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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 9f8380b42532c10cab5eb8616f962e10828e765f / . / 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 Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2024<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]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
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2061such, it is unsafe to optimize or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef could be 0, and
2063optimize the and to 0. Likewise, it is safe to assume that all the bits of
2064the undef operand to the or could be set, allowing the or to be folded to
2065-1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2066
2067<div class="doc_code">
2068<pre>
2069 %A = select undef, %X, %Y
2070 %B = select undef, 42, %Y
2071 %C = select %X, %Y, undef
2072Safe:
2073 %A = %X (or %Y)
2074 %B = 42 (or %Y)
2075 %C = %Y
2076Unsafe:
2077 %A = undef
2078 %B = undef
2079 %C = undef
2080</pre>
2081</div>
2082
2083<p>This set of examples show that undefined select (and conditional branch)
2084conditions can go "either way" but they have to come from one of the two
2085operands. In the %A example, if %X and %Y were both known to have a clear low
2086bit, then %A would have to have a cleared low bit. However, in the %C example,
2087the optimizer is allowed to assume that the undef operand could be the same as
2088%Y, allowing the whole select to be eliminated.</p>
2089
2090
2091<div class="doc_code">
2092<pre>
2093 %A = xor undef, undef
2094
2095 %B = undef
2096 %C = xor %B, %B
2097
2098 %D = undef
2099 %E = icmp lt %D, 4
2100 %F = icmp gte %D, 4
2101
2102Safe:
2103 %A = undef
2104 %B = undef
2105 %C = undef
2106 %D = undef
2107 %E = undef
2108 %F = undef
2109</pre>
2110</div>
2111
2112<p>This example points out that two undef operands are not necessarily the same.
2113This can be surprising to people (and also matches C semantics) where they
2114assume that "X^X" is always zero, even if X is undef. This isn't true for a
2115number of reasons, but the short answer is that an undef "variable" can
2116arbitrarily change its value over its "live range". This is true because the
2117"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2118logically read from arbitrary registers that happen to be around when needed,
2119so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattner349eb412009-09-08 15:13:16 +0000[diff] [blame]2120to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2121would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2122
2123<div class="doc_code">
2124<pre>
2125 %A = fdiv undef, %X
2126 %B = fdiv %X, undef
2127Safe:
2128 %A = undef
2129b: unreachable
2130</pre>
2131</div>
2132
2133<p>These examples show the crucial difference between an <em>undefined
2134value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2135allowed to have an arbitrary bit-pattern. This means that the %A operation
2136can be constant folded to undef because the undef could be an SNaN, and fdiv is
2137not (currently) defined on SNaN's. However, in the second example, we can make
2138a more aggressive assumption: because the undef is allowed to be an arbitrary
2139value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner8e371aa2009-09-08 19:45:34 +0000[diff] [blame]2140has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2141does not execute at all. This allows us to delete the divide and all code after
2142it: since the undefined operation "can't happen", the optimizer can assume that
2143it occurs in dead code.
2144</p>
2145
2146<div class="doc_code">
2147<pre>
2148a: store undef -> %X
2149b: store %X -> undef
2150Safe:
2151a: &lt;deleted&gt;
2152b: unreachable
2153</pre>
2154</div>
2155
2156<p>These examples reiterate the fdiv example: a store "of" an undefined value
2157can be assumed to not have any effect: we can assume that the value is
2158overwritten with bits that happen to match what was already there. However, a
2159store "to" an undefined location could clobber arbitrary memory, therefore, it
2160has undefined behavior.</p>
2161
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2162</div>
2163
2164<!-- ======================================================================= -->
2165<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2166</div>
2167
2168<div class="doc_text">
2169
2170<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2171 to be used as constants. Constant expressions may be of
2172 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2173 operation that does not have side effects (e.g. load and call are not
2174 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2175
2176<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2177 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2178 <dd>Truncate a constant to another type. The bit size of CST must be larger
2179 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2180
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2181 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2182 <dd>Zero extend a constant to another type. The bit size of CST must be
2183 smaller or equal to the bit size of TYPE. Both types must be
2184 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2185
2186 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2187 <dd>Sign extend a constant to another type. The bit size of CST must be
2188 smaller or equal to the bit size of TYPE. Both types must be
2189 integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2190
2191 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Truncate a floating point constant to another floating point type. The
2193 size of CST must be larger than the size of TYPE. Both types must be
2194 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2195
2196 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Floating point extend a constant to another type. The size of CST must be
2198 smaller or equal to the size of TYPE. Both types must be floating
2199 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2200
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]2201 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2202 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2203 constant. TYPE must be a scalar or vector integer type. CST must be of
2204 scalar or vector floating point type. Both CST and TYPE must be scalars,
2205 or vectors of the same number of elements. If the value won't fit in the
2206 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2207
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2208 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2209 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2210 constant. TYPE must be a scalar or vector integer type. CST must be of
2211 scalar or vector floating point type. Both CST and TYPE must be scalars,
2212 or vectors of the same number of elements. If the value won't fit in the
2213 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2214
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2215 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2216 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2217 constant. TYPE must be a scalar or vector floating point type. CST must be
2218 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2219 vectors of the same number of elements. If the value won't fit in the
2220 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2221
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2222 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2223 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2224 constant. TYPE must be a scalar or vector floating point type. CST must be
2225 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2226 vectors of the same number of elements. If the value won't fit in the
2227 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2228
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2229 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2230 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2231 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2232 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2233 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2234
2235 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2236 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2237 type. CST must be of integer type. The CST value is zero extended,
2238 truncated, or unchanged to make it fit in a pointer size. This one is
2239 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2240
2241 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2242 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2243 are the same as those for the <a href="#i_bitcast">bitcast
2244 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2245
2246 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]2247 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2248 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2249 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2250 instruction, the index list may have zero or more indexes, which are
2251 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2252
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2253 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2254 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2255
2256 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2257 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2258
2259 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2260 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2261
2262 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2263 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2264 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2265
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2266 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2267 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2268 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2269
2270 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2271 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2272 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2273
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2274 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2275 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2276 be any of the <a href="#binaryops">binary</a>
2277 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2278 on operands are the same as those for the corresponding instruction
2279 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2280</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2281
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2282</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2283
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2284<!-- ======================================================================= -->
2285<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2286</div>
2287
2288<div class="doc_text">
2289
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2290<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2291 stream without affecting the behaviour of the program. There are two
2292 metadata primitives, strings and nodes. All metadata has the
2293 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2294 point ('<tt>!</tt>').</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2295
2296<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2297 any character by escaping non-printable characters with "\xx" where "xx" is
2298 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2299
2300<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2301 (a comma separated list of elements, surrounded by braces and preceeded by an
2302 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2303 10}</tt>".</p>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2304
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2305<p>A metadata node will attempt to track changes to the values it holds. In the
2306 event that a value is deleted, it will be replaced with a typeless
2307 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckycb337992009-05-10 20:57:05 +0000[diff] [blame]2308
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2309<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2310 the program that isn't available in the instructions, or that isn't easily
2311 computable. Similarly, the code generator may expect a certain metadata
2312 format to be used to express debugging information.</p>
2313
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2314</div>
2315
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2316<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2317<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2318<!-- *********************************************************************** -->
2319
2320<!-- ======================================================================= -->
2321<div class="doc_subsection">
2322<a name="inlineasm">Inline Assembler Expressions</a>
2323</div>
2324
2325<div class="doc_text">
2326
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2327<p>LLVM supports inline assembler expressions (as opposed
2328 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2329 a special value. This value represents the inline assembler as a string
2330 (containing the instructions to emit), a list of operand constraints (stored
2331 as a string), and a flag that indicates whether or not the inline asm
2332 expression has side effects. An example inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2333
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2334<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2335<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2336i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2337</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2338</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2339
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2340<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2341 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2342 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2343
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2344<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2345<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2346%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]2347</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2348</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2349
