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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 349eb41af479b1e7412c2661d8e70c7a6415501a / . / 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
Chris Lattnere1eaf912009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen2307a7f2008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]542
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]551
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]558
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]575
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]576
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]583
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]588
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]598
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]603</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]604
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]608
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]623</dl>
624
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]680
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]685</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]717
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]778
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]797
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]800
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]801<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]806
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]809
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]810<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]811<pre>
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]813</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]814</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]815
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]836
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]851<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]856
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]859
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]860<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]865
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]877</div>
878
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]883
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]890
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]893<pre>
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]895</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]896</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]897
898</div>
899
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]900<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]926
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be sign-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]990
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]991</div>
992
993<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]994<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesende86d472009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1130</div>
1131
1132<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1138
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1148 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1149
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1153</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1154
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1161
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1180 bits with the most significance have the lowest address location.</dd>
1181
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1204 (double).</dd>
1205
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1213</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1214
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1227 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1235</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1240<ol>
1241 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1242 specification is used.</li>
1243
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1244 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1252 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1256</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1257
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1258</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1259
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1312<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1315
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1316<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1317
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1318<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1325
1326</div>
1327
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1328<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1337 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1338 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1339 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342 </tr>
1343 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1357 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1378 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1379</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1380
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
1383 instructions, passed as arguments, or used as operands to instructions.</p>
1384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1385</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1387<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
1398<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1399
1400<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1401
1402<table>
1403 <tbody>
1404 <tr><th>Type</th><th>Description</th></tr>
1405 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1406 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1407 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1408 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1409 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1410 </tbody>
1411</table>
1412
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1413</div>
1414
1415<!-- _______________________________________________________________________ -->
1416<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1417
1418<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1419
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1420<h5>Overview:</h5>
1421<p>The void type does not represent any value and has no size.</p>
1422
1423<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1424<pre>
1425 void
1426</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1427
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1432
1433<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1434
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1435<h5>Overview:</h5>
1436<p>The label type represents code labels.</p>
1437
1438<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1439<pre>
1440 label
1441</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1442
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1443</div>
1444
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
1446<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1447
1448<div class="doc_text">
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1449
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1450<h5>Overview:</h5>
1451<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1452 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1453 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1454
1455<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1456<pre>
1457 metadata
1458</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1459
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1460</div>
1461
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1462
1463<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1464<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1466<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1468<p>The real power in LLVM comes from the derived types in the system. This is
1469 what allows a programmer to represent arrays, functions, pointers, and other
1470 useful types. Note that these derived types may be recursive: For example,
1471 it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1473</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1475<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1476<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1477
1478<div class="doc_text">
1479
1480<h5>Overview:</h5>
1481<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1482 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1483 2^23-1 (about 8 million) can be specified.</p>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1484
1485<h5>Syntax:</h5>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1486<pre>
1487 iN
1488</pre>
1489
1490<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]1491 value.</p>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1492
1493<h5>Examples:</h5>
1494<table class="layout">
Nick Lewycky86c48642009-05-24 02:46:06 +0000[diff] [blame]1495 <tr class="layout">
1496 <td class="left"><tt>i1</tt></td>
1497 <td class="left">a single-bit integer.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1498 </tr>
Nick Lewycky86c48642009-05-24 02:46:06 +0000[diff] [blame]1499 <tr class="layout">
1500 <td class="left"><tt>i32</tt></td>
1501 <td class="left">a 32-bit integer.</td>
1502 </tr>
1503 <tr class="layout">
1504 <td class="left"><tt>i1942652</tt></td>
1505 <td class="left">a really big integer of over 1 million bits.</td>
1506 </tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1507</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1508
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1509<p>Note that the code generator does not yet support large integer types to be
1510 used as function return types. The specific limit on how large a return type
1511 the code generator can currently handle is target-dependent; currently it's
1512 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]1513
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1514</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1515
1516<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1517<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1518
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1519<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1522<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1523 sequentially in memory. The array type requires a size (number of elements)
1524 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1525
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1526<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527<pre>
1528 [&lt;# elements&gt; x &lt;elementtype&gt;]
1529</pre>
1530
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1531<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1532 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1533
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1534<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1535<table class="layout">
1536 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1537 <td class="left"><tt>[40 x i32]</tt></td>
1538 <td class="left">Array of 40 32-bit integer values.</td>
1539 </tr>
1540 <tr class="layout">
1541 <td class="left"><tt>[41 x i32]</tt></td>
1542 <td class="left">Array of 41 32-bit integer values.</td>
1543 </tr>
1544 <tr class="layout">
1545 <td class="left"><tt>[4 x i8]</tt></td>
1546 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1547 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1548</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1549<p>Here are some examples of multidimensional arrays:</p>
1550<table class="layout">
1551 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1552 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1553 <td class="left">3x4 array of 32-bit integer values.</td>
1554 </tr>
1555 <tr class="layout">
1556 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1557 <td class="left">12x10 array of single precision floating point values.</td>
1558 </tr>
1559 <tr class="layout">
1560 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1561 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1562 </tr>
1563</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1564
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1565<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1566 length array. Normally, accesses past the end of an array are undefined in
1567 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1568 a special case, however, zero length arrays are recognized to be variable
1569 length. This allows implementation of 'pascal style arrays' with the LLVM
1570 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1571
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1572<p>Note that the code generator does not yet support large aggregate types to be
1573 used as function return types. The specific limit on how large an aggregate
1574 return type the code generator can currently handle is target-dependent, and
1575 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1576
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1577</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1578
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1579<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1580<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1582<div class="doc_text">
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1583
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1584<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1585<p>The function type can be thought of as a function signature. It consists of
1586 a return type and a list of formal parameter types. The return type of a
1587 function type is a scalar type, a void type, or a struct type. If the return
1588 type is a struct type then all struct elements must be of first class types,
1589 and the struct must have at least one element.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1591<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1592<pre>
1593 &lt;returntype list&gt; (&lt;parameter list&gt;)
1594</pre>
1595
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1596<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]1597 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1598 which indicates that the function takes a variable number of arguments.
1599 Variable argument functions can access their arguments with
1600 the <a href="#int_varargs">variable argument handling intrinsic</a>
1601 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1602 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1605<table class="layout">
1606 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1607 <td class="left"><tt>i32 (i32)</tt></td>
1608 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1609 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1610 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1611 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1612 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1613 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1614 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1615 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1616 <tt>float</tt>.
1617 </td>
1618 </tr><tr class="layout">
1619 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1620 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1621 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1622 which returns an integer. This is the signature for <tt>printf</tt> in
1623 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1624 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1625 </tr><tr class="layout">
1626 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanb0a57aa2008-11-27 06:41:20 +0000[diff] [blame]1627 <td class="left">A function taking an <tt>i32</tt>, returning two
1628 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1629 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1630 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1631</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1632
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1633</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1634
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1635<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1636<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1637
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1638<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1639
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1640<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1641<p>The structure type is used to represent a collection of data members together
1642 in memory. The packing of the field types is defined to match the ABI of the
1643 underlying processor. The elements of a structure may be any type that has a
1644 size.</p>
1645
1646<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1647 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1648 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1649
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1650<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1651<pre>
1652 { &lt;type list&gt; }
1653</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1654
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1656<table class="layout">
1657 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1658 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1659 <td class="left">A triple of three <tt>i32</tt> values</td>
1660 </tr><tr class="layout">
1661 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1662 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1663 second element is a <a href="#t_pointer">pointer</a> to a
1664 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1665 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1666 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1667</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1668
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1669<p>Note that the code generator does not yet support large aggregate types to be
1670 used as function return types. The specific limit on how large an aggregate
1671 return type the code generator can currently handle is target-dependent, and
1672 also dependent on the aggregate element types.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1673
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1674</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1676<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1677<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1678</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1679
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1680<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1681
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1682<h5>Overview:</h5>
1683<p>The packed structure type is used to represent a collection of data members
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1684 together in memory. There is no padding between fields. Further, the
1685 alignment of a packed structure is 1 byte. The elements of a packed
1686 structure may be any type that has a size.</p>
1687
1688<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1689 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1690 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1691
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1692<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1693<pre>
1694 &lt; { &lt;type list&gt; } &gt;
1695</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1696
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1700 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1701 <td class="left">A triple of three <tt>i32</tt> values</td>
1702 </tr><tr class="layout">
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1703 <td class="left">
1704<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1705 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1706 second element is a <a href="#t_pointer">pointer</a> to a
1707 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1708 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1709 </tr>
1710</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1711
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1712</div>
1713
1714<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1715<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1716
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1717<div class="doc_text">
1718
1719<h5>Overview:</h5>
1720<p>As in many languages, the pointer type represents a pointer or reference to
1721 another object, which must live in memory. Pointer types may have an optional
1722 address space attribute defining the target-specific numbered address space
1723 where the pointed-to object resides. The default address space is zero.</p>
1724
1725<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1726 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]1727
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1728<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1729<pre>
1730 &lt;type&gt; *
1731</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1732
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1733<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1734<table class="layout">
1735 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]1736 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1737 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1738 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1739 </tr>
1740 <tr class="layout">
1741 <td class="left"><tt>i32 (i32 *) *</tt></td>
1742 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1743 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1744 <tt>i32</tt>.</td>
1745 </tr>
1746 <tr class="layout">
1747 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1748 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1749 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1750 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1754
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1755<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1756<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1757
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1758<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1759
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1760<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1761<p>A vector type is a simple derived type that represents a vector of elements.
1762 Vector types are used when multiple primitive data are operated in parallel
1763 using a single instruction (SIMD). A vector type requires a size (number of
1764 elements) and an underlying primitive data type. Vectors must have a power
1765 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1766 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1767
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1768<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1769<pre>
1770 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1771</pre>
1772
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1773<p>The number of elements is a constant integer value; elementtype may be any
1774 integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1775
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1776<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1779 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1780 <td class="left">Vector of 4 32-bit integer values.</td>
1781 </tr>
1782 <tr class="layout">
1783 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1784 <td class="left">Vector of 8 32-bit floating-point values.</td>
1785 </tr>
1786 <tr class="layout">
1787 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1788 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1789 </tr>
1790</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1791
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1792<p>Note that the code generator does not yet support large vector types to be
1793 used as function return types. The specific limit on how large a vector
1794 return type codegen can currently handle is target-dependent; currently it's
1795 often a few times longer than a hardware vector register.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1797</div>
1798
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1799<!-- _______________________________________________________________________ -->
1800<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1801<div class="doc_text">
1802
1803<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1804<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1805 corresponds (for example) to the C notion of a forward declared structure
1806 type. In LLVM, opaque types can eventually be resolved to any type (not just
1807 a structure type).</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1808
1809<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1810<pre>
1811 opaque
1812</pre>
1813
1814<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1815<table class="layout">
1816 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1817 <td class="left"><tt>opaque</tt></td>
1818 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1819 </tr>
1820</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1821
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1822</div>
1823
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1824<!-- ======================================================================= -->
1825<div class="doc_subsection">
1826 <a name="t_uprefs">Type Up-references</a>
1827</div>
1828
1829<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1830
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1831<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1832<p>An "up reference" allows you to refer to a lexically enclosing type without
1833 requiring it to have a name. For instance, a structure declaration may
1834 contain a pointer to any of the types it is lexically a member of. Example
1835 of up references (with their equivalent as named type declarations)
1836 include:</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1837
1838<pre>
Chris Lattner3060f5b2009-02-09 10:00:56 +0000[diff] [blame]1839 { \2 * } %x = type { %x* }
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1840 { \2 }* %y = type { %y }*
1841 \1* %z = type %z*
1842</pre>
1843
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1844<p>An up reference is needed by the asmprinter for printing out cyclic types
1845 when there is no declared name for a type in the cycle. Because the
1846 asmprinter does not want to print out an infinite type string, it needs a
1847 syntax to handle recursive types that have no names (all names are optional
1848 in llvm IR).</p>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1849
1850<h5>Syntax:</h5>
1851<pre>
1852 \&lt;level&gt;
1853</pre>
1854
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1855<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]1856
1857<h5>Examples:</h5>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1858<table class="layout">
1859 <tr class="layout">
1860 <td class="left"><tt>\1*</tt></td>
1861 <td class="left">Self-referential pointer.</td>
1862 </tr>
1863 <tr class="layout">
1864 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1865 <td class="left">Recursive structure where the upref refers to the out-most
1866 structure.</td>
1867 </tr>
1868</table>
Chris Lattner242d61d2009-02-02 07:32:36 +0000[diff] [blame]1869
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1870</div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1871
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1872<!-- *********************************************************************** -->
1873<div class="doc_section"> <a name="constants">Constants</a> </div>
1874<!-- *********************************************************************** -->
1875
1876<div class="doc_text">
1877
1878<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1879 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1880
1881</div>
1882
1883<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1884<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1885
1886<div class="doc_text">
1887
1888<dl>
1889 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1890 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1891 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1892
1893 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1894 <dd>Standard integers (such as '4') are constants of
1895 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1896 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1897
1898 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1900 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1901 notation (see below). The assembler requires the exact decimal value of a
1902 floating-point constant. For example, the assembler accepts 1.25 but
1903 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1904 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1905
1906 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1907 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1908 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1909</dl>
1910
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1911<p>The one non-intuitive notation for constants is the hexadecimal form of
1912 floating point constants. For example, the form '<tt>double
1913 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1914 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1915 constants are required (and the only time that they are generated by the
1916 disassembler) is when a floating point constant must be emitted but it cannot
1917 be represented as a decimal floating point number in a reasonable number of
1918 digits. For example, NaN's, infinities, and other special values are
1919 represented in their IEEE hexadecimal format so that assembly and disassembly
1920 do not cause any bits to change in the constants.</p>
1921
Dale Johannesenbd5e5a82009-02-11 22:14:51 +0000[diff] [blame]1922<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1923 represented using the 16-digit form shown above (which matches the IEEE754
1924 representation for double); float values must, however, be exactly
1925 representable as IEE754 single precision. Hexadecimal format is always used
1926 for long double, and there are three forms of long double. The 80-bit format
1927 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1928 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1929 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1930 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1931 currently supported target uses this format. Long doubles will only work if
1932 they match the long double format on your target. All hexadecimal formats
1933 are big-endian (sign bit at the left).</p>
1934
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1935</div>
1936
1937<!-- ======================================================================= -->
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1938<div class="doc_subsection">
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]1939<a name="aggregateconstants"></a> <!-- old anchor -->
1940<a name="complexconstants">Complex Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1941</div>
1942
1943<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1944
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]1945<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1946 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1947
1948<dl>
1949 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1950 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1951 type definitions (a comma separated list of elements, surrounded by braces
1952 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1953 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1954 Structure constants must have <a href="#t_struct">structure type</a>, and
1955 the number and types of elements must match those specified by the
1956 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1957
1958 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1959 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1960 definitions (a comma separated list of elements, surrounded by square
1961 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1962 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1963 the number and types of elements must match those specified by the
1964 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1965
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1966 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1967 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1968 definitions (a comma separated list of elements, surrounded by
1969 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1970 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1971 have <a href="#t_vector">vector type</a>, and the number and types of
1972 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1973
1974 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1975 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1976 value to zero of <em>any</em> type, including scalar and aggregate types.
