6656
6657<h5>Examples:</h5>
6658<pre>
6659%ptr = malloc i32
6660 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6661%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6662 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6663%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6664 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6665%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6666 <i>; yields {i32}:result3 = 2</i>
6667%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6668</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6670</div>
6671
6672<!-- _______________________________________________________________________ -->
6673<div class="doc_subsubsection">
6674 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6675 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6676 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6677 <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]6678</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6679
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6680<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6681
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6682<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6683<p>These are overloaded intrinsics. You can
6684 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6685 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6686 bit width and for different address spaces. Not all targets support all bit
6687 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6688
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6689<pre>
6690 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6691 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6692 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6693 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]6694</pre>
6695
6696<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6697 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6698 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6699 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6700 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]6701</pre>
6702
6703<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6704 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6705 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6706 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6707 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]6708</pre>
6709
6710<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6711 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6712 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6713 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6714 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]6715</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6716
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6717<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6718<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6719 the value stored in memory at <tt>ptr</tt>. It yields the original value
6720 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6721
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722<h5>Arguments:</h5>
6723<p>These intrinsics take two arguments, the first a pointer to an integer value
6724 and the second an integer value. The result is also an integer value. These
6725 integer types can have any bit width, but they must all have the same bit
6726 width. The targets may only lower integer representations they support.</p>
6727
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6728<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6729<p>These intrinsics does a series of operations atomically. They first load the
6730 value stored at <tt>ptr</tt>. They then do the bitwise
6731 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6732 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6733
6734<h5>Examples:</h5>
6735<pre>
6736%ptr = malloc i32
6737 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6738%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6739 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6740%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6741 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6742%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6743 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6744%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6745 <i>; yields {i32}:result3 = FF</i>
6746%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6747</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6748
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6749</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6750
6751<!-- _______________________________________________________________________ -->
6752<div class="doc_subsubsection">
6753 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6754 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6755 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6756 <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]6757</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6758
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6759<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6760
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6761<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6762<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6763 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6764 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6765 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6766
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6767<pre>
6768 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6769 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6770 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6771 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]6772</pre>
6773
6774<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6775 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6776 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6777 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6778 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]6779</pre>
6780
6781<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6783 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6784 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6785 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]6786</pre>
6787
6788<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6789 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6790 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6791 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6792 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]6793</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6794
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6795<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6796<p>These intrinsics takes the signed or unsigned minimum or maximum of
6797 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6798 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6799
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6800<h5>Arguments:</h5>
6801<p>These intrinsics take two arguments, the first a pointer to an integer value
6802 and the second an integer value. The result is also an integer value. These
6803 integer types can have any bit width, but they must all have the same bit
6804 width. The targets may only lower integer representations they support.</p>
6805
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6806<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6807<p>These intrinsics does a series of operations atomically. They first load the
6808 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6809 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6810 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6811
6812<h5>Examples:</h5>
6813<pre>
6814%ptr = malloc i32
6815 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6816%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6817 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6818%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6819 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6820%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6821 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6822%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result3 = 8</i>
6824%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6825</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6826
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6827</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6828
6829<!-- ======================================================================= -->
6830<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6831 <a name="int_general">General Intrinsics</a>
6832</div>
6833
6834<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835
6836<p>This class of intrinsics is designed to be generic and has no specific
6837 purpose.</p>
6838
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6839</div>
6840
6841<!-- _______________________________________________________________________ -->
6842<div class="doc_subsubsection">
6843 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6844</div>
6845
6846<div class="doc_text">
6847
6848<h5>Syntax:</h5>
6849<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]6850 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]6851</pre>
6852
6853<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6854<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6855
6856<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6857<p>The first argument is a pointer to a value, the second is a pointer to a
6858 global string, the third is a pointer to a global string which is the source
6859 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6860
6861<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6862<p>This intrinsic allows annotation of local variables with arbitrary strings.
6863 This can be useful for special purpose optimizations that want to look for
6864 these annotations. These have no other defined use, they are ignored by code
6865 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6866
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6867</div>
6868
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6869<!-- _______________________________________________________________________ -->
6870<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]6871 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6872</div>
6873
6874<div class="doc_text">
6875
6876<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6877<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6878 any integer bit width.</p>
6879
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6880<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]6881 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6882 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6883 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6884 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6885 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]6886</pre>
6887
6888<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6889<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6890
6891<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6892<p>The first argument is an integer value (result of some expression), the
6893 second is a pointer to a global string, the third is a pointer to a global
6894 string which is the source file name, and the last argument is the line
6895 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6896
6897<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6898<p>This intrinsic allows annotations to be put on arbitrary expressions with
6899 arbitrary strings. This can be useful for special purpose optimizations that
6900 want to look for these annotations. These have no other defined use, they
6901 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6902
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]6903</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6904
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]6905<!-- _______________________________________________________________________ -->
6906<div class="doc_subsubsection">
6907 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6908</div>
6909
6910<div class="doc_text">
6911
6912<h5>Syntax:</h5>
6913<pre>
6914 declare void @llvm.trap()
6915</pre>
6916
6917<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6918<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]6919
6920<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6921<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]6922
6923<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6924<p>This intrinsics is lowered to the target dependent trap instruction. If the
6925 target does not have a trap instruction, this intrinsic will be lowered to
6926 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]6927
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]6928</div>
6929
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6930<!-- _______________________________________________________________________ -->
6931<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]6932 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6933</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6935<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6936
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6937<h5>Syntax:</h5>
6938<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6942<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
6944 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
6945 ensure that it is placed on the stack before local variables.</p>
6946
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6947<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6948<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
6949 arguments. The first argument is the value loaded from the stack
6950 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
6951 that has enough space to hold the value of the guard.</p>
6952
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6953<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6954<p>This intrinsic causes the prologue/epilogue inserter to force the position of
6955 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6956 stack. This is to ensure that if a local variable on the stack is
6957 overwritten, it will destroy the value of the guard. When the function exits,
6958 the guard on the stack is checked against the original guard. If they're
6959 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
6960 function.</p>
6961
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]6962</div>
6963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6964<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6965<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]6966<address>
6967 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]6968 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]6969 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]6970 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]6971
6972 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]6973 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]6974 Last modified: $Date$
6975</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]6976
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6977</body>
6978</html>