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2350<p>Inline asms with side effects not visible in the constraint list must be
2351 marked as having side effects. This is done through the use of the
2352 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2353
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2354<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2355<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2356call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2357</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2358</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2359
2360<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2361 documented here. Constraints on what can be done (e.g. duplication, moving,
2362 etc need to be documented). This is probably best done by reference to
2363 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2364
2365</div>
2366
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2367
2368<!-- *********************************************************************** -->
2369<div class="doc_section">
2370 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2371</div>
2372<!-- *********************************************************************** -->
2373
2374<p>LLVM has a number of "magic" global variables that contain data that affect
2375code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2376of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2377section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2378by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2379
2380<!-- ======================================================================= -->
2381<div class="doc_subsection">
2382<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2383</div>
2384
2385<div class="doc_text">
2386
2387<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2388href="#linkage_appending">appending linkage</a>. This array contains a list of
2389pointers to global variables and functions which may optionally have a pointer
2390cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2391
2392<pre>
2393 @X = global i8 4
2394 @Y = global i32 123
2395
2396 @llvm.used = appending global [2 x i8*] [
2397 i8* @X,
2398 i8* bitcast (i32* @Y to i8*)
2399 ], section "llvm.metadata"
2400</pre>
2401
2402<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2403compiler, assembler, and linker are required to treat the symbol as if there is
2404a reference to the global that it cannot see. For example, if a variable has
2405internal linkage and no references other than that from the <tt>@llvm.used</tt>
2406list, it cannot be deleted. This is commonly used to represent references from
2407inline asms and other things the compiler cannot "see", and corresponds to
2408"attribute((used))" in GNU C.</p>
2409
2410<p>On some targets, the code generator must emit a directive to the assembler or
2411object file to prevent the assembler and linker from molesting the symbol.</p>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
2416<div class="doc_subsection">
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]2417<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2418</div>
2419
2420<div class="doc_text">
2421
2422<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2423<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2424touching the symbol. On targets that support it, this allows an intelligent
2425linker to optimize references to the symbol without being impeded as it would be
2426by <tt>@llvm.used</tt>.</p>
2427
2428<p>This is a rare construct that should only be used in rare circumstances, and
2429should not be exposed to source languages.</p>
2430
2431</div>
2432
2433<!-- ======================================================================= -->
2434<div class="doc_subsection">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]2435<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2436</div>
2437
2438<div class="doc_text">
2439
2440<p>TODO: Describe this.</p>
2441
2442</div>
2443
2444<!-- ======================================================================= -->
2445<div class="doc_subsection">
2446<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2447</div>
2448
2449<div class="doc_text">
2450
2451<p>TODO: Describe this.</p>
2452
2453</div>
2454
2455
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2456<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2457<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2458<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2460<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2461
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2462<p>The LLVM instruction set consists of several different classifications of
2463 instructions: <a href="#terminators">terminator
2464 instructions</a>, <a href="#binaryops">binary instructions</a>,
2465 <a href="#bitwiseops">bitwise binary instructions</a>,
2466 <a href="#memoryops">memory instructions</a>, and
2467 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2469</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2471<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2472<div class="doc_subsection"> <a name="terminators">Terminator
2473Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2474
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2475<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2476
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2477<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2478 in a program ends with a "Terminator" instruction, which indicates which
2479 block should be executed after the current block is finished. These
2480 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2481 control flow, not values (the one exception being the
2482 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2483
2484<p>There are six different terminator instructions: the
2485 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2486 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2487 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2488 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2489 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2490 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2491
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2492</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2493
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2494<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2495<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2496Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2498<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2500<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2501<pre>
2502 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]2503 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2504</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2505
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2506<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2507<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2508 a value) from a function back to the caller.</p>
2509
2510<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2511 value and then causes control flow, and one that just causes control flow to
2512 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2513
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2514<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2515<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2516 return value. The type of the return value must be a
2517 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]2518
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2519<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2520 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2521 value or a return value with a type that does not match its type, or if it
2522 has a void return type and contains a '<tt>ret</tt>' instruction with a
2523 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2525<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2526<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2527 the calling function's context. If the caller is a
2528 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2529 instruction after the call. If the caller was an
2530 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2531 the beginning of the "normal" destination block. If the instruction returns
2532 a value, that value shall set the call or invoke instruction's return
2533 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2534
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2536<pre>
2537 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2538 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]2539 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]2540</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2541
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2542<p>Note that the code generator does not yet fully support large
2543 return values. The specific sizes that are currently supported are
2544 dependent on the target. For integers, on 32-bit targets the limit
2545 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2546 For aggregate types, the current limits are dependent on the element
2547 types; for example targets are often limited to 2 total integer
2548 elements and 2 total floating-point elements.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]2549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2551<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2552<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2553
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2554<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2555
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2557<pre>
2558 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]2559</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2560
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2561<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2562<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2563 different basic block in the current function. There are two forms of this
2564 instruction, corresponding to a conditional branch and an unconditional
2565 branch.</p>
2566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2568<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2569 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2570 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2571 target.</p>
2572
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2573<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2574<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2575 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2576 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2577 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2578
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2580<pre>
2581Test:
2582 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2583 br i1 %cond, label %IfEqual, label %IfUnequal
2584IfEqual:
2585 <a href="#i_ret">ret</a> i32 1
2586IfUnequal:
2587 <a href="#i_ret">ret</a> i32 0
2588</pre>
2589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2590</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2592<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2593<div class="doc_subsubsection">
2594 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2595</div>
2596
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2597<div class="doc_text">
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2598
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2599<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2600<pre>
2601 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2602</pre>
2603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2604<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2605<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]2606 several different places. It is a generalization of the '<tt>br</tt>'
2607 instruction, allowing a branch to occur to one of many possible
2608 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2609
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2610<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2611<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2612 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2613 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2614 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2615
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2616<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2617<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2618 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2619 is searched for the given value. If the value is found, control flow is
2620 transfered to the corresponding destination; otherwise, control flow is
2621 transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2622
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2623<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2624<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2625 <tt>switch</tt> instruction, this instruction may be code generated in
2626 different ways. For example, it could be generated as a series of chained
2627 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2628
2629<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2630<pre>
2631 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2632 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2633 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2634
2635 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2636 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]2637
2638 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2639 switch i32 %val, label %otherwise [ i32 0, label %onzero
2640 i32 1, label %onone
2641 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2642</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2643
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2644</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2646<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2647<div class="doc_subsubsection">
2648 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2649</div>