1977 This is often used to avoid having to print large zero initializers
1978 (e.g. for large arrays) and is always exactly equivalent to using explicit
1979 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]1980
1981 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]1982 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1983 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1984 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1985 be interpreted as part of the instruction stream, metadata is a place to
1986 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1987</dl>
1988
1989</div>
1990
1991<!-- ======================================================================= -->
1992<div class="doc_subsection">
1993 <a name="globalconstants">Global Variable and Function Addresses</a>
1994</div>
1995
1996<div class="doc_text">
1997
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1998<p>The addresses of <a href="#globalvars">global variables</a>
1999 and <a href="#functionstructure">functions</a> are always implicitly valid
2000 (link-time) constants. These constants are explicitly referenced when
2001 the <a href="#identifiers">identifier for the global</a> is used and always
2002 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2003 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2004
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2005<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2006<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2007@X = global i32 17
2008@Y = global i32 42
2009@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2010</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2011</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2012
2013</div>
2014
2015<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]2016<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2017<div class="doc_text">
2018
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2019<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2020 indicates that the user of the value may recieve an unspecified bit-pattern.
2021 Undefined values may be of any type (other than label or void) and be used
2022 anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2023
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2024<p>Undefined values are useful, because it indicates to the compiler that the
2025 program is well defined no matter what value is used. This gives the
2026 compiler more freedom to optimize. Here are some examples of (potentially
2027 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2028
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2029
2030<div class="doc_code">
2031<pre>
2032 %A = add %X, undef
2033 %B = sub %X, undef
2034 %C = xor %X, undef
2035Safe:
2036 %A = undef
2037 %B = undef
2038 %C = undef
2039</pre>
2040</div>
2041
2042<p>This is safe because all of the output bits are affected by the undef bits.
2043Any output bit can have a zero or one depending on the input bits.</p>
2044
2045<div class="doc_code">
2046<pre>
2047 %A = or %X, undef
2048 %B = and %X, undef
2049Safe:
2050 %A = -1
2051 %B = 0
2052Unsafe:
2053 %A = undef
2054 %B = undef
2055</pre>
2056</div>
2057
2058<p>These logical operations have bits that are not always affected by the input.
2059For example, if "%X" has a zero bit, then the output of the 'and' operation will
2060always be a zero, no matter what the corresponding bit from the undef is. As
2061such, it is unsafe to optimizer or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef are 0, and optimize the
2063and to 0. Likewise, it is safe to assume that all the bits of the undef operand
2064to the or could be set, allowing the or to be folded to -1.</p>
2065
2066<div class="doc_code">
2067<pre>
2068 %A = select undef, %X, %Y
2069 %B = select undef, 42, %Y
2070 %C = select %X, %Y, undef
2071Safe:
2072 %A = %X (or %Y)
2073 %B = 42 (or %Y)
2074 %C = %Y
2075Unsafe:
2076 %A = undef
2077 %B = undef
2078 %C = undef
2079</pre>
2080</div>
2081
2082<p>This set of examples show that undefined select (and conditional branch)
2083conditions can go "either way" but they have to come from one of the two
2084operands. In the %A example, if %X and %Y were both known to have a clear low
2085bit, then %A would have to have a cleared low bit. However, in the %C example,
2086the optimizer is allowed to assume that the undef operand could be the same as
2087%Y, allowing the whole select to be eliminated.</p>
2088
2089
2090<div class="doc_code">
2091<pre>
2092 %A = xor undef, undef
2093
2094 %B = undef
2095 %C = xor %B, %B
2096
2097 %D = undef
2098 %E = icmp lt %D, 4
2099 %F = icmp gte %D, 4
2100
2101Safe:
2102 %A = undef
2103 %B = undef
2104 %C = undef
2105 %D = undef
2106 %E = undef
2107 %F = undef
2108</pre>
2109</div>
2110
2111<p>This example points out that two undef operands are not necessarily the same.
2112This can be surprising to people (and also matches C semantics) where they
2113assume that "X^X" is always zero, even if X is undef. This isn't true for a
2114number of reasons, but the short answer is that an undef "variable" can
2115arbitrarily change its value over its "live range". This is true because the
2116"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2117logically read from arbitrary registers that happen to be around when needed,
2118so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame^]2119to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2120would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2121
2122<div class="doc_code">
2123<pre>
2124 %A = fdiv undef, %X
2125 %B = fdiv %X, undef
2126Safe:
2127 %A = undef
2128b: unreachable
2129</pre>
2130</div>
2131
2132<p>These examples show the crucial difference between an <em>undefined
2133value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2134allowed to have an arbitrary bit-pattern. This means that the %A operation
2135can be constant folded to undef because the undef could be an SNaN, and fdiv is
2136not (currently) defined on SNaN's. However, in the second example, we can make
2137a more aggressive assumption: because the undef is allowed to be an arbitrary
2138value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame^]2139it has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2140does not execute at all. This allows us to delete the divide and all code after
2141it: since the undefined operation "can't happen", the optimizer can assume that
2142it occurs in dead code.
2143</p>
2144
2145<div class="doc_code">
2146<pre>
2147a: store undef -> %X
2148b: store %X -> undef
2149Safe:
2150a: &lt;deleted&gt;
2151b: unreachable
2152</pre>
2153</div>
2154
2155<p>These examples reiterate the fdiv example: a store "of" an undefined value
2156can be assumed to not have any effect: we can assume that the value is
2157overwritten with bits that happen to match what was already there. However, a
2158store "to" an undefined location could clobber arbitrary memory, therefore, it
2159has undefined behavior.</p>
2160
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2161</div>
2162
2163<!-- ======================================================================= -->
2164<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2165</div>
2166
2167<div class="doc_text">
2168
2169<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2170 to be used as constants. Constant expressions may be of
2171 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2172 operation that does not have side effects (e.g. load and call are not
2173 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2174
2175<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2176 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177 <dd>Truncate a constant to another type. The bit size of CST must be larger
2178 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2179
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2180 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181 <dd>Zero extend a constant to another type. The bit size of CST must be
2182 smaller or equal to the bit size of TYPE. Both types must be
2183 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2184
2185 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2186 <dd>Sign extend a constant to another type. The bit size of CST must be
2187 smaller or equal to the bit size of TYPE. Both types must be
2188 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2189
2190 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2191 <dd>Truncate a floating point constant to another floating point type. The
2192 size of CST must be larger than the size of TYPE. Both types must be
2193 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2194
2195 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2196 <dd>Floating point extend a constant to another type. The size of CST must be
2197 smaller or equal to the size of TYPE. Both types must be floating
2198 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2199
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2200 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2201 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2202 constant. TYPE must be a scalar or vector integer type. CST must be of
2203 scalar or vector floating point type. Both CST and TYPE must be scalars,
2204 or vectors of the same number of elements. If the value won't fit in the
2205 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2206
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2207 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2208 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2209 constant. TYPE must be a scalar or vector integer type. CST must be of
2210 scalar or vector floating point type. Both CST and TYPE must be scalars,
2211 or vectors of the same number of elements. If the value won't fit in the
2212 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2213
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2214 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2215 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2216 constant. TYPE must be a scalar or vector floating point type. CST must be
2217 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2218 vectors of the same number of elements. If the value won't fit in the
2219 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2220
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2221 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2222 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2223 constant. TYPE must be a scalar or vector floating point type. CST must be
2224 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2225 vectors of the same number of elements. If the value won't fit in the
2226 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2227
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2228 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2229 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2230 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2231 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2232 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2233
2234 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2235 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2236 type. CST must be of integer type. The CST value is zero extended,
2237 truncated, or unchanged to make it fit in a pointer size. This one is
2238 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2239
2240 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2241 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2242 are the same as those for the <a href="#i_bitcast">bitcast
2243 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2244
2245 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2246 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2247 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2248 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2249 instruction, the index list may have zero or more indexes, which are
2250 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2251
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2252 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2253 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2254
2255 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2256 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2257
2258 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2259 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2260
2261 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2262 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2263 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2264
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2265 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2266 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2267 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2268
2269 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2270 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2271 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2272
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2273 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2274 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2275 be any of the <a href="#binaryops">binary</a>
2276 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2277 on operands are the same as those for the corresponding instruction
2278 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2279</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2280
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2281</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2282
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2283<!-- ======================================================================= -->
2284<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2285</div>
2286
2287<div class="doc_text">
2288
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2289<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2290 stream without affecting the behaviour of the program. There are two
2291 metadata primitives, strings and nodes. All metadata has the
2292 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2293 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2294
2295<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2296 any character by escaping non-printable characters with "\xx" where "xx" is
2297 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2298
2299<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2300 (a comma separated list of elements, surrounded by braces and preceeded by an
2301 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2302 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2303
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2304<p>A metadata node will attempt to track changes to the values it holds. In the
2305 event that a value is deleted, it will be replaced with a typeless
2306 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2307
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2308<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2309 the program that isn't available in the instructions, or that isn't easily
2310 computable. Similarly, the code generator may expect a certain metadata
2311 format to be used to express debugging information.</p>
2312
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2313</div>
2314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2315<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2316<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2317<!-- *********************************************************************** -->
2318
2319<!-- ======================================================================= -->
2320<div class="doc_subsection">
2321<a name="inlineasm">Inline Assembler Expressions</a>
2322</div>
2323
2324<div class="doc_text">
2325
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2326<p>LLVM supports inline assembler expressions (as opposed
2327 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2328 a special value. This value represents the inline assembler as a string
2329 (containing the instructions to emit), a list of operand constraints (stored
2330 as a string), and a flag that indicates whether or not the inline asm
2331 expression has side effects. An example inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2332
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2333<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2334<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2335i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2336</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2337</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2338
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2339<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2340 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2341 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2342
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2343<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2344<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2345%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]2346</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2347</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2348
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2349<p>Inline asms with side effects not visible in the constraint list must be
2350 marked as having side effects. This is done through the use of the
2351 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2352
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2353<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2354<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2355call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2356</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2357</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2358
2359<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2360 documented here. Constraints on what can be done (e.g. duplication, moving,
2361 etc need to be documented). This is probably best done by reference to
2362 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2363
2364</div>
2365
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2366
2367<!-- *********************************************************************** -->
2368<div class="doc_section">
2369 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2370</div>
2371<!-- *********************************************************************** -->
2372
2373<p>LLVM has a number of "magic" global variables that contain data that affect
2374code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2375of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2376section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2377by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2378
2379<!-- ======================================================================= -->
2380<div class="doc_subsection">
2381<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2382</div>
2383
2384<div class="doc_text">
2385
2386<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2387href="#linkage_appending">appending linkage</a>. This array contains a list of
2388pointers to global variables and functions which may optionally have a pointer
2389cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2390
2391<pre>
2392 @X = global i8 4
2393 @Y = global i32 123
2394
2395 @llvm.used = appending global [2 x i8*] [
2396 i8* @X,
2397 i8* bitcast (i32* @Y to i8*)
2398 ], section "llvm.metadata"
2399</pre>
2400
2401<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2402compiler, assembler, and linker are required to treat the symbol as if there is
2403a reference to the global that it cannot see. For example, if a variable has
2404internal linkage and no references other than that from the <tt>@llvm.used</tt>
2405list, it cannot be deleted. This is commonly used to represent references from
2406inline asms and other things the compiler cannot "see", and corresponds to
2407"attribute((used))" in GNU C.</p>
2408
2409<p>On some targets, the code generator must emit a directive to the assembler or
2410object file to prevent the assembler and linker from molesting the symbol.</p>
2411
2412</div>
2413
2414<!-- ======================================================================= -->
2415<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2416<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2417</div>
2418
2419<div class="doc_text">
2420
2421<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2422<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2423touching the symbol. On targets that support it, this allows an intelligent
2424linker to optimize references to the symbol without being impeded as it would be
2425by <tt>@llvm.used</tt>.</p>
2426
2427<p>This is a rare construct that should only be used in rare circumstances, and
2428should not be exposed to source languages.</p>
2429
2430</div>
2431
2432<!-- ======================================================================= -->
2433<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2434<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2435</div>
2436
2437<div class="doc_text">
2438
2439<p>TODO: Describe this.</p>
2440
2441</div>
2442
2443<!-- ======================================================================= -->
2444<div class="doc_subsection">
2445<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<p>TODO: Describe this.</p>
2451
2452</div>
2453
2454
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2455<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2456<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2457<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2458
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2459<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2460
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2461<p>The LLVM instruction set consists of several different classifications of
2462 instructions: <a href="#terminators">terminator
2463 instructions</a>, <a href="#binaryops">binary instructions</a>,
2464 <a href="#bitwiseops">bitwise binary instructions</a>,
2465 <a href="#memoryops">memory instructions</a>, and
2466 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2468</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2470<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2471<div class="doc_subsection"> <a name="terminators">Terminator
2472Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2474<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2475
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2476<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2477 in a program ends with a "Terminator" instruction, which indicates which
2478 block should be executed after the current block is finished. These
2479 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2480 control flow, not values (the one exception being the
2481 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2482
2483<p>There are six different terminator instructions: the
2484 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2485 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2486 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2487 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2488 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2489 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2490
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2491</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2492
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2493<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2494<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2495Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2497<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2498
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2499<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2500<pre>
2501 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]2502 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2503</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2504
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2505<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2506<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2507 a value) from a function back to the caller.</p>
2508
2509<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2510 value and then causes control flow, and one that just causes control flow to
2511 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2512
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2513<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2514<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2515 return value. The type of the return value must be a
2516 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2518<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2519 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2520 value or a return value with a type that does not match its type, or if it
2521 has a void return type and contains a '<tt>ret</tt>' instruction with a
2522 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2525<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2526 the calling function's context. If the caller is a
2527 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2528 instruction after the call. If the caller was an
2529 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2530 the beginning of the "normal" destination block. If the instruction returns
2531 a value, that value shall set the call or invoke instruction's return
2532 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2534<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2535<pre>
2536 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2537 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2538 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]2539</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2540
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2541<p>Note that the code generator does not yet fully support large
2542 return values. The specific sizes that are currently supported are
2543 dependent on the target. For integers, on 32-bit targets the limit
2544 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2545 For aggregate types, the current limits are dependent on the element
2546 types; for example targets are often limited to 2 total integer
2547 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2548
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2549</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2550<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2551<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2552
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2553<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2554
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2555<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2556<pre>
2557 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]2558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2559
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2560<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2561<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2562 different basic block in the current function. There are two forms of this
2563 instruction, corresponding to a conditional branch and an unconditional
2564 branch.</p>
2565
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2567<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2568 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2569 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2570 target.</p>
2571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2572<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2573<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2574 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2575 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2576 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2578<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2579<pre>
2580Test:
2581 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2582 br i1 %cond, label %IfEqual, label %IfUnequal
2583IfEqual:
2584 <a href="#i_ret">ret</a> i32 1
2585IfUnequal:
2586 <a href="#i_ret">ret</a> i32 0
2587</pre>
2588
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2589</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2590
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2591<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2592<div class="doc_subsubsection">
2593 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2594</div>
2595
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2596<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2597
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2598<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2599<pre>
2600 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2601</pre>
2602
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2603<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2604<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]2605 several different places. It is a generalization of the '<tt>br</tt>'
2606 instruction, allowing a branch to occur to one of many possible
2607 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2608
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2609<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2610<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2611 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2612 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2613 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2614
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2615<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2616<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2617 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2618 is searched for the given value. If the value is found, control flow is
2619 transfered to the corresponding destination; otherwise, control flow is
2620 transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2621
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2622<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2623<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2624 <tt>switch</tt> instruction, this instruction may be code generated in
2625 different ways. For example, it could be generated as a series of chained
2626 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2627
2628<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2629<pre>
2630 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2631 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2632 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2633
2634 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2635 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2636
2637 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2638 switch i32 %val, label %otherwise [ i32 0, label %onzero
2639 i32 1, label %onone
2640 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2641</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2642
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2643</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2645<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2646<div class="doc_subsubsection">
2647 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2648</div>
2649
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2650<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2651
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2652<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2653<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2654 &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]2655 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2656</pre>
2657
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2658<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2659<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2660 function, with the possibility of control flow transfer to either the
2661 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2662 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2663 control flow will return to the "normal" label. If the callee (or any
2664 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2665 instruction, control is interrupted and continued at the dynamically nearest
2666 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2667
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2668<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2669<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2671<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2672 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2673 convention</a> the call should use. If none is specified, the call
2674 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2675
2676 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2677 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2678 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2679
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2680 <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]2681 function value being invoked. In most cases, this is a direct function
2682 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2683 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2684
2685 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2686 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2687
2688 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2689 signature argument types. If the function signature indicates the
2690 function accepts a variable number of arguments, the extra arguments can
2691 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2692
2693 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2694 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2695
2696 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2697 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2698
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2699 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2700 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2701 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2702</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2703
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2704<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2705<p>This instruction is designed to operate as a standard
2706 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2707 primary difference is that it establishes an association with a label, which
2708 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2709
2710<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2711 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2712 exception. Additionally, this is important for implementation of
2713 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2714
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2715<p>For the purposes of the SSA form, the definition of the value returned by the
2716 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2717 block to the "normal" label. If the callee unwinds then no return value is
2718 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2720<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2721<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2722 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2723 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2724 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2725 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2726</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2727
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2728</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2729
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2730<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2731
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2732<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2733Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2734
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2735<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2736
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2737<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2738<pre>
2739 unwind
2740</pre>
2741
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2742<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2743<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2744 at the first callee in the dynamic call stack which used
2745 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2746 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2747
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2748<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2749<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2750 immediately halt. The dynamic call stack is then searched for the
2751 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2752 Once found, execution continues at the "exceptional" destination block
2753 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2754 instruction in the dynamic call chain, undefined behavior results.</p>
2755
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2756</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2757
2758<!-- _______________________________________________________________________ -->
2759
2760<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2761Instruction</a> </div>
2762
2763<div class="doc_text">
2764
2765<h5>Syntax:</h5>
2766<pre>
2767 unreachable
2768</pre>
2769
2770<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2771<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2772 instruction is used to inform the optimizer that a particular portion of the
2773 code is not reachable. This can be used to indicate that the code after a
2774 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2775
2776<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2777<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2778
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2779</div>
2780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2781<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2782<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2784<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2785
2786<p>Binary operators are used to do most of the computation in a program. They
2787 require two operands of the same type, execute an operation on them, and
2788 produce a single value. The operands might represent multiple data, as is
2789 the case with the <a href="#t_vector">vector</a> data type. The result value
2790 has the same type as its operands.</p>
2791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2792<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2794</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2795
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2796<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2797<div class="doc_subsubsection">
2798 <a name="i_add">'<tt>add</tt>' Instruction</a>
2799</div>
2800
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2801<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2802
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2803<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2804<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2805 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2806 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2807 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2808 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2809</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2811<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2812<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2815<p>The two arguments to the '<tt>add</tt>' instruction must
2816 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2817 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2819<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2820<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2821
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2822<p>If the sum has unsigned overflow, the result returned is the mathematical
2823 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]2824
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2825<p>Because LLVM integers use a two's complement representation, this instruction
2826 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2827
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2828<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2829 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2830 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2831 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2833<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2834<pre>
2835 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2838</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2840<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2841<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2842 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2843</div>
2844
2845<div class="doc_text">
2846
2847<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2848<pre>
2849 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2850</pre>
2851
2852<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2853<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2854
2855<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2856<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2857 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2858 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2859
2860<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2861<p>The value produced is the floating point sum of the two operands.</p>
2862
2863<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2864<pre>
2865 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2866</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2867
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2868</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2869
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2870<!-- _______________________________________________________________________ -->
2871<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2872 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2873</div>
2874
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2875<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2877<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2878<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2879 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2880 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2881 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2882 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2885<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2886<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2887 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2888
2889<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2890 '<tt>neg</tt>' instruction present in most other intermediate
2891 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2894<p>The two arguments to the '<tt>sub</tt>' instruction must
2895 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2896 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2898<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2899<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2900
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2901<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2902 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2903 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2904
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2905<p>Because LLVM integers use a two's complement representation, this instruction
2906 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2907
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2908<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2909 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2910 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2911 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2913<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2914<pre>
2915 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2916 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2917</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2919</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2921<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2922<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2923 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2924</div>
2925
2926<div class="doc_text">
2927
2928<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2929<pre>
2930 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2931</pre>
2932
2933<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2934<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2935 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2936
2937<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2938 '<tt>fneg</tt>' instruction present in most other intermediate
2939 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2940
2941<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2942<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2943 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2944 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2945
2946<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2947<p>The value produced is the floating point difference of the two operands.</p>
2948
2949<h5>Example:</h5>
2950<pre>
2951 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2952 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2953</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2954
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2955</div>
2956
2957<!-- _______________________________________________________________________ -->
2958<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2959 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2960</div>
2961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2962<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2964<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2965<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2966 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]2967 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2968 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2972<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2973<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2975<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2976<p>The two arguments to the '<tt>mul</tt>' instruction must
2977 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2978 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2980<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2981<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2982
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2983<p>If the result of the multiplication has unsigned overflow, the result
2984 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2985 width of the result.</p>
2986
2987<p>Because LLVM integers use a two's complement representation, and the result
2988 is the same width as the operands, this instruction returns the correct
2989 result for both signed and unsigned integers. If a full product
2990 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2991 be sign-extended or zero-extended as appropriate to the width of the full
2992 product.</p>
2993
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2994<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2995 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2996 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2997 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2998
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2999<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3000<pre>
3001 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3002</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3003
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3004</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3005
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3006<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3007<div class="doc_subsubsection">
3008 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3009</div>
3010
3011<div class="doc_text">
3012
3013<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3014<pre>
3015 &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]3016</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3017
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3018<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3019<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3020
3021<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3022<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3023 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3024 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3025
3026<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3027<p>The value produced is the floating point product of the two operands.</p>
3028
3029<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3030<pre>
3031 &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]3032</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3033
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3034</div>
3035
3036<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3037<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3038</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3039
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3040<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3041
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3042<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3043<pre>
3044 &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]3045</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3046
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3047<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3048<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3049
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3050<h5>Arguments:</h5>
3051<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3052 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3053 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3054
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3055<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3056<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3057
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3058<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3059 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3060
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3061<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3062
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3063<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3064<pre>
3065 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3066</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3067
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3068</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3069
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3070<!-- _______________________________________________________________________ -->
3071<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3072</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3073
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3074<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3075
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3076<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3077<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3078 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3079 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3080</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3081
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3082<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3083<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3084
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3085<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3086<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3087 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3088 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3089
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3090<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3091<p>The value produced is the signed integer quotient of the two operands rounded
3092 towards zero.</p>
3093
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3094<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3095 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3096
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3097<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3098 undefined behavior; this is a rare case, but can occur, for example, by doing
3099 a 32-bit division of -2147483648 by -1.</p>
3100
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3101<p>If the <tt>exact</tt> keyword is present, the result value of the
3102 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3103 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3104
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3105<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3106<pre>
3107 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3108</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3109
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3110</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3111
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3112<!-- _______________________________________________________________________ -->
3113<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3114Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3115
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3116<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3117
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3118<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3119<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3120 &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]3121</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3122
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3123<h5>Overview:</h5>
3124<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3125
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3126<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3127<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3128 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3129 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3130
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3131<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3132<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3133
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3134<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3135<pre>
3136 &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]3137</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3138
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3139</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3140
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3141<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3142<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3143</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3144
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3145<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3146
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3147<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3148<pre>
3149 &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]3150</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3151
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3152<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3153<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3154 division of its two arguments.</p>
3155
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3156<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3157<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3158 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3159 values. Both arguments must have identical types.</p>
3160
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3161<h5>Semantics:</h5>
3162<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3163 This instruction always performs an unsigned division to get the
3164 remainder.</p>
3165
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3166<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3167 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3168
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3169<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3170
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3171<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3172<pre>
3173 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3174</pre>
3175
3176</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3177
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3178<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3179<div class="doc_subsubsection">
3180 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3181</div>
3182
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3183<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3184
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3185<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3186<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3187 &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]3188</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3189
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3190<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3191<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3192 division of its two operands. This instruction can also take
3193 <a href="#t_vector">vector</a> versions of the values in which case the
3194 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3195
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3196<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3197<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3198 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3199 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3200
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3201<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3202<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3203 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3204 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3205 a value. For more information about the difference,
3206 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3207 Math Forum</a>. For a table of how this is implemented in various languages,
3208 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3209 Wikipedia: modulo operation</a>.</p>
3210
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3211<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3212 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3213
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3214<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3215 Overflow also leads to undefined behavior; this is a rare case, but can
3216 occur, for example, by taking the remainder of a 32-bit division of
3217 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3218 lets srem be implemented using instructions that return both the result of
3219 the division and the remainder.)</p>
3220
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3221<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3222<pre>
3223 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3224</pre>
3225
3226</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3227
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3228<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3229<div class="doc_subsubsection">
3230 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3231
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3232<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3233
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3234<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
3236 &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]3237</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3238
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3239<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3240<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3241 its two operands.</p>
3242
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3243<h5>Arguments:</h5>
3244<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3246 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3247
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3248<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3249<p>This instruction returns the <i>remainder</i> of a division. The remainder
3250 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3251
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3252<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3253<pre>
3254 &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]3255</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3256
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3257</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3258
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3259<!-- ======================================================================= -->
3260<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3261Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3262
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3263<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3264
3265<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3266 program. They are generally very efficient instructions and can commonly be
3267 strength reduced from other instructions. They require two operands of the
3268 same type, execute an operation on them, and produce a single value. The
3269 resulting value is the same type as its operands.</p>
3270
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3271</div>
3272
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
3274<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3275Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3277<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3278
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3279<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3280<pre>
3281 &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]3282</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3283
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3284<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3285<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3286 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3287
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3288<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3289<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3290 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3291 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3292
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3293<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3294<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3295 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3296 is (statically or dynamically) negative or equal to or larger than the number
3297 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3298 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3299 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3300
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3301<h5>Example:</h5>
3302<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3303 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3304 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3305 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3306 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3307 &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]3308</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3309
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3310</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3311
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3312<!-- _______________________________________________________________________ -->
3313<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3314Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3315
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3316<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3317
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3318<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3319<pre>
3320 &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]3321</pre>
3322
3323<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3324<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3325 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3326
3327<h5>Arguments:</h5>
3328<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3329 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3330 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3331
3332<h5>Semantics:</h5>
3333<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3334 significant bits of the result will be filled with zero bits after the shift.