2650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2651<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2654<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2655 &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]2656 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2657</pre>
2658
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2659<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2660<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2661 function, with the possibility of control flow transfer to either the
2662 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2663 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2664 control flow will return to the "normal" label. If the callee (or any
2665 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2666 instruction, control is interrupted and continued at the dynamically nearest
2667 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2670<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2671
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2672<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2673 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2674 convention</a> the call should use. If none is specified, the call
2675 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2676
2677 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2678 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2679 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]2680
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2681 <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]2682 function value being invoked. In most cases, this is a direct function
2683 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2684 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2685
2686 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2687 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2688
2689 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2690 signature argument types. If the function signature indicates the
2691 function accepts a variable number of arguments, the extra arguments can
2692 be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2693
2694 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2695 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2696
2697 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2698 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2699
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]2700 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2701 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2702 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2703</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2704
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2705<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2706<p>This instruction is designed to operate as a standard
2707 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2708 primary difference is that it establishes an association with a label, which
2709 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2710
2711<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2712 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2713 exception. Additionally, this is important for implementation of
2714 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2715
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2716<p>For the purposes of the SSA form, the definition of the value returned by the
2717 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2718 block to the "normal" label. If the callee unwinds then no return value is
2719 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]2720
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2721<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2722<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2723 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2724 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2725 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2726 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2727</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2728
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2729</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2730
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2731<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2732
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2733<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2734Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2735
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2736<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2737
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2738<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2739<pre>
2740 unwind
2741</pre>
2742
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2743<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2744<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2745 at the first callee in the dynamic call stack which used
2746 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2747 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2748
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2749<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2750<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2751 immediately halt. The dynamic call stack is then searched for the
2752 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2753 Once found, execution continues at the "exceptional" destination block
2754 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2755 instruction in the dynamic call chain, undefined behavior results.</p>
2756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2757</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2758
2759<!-- _______________________________________________________________________ -->
2760
2761<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2762Instruction</a> </div>
2763
2764<div class="doc_text">
2765
2766<h5>Syntax:</h5>
2767<pre>
2768 unreachable
2769</pre>
2770
2771<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2772<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2773 instruction is used to inform the optimizer that a particular portion of the
2774 code is not reachable. This can be used to indicate that the code after a
2775 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2776
2777<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2778<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2779
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2780</div>
2781
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2782<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2783<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2785<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786
2787<p>Binary operators are used to do most of the computation in a program. They
2788 require two operands of the same type, execute an operation on them, and
2789 produce a single value. The operands might represent multiple data, as is
2790 the case with the <a href="#t_vector">vector</a> data type. The result value
2791 has the same type as its operands.</p>
2792
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2793<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2794
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2795</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2797<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2798<div class="doc_subsubsection">
2799 <a name="i_add">'<tt>add</tt>' Instruction</a>
2800</div>
2801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2803
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2804<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2805<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2806 &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]2807 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2808 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2809 &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]2810</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2812<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2813<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2814
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2815<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2816<p>The two arguments to the '<tt>add</tt>' instruction must
2817 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2818 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2820<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2821<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2822
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2823<p>If the sum has unsigned overflow, the result returned is the mathematical
2824 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]2825
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2826<p>Because LLVM integers use a two's complement representation, this instruction
2827 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2828
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2829<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2830 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2831 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2832 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2835<pre>
2836 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2837</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2839</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2841<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2842<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2843 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2844</div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2849<pre>
2850 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2851</pre>
2852
2853<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2854<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2855
2856<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2857<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2858 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2859 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2860
2861<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2862<p>The value produced is the floating point sum of the two operands.</p>
2863
2864<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2865<pre>
2866 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2868
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2869</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
2872<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2873 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2874</div>
2875
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2876<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2879<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2880 &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]2881 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2882 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2883 &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]2884</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2886<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2887<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2888 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2889
2890<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2891 '<tt>neg</tt>' instruction present in most other intermediate
2892 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2894<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2895<p>The two arguments to the '<tt>sub</tt>' instruction must
2896 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2897 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2900<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2901
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2902<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2903 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2904 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2906<p>Because LLVM integers use a two's complement representation, this instruction
2907 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2908
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2909<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2910 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2911 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2912 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2915<pre>
2916 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2917 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2918</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2919
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2920</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2921
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2922<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2923<div class="doc_subsubsection">
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2924 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2925</div>
2926
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2930<pre>
2931 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2932</pre>
2933
2934<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2935<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2936 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2937
2938<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2939 '<tt>fneg</tt>' instruction present in most other intermediate
2940 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2941
2942<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2943<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2945 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2948<p>The value produced is the floating point difference of the two operands.</p>
2949
2950<h5>Example:</h5>
2951<pre>
2952 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2953 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2955
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2956</div>
2957
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2960 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2961</div>
2962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2963<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2964