3335 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3336 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3337 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3338 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3339
3340<h5>Example:</h5>
3341<pre>
3342 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3343 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3344 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3345 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3346 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3347 &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]3348</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3349
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3350</div>
3351
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3352<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3353<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3354Instruction</a> </div>
3355<div class="doc_text">
3356
3357<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3358<pre>
3359 &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]3360</pre>
3361
3362<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3363<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3364 operand shifted to the right a specified number of bits with sign
3365 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3366
3367<h5>Arguments:</h5>
3368<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3369 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3370 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3371
3372<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3373<p>This instruction always performs an arithmetic shift right operation, The
3374 most significant bits of the result will be filled with the sign bit
3375 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3376 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3377 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3378 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3379
3380<h5>Example:</h5>
3381<pre>
3382 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3383 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3384 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3385 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3386 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3387 &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]3388</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3389
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3390</div>
3391
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3392<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3393<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3394Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3395
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3396<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3397
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3398<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3399<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3400 &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]3401</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3402
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3403<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3404<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3405 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3407<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3408<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3409 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3410 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3411
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3412<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3413<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3414
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3415<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3416 <tbody>
3417 <tr>
3418 <td>In0</td>
3419 <td>In1</td>
3420 <td>Out</td>
3421 </tr>
3422 <tr>
3423 <td>0</td>
3424 <td>0</td>
3425 <td>0</td>
3426 </tr>
3427 <tr>
3428 <td>0</td>
3429 <td>1</td>
3430 <td>0</td>
3431 </tr>
3432 <tr>
3433 <td>1</td>
3434 <td>0</td>
3435 <td>0</td>
3436 </tr>
3437 <tr>
3438 <td>1</td>
3439 <td>1</td>
3440 <td>1</td>
3441 </tr>
3442 </tbody>
3443</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3445<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3446<pre>
3447 &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]3448 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3449 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3450</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3451</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3452<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3453<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3454
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3455<div class="doc_text">
3456
3457<h5>Syntax:</h5>
3458<pre>
3459 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3460</pre>
3461
3462<h5>Overview:</h5>
3463<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3464 two operands.</p>
3465
3466<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3467<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3468 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3469 values. Both arguments must have identical types.</p>
3470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3471<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3472<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3473
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3474<table border="1" cellspacing="0" cellpadding="4">
3475 <tbody>
3476 <tr>
3477 <td>In0</td>
3478 <td>In1</td>
3479 <td>Out</td>
3480 </tr>
3481 <tr>
3482 <td>0</td>
3483 <td>0</td>
3484 <td>0</td>
3485 </tr>
3486 <tr>
3487 <td>0</td>
3488 <td>1</td>
3489 <td>1</td>
3490 </tr>
3491 <tr>
3492 <td>1</td>
3493 <td>0</td>
3494 <td>1</td>
3495 </tr>
3496 <tr>
3497 <td>1</td>
3498 <td>1</td>
3499 <td>1</td>
3500 </tr>
3501 </tbody>
3502</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3503
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3504<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3505<pre>
3506 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3507 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3508 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3509</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3510
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3511</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3512
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3513<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3514<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3515Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3516
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3517<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3519<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3520<pre>
3521 &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]3522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3524<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3525<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3526 its two operands. The <tt>xor</tt> is used to implement the "one's
3527 complement" operation, which is the "~" operator in C.</p>
3528
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3529<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3530<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3531 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3532 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3535<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3536
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3537<table border="1" cellspacing="0" cellpadding="4">
3538 <tbody>
3539 <tr>
3540 <td>In0</td>
3541 <td>In1</td>
3542 <td>Out</td>
3543 </tr>
3544 <tr>
3545 <td>0</td>
3546 <td>0</td>
3547 <td>0</td>
3548 </tr>
3549 <tr>
3550 <td>0</td>
3551 <td>1</td>
3552 <td>1</td>
3553 </tr>
3554 <tr>
3555 <td>1</td>
3556 <td>0</td>
3557 <td>1</td>
3558 </tr>
3559 <tr>
3560 <td>1</td>
3561 <td>1</td>
3562 <td>0</td>
3563 </tr>
3564 </tbody>
3565</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3567<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3568<pre>
3569 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3570 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3571 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3572 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3573</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3574
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3575</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3577<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3578<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3579 <a name="vectorops">Vector Operations</a>
3580</div>
3581
3582<div class="doc_text">
3583
3584<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3585 target-independent manner. These instructions cover the element-access and
3586 vector-specific operations needed to process vectors effectively. While LLVM
3587 does directly support these vector operations, many sophisticated algorithms
3588 will want to use target-specific intrinsics to take full advantage of a
3589 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3590
3591</div>
3592
3593<!-- _______________________________________________________________________ -->
3594<div class="doc_subsubsection">
3595 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3596</div>
3597
3598<div class="doc_text">
3599
3600<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3601<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3602 &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]3603</pre>
3604
3605<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3607 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3608
3609
3610<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3611<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3612 of <a href="#t_vector">vector</a> type. The second operand is an index
3613 indicating the position from which to extract the element. The index may be
3614 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3615
3616<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3617<p>The result is a scalar of the same type as the element type of
3618 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3619 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3620 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3621
3622<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3623<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3624 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3625</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3626
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3627</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3628
3629<!-- _______________________________________________________________________ -->
3630<div class="doc_subsubsection">
3631 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3632</div>
3633
3634<div class="doc_text">
3635
3636<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3637<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3638 &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]3639</pre>
3640
3641<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3643 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3644
3645<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3646<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3647 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3648 whose type must equal the element type of the first operand. The third
3649 operand is an index indicating the position at which to insert the value.
3650 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3651
3652<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3654 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3655 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3656 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3657
3658<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3659<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3660 %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]3661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3662
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3663</div>
3664
3665<!-- _______________________________________________________________________ -->
3666<div class="doc_subsubsection">
3667 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3668</div>
3669
3670<div class="doc_text">
3671
3672<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3673<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3674 &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]3675</pre>
3676
3677<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3678<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3679 from two input vectors, returning a vector with the same element type as the
3680 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3681
3682<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3683<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3684 with types that match each other. The third argument is a shuffle mask whose
3685 element type is always 'i32'. The result of the instruction is a vector
3686 whose length is the same as the shuffle mask and whose element type is the
3687 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3688
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3689<p>The shuffle mask operand is required to be a constant vector with either
3690 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3691
3692<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3693<p>The elements of the two input vectors are numbered from left to right across
3694 both of the vectors. The shuffle mask operand specifies, for each element of
3695 the result vector, which element of the two input vectors the result element
3696 gets. The element selector may be undef (meaning "don't care") and the
3697 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3698
3699<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3700<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3701 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3702 &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]3703 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3704 &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]3705 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3706 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3707 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3708 &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]3709</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3710
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3712
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3713<!-- ======================================================================= -->
3714<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3715 <a name="aggregateops">Aggregate Operations</a>
3716</div>
3717
3718<div class="doc_text">
3719
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3720<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3721
3722</div>
3723
3724<!-- _______________________________________________________________________ -->
3725<div class="doc_subsubsection">
3726 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3727</div>
3728
3729<div class="doc_text">
3730
3731<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3738 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3741<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3742 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3743 operands are constant indices to specify which value to extract in a similar
3744 manner as indices in a
3745 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3746
3747<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3748<p>The result is the value at the position in the aggregate specified by the
3749 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3750
3751<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3752<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3753 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3754</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3755
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3756</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3757
3758<!-- _______________________________________________________________________ -->
3759<div class="doc_subsubsection">
3760 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3761</div>
3762
3763<div class="doc_text">
3764
3765<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3766<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3767 &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]3768</pre>
3769
3770<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3771<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3772 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3773
3774
3775<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3777 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3778 second operand is a first-class value to insert. The following operands are
3779 constant indices indicating the position at which to insert the value in a
3780 similar manner as indices in a
3781 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3782 value to insert must have the same type as the value identified by the
3783 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3787 that of <tt>val</tt> except that the value at the position specified by the
3788 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3789
3790<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3791<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3792 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3793</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3795</div>
3796
3797
3798<!-- ======================================================================= -->
3799<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3800 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3801</div>
3802
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3803<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3804
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3805<p>A key design point of an SSA-based representation is how it represents
3806 memory. In LLVM, no memory locations are in SSA form, which makes things
3807 very simple. This section describes how to read, write, allocate, and free
3808 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3809
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3810</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3812<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3813<div class="doc_subsubsection">
3814 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3815</div>
3816
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3817<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3819<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3820<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3821 &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]3822</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3823
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3824<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3826 returns a pointer to it. The object is always allocated in the generic
3827 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3828
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3829<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3830<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3831 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3832 system and returns a pointer of the appropriate type to the program. If
3833 "NumElements" is specified, it is the number of elements allocated, otherwise
3834 "NumElements" is defaulted to be one. If a constant alignment is specified,
3835 the value result of the allocation is guaranteed to be aligned to at least
3836 that boundary. If not specified, or if zero, the target can choose to align
3837 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3839<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3841<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3843 pointer is returned. The result of a zero byte allocation is undefined. The
3844 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3845
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3846<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3847<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3848 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3849
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3850 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3851 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3852 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3853 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3854 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3855</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3856
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3857<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3859</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3860
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3861<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3862<div class="doc_subsubsection">
3863 <a name="i_free">'<tt>free</tt>' Instruction</a>
3864</div>
3865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3866<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3867
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3868<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3869<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3870 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3871</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3872
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3873<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3874<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3875 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3877<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3878<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3879 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3880
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3881<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3882<p>Access to the memory pointed to by the pointer is no longer defined after
3883 this instruction executes. If the pointer is null, the operation is a
3884 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3886<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3887<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3888 %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]3889 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3890</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3891
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3892</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3894<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3895<div class="doc_subsubsection">
3896 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3897</div>
3898
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3899<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3901<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3902<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3903 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3904</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3906<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3907<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908 currently executing function, to be automatically released when this function
3909 returns to its caller. The object is always allocated in the generic address
3910 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3911
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3912<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913<p>The '<tt>alloca</tt>' instruction
3914 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3915 runtime stack, returning a pointer of the appropriate type to the program.
3916 If "NumElements" is specified, it is the number of elements allocated,
3917 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3918 specified, the value result of the allocation is guaranteed to be aligned to
3919 at least that boundary. If not specified, or if zero, the target can choose
3920 to align the allocation on any convenient boundary compatible with the
3921 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3923<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3925<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3926<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3927 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3928 memory is automatically released when the function returns. The
3929 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3930 variables that must have an address available. When the function returns
3931 (either with the <tt><a href="#i_ret">ret</a></tt>
3932 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3933 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3934
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3935<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3936<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3937 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3938 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3941</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3942
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3943</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3945<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3946<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3947Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3949<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3951<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952<pre>
3953 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3954 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955</pre>
3956
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3957<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3958<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3959
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3960<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3961<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3962 from which to load. The pointer must point to
3963 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3964 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3965 number or order of execution of this <tt>load</tt> with other
3966 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3967 instructions. </p>
3968
3969<p>The optional constant "align" argument specifies the alignment of the
3970 operation (that is, the alignment of the memory address). A value of 0 or an
3971 omitted "align" argument means that the operation has the preferential
3972 alignment for the target. It is the responsibility of the code emitter to
3973 ensure that the alignment information is correct. Overestimating the
3974 alignment results in an undefined behavior. Underestimating the alignment may
3975 produce less efficient code. An alignment of 1 is always safe.</p>
3976
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3977<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3978<p>The location of memory pointed to is loaded. If the value being loaded is of
3979 scalar type then the number of bytes read does not exceed the minimum number
3980 of bytes needed to hold all bits of the type. For example, loading an
3981 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3982 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3983 is undefined if the value was not originally written using a store of the
3984 same type.</p>
3985
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3986<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3987<pre>
3988 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3989 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3990 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3991</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3992
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3993</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3994
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3995<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3996<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3997Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3998
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]3999<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4000
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4001<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]4004 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4005</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4006
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4007<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4008<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4009
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4010<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4012 and an address at which to store it. The type of the
4013 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4014 the <a href="#t_firstclass">first class</a> type of the
4015 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4016 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4017 or order of execution of this <tt>store</tt> with other
4018 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4019 instructions.</p>
4020
4021<p>The optional constant "align" argument specifies the alignment of the
4022 operation (that is, the alignment of the memory address). A value of 0 or an
4023 omitted "align" argument means that the operation has the preferential
4024 alignment for the target. It is the responsibility of the code emitter to
4025 ensure that the alignment information is correct. Overestimating the
4026 alignment results in an undefined behavior. Underestimating the alignment may
4027 produce less efficient code. An alignment of 1 is always safe.</p>
4028
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4029<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4031 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4032 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4033 does not exceed the minimum number of bytes needed to hold all bits of the
4034 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4035 writing a value of a type like <tt>i20</tt> with a size that is not an
4036 integral number of bytes, it is unspecified what happens to the extra bits
4037 that do not belong to the type, but they will typically be overwritten.</p>
4038
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4039<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4040<pre>
4041 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4042 store i32 3, i32* %ptr <i>; yields {void}</i>
4043 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4044</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4045
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4046</div>
4047
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4048<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4049<div class="doc_subsubsection">
4050 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4051</div>
4052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4053<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4054
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4055<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4056<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4057 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4058 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4059</pre>
4060
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4061<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4063 subelement of an aggregate data structure. It performs address calculation
4064 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4065
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4066<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4067<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4068 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4069 elements of the aggregate object are indexed. The interpretation of each
4070 index is dependent on the type being indexed into. The first index always
4071 indexes the pointer value given as the first argument, the second index
4072 indexes a value of the type pointed to (not necessarily the value directly
4073 pointed to, since the first index can be non-zero), etc. The first type
4074 indexed into must be a pointer value, subsequent types can be arrays, vectors
4075 and structs. Note that subsequent types being indexed into can never be
4076 pointers, since that would require loading the pointer before continuing
4077 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4078
4079<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4080 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4081 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4082 vector, integers of any width are allowed, and they are not required to be
4083 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4084
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4085<p>For example, let's consider a C code fragment and how it gets compiled to
4086 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4087
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4088<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4089<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4090struct RT {
4091 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4092 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4093 char C;
4094};
4095struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4096 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4097 double Y;
4098 struct RT Z;
4099};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4100
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4101int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4102 return &amp;s[1].Z.B[5][13];
4103}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4104</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4105</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4106
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4107<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4108
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4109<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4110<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4111%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4112%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4113
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4114define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4115entry:
4116 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4117 ret i32* %reg
4118}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4119</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4120</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4121
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4122<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4123<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4124 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4125 }</tt>' type, a structure. The second index indexes into the third element
4126 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4127 i8 }</tt>' type, another structure. The third index indexes into the second
4128 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4129 array. The two dimensions of the array are subscripted into, yielding an
4130 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4131 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4132