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2965<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2966<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2967 &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]2968 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2970 &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]2971</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2973<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2974<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2975
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2976<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2977<p>The two arguments to the '<tt>mul</tt>' instruction must
2978 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2979 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2981<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]2982<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]2983
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2984<p>If the result of the multiplication has unsigned overflow, the result
2985 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2986 width of the result.</p>
2987
2988<p>Because LLVM integers use a two's complement representation, and the result
2989 is the same width as the operands, this instruction returns the correct
2990 result for both signed and unsigned integers. If a full product
2991 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2992 be sign-extended or zero-extended as appropriate to the width of the full
2993 product.</p>
2994
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]2995<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2996 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2997 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2998 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]2999
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3000<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3001<pre>
3002 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3003</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3004
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3005</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3007<!-- _______________________________________________________________________ -->
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3008<div class="doc_subsubsection">
3009 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3010</div>
3011
3012<div class="doc_text">
3013
3014<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3015<pre>
3016 &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]3017</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3018
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3019<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3020<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3021
3022<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3023<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3024 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3025 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3026
3027<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3028<p>The value produced is the floating point product of the two operands.</p>
3029
3030<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3031<pre>
3032 &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]3033</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3034
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3035</div>
3036
3037<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3038<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3039</a></div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3040
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3041<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3042
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3043<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3044<pre>
3045 &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]3046</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3047
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3048<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3049<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3050
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3051<h5>Arguments:</h5>
3052<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3053 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3054 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3055
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3056<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3057<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3058
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3059<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3060 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3061
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3062<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3063
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3064<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3065<pre>
3066 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3067</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3068
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3069</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3070
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3073</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3074
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3075<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3076
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3077<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3078<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3079 &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]3080 &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]3081</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3082
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3083<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3084<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3085
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3086<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3087<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3088 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3089 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3090
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3091<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3092<p>The value produced is the signed integer quotient of the two operands rounded
3093 towards zero.</p>
3094
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3095<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3096 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3097
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3098<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3099 undefined behavior; this is a rare case, but can occur, for example, by doing
3100 a 32-bit division of -2147483648 by -1.</p>
3101
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3102<p>If the <tt>exact</tt> keyword is present, the result value of the
3103 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3104 would occur.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3105
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3106<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3107<pre>
3108 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3109</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3110
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3111</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3112
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3113<!-- _______________________________________________________________________ -->
3114<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3115Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3116
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3117<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3118
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3119<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3120<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3121 &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]3122</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3124<h5>Overview:</h5>
3125<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3126
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3127<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3128<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3129 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3130 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3131
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3132<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3133<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3134
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3135<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3136<pre>
3137 &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]3138</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3139
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3140</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3141
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3142<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3143<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3144</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3145
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3146<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3147
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3148<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3149<pre>
3150 &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]3151</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3153<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3154<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3155 division of its two arguments.</p>
3156
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3157<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3158<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3159 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3160 values. Both arguments must have identical types.</p>
3161
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3162<h5>Semantics:</h5>
3163<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3164 This instruction always performs an unsigned division to get the
3165 remainder.</p>
3166
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3167<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3168 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3169
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3170<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3171
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3172<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
3174 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3175</pre>
3176
3177</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3178
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3180<div class="doc_subsubsection">
3181 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3182</div>
3183
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3184<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3185
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3186<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3187<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3188 &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]3189</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3190
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3191<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3192<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3193 division of its two operands. This instruction can also take
3194 <a href="#t_vector">vector</a> versions of the values in which case the
3195 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3196
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3197<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3198<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3199 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3200 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3201
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3202<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3203<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3204 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3205 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3206 a value. For more information about the difference,
3207 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3208 Math Forum</a>. For a table of how this is implemented in various languages,
3209 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3210 Wikipedia: modulo operation</a>.</p>
3211
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3212<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3213 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3214
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3215<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216 Overflow also leads to undefined behavior; this is a rare case, but can
3217 occur, for example, by taking the remainder of a 32-bit division of
3218 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3219 lets srem be implemented using instructions that return both the result of
3220 the division and the remainder.)</p>
3221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3222<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3223<pre>
3224 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3225</pre>
3226
3227</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3228
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3230<div class="doc_subsubsection">
3231 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3232
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3233<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3234
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3235<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3236<pre>
3237 &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]3238</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3239
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3240<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3242 its two operands.</p>
3243
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3244<h5>Arguments:</h5>
3245<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3246 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3247 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3248
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3249<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3250<p>This instruction returns the <i>remainder</i> of a division. The remainder