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4133<p>Note that it is perfectly legal to index partially through a structure,
4134 returning a pointer to an inner element. Because of this, the LLVM code for
4135 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4136
4137<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4138 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4139 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4140 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4141 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4142 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4143 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4144 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4145 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4146</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4147
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4148<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4149 <tt>getelementptr</tt> is undefined if the base pointer is not an
4150 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4151 that would be formed by successive addition of the offsets implied by the
4152 indices to the base address with infinitely precise arithmetic are not an
4153 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4154 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4155 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4156
4157<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4158 the base address with silently-wrapping two's complement arithmetic, and
4159 the result value of the <tt>getelementptr</tt> may be outside the object
4160 pointed to by the base pointer. The result value may not necessarily be
4161 used to access memory though, even if it happens to point into allocated
4162 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4163 section for more information.</p>
4164
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The getelementptr instruction is often confusing. For some more insight into
4166 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4167
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4168<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4169<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4170 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4171 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4172 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4173 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4174 <i>; yields i8*:eptr</i>
4175 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4176 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4177 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4178</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4179
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4180</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4181
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4182<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4183<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4184</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4185
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4186<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4187
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4188<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4189 which all take a single operand and a type. They perform various bit
4190 conversions on the operand.</p>
4191
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4192</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4193
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4194<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4195<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4196 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4197</div>
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
4201<pre>
4202 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4203</pre>
4204
4205<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4206<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4207 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4208
4209<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4210<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4211 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4212 size and type of the result, which must be
4213 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4214 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4215 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4216
4217<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4218<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4219 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4220 source size must be larger than the destination size, <tt>trunc</tt> cannot
4221 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4222
4223<h5>Example:</h5>
4224<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4225 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4226 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4227 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4228</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4229
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4230</div>
4231
4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
4234 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4235</div>
4236<div class="doc_text">
4237
4238<h5>Syntax:</h5>
4239<pre>
4240 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4241</pre>
4242
4243<h5>Overview:</h5>
4244<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4245 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4246
4247
4248<h5>Arguments:</h5>
4249<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4250 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4251 also be of <a href="#t_integer">integer</a> type. The bit size of the
4252 <tt>value</tt> must be smaller than the bit size of the destination type,
4253 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4254
4255<h5>Semantics:</h5>
4256<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4257 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4258
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4259<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4260
4261<h5>Example:</h5>
4262<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4263 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4264 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4265</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4266
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4267</div>
4268
4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
4271 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4272</div>
4273<div class="doc_text">
4274
4275<h5>Syntax:</h5>
4276<pre>
4277 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4278</pre>
4279
4280<h5>Overview:</h5>
4281<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4282
4283<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4285 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4286 also be of <a href="#t_integer">integer</a> type. The bit size of the
4287 <tt>value</tt> must be smaller than the bit size of the destination type,
4288 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4289
4290<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4291<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4292 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4293 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4294
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4295<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4296
4297<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4298<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4299 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4300 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4301</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4302
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4303</div>
4304
4305<!-- _______________________________________________________________________ -->
4306<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4307 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4308</div>
4309
4310<div class="doc_text">
4311
4312<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4313<pre>
4314 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4315</pre>
4316
4317<h5>Overview:</h5>
4318<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4319 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4320
4321<h5>Arguments:</h5>
4322<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4323 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4324 to cast it to. The size of <tt>value</tt> must be larger than the size of
4325 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4326 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4327
4328<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4329<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4330 <a href="#t_floating">floating point</a> type to a smaller
4331 <a href="#t_floating">floating point</a> type. If the value cannot fit
4332 within the destination type, <tt>ty2</tt>, then the results are
4333 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4334
4335<h5>Example:</h5>
4336<pre>
4337 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4338 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4339</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4340
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4341</div>
4342
4343<!-- _______________________________________________________________________ -->
4344<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4345 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4346</div>
4347<div class="doc_text">
4348
4349<h5>Syntax:</h5>
4350<pre>
4351 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4352</pre>
4353
4354<h5>Overview:</h5>
4355<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4356 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4357
4358<h5>Arguments:</h5>
4359<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4361 a <a href="#t_floating">floating point</a> type to cast it to. The source
4362 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4363
4364<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4365<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4366 <a href="#t_floating">floating point</a> type to a larger
4367 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4368 used to make a <i>no-op cast</i> because it always changes bits. Use
4369 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4370
4371<h5>Example:</h5>
4372<pre>
4373 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4374 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4375</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4376
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4377</div>
4378
4379<!-- _______________________________________________________________________ -->
4380<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4381 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4382</div>
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4387 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4388</pre>
4389
4390<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4391<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4392 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4393
4394<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4395<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4396 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4397 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4398 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4399 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4400
4401<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4402<p>The '<tt>fptoui</tt>' instruction converts its
4403 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4404 towards zero) unsigned integer value. If the value cannot fit
4405 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4406
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4407<h5>Example:</h5>
4408<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4409 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4410 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4411 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4412</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4413
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4414</div>
4415
4416<!-- _______________________________________________________________________ -->
4417<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4418 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4419</div>
4420<div class="doc_text">
4421
4422<h5>Syntax:</h5>
4423<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4424 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4425</pre>
4426
4427<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4428<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4429 <a href="#t_floating">floating point</a> <tt>value</tt> to
4430 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4431
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4432<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4434 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4435 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4436 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4437 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4438
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4439<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4440<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4441 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4442 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4443 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4444
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4445<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4446<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4447 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4448 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4449 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4450</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4451
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4456 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4457</div>
4458<div class="doc_text">
4459
4460<h5>Syntax:</h5>
4461<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4462 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4463</pre>
4464
4465<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4466<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4467 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4468
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4469<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4470<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4471 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4472 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4473 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4474 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4475
4476<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4477<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4478 integer quantity and converts it to the corresponding floating point
4479 value. If the value cannot fit in the floating point value, the results are
4480 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4481
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4482<h5>Example:</h5>
4483<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4484 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4485 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4486</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4487
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4488</div>
4489
4490<!-- _______________________________________________________________________ -->
4491<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4492 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4493</div>
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
4497<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4498 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4499</pre>
4500
4501<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4502<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4503 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4504
4505<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4506<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4507 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4508 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4509 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4510 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4511
4512<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4513<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4514 quantity and converts it to the corresponding floating point value. If the
4515 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4516
4517<h5>Example:</h5>
4518<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4519 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4520 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4521</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4522
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4523</div>
4524
4525<!-- _______________________________________________________________________ -->
4526<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4527 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4528</div>
4529<div class="doc_text">
4530
4531<h5>Syntax:</h5>
4532<pre>
4533 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4534</pre>
4535
4536<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4538 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4539
4540<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4541<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4542 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4543 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4544
4545<h5>Semantics:</h5>
4546<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4547 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4548 truncating or zero extending that value to the size of the integer type. If
4549 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4550 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4551 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4552 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4553
4554<h5>Example:</h5>
4555<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4556 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4557 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4558</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4559
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4560</div>
4561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
4564 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4565</div>
4566<div class="doc_text">
4567
4568<h5>Syntax:</h5>
4569<pre>
4570 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4571</pre>
4572
4573<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4574<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4575 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4576
4577<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4578<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579 value to cast, and a type to cast it to, which must be a
4580 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4581
4582<h5>Semantics:</h5>
4583<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4584 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4585 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4586 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4587 than the size of a pointer then a zero extension is done. If they are the
4588 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4589
4590<h5>Example:</h5>
4591<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4592 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4593 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4594 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4595</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4596
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4597</div>
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4601 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4602</div>
4603<div class="doc_text">
4604
4605<h5>Syntax:</h5>
4606<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4607 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4608</pre>
4609
4610<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4611<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4612 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4613
4614<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4615<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4616 non-aggregate first class value, and a type to cast it to, which must also be
4617 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4618 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4619 identical. If the source type is a pointer, the destination type must also be
4620 a pointer. This instruction supports bitwise conversion of vectors to
4621 integers and to vectors of other types (as long as they have the same
4622 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4625<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4626 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4627 this conversion. The conversion is done as if the <tt>value</tt> had been
4628 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4629 be converted to other pointer types with this instruction. To convert
4630 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4631 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4632
4633<h5>Example:</h5>
4634<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4635 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4636 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4637 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4638</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4639
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4640</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4641
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4642<!-- ======================================================================= -->
4643<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4644
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4645<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4646
4647<p>The instructions in this category are the "miscellaneous" instructions, which
4648 defy better classification.</p>
4649
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4650</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4651
4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4654</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4655
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4656<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4657
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4658<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4659<pre>
4660 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4661</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4662
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4663<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4665 boolean values based on comparison of its two integer, integer vector, or
4666 pointer operands.</p>
4667
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4668<h5>Arguments:</h5>
4669<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4670 the condition code indicating the kind of comparison to perform. It is not a
4671 value, just a keyword. The possible condition code are:</p>
4672
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4673<ol>
4674 <li><tt>eq</tt>: equal</li>
4675 <li><tt>ne</tt>: not equal </li>
4676 <li><tt>ugt</tt>: unsigned greater than</li>
4677 <li><tt>uge</tt>: unsigned greater or equal</li>
4678 <li><tt>ult</tt>: unsigned less than</li>
4679 <li><tt>ule</tt>: unsigned less or equal</li>
4680 <li><tt>sgt</tt>: signed greater than</li>
4681 <li><tt>sge</tt>: signed greater or equal</li>
4682 <li><tt>slt</tt>: signed less than</li>
4683 <li><tt>sle</tt>: signed less or equal</li>
4684</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4685
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4686<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4688 typed. They must also be identical types.</p>
4689
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4690<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4692 condition code given as <tt>cond</tt>. The comparison performed always yields
4693 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4694 result, as follows:</p>
4695
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4696<ol>
4697 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4698 <tt>false</tt> otherwise. No sign interpretation is necessary or
4699 performed.</li>
4700
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4701 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4702 <tt>false</tt> otherwise. No sign interpretation is necessary or
4703 performed.</li>
4704
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4705 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4707
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4708 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4710 to <tt>op2</tt>.</li>
4711
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4712 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4714
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4715 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4716 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4718 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4720
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4721 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4722 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4723 to <tt>op2</tt>.</li>
4724
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4725 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4726 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4728 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4729 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4730</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4731
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4732<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733 values are compared as if they were integers.</p>
4734
4735<p>If the operands are integer vectors, then they are compared element by
4736 element. The result is an <tt>i1</tt> vector with the same number of elements
4737 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4738
4739<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4740<pre>
4741 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4742 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4743 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4744 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4745 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4747</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4748
4749<p>Note that the code generator does not yet support vector types with
4750 the <tt>icmp</tt> instruction.</p>
4751
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
4755<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4756</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4757
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4758<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4759
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4760<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4761<pre>
4762 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4763</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4766<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4767 values based on comparison of its operands.</p>
4768
4769<p>If the operands are floating point scalars, then the result type is a boolean
4770(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4771
4772<p>If the operands are floating point vectors, then the result type is a vector
4773 of boolean with the same number of elements as the operands being
4774 compared.</p>
4775
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4776<h5>Arguments:</h5>
4777<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778 the condition code indicating the kind of comparison to perform. It is not a
4779 value, just a keyword. The possible condition code are:</p>
4780
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4781<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4782 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4783 <li><tt>oeq</tt>: ordered and equal</li>
4784 <li><tt>ogt</tt>: ordered and greater than </li>
4785 <li><tt>oge</tt>: ordered and greater than or equal</li>
4786 <li><tt>olt</tt>: ordered and less than </li>
4787 <li><tt>ole</tt>: ordered and less than or equal</li>
4788 <li><tt>one</tt>: ordered and not equal</li>
4789 <li><tt>ord</tt>: ordered (no nans)</li>
4790 <li><tt>ueq</tt>: unordered or equal</li>
4791 <li><tt>ugt</tt>: unordered or greater than </li>
4792 <li><tt>uge</tt>: unordered or greater than or equal</li>
4793 <li><tt>ult</tt>: unordered or less than </li>
4794 <li><tt>ule</tt>: unordered or less than or equal</li>
4795 <li><tt>une</tt>: unordered or not equal</li>
4796 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4797 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4798</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4799
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4800<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4801 <i>unordered</i> means that either operand may be a QNAN.</p>
4802
4803<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4804 a <a href="#t_floating">floating point</a> type or
4805 a <a href="#t_vector">vector</a> of floating point type. They must have
4806 identical types.</p>
4807
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4808<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4809<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4810 according to the condition code given as <tt>cond</tt>. If the operands are
4811 vectors, then the vectors are compared element by element. Each comparison
4812 performed always yields an <a href="#t_primitive">i1</a> result, as
4813 follows:</p>
4814
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4815<ol>
4816 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4817
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4818 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4819 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4820
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4821 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4822 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4823
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4824 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4825 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4826
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4827 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4828 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4829
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4830 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4831 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4832
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4833 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4834 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4835
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4836 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4837
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4838 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4839 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4840
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4841 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4842 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4843
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4844 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4845 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4846
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4847 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4849
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4850 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4851 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4852
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4853 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4854 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4855
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4856 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4857
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4858 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4859</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4860
4861<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4862<pre>
4863 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4864 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4865 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4866 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4867</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4868
4869<p>Note that the code generator does not yet support vector types with
4870 the <tt>fcmp</tt> instruction.</p>
4871
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4872</div>
4873
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4874<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4875<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4876 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4877</div>
4878
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4879<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4880
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4881<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4882<pre>
4883 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4884</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4885
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4886<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4887<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4888 SSA graph representing the function.</p>
4889
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4890<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4891<p>The type of the incoming values is specified with the first type field. After
4892 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4893 one pair for each predecessor basic block of the current block. Only values
4894 of <a href="#t_firstclass">first class</a> type may be used as the value
4895 arguments to the PHI node. Only labels may be used as the label
4896 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4897
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4898<p>There must be no non-phi instructions between the start of a basic block and
4899 the PHI instructions: i.e. PHI instructions must be first in a basic
4900 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4901
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4902<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4903 occur on the edge from the corresponding predecessor block to the current
4904 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4905 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4906
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4907<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4908<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4909 specified by the pair corresponding to the predecessor basic block that
4910 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4911
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4912<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4913<pre>
4914Loop: ; Infinite loop that counts from 0 on up...
4915 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4916 %nextindvar = add i32 %indvar, 1
4917 br label %Loop
4918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4919
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4920</div>
4921
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4922<!-- _______________________________________________________________________ -->
4923<div class="doc_subsubsection">
4924 <a name="i_select">'<tt>select</tt>' Instruction</a>
4925</div>
4926
4927<div class="doc_text">
4928
4929<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4930<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4931 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4932
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4933 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4934</pre>
4935
4936<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4938 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4939
4940
4941<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4943 values indicating the condition, and two values of the
4944 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4945 vectors and the condition is a scalar, then entire vectors are selected, not
4946 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4947
4948<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4949<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4950 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4952<p>If the condition is a vector of i1, then the value arguments must be vectors
4953 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4954
4955<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4956<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4957 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4958</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4959
4960<p>Note that the code generator does not yet support conditions
4961 with vector type.</p>
4962
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4963</div>
4964
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4965<!-- _______________________________________________________________________ -->
4966<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4967 <a name="i_call">'<tt>call</tt>' Instruction</a>
4968</div>
4969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4970<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4971
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4972<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4973<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4974 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4975</pre>
4976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4977<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4978<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4981<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4982
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4983<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4984 <li>The optional "tail" marker indicates whether the callee function accesses
4985 any allocas or varargs in the caller. If the "tail" marker is present,
4986 the function call is eligible for tail call optimization. Note that calls
4987 may be marked "tail" even if they do not occur before
4988 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4989
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4990 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4991 convention</a> the call should use. If none is specified, the call
4992 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4993
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4994 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4995 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4996 '<tt>inreg</tt>' attributes are valid here.</li>
4997
4998 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4999 type of the return value. Functions that return no value are marked
5000 <tt><a href="#t_void">void</a></tt>.</li>
5001
5002 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5003 being invoked. The argument types must match the types implied by this
5004 signature. This type can be omitted if the function is not varargs and if
5005 the function type does not return a pointer to a function.</li>
5006
5007 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5008 be invoked. In most cases, this is a direct function invocation, but
5009 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5010 to function value.</li>
5011
5012 <li>'<tt>function args</tt>': argument list whose types match the function
5013 signature argument types. All arguments must be of
5014 <a href="#t_firstclass">first class</a> type. If the function signature
5015 indicates the function accepts a variable number of arguments, the extra
5016 arguments can be specified.</li>
5017
5018 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5019 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5020 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5021</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5022
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5023<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5024<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5025 a specified function, with its incoming arguments bound to the specified
5026 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5027 function, control flow continues with the instruction after the function
5028 call, and the return value of the function is bound to the result
5029 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5030
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5031<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5032<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5033 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5034 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5035 %X = tail call i32 @foo() <i>; yields i32</i>
5036 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5037 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5038
5039 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5040 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5041 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5042 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5043 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5044 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5045</pre>
5046
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5047</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5048
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5049<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5050<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5051 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5052</div>
5053
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5054<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5055
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5056<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5057<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5058 &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]5059</pre>
5060
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5061<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5062<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5063 the "variable argument" area of a function call. It is used to implement the
5064 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5065
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5066<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5067<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5068 argument. It returns a value of the specified argument type and increments
5069 the <tt>va_list</tt> to point to the next argument. The actual type
5070 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5071
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5072<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5073<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5074 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5075 to the next argument. For more information, see the variable argument
5076 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5077
5078<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]5079 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5080 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5081
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5082<p><tt>va_arg</tt> is an LLVM instruction instead of
5083 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5084 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5085
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5086<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5087<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089<p>Note that the code generator does not yet fully support va_arg on many
5090 targets. Also, it does not currently support va_arg with aggregate types on
5091 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5092
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5093</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5094
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5095<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5096<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5097<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5098
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5099<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5100
5101<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5102 well known names and semantics and are required to follow certain
5103 restrictions. Overall, these intrinsics represent an extension mechanism for
5104 the LLVM language that does not require changing all of the transformations
5105 in LLVM when adding to the language (or the bitcode reader/writer, the
5106 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5107
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5108<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5110 begin with this prefix. Intrinsic functions must always be external
5111 functions: you cannot define the body of intrinsic functions. Intrinsic
5112 functions may only be used in call or invoke instructions: it is illegal to
5113 take the address of an intrinsic function. Additionally, because intrinsic
5114 functions are part of the LLVM language, it is required if any are added that
5115 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5116
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5117<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5118 family of functions that perform the same operation but on different data
5119 types. Because LLVM can represent over 8 million different integer types,
5120 overloading is used commonly to allow an intrinsic function to operate on any
5121 integer type. One or more of the argument types or the result type can be
5122 overloaded to accept any integer type. Argument types may also be defined as
5123 exactly matching a previous argument's type or the result type. This allows
5124 an intrinsic function which accepts multiple arguments, but needs all of them
5125 to be of the same type, to only be overloaded with respect to a single
5126 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5127
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5128<p>Overloaded intrinsics will have the names of its overloaded argument types
5129 encoded into its function name, each preceded by a period. Only those types
5130 which are overloaded result in a name suffix. Arguments whose type is matched
5131 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5132 can take an integer of any width and returns an integer of exactly the same
5133 integer width. This leads to a family of functions such as
5134 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5135 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5136 suffix is required. Because the argument's type is matched against the return
5137 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5138
5139<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5140 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5141
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5142</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5143
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5144<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5145<div class="doc_subsection">
5146 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5147</div>
5148
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5149<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5150
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5151<p>Variable argument support is defined in LLVM with
5152 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5153 intrinsic functions. These functions are related to the similarly named
5154 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5155
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5156<p>All of these functions operate on arguments that use a target-specific value
5157 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5158 not define what this type is, so all transformations should be prepared to
5159 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5160
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5161<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]5162 instruction and the variable argument handling intrinsic functions are
5163 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5164
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5165<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5166<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5167define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5168 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5169 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5170 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5171 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5172
5173 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5174 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5175
5176 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5177 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5178 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5179 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5180 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5181
5182 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5183 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5184 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5185}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5186
5187declare void @llvm.va_start(i8*)
5188declare void @llvm.va_copy(i8*, i8*)
5189declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5190</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5191</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5192
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5193</div>
5194
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5195<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5196<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5197 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5198</div>
5199
5200
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5201<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5202
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5203<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5204<pre>
5205 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5206</pre>
5207
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5208<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5210 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]5211
5212<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5213<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]5214
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5215<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5216<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]5217 macro available in C. In a target-dependent way, it initializes
5218 the <tt>va_list</tt> element to which the argument points, so that the next
5219 call to <tt>va_arg</tt> will produce the first variable argument passed to
5220 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5221 need to know the last argument of the function as the compiler can figure
5222 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5224</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5225
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5226<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5227<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5228 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5229</div>
5230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5231<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5232
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5233<h5>Syntax:</h5>
5234<pre>
5235 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5236</pre>
5237
5238<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5239<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240 which has been initialized previously
5241 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5242 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5243
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5244<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5245<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]5246
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5247<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5248<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]5249 macro available in C. In a target-dependent way, it destroys
5250 the <tt>va_list</tt> element to which the argument points. Calls
5251 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5252 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5253 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5254
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5255</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5256
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5257<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5258<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5259 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5260</div>
5261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5262<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5263
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5264<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5265<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5266 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5267</pre>
5268
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5269<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5270<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5271 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5272
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5273<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5274<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]5275 The second argument is a pointer to a <tt>va_list</tt> element to copy
5276 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5277
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5278<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5279<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]5280 macro available in C. In a target-dependent way, it copies the
5281 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5282 element. This intrinsic is necessary because
5283 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5284 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5286</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5287
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5288<!-- ======================================================================= -->
5289<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5290 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5291</div>
5292
5293<div class="doc_text">
5294
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5295<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5296Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5297intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5298roots on the stack</a>, as well as garbage collector implementations that
5299require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5300barriers. Front-ends for type-safe garbage collected languages should generate
5301these intrinsics to make use of the LLVM garbage collectors. For more details,
5302see <a href="GarbageCollection.html">Accurate Garbage Collection with
5303LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5304
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5305<p>The garbage collection intrinsics only operate on objects in the generic
5306 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5307
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5308</div>
5309
5310<!-- _______________________________________________________________________ -->
5311<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5312 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5313</div>
5314
5315<div class="doc_text">
5316
5317<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5318<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5319 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5320</pre>
5321
5322<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5323<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]5324 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5325
5326<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5327<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5328 root pointer. The second pointer (which must be either a constant or a
5329 global value address) contains the meta-data to be associated with the
5330 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5331
5332<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5333<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]5334 location. At compile-time, the code generator generates information to allow
5335 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5336 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5337 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5338
5339</div>
5340
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5341<!-- _______________________________________________________________________ -->
5342<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5343 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5344</div>
5345
5346<div class="doc_text">
5347
5348<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5349<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5350 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5351</pre>
5352
5353<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5354<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5355 locations, allowing garbage collector implementations that require read
5356 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5357
5358<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5359<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]5360 allocated from the garbage collector. The first object is a pointer to the
5361 start of the referenced object, if needed by the language runtime (otherwise
5362 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5363
5364<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5365<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5366 instruction, but may be replaced with substantially more complex code by the
5367 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5368 may only be used in a function which <a href="#gc">specifies a GC
5369 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5370
5371</div>
5372
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5373<!-- _______________________________________________________________________ -->
5374<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5375 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5376</div>
5377
5378<div class="doc_text">
5379
5380<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5381<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5382 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5383</pre>
5384
5385<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5386<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5387 locations, allowing garbage collector implementations that require write
5388 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5389
5390<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5391<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]5392 object to store it to, and the third is the address of the field of Obj to
5393 store to. If the runtime does not require a pointer to the object, Obj may
5394 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5395
5396<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5397<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5398 instruction, but may be replaced with substantially more complex code by the
5399 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5400 may only be used in a function which <a href="#gc">specifies a GC
5401 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5402
5403</div>
5404
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5405<!-- ======================================================================= -->
5406<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5407 <a name="int_codegen">Code Generator Intrinsics</a>
5408</div>
5409
5410<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5411
5412<p>These intrinsics are provided by LLVM to expose special features that may
5413 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5414
5415</div>
5416
5417<!-- _______________________________________________________________________ -->
5418<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5419 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5420</div>
5421
5422<div class="doc_text">
5423
5424<h5>Syntax:</h5>
5425<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5426 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5427</pre>
5428
5429<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5430<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5431 target-specific value indicating the return address of the current function
5432 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5433
5434<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5435<p>The argument to this intrinsic indicates which function to return the address
5436 for. Zero indicates the calling function, one indicates its caller, etc.
5437 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5438
5439<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5440<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5441 indicating the return address of the specified call frame, or zero if it
5442 cannot be identified. The value returned by this intrinsic is likely to be
5443 incorrect or 0 for arguments other than zero, so it should only be used for
5444 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5445
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5446<p>Note that calling this intrinsic does not prevent function inlining or other
5447 aggressive transformations, so the value returned may not be that of the
5448 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5449
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5450</div>
5451
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5452<!-- _______________________________________________________________________ -->
5453<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5454 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5455</div>
5456
5457<div class="doc_text">
5458
5459<h5>Syntax:</h5>
5460<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5461 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5462</pre>
5463
5464<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5465<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5466 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5467
5468<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5469<p>The argument to this intrinsic indicates which function to return the frame
5470 pointer for. Zero indicates the calling function, one indicates its caller,
5471 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5472
5473<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5475 indicating the frame address of the specified call frame, or zero if it
5476 cannot be identified. The value returned by this intrinsic is likely to be
5477 incorrect or 0 for arguments other than zero, so it should only be used for
5478 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5479
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5480<p>Note that calling this intrinsic does not prevent function inlining or other
5481 aggressive transformations, so the value returned may not be that of the
5482 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5483
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5484</div>
5485
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5486<!-- _______________________________________________________________________ -->
5487<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5488 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5489</div>
5490
5491<div class="doc_text">
5492
5493<h5>Syntax:</h5>
5494<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5495 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5496</pre>
5497
5498<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5500 of the function stack, for use
5501 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5502 useful for implementing language features like scoped automatic variable
5503 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5504
5505<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5506<p>This intrinsic returns a opaque pointer value that can be passed
5507 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5508 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5509 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5510 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5511 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5512 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5513
5514</div>
5515
5516<!-- _______________________________________________________________________ -->
5517<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5518 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5519</div>
5520
5521<div class="doc_text">
5522
5523<h5>Syntax:</h5>
5524<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5525 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5526</pre>
5527
5528<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5529<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5530 the function stack to the state it was in when the
5531 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5532 executed. This is useful for implementing language features like scoped
5533 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5534
5535<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536<p>See the description
5537 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5538
5539</div>
5540
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5541<!-- _______________________________________________________________________ -->
5542<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5543 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5544</div>
5545
5546<div class="doc_text">
5547
5548<h5>Syntax:</h5>
5549<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5550 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]5551</pre>
5552
5553<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5554<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5555 insert a prefetch instruction if supported; otherwise, it is a noop.
5556 Prefetches have no effect on the behavior of the program but can change its
5557 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5558
5559<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5560<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5561 specifier determining if the fetch should be for a read (0) or write (1),
5562 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5563 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5564 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5565
5566<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p>This intrinsic does not modify the behavior of the program. In particular,
5568 prefetches cannot trap and do not produce a value. On targets that support
5569 this intrinsic, the prefetch can provide hints to the processor cache for
5570 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5571
5572</div>
5573
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5574<!-- _______________________________________________________________________ -->
5575<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5576 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5577</div>
5578
5579<div class="doc_text">
5580
5581<h5>Syntax:</h5>
5582<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5583 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5584</pre>
5585
5586<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5587<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5588 Counter (PC) in a region of code to simulators and other tools. The method
5589 is target specific, but it is expected that the marker will use exported
5590 symbols to transmit the PC of the marker. The marker makes no guarantees
5591 that it will remain with any specific instruction after optimizations. It is
5592 possible that the presence of a marker will inhibit optimizations. The
5593 intended use is to be inserted after optimizations to allow correlations of
5594 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5595
5596<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5597<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5598
5599<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5600<p>This intrinsic does not modify the behavior of the program. Backends that do
5601 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5602
5603</div>
5604
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5607 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
5613<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5614 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5615</pre>
5616
5617<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5618<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5619 counter register (or similar low latency, high accuracy clocks) on those
5620 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5621 should map to RPCC. As the backing counters overflow quickly (on the order
5622 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5623
5624<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625<p>When directly supported, reading the cycle counter should not modify any
5626 memory. Implementations are allowed to either return a application specific
5627 value or a system wide value. On backends without support, this is lowered
5628 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5629
5630</div>
5631
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5632<!-- ======================================================================= -->
5633<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5634 <a name="int_libc">Standard C Library Intrinsics</a>
5635</div>
5636
5637<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5638
5639<p>LLVM provides intrinsics for a few important standard C library functions.