3251 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3252
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3253<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
3255 &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]3256</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3257
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3258</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]3259
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3260<!-- ======================================================================= -->
3261<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3262Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3263
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3264<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3265
3266<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3267 program. They are generally very efficient instructions and can commonly be
3268 strength reduced from other instructions. They require two operands of the
3269 same type, execute an operation on them, and produce a single value. The
3270 resulting value is the same type as its operands.</p>
3271
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3272</div>
3273
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3276Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3277
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3278<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3279
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3280<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3281<pre>
3282 &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]3283</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3284
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3285<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3286<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3287 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3288
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3289<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3290<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3291 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3292 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3293
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3294<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3295<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3296 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3297 is (statically or dynamically) negative or equal to or larger than the number
3298 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3299 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3300 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3301
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3302<h5>Example:</h5>
3303<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3304 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3305 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3306 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3307 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3308 &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]3309</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3311</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3312
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3313<!-- _______________________________________________________________________ -->
3314<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3315Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3316
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3317<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3318
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3319<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3320<pre>
3321 &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]3322</pre>
3323
3324<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3325<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3326 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3327
3328<h5>Arguments:</h5>
3329<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3330 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3331 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3332
3333<h5>Semantics:</h5>
3334<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3335 significant bits of the result will be filled with zero bits after the shift.
3336 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3337 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3338 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3339 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3340
3341<h5>Example:</h5>
3342<pre>
3343 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3344 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3345 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3346 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3347 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3348 &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]3349</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3350
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3351</div>
3352
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]3353<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3354<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3355Instruction</a> </div>
3356<div class="doc_text">
3357
3358<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3359<pre>
3360 &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]3361</pre>
3362
3363<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3364<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3365 operand shifted to the right a specified number of bits with sign
3366 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3367
3368<h5>Arguments:</h5>
3369<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3370 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3371 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3372
3373<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3374<p>This instruction always performs an arithmetic shift right operation, The
3375 most significant bits of the result will be filled with the sign bit
3376 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3377 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3378 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3379 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3380
3381<h5>Example:</h5>
3382<pre>
3383 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3384 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3385 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3386 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]3387 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]3388 &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]3389</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3390
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]3391</div>
3392
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3393<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3394<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3395Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3396
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3397<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3398
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3399<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3400<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3401 &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]3402</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3403
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3404<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3405<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3406 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3407
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3408<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3409<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3410 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3411 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3413<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3414<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3415
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3416<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3417 <tbody>
3418 <tr>
3419 <td>In0</td>
3420 <td>In1</td>
3421 <td>Out</td>
3422 </tr>
3423 <tr>
3424 <td>0</td>
3425 <td>0</td>
3426 <td>0</td>
3427 </tr>
3428 <tr>
3429 <td>0</td>
3430 <td>1</td>
3431 <td>0</td>
3432 </tr>
3433 <tr>
3434 <td>1</td>
3435 <td>0</td>
3436 <td>0</td>
3437 </tr>
3438 <tr>
3439 <td>1</td>
3440 <td>1</td>
3441 <td>1</td>
3442 </tr>
3443 </tbody>
3444</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3445
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3446<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3447<pre>
3448 &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]3449 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3450 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3451</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3452</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3453<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3454<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3455
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3456<div class="doc_text">
3457
3458<h5>Syntax:</h5>
3459<pre>
3460 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3461</pre>
3462
3463<h5>Overview:</h5>
3464<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3465 two operands.</p>
3466
3467<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3468<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3469 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3470 values. Both arguments must have identical types.</p>
3471
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3472<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3473<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3474
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3475<table border="1" cellspacing="0" cellpadding="4">
3476 <tbody>
3477 <tr>
3478 <td>In0</td>
3479 <td>In1</td>
3480 <td>Out</td>
3481 </tr>
3482 <tr>
3483 <td>0</td>
3484 <td>0</td>
3485 <td>0</td>
3486 </tr>
3487 <tr>
3488 <td>0</td>
3489 <td>1</td>
3490 <td>1</td>
3491 </tr>
3492 <tr>
3493 <td>1</td>
3494 <td>0</td>
3495 <td>1</td>
3496 </tr>
3497 <tr>
3498 <td>1</td>
3499 <td>1</td>
3500 <td>1</td>
3501 </tr>
3502 </tbody>
3503</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3504
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3508 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3509 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3510</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3511
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3512</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3513
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3514<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3515<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3516Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3517
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3518<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3519
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3520<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3521<pre>
3522 &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]3523</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3526<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3527 its two operands. The <tt>xor</tt> is used to implement the "one's
3528 complement" operation, which is the "~" operator in C.</p>
3529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3530<h5>Arguments:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3531<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3532 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3533 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3534
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3535<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3536<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3537
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3538<table border="1" cellspacing="0" cellpadding="4">
3539 <tbody>
3540 <tr>
3541 <td>In0</td>
3542 <td>In1</td>
3543 <td>Out</td>
3544 </tr>
3545 <tr>
3546 <td>0</td>
3547 <td>0</td>
3548 <td>0</td>
3549 </tr>
3550 <tr>
3551 <td>0</td>
3552 <td>1</td>
3553 <td>1</td>
3554 </tr>
3555 <tr>
3556 <td>1</td>
3557 <td>0</td>
3558 <td>1</td>
3559 </tr>
3560 <tr>
3561 <td>1</td>
3562 <td>1</td>
3563 <td>0</td>
3564 </tr>
3565 </tbody>
3566</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3568<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3569<pre>
3570 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3571 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3572 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3573 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3574</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3575
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3576</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3578<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3579<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3580 <a name="vectorops">Vector Operations</a>
3581</div>
3582
3583<div class="doc_text">
3584
3585<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586 target-independent manner. These instructions cover the element-access and
3587 vector-specific operations needed to process vectors effectively. While LLVM
3588 does directly support these vector operations, many sophisticated algorithms
3589 will want to use target-specific intrinsics to take full advantage of a
3590 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3591
3592</div>
3593
3594<!-- _______________________________________________________________________ -->
3595<div class="doc_subsubsection">
3596 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3597</div>
3598
3599<div class="doc_text">
3600
3601<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3602<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3603 &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]3604</pre>
3605
3606<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3607<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3608 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3609
3610
3611<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3612<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3613 of <a href="#t_vector">vector</a> type. The second operand is an index
3614 indicating the position from which to extract the element. The index may be
3615 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3616
3617<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3618<p>The result is a scalar of the same type as the element type of
3619 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3620 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3621 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3622
3623<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3624<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3625 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3626</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3627
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3628</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
3632 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3633</div>
3634
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3638<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]3639 &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]3640</pre>
3641
3642<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3643<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3644 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3645
3646<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3647<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3648 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3649 whose type must equal the element type of the first operand. The third
3650 operand is an index indicating the position at which to insert the value.
3651 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3654<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3655 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3656 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3657 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3658
3659<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3660<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3661 %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]3662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3663
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3664</div>
3665
3666<!-- _______________________________________________________________________ -->
3667<div class="doc_subsubsection">
3668 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3669</div>
3670
3671<div class="doc_text">
3672
3673<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3674<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]3675 &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]3676</pre>
3677
3678<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3680 from two input vectors, returning a vector with the same element type as the
3681 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3682
3683<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3684<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3685 with types that match each other. The third argument is a shuffle mask whose
3686 element type is always 'i32'. The result of the instruction is a vector
3687 whose length is the same as the shuffle mask and whose element type is the
3688 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3689
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3690<p>The shuffle mask operand is required to be a constant vector with either
3691 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The elements of the two input vectors are numbered from left to right across
3695 both of the vectors. The shuffle mask operand specifies, for each element of
3696 the result vector, which element of the two input vectors the result element
3697 gets. The element selector may be undef (meaning "don't care") and the
3698 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3699
3700<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3701<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3702 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3703 &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]3704 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3705 &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]3706 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3707 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3708 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3709 &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]3710</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3711
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3712</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]3713
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]3714<!-- ======================================================================= -->
3715<div class="doc_subsection">
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3716 <a name="aggregateops">Aggregate Operations</a>
3717</div>
3718
3719<div class="doc_text">
3720
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3721<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3722
3723</div>
3724
3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection">
3727 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3728</div>
3729
3730<div class="doc_text">
3731
3732<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3733<pre>
3734 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3735</pre>
3736
3737<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3738<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3739 or array element from an aggregate value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3740
3741<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3742<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3743 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3744 operands are constant indices to specify which value to extract in a similar
3745 manner as indices in a
3746 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3747
3748<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3749<p>The result is the value at the position in the aggregate specified by the
3750 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3751
3752<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3753<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3754 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3755</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3756
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3757</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3758
3759<!-- _______________________________________________________________________ -->
3760<div class="doc_subsubsection">
3761 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3762</div>
3763
3764<div class="doc_text">
3765
3766<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3767<pre>
Dan Gohman81a0c0b2008-05-31 00:58:22 +0000[diff] [blame]3768 &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]3769</pre>
3770
3771<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3772<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3773 array element in an aggregate.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3774
3775
3776<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3777<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3778 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3779 second operand is a first-class value to insert. The following operands are
3780 constant indices indicating the position at which to insert the value in a
3781 similar manner as indices in a
3782 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3783 value to insert must have the same type as the value identified by the
3784 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3788 that of <tt>val</tt> except that the value at the position specified by the
3789 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3790
3791<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3792<pre>
Dan Gohman52bb2db2008-06-23 15:26:37 +0000[diff] [blame]3793 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3794</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3795
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]3796</div>
3797
3798
3799<!-- ======================================================================= -->
3800<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3801 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3802</div>
3803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3804<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3805
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3806<p>A key design point of an SSA-based representation is how it represents
3807 memory. In LLVM, no memory locations are in SSA form, which makes things
3808 very simple. This section describes how to read, write, allocate, and free
3809 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3810
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3811</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3813<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3814<div class="doc_subsubsection">
3815 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3816</div>
3817
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3818<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3820<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3821<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3822 &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]3823</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3826<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3827 returns a pointer to it. The object is always allocated in the generic
3828 address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3830<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3831<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3832 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3833 system and returns a pointer of the appropriate type to the program. If
3834 "NumElements" is specified, it is the number of elements allocated, otherwise
3835 "NumElements" is defaulted to be one. If a constant alignment is specified,
3836 the value result of the allocation is guaranteed to be aligned to at least
3837 that boundary. If not specified, or if zero, the target can choose to align
3838 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3839
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3840<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3842<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3843<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3844 pointer is returned. The result of a zero byte allocation is undefined. The
3845 result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3846
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3847<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3848<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3849 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3850
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3851 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3852 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3853 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3854 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3855 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3856</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3857
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3860</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3862<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3863<div class="doc_subsubsection">
3864 <a name="i_free">'<tt>free</tt>' Instruction</a>
3865</div>
3866
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3867<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3869<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3870<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3871 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3872</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3873
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3874<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3876 to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3878<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3879<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3880 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3881
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3882<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3883<p>Access to the memory pointed to by the pointer is no longer defined after
3884 this instruction executes. If the pointer is null, the operation is a
3885 noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3886
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3887<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3888<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3889 %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]3890 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3891</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3892
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3893</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3895<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3896<div class="doc_subsubsection">
3897 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3898</div>
3899
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3900<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3902<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3903<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3904 &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]3905</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3907<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3908<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3909 currently executing function, to be automatically released when this function
3910 returns to its caller. The object is always allocated in the generic address
3911 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3912
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3913<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>alloca</tt>' instruction
3915 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3916 runtime stack, returning a pointer of the appropriate type to the program.