5640 These intrinsics allow source-language front-ends to pass information about
5641 the alignment of the pointer arguments to the code generator, providing
5642 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5643
5644</div>
5645
5646<!-- _______________________________________________________________________ -->
5647<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5648 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +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.memcpy</tt> on any
5655 integer bit width. Not all targets support all bit widths however.</p>
5656
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5657<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5658 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5659 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5660 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5661 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5662 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5663 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5664 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5665 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5666</pre>
5667
5668<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5669<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5670 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5671
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5672<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5673 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5674
5675<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676<p>The first argument is a pointer to the destination, the second is a pointer
5677 to the source. The third argument is an integer argument specifying the
5678 number of bytes to copy, and the fourth argument is the alignment of the
5679 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5680
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5681<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5682 then the caller guarantees that both the source and destination pointers are
5683 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5684
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5685<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5686<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5687 source location to the destination location, which are not allowed to
5688 overlap. It copies "len" bytes of memory over. If the argument is known to
5689 be aligned to some boundary, this can be specified as the fourth argument,
5690 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5691
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5692</div>
5693
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5694<!-- _______________________________________________________________________ -->
5695<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5696 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5697</div>
5698
5699<div class="doc_text">
5700
5701<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5702<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]5703 width. Not all targets support all bit widths however.</p>
5704
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5705<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5706 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5707 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5708 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5709 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5710 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5711 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5712 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5713 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5714</pre>
5715
5716<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5717<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5718 source location to the destination location. It is similar to the
5719 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5720 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5721
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5723 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5726<p>The first argument is a pointer to the destination, the second is a pointer
5727 to the source. The third argument is an integer argument specifying the
5728 number of bytes to copy, and the fourth argument is the alignment of the
5729 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5730
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5731<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5732 then the caller guarantees that the source and destination pointers are
5733 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5734
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5735<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5736<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5737 source location to the destination location, which may overlap. It copies
5738 "len" bytes of memory over. If the argument is known to be aligned to some
5739 boundary, this can be specified as the fourth argument, otherwise it should
5740 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5741
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5742</div>
5743
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5744<!-- _______________________________________________________________________ -->
5745<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5746 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5747</div>
5748
5749<div class="doc_text">
5750
5751<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5752<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]5753 width. Not all targets support all bit widths however.</p>
5754
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5755<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5756 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5758 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5759 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5760 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5761 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5762 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5763 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5764</pre>
5765
5766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5768 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5769
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5770<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5771 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5772
5773<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774<p>The first argument is a pointer to the destination to fill, the second is the
5775 byte value to fill it with, the third argument is an integer argument
5776 specifying the number of bytes to fill, and the fourth argument is the known
5777 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5778
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5779<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5780 then the caller guarantees that the destination pointer is aligned to that
5781 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5782
5783<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5784<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5785 at the destination location. If the argument is known to be aligned to some
5786 boundary, this can be specified as the fourth argument, otherwise it should
5787 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5788
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789</div>
5790
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5793 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5799<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5800 floating point or vector of floating point type. Not all targets support all
5801 types however.</p>
5802
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5803<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5804 declare float @llvm.sqrt.f32(float %Val)
5805 declare double @llvm.sqrt.f64(double %Val)
5806 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5807 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5808 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5809</pre>
5810
5811<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5812<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5813 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5814 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5815 behavior for negative numbers other than -0.0 (which allows for better
5816 optimization, because there is no need to worry about errno being
5817 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]5818
5819<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The argument and return value are floating point numbers of the same
5821 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5822
5823<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5824<p>This function returns the sqrt of the specified operand if it is a
5825 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5826
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5827</div>
5828
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5829<!-- _______________________________________________________________________ -->
5830<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5831 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5832</div>
5833
5834<div class="doc_text">
5835
5836<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5837<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5838 floating point or vector of floating point type. Not all targets support all
5839 types however.</p>
5840
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5841<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5842 declare float @llvm.powi.f32(float %Val, i32 %power)
5843 declare double @llvm.powi.f64(double %Val, i32 %power)
5844 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5845 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5846 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5847</pre>
5848
5849<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5851 specified (positive or negative) power. The order of evaluation of
5852 multiplications is not defined. When a vector of floating point type is
5853 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5854
5855<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The second argument is an integer power, and the first is a value to raise to
5857 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5858
5859<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5860<p>This function returns the first value raised to the second power with an
5861 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5862
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5863</div>
5864
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5865<!-- _______________________________________________________________________ -->
5866<div class="doc_subsubsection">
5867 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5868</div>
5869
5870<div class="doc_text">
5871
5872<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5874 floating point or vector of floating point type. Not all targets support all
5875 types however.</p>
5876
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5877<pre>
5878 declare float @llvm.sin.f32(float %Val)
5879 declare double @llvm.sin.f64(double %Val)
5880 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5881 declare fp128 @llvm.sin.f128(fp128 %Val)
5882 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5887
5888<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The argument and return value are floating point numbers of the same
5890 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5891
5892<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893<p>This function returns the sine of the specified operand, returning the same
5894 values as the libm <tt>sin</tt> functions would, and handles error conditions
5895 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5896
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5897</div>
5898
5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
5901 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5907<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5908 floating point or vector of floating point type. Not all targets support all
5909 types however.</p>
5910
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5911<pre>
5912 declare float @llvm.cos.f32(float %Val)
5913 declare double @llvm.cos.f64(double %Val)
5914 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5915 declare fp128 @llvm.cos.f128(fp128 %Val)
5916 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5917</pre>
5918
5919<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5923<p>The argument and return value are floating point numbers of the same
5924 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5925
5926<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5927<p>This function returns the cosine of the specified operand, returning the same
5928 values as the libm <tt>cos</tt> functions would, and handles error conditions
5929 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5930
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5931</div>
5932
5933<!-- _______________________________________________________________________ -->
5934<div class="doc_subsubsection">
5935 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5936</div>
5937
5938<div class="doc_text">
5939
5940<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5941<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5942 floating point or vector of floating point type. Not all targets support all
5943 types however.</p>
5944
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5945<pre>
5946 declare float @llvm.pow.f32(float %Val, float %Power)
5947 declare double @llvm.pow.f64(double %Val, double %Power)
5948 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5949 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5950 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5955 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5956
5957<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The second argument is a floating point power, and the first is a value to
5959 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5962<p>This function returns the first value raised to the second power, returning
5963 the same values as the libm <tt>pow</tt> functions would, and handles error
5964 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5965
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5966</div>
5967
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5968<!-- ======================================================================= -->
5969<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5970 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5971</div>
5972
5973<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5974
5975<p>LLVM provides intrinsics for a few important bit manipulation operations.
5976 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5977
5978</div>
5979
5980<!-- _______________________________________________________________________ -->
5981<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5982 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5983</div>
5984
5985<div class="doc_text">
5986
5987<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5988<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5989 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5990
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5991<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5992 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5993 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5994 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5995</pre>
5996
5997<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5998<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5999 values with an even number of bytes (positive multiple of 16 bits). These
6000 are useful for performing operations on data that is not in the target's
6001 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6004<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6005 and low byte of the input i16 swapped. Similarly,
6006 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6007 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6008 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6009 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6010 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6011 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6012
6013</div>
6014
6015<!-- _______________________________________________________________________ -->
6016<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6017 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6018</div>
6019
6020<div class="doc_text">
6021
6022<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6023<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]6024 width. Not all targets support all bit widths however.</p>
6025
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6026<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6027 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6028 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6029 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6030 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6031 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6032</pre>
6033
6034<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6036 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6037
6038<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6039<p>The only argument is the value to be counted. The argument may be of any
6040 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6041
6042<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6043<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]6044
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6045</div>
6046
6047<!-- _______________________________________________________________________ -->
6048<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6049 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6050</div>
6051
6052<div class="doc_text">
6053
6054<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6055<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6056 integer bit width. Not all targets support all bit widths however.</p>
6057
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6058<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6059 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6060 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6061 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6062 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6063 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6064</pre>
6065
6066<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6067<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6068 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6069
6070<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6071<p>The only argument is the value to be counted. The argument may be of any
6072 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6073
6074<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6076 zeros in a variable. If the src == 0 then the result is the size in bits of
6077 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6078
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6079</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6080
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6083 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6090 integer bit width. Not all targets support all bit widths however.</p>
6091
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6092<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6093 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6094 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6095 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6096 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6097 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6098</pre>
6099
6100<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6101<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6102 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6103
6104<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6105<p>The only argument is the value to be counted. The argument may be of any
6106 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6107
6108<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6109<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6110 zeros in a variable. If the src == 0 then the result is the size in bits of
6111 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6112
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6113</div>
6114
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6115<!-- ======================================================================= -->
6116<div class="doc_subsection">
6117 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6118</div>
6119
6120<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6121
6122<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6123
6124</div>
6125
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6126<!-- _______________________________________________________________________ -->
6127<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6128 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6129</div>
6130
6131<div class="doc_text">
6132
6133<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6134<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]6135 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6136
6137<pre>
6138 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6139 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6140 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6141</pre>
6142
6143<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6144<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6145 a signed addition of the two arguments, and indicate whether an overflow
6146 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6147
6148<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6149<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]6150 be of integer types of any bit width, but they must have the same bit
6151 width. The second element of the result structure must be of
6152 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6153 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6156<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6157 a signed addition of the two variables. They return a structure &mdash; the
6158 first element of which is the signed summation, and the second element of
6159 which is a bit specifying if the signed summation resulted in an
6160 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Examples:</h5>
6163<pre>
6164 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6165 %sum = extractvalue {i32, i1} %res, 0
6166 %obit = extractvalue {i32, i1} %res, 1
6167 br i1 %obit, label %overflow, label %normal
6168</pre>
6169
6170</div>
6171
6172<!-- _______________________________________________________________________ -->
6173<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6174 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6175</div>
6176
6177<div class="doc_text">
6178
6179<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6180<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]6181 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182
6183<pre>
6184 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6185 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6186 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6187</pre>
6188
6189<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6190<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6191 an unsigned addition of the two arguments, and indicate whether a carry
6192 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6193
6194<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6195<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]6196 be of integer types of any bit width, but they must have the same bit
6197 width. The second element of the result structure must be of
6198 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6199 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6202<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6203 an unsigned addition of the two arguments. They return a structure &mdash;
6204 the first element of which is the sum, and the second element of which is a
6205 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6206
6207<h5>Examples:</h5>
6208<pre>
6209 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6210 %sum = extractvalue {i32, i1} %res, 0
6211 %obit = extractvalue {i32, i1} %res, 1
6212 br i1 %obit, label %carry, label %normal
6213</pre>
6214
6215</div>
6216
6217<!-- _______________________________________________________________________ -->
6218<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6219 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6220</div>
6221
6222<div class="doc_text">
6223
6224<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6225<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]6226 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6227
6228<pre>
6229 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6230 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6231 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6232</pre>
6233
6234<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6235<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6236 a signed subtraction of the two arguments, and indicate whether an overflow
6237 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6238
6239<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6240<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]6241 be of integer types of any bit width, but they must have the same bit
6242 width. The second element of the result structure must be of
6243 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6244 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6247<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6248 a signed subtraction of the two arguments. They return a structure &mdash;
6249 the first element of which is the subtraction, and the second element of
6250 which is a bit specifying if the signed subtraction resulted in an
6251 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Examples:</h5>
6254<pre>
6255 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6256 %sum = extractvalue {i32, i1} %res, 0
6257 %obit = extractvalue {i32, i1} %res, 1
6258 br i1 %obit, label %overflow, label %normal
6259</pre>
6260
6261</div>
6262
6263<!-- _______________________________________________________________________ -->
6264<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6265 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6266</div>
6267
6268<div class="doc_text">
6269
6270<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6271<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]6272 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273
6274<pre>
6275 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6276 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6277 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6278</pre>
6279
6280<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6281<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6282 an unsigned subtraction of the two arguments, and indicate whether an
6283 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6284
6285<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6286<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]6287 be of integer types of any bit width, but they must have the same bit
6288 width. The second element of the result structure must be of
6289 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6290 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6291
6292<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6293<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6294 an unsigned subtraction of the two arguments. They return a structure &mdash;
6295 the first element of which is the subtraction, and the second element of
6296 which is a bit specifying if the unsigned subtraction resulted in an
6297 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6298
6299<h5>Examples:</h5>
6300<pre>
6301 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6302 %sum = extractvalue {i32, i1} %res, 0
6303 %obit = extractvalue {i32, i1} %res, 1
6304 br i1 %obit, label %overflow, label %normal
6305</pre>
6306
6307</div>
6308
6309<!-- _______________________________________________________________________ -->
6310<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6311 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6312</div>
6313
6314<div class="doc_text">
6315
6316<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6317<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]6318 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319
6320<pre>
6321 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6322 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6323 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6324</pre>
6325
6326<h5>Overview:</h5>
6327
6328<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6329 a signed multiplication of the two arguments, and indicate whether an
6330 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6331
6332<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6333<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]6334 be of integer types of any bit width, but they must have the same bit
6335 width. The second element of the result structure must be of
6336 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6337 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6340<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6341 a signed multiplication of the two arguments. They return a structure &mdash;
6342 the first element of which is the multiplication, and the second element of
6343 which is a bit specifying if the signed multiplication resulted in an
6344 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Examples:</h5>
6347<pre>
6348 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6349 %sum = extractvalue {i32, i1} %res, 0
6350 %obit = extractvalue {i32, i1} %res, 1
6351 br i1 %obit, label %overflow, label %normal
6352</pre>
6353
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6354</div>
6355
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6356<!-- _______________________________________________________________________ -->
6357<div class="doc_subsubsection">
6358 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6359</div>
6360
6361<div class="doc_text">
6362
6363<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6364<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]6365 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6366
6367<pre>
6368 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6369 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6370 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6371</pre>
6372
6373<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6374<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6375 a unsigned multiplication of the two arguments, and indicate whether an
6376 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6377
6378<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6379<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]6380 be of integer types of any bit width, but they must have the same bit
6381 width. The second element of the result structure must be of
6382 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6383 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6384
6385<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6386<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6387 an unsigned multiplication of the two arguments. They return a structure
6388 &mdash; the first element of which is the multiplication, and the second
6389 element of which is a bit specifying if the unsigned multiplication resulted
6390 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6391
6392<h5>Examples:</h5>
6393<pre>
6394 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6395 %sum = extractvalue {i32, i1} %res, 0
6396 %obit = extractvalue {i32, i1} %res, 1
6397 br i1 %obit, label %overflow, label %normal
6398</pre>
6399
6400</div>
6401
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6402<!-- ======================================================================= -->
6403<div class="doc_subsection">
6404 <a name="int_debugger">Debugger Intrinsics</a>
6405</div>
6406
6407<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6408
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6409<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6410 prefix), are described in
6411 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6412 Level Debugging</a> document.</p>
6413
6414</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6415
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6416<!-- ======================================================================= -->
6417<div class="doc_subsection">
6418 <a name="int_eh">Exception Handling Intrinsics</a>
6419</div>
6420
6421<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6422
6423<p>The LLVM exception handling intrinsics (which all start with
6424 <tt>llvm.eh.</tt> prefix), are described in
6425 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6426 Handling</a> document.</p>
6427
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6428</div>
6429
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6430<!-- ======================================================================= -->
6431<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6432 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6436
6437<p>This intrinsic makes it possible to excise one parameter, marked with
6438 the <tt>nest</tt> attribute, from a function. The result is a callable
6439 function pointer lacking the nest parameter - the caller does not need to
6440 provide a value for it. Instead, the value to use is stored in advance in a
6441 "trampoline", a block of memory usually allocated on the stack, which also
6442 contains code to splice the nest value into the argument list. This is used
6443 to implement the GCC nested function address extension.</p>
6444
6445<p>For example, if the function is
6446 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6447 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6448 follows:</p>
6449
6450<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6451<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6452 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6453 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6454 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6455 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6456</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6457</div>
6458
6459<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6460 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6461
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6462</div>
6463
6464<!-- _______________________________________________________________________ -->
6465<div class="doc_subsubsection">
6466 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6467</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6468
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6469<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6470
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6471<h5>Syntax:</h5>
6472<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6473 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]6474</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6475
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6476<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6477<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6478 function pointer suitable for executing it.</p>
6479
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6480<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6481<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6482 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6483 sufficiently aligned block of memory; this memory is written to by the
6484 intrinsic. Note that the size and the alignment are target-specific - LLVM
6485 currently provides no portable way of determining them, so a front-end that
6486 generates this intrinsic needs to have some target-specific knowledge.