3917 If "NumElements" is specified, it is the number of elements allocated,
3918 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3919 specified, the value result of the allocation is guaranteed to be aligned to
3920 at least that boundary. If not specified, or if zero, the target can choose
3921 to align the allocation on any convenient boundary compatible with the
3922 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3923
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3924<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3925
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3926<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]3927<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3928 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3929 memory is automatically released when the function returns. The
3930 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3931 variables that must have an address available. When the function returns
3932 (either with the <tt><a href="#i_ret">ret</a></tt>
3933 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3934 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3936<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3937<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]3938 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3942</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3944</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]3945
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3946<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3947<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3948Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3949
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3950<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3951
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3952<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3956</pre>
3957
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3958<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3959<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3960
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3961<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3963 from which to load. The pointer must point to
3964 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3965 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3966 number or order of execution of this <tt>load</tt> with other
3967 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3968 instructions. </p>
3969
3970<p>The optional constant "align" argument specifies the alignment of the
3971 operation (that is, the alignment of the memory address). A value of 0 or an
3972 omitted "align" argument means that the operation has the preferential
3973 alignment for the target. It is the responsibility of the code emitter to
3974 ensure that the alignment information is correct. Overestimating the
3975 alignment results in an undefined behavior. Underestimating the alignment may
3976 produce less efficient code. An alignment of 1 is always safe.</p>
3977
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3978<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3979<p>The location of memory pointed to is loaded. If the value being loaded is of
3980 scalar type then the number of bytes read does not exceed the minimum number
3981 of bytes needed to hold all bits of the type. For example, loading an
3982 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3983 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3984 is undefined if the value was not originally written using a store of the
3985 same type.</p>
3986
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3987<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3988<pre>
3989 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3990 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3991 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3992</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3993
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3994</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]3996<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3997<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3998Instruction</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3999
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]4000<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4001
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4002<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4003<pre>
4004 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]4005 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]4006</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4007
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4008<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4009<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4010
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4011<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4012<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4013 and an address at which to store it. The type of the
4014 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4015 the <a href="#t_firstclass">first class</a> type of the
4016 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4017 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4018 or order of execution of this <tt>store</tt> with other
4019 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4020 instructions.</p>
4021
4022<p>The optional constant "align" argument specifies the alignment of the
4023 operation (that is, the alignment of the memory address). A value of 0 or an
4024 omitted "align" argument means that the operation has the preferential
4025 alignment for the target. It is the responsibility of the code emitter to
4026 ensure that the alignment information is correct. Overestimating the
4027 alignment results in an undefined behavior. Underestimating the alignment may
4028 produce less efficient code. An alignment of 1 is always safe.</p>
4029
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4030<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4031<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4032 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4033 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4034 does not exceed the minimum number of bytes needed to hold all bits of the
4035 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4036 writing a value of a type like <tt>i20</tt> with a size that is not an
4037 integral number of bytes, it is unspecified what happens to the extra bits
4038 that do not belong to the type, but they will typically be overwritten.</p>
4039
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4040<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4043 store i32 3, i32* %ptr <i>; yields {void}</i>
4044 %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]4045</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4047</div>
4048
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4049<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4050<div class="doc_subsubsection">
4051 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4052</div>
4053
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4054<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4056<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4057<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4058 &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]4059 &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]4060</pre>
4061
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4062<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4064 subelement of an aggregate data structure. It performs address calculation
4065 only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4066
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4067<h5>Arguments:</h5>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4068<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4069 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4070 elements of the aggregate object are indexed. The interpretation of each
4071 index is dependent on the type being indexed into. The first index always
4072 indexes the pointer value given as the first argument, the second index
4073 indexes a value of the type pointed to (not necessarily the value directly
4074 pointed to, since the first index can be non-zero), etc. The first type
4075 indexed into must be a pointer value, subsequent types can be arrays, vectors
4076 and structs. Note that subsequent types being indexed into can never be
4077 pointers, since that would require loading the pointer before continuing
4078 calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4079
4080<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]4081 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4082 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]4083 vector, integers of any width are allowed, and they are not required to be
4084 constant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4085
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086<p>For example, let's consider a C code fragment and how it gets compiled to
4087 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4088
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4089<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4090<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4091struct RT {
4092 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4093 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4094 char C;
4095};
4096struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4097 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4098 double Y;
4099 struct RT Z;
4100};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4101
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]4102int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4103 return &amp;s[1].Z.B[5][13];
4104}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4105</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4106</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4108<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4109
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4110<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4111<pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]4112%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4113%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4114
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4115define i32* @foo(%ST* %s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4116entry:
4117 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4118 ret i32* %reg
4119}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4120</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4121</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4122
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4123<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4124<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]4125 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4126 }</tt>' type, a structure. The second index indexes into the third element
4127 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4128 i8 }</tt>' type, another structure. The third index indexes into the second
4129 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4130 array. The two dimensions of the array are subscripted into, yielding an
4131 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4132 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4133
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4134<p>Note that it is perfectly legal to index partially through a structure,
4135 returning a pointer to an inner element. Because of this, the LLVM code for
4136 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4137
4138<pre>
Dan Gohman4df605b2009-07-25 02:23:48 +0000[diff] [blame]4139 define i32* @foo(%ST* %s) {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4140 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4141 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4142 %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]4143 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4144 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4145 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4146 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4147</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]4148
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4149<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4150 <tt>getelementptr</tt> is undefined if the base pointer is not an
4151 <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]4152 that would be formed by successive addition of the offsets implied by the
4153 indices to the base address with infinitely precise arithmetic are not an
4154 <i>in bounds</i> address of that allocated object.