6487 The <tt>func</tt> argument must hold a function bitcast to
6488 an <tt>i8*</tt>.</p>
6489
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6490<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6491<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6492 dependent code, turning it into a function. A pointer to this function is
6493 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6494 function pointer type</a> before being called. The new function's signature
6495 is the same as that of <tt>func</tt> with any arguments marked with
6496 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6497 is allowed, and it must be of pointer type. Calling the new function is
6498 equivalent to calling <tt>func</tt> with the same argument list, but
6499 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6500 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6501 by <tt>tramp</tt> is modified, then the effect of any later call to the
6502 returned function pointer is undefined.</p>
6503
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6504</div>
6505
6506<!-- ======================================================================= -->
6507<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6508 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6509</div>
6510
6511<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6512
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6513<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6514 hardware constructs for atomic operations and memory synchronization. This
6515 provides an interface to the hardware, not an interface to the programmer. It
6516 is aimed at a low enough level to allow any programming models or APIs
6517 (Application Programming Interfaces) which need atomic behaviors to map
6518 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6519 hardware provides a "universal IR" for source languages, it also provides a
6520 starting point for developing a "universal" atomic operation and
6521 synchronization IR.</p>
6522
6523<p>These do <em>not</em> form an API such as high-level threading libraries,
6524 software transaction memory systems, atomic primitives, and intrinsic
6525 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6526 application libraries. The hardware interface provided by LLVM should allow
6527 a clean implementation of all of these APIs and parallel programming models.
6528 No one model or paradigm should be selected above others unless the hardware
6529 itself ubiquitously does so.</p>
6530
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6531</div>
6532
6533<!-- _______________________________________________________________________ -->
6534<div class="doc_subsubsection">
6535 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6536</div>
6537<div class="doc_text">
6538<h5>Syntax:</h5>
6539<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6540 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]6541</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6542
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6543<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6545 specific pairs of memory access types.</p>
6546
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6547<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6548<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6549 The first four arguments enables a specific barrier as listed below. The
6550 fith argument specifies that the barrier applies to io or device or uncached
6551 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6552
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6553<ul>
6554 <li><tt>ll</tt>: load-load barrier</li>
6555 <li><tt>ls</tt>: load-store barrier</li>
6556 <li><tt>sl</tt>: store-load barrier</li>
6557 <li><tt>ss</tt>: store-store barrier</li>
6558 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6559</ul>
6560
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6561<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6562<p>This intrinsic causes the system to enforce some ordering constraints upon
6563 the loads and stores of the program. This barrier does not
6564 indicate <em>when</em> any events will occur, it only enforces
6565 an <em>order</em> in which they occur. For any of the specified pairs of load
6566 and store operations (f.ex. load-load, or store-load), all of the first
6567 operations preceding the barrier will complete before any of the second
6568 operations succeeding the barrier begin. Specifically the semantics for each
6569 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6570
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6571<ul>
6572 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6573 after the barrier begins.</li>
6574 <li><tt>ls</tt>: All loads before the barrier must complete before any
6575 store after the barrier begins.</li>
6576 <li><tt>ss</tt>: All stores before the barrier must complete before any
6577 store after the barrier begins.</li>
6578 <li><tt>sl</tt>: All stores before the barrier must complete before any
6579 load after the barrier begins.</li>
6580</ul>
6581
6582<p>These semantics are applied with a logical "and" behavior when more than one
6583 is enabled in a single memory barrier intrinsic.</p>
6584
6585<p>Backends may implement stronger barriers than those requested when they do
6586 not support as fine grained a barrier as requested. Some architectures do
6587 not need all types of barriers and on such architectures, these become
6588 noops.</p>
6589
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6590<h5>Example:</h5>
6591<pre>
6592%ptr = malloc i32
6593 store i32 4, %ptr
6594
6595%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6596 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6597 <i>; guarantee the above finishes</i>
6598 store i32 8, %ptr <i>; before this begins</i>
6599</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6600
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6601</div>
6602
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6603<!-- _______________________________________________________________________ -->
6604<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6605 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6606</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6607
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6608<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6610<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6611<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6612 any integer bit width and for different address spaces. Not all targets
6613 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6614
6615<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6616 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6617 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6618 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6619 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]6620</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6621
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6622<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6623<p>This loads a value in memory and compares it to a given value. If they are
6624 equal, it stores a new value into the memory.</p>
6625
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6626<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6627<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6628 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6629 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6630 this integer type. While any bit width integer may be used, targets may only
6631 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6632
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6633<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634<p>This entire intrinsic must be executed atomically. It first loads the value
6635 in memory pointed to by <tt>ptr</tt> and compares it with the
6636 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6637 memory. The loaded value is yielded in all cases. This provides the
6638 equivalent of an atomic compare-and-swap operation within the SSA
6639 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6640
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6642<pre>
6643%ptr = malloc i32
6644 store i32 4, %ptr
6645
6646%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6647%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6648 <i>; yields {i32}:result1 = 4</i>
6649%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6650%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6651
6652%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6653%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6654 <i>; yields {i32}:result2 = 8</i>
6655%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6656
6657%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6659
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6660</div>
6661
6662<!-- _______________________________________________________________________ -->
6663<div class="doc_subsubsection">
6664 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6665</div>
6666<div class="doc_text">
6667<h5>Syntax:</h5>
6668
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6669<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6670 integer bit width. Not all targets support all bit widths however.</p>
6671
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6672<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6673 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6674 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6675 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6676 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]6677</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6678
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6679<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6680<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6681 the value from memory. It then stores the value in <tt>val</tt> in the memory
6682 at <tt>ptr</tt>.</p>
6683
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6684<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6685<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6686 the <tt>val</tt> argument and the result must be integers of the same bit
6687 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6688 integer type. The targets may only lower integer representations they
6689 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6690
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6691<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6692<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6693 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6694 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6695
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6696<h5>Examples:</h5>
6697<pre>
6698%ptr = malloc i32
6699 store i32 4, %ptr
6700
6701%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6702%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6703 <i>; yields {i32}:result1 = 4</i>
6704%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6705%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6706
6707%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6708%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6709 <i>; yields {i32}:result2 = 8</i>
6710
6711%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6712%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6713</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6714
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6715</div>
6716
6717<!-- _______________________________________________________________________ -->
6718<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6719 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6720
6721</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6722
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6723<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6724
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6725<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6726<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6727 any integer bit width. Not all targets support all bit widths however.</p>
6728
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6729<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6730 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6731 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6732 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6733 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]6734</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6735
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6736<h5>Overview:</h5>
6737<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6738 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6739
6740<h5>Arguments:</h5>
6741<p>The intrinsic takes two arguments, the first a pointer to an integer value
6742 and the second an integer value. The result is also an integer value. These
6743 integer types can have any bit width, but they must all have the same bit
6744 width. The targets may only lower integer representations they support.</p>
6745
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6746<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6747<p>This intrinsic does a series of operations atomically. It first loads the
6748 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6749 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]6750
6751<h5>Examples:</h5>
6752<pre>
6753%ptr = malloc i32
6754 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6755%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6756 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6757%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6758 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6759%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6760 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6761%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6762</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6763
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6764</div>
6765
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
6767<div class="doc_subsubsection">
6768 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6769
6770</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6771
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6772<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6773
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6774<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6775<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6776 any integer bit width and for different address spaces. Not all targets
6777 support all bit widths however.</p>
6778
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6779<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6780 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6781 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6782 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6783 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]6784</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6786<h5>Overview:</h5>
6787<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6788 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6789
6790<h5>Arguments:</h5>
6791<p>The intrinsic takes two arguments, the first a pointer to an integer value
6792 and the second an integer value. The result is also an integer value. These
6793 integer types can have any bit width, but they must all have the same bit
6794 width. The targets may only lower integer representations they support.</p>
6795
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6796<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6797<p>This intrinsic does a series of operations atomically. It first loads the
6798 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6799 result to <tt>ptr</tt>. It yields the original value stored
6800 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6801
6802<h5>Examples:</h5>
6803<pre>
6804%ptr = malloc i32
6805 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6806%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6807 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6808%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6809 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6810%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6811 <i>; yields {i32}:result3 = 2</i>
6812%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6813</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6814
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6815</div>
6816
6817<!-- _______________________________________________________________________ -->
6818<div class="doc_subsubsection">
6819 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6820 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6821 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6822 <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]6823</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6824
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6825<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6826
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6827<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6828<p>These are overloaded intrinsics. You can
6829 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6830 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6831 bit width and for different address spaces. Not all targets support all bit
6832 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6834<pre>
6835 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6836 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6837 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6838 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]6839</pre>
6840
6841<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6842 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6843 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6844 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6845 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]6846</pre>
6847
6848<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6849 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6850 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6851 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6852 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]6853</pre>
6854
6855<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6856 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859 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]6860</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6861
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6862<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6864 the value stored in memory at <tt>ptr</tt>. It yields the original value
6865 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6866
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6867<h5>Arguments:</h5>
6868<p>These intrinsics take two arguments, the first a pointer to an integer value
6869 and the second an integer value. The result is also an integer value. These
6870 integer types can have any bit width, but they must all have the same bit
6871 width. The targets may only lower integer representations they support.</p>
6872
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6873<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6874<p>These intrinsics does a series of operations atomically. They first load the
6875 value stored at <tt>ptr</tt>. They then do the bitwise
6876 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6877 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6878
6879<h5>Examples:</h5>
6880<pre>
6881%ptr = malloc i32
6882 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6883%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6884 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6885%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6886 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6887%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6888 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6889%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6890 <i>; yields {i32}:result3 = FF</i>
6891%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6892</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6893
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6894</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6895
6896<!-- _______________________________________________________________________ -->
6897<div class="doc_subsubsection">
6898 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6899 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6900 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6901 <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]6902</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6903
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6904<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6905
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6906<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6908 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6909 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6910 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6911
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912<pre>
6913 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6914 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6915 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6916 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]6917</pre>
6918
6919<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6920 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6921 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6922 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6923 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]6924</pre>
6925
6926<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6927 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 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]6931</pre>
6932
6933<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 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]6938</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6939
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6940<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941<p>These intrinsics takes the signed or unsigned minimum or maximum of
6942 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6943 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6944
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945<h5>Arguments:</h5>
6946<p>These intrinsics take two arguments, the first a pointer to an integer value
6947 and the second an integer value. The result is also an integer value. These
6948 integer types can have any bit width, but they must all have the same bit
6949 width. The targets may only lower integer representations they support.</p>
6950
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6951<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952<p>These intrinsics does a series of operations atomically. They first load the
6953 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6954 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6955 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6956
6957<h5>Examples:</h5>
6958<pre>
6959%ptr = malloc i32
6960 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6961%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6962 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6963%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6964 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6965%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6966 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6967%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6968 <i>; yields {i32}:result3 = 8</i>
6969%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6970</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6971
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6972</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6973
6974<!-- ======================================================================= -->
6975<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6976 <a name="int_general">General Intrinsics</a>
6977</div>
6978
6979<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6980
6981<p>This class of intrinsics is designed to be generic and has no specific
6982 purpose.</p>
6983
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
6987<div class="doc_subsubsection">
6988 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6989</div>
6990
6991<div class="doc_text">
6992
6993<h5>Syntax:</h5>
6994<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]6995 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]6996</pre>
6997
6998<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6999<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7000
7001<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7002<p>The first argument is a pointer to a value, the second is a pointer to a
7003 global string, the third is a pointer to a global string which is the source
7004 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7005
7006<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7007<p>This intrinsic allows annotation of local variables with arbitrary strings.
7008 This can be useful for special purpose optimizations that want to look for
7009 these annotations. These have no other defined use, they are ignored by code
7010 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7011
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7012</div>
7013
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7014<!-- _______________________________________________________________________ -->
7015<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7016 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7017</div>
7018
7019<div class="doc_text">
7020
7021<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7022<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7023 any integer bit width.</p>
7024
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7025<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7026 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7027 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7028 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7029 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7030 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]7031</pre>
7032
7033<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7034<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7037<p>The first argument is an integer value (result of some expression), the
7038 second is a pointer to a global string, the third is a pointer to a global
7039 string which is the source file name, and the last argument is the line
7040 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7041
7042<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7043<p>This intrinsic allows annotations to be put on arbitrary expressions with
7044 arbitrary strings. This can be useful for special purpose optimizations that
7045 want to look for these annotations. These have no other defined use, they
7046 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7047
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7048</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7049
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7050<!-- _______________________________________________________________________ -->
7051<div class="doc_subsubsection">
7052 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7053</div>
7054
7055<div class="doc_text">
7056
7057<h5>Syntax:</h5>
7058<pre>
7059 declare void @llvm.trap()
7060</pre>
7061
7062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7063<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7064
7065<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7066<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7067
7068<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7069<p>This intrinsics is lowered to the target dependent trap instruction. If the
7070 target does not have a trap instruction, this intrinsic will be lowered to
7071 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7072
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7073</div>
7074
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7075<!-- _______________________________________________________________________ -->
7076<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7077 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7078</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7079
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7080<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7082<h5>Syntax:</h5>
7083<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7084 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7085</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7086
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7087<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7088<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7089 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7090 ensure that it is placed on the stack before local variables.</p>
7091
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7092<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7093<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7094 arguments. The first argument is the value loaded from the stack
7095 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7096 that has enough space to hold the value of the guard.</p>
7097
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7098<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7099<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7100 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7101 stack. This is to ensure that if a local variable on the stack is
7102 overwritten, it will destroy the value of the guard. When the function exits,
7103 the guard on the stack is checked against the original guard. If they're
7104 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7105 function.</p>
7106
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7107</div>
7108
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7109<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7110<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7111<address>
7112 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7113 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7114 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7115 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]7116
7117 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7118 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7119 Last modified: $Date$
7120</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7121
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7122</body>
7123</html>