Dan Gohman0a28d182009-07-29 16:00:30 +0000[diff] [blame]4155 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanb255b882009-08-20 17:08:17 +0000[diff] [blame]4156 that point into the object, plus the address one byte past the end.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]4157
4158<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4159 the base address with silently-wrapping two's complement arithmetic, and
4160 the result value of the <tt>getelementptr</tt> may be outside the object
4161 pointed to by the base pointer. The result value may not necessarily be
4162 used to access memory though, even if it happens to point into allocated
4163 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4164 section for more information.</p>
4165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4166<p>The getelementptr instruction is often confusing. For some more insight into
4167 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4168
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]4169<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4170<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4171 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]4172 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4173 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4174 %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]4175 <i>; yields i8*:eptr</i>
4176 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]4177 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]4178 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4179</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4180
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]4181</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4183<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4184<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4185</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4187<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4188
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4189<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4190 which all take a single operand and a type. They perform various bit
4191 conversions on the operand.</p>
4192
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4193</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4194
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4195<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4196<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4197 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4198</div>
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
4203 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4204</pre>
4205
4206<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4207<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4208 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4209
4210<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4212 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4213 size and type of the result, which must be
4214 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4215 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4216 allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4217
4218<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4219<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4220 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4221 source size must be larger than the destination size, <tt>trunc</tt> cannot
4222 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4223
4224<h5>Example:</h5>
4225<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4226 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4227 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4228 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4229</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4230
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4231</div>
4232
4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4236</div>
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
4241 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4242</pre>
4243
4244<h5>Overview:</h5>
4245<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4246 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4247
4248
4249<h5>Arguments:</h5>
4250<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]4251 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4252 also be of <a href="#t_integer">integer</a> type. The bit size of the
4253 <tt>value</tt> must be smaller than the bit size of the destination type,
4254 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
4257<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]4258 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4259
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]4260<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]4261
4262<h5>Example:</h5>
4263<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4264 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4265 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4266</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4267
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4268</div>
4269
4270<!-- _______________________________________________________________________ -->
4271<div class="doc_subsubsection">
4272 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4273</div>
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
4278 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4279</pre>
4280
4281<h5>Overview:</h5>
4282<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4283
4284<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4285<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4286 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4287 also be of <a href="#t_integer">integer</a> type. The bit size of the
4288 <tt>value</tt> must be smaller than the bit size of the destination type,
4289 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4290
4291<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4293 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4294 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4295
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4296<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]4297
4298<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4299<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4300 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4301 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4302</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4303
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4304</div>
4305
4306<!-- _______________________________________________________________________ -->
4307<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4308 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4309</div>
4310
4311<div class="doc_text">
4312
4313<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4314<pre>
4315 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4316</pre>
4317
4318<h5>Overview:</h5>
4319<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4320 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4321
4322<h5>Arguments:</h5>
4323<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4324 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4325 to cast it to. The size of <tt>value</tt> must be larger than the size of
4326 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4327 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4331 <a href="#t_floating">floating point</a> type to a smaller
4332 <a href="#t_floating">floating point</a> type. If the value cannot fit
4333 within the destination type, <tt>ty2</tt>, then the results are
4334 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4335
4336<h5>Example:</h5>
4337<pre>
4338 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4339 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4340</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]4342</div>
4343
4344<!-- _______________________________________________________________________ -->
4345<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4346 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4347</div>
4348<div class="doc_text">
4349
4350<h5>Syntax:</h5>
4351<pre>
4352 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4353</pre>
4354
4355<h5>Overview:</h5>
4356<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]4357 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4358
4359<h5>Arguments:</h5>
4360<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4362 a <a href="#t_floating">floating point</a> type to cast it to. The source
4363 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4366<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4367 <a href="#t_floating">floating point</a> type to a larger
4368 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4369 used to make a <i>no-op cast</i> because it always changes bits. Use
4370 <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]4371
4372<h5>Example:</h5>
4373<pre>
4374 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4375 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4377
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4378</div>
4379
4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]4382 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4383</div>
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4388 &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]4389</pre>
4390
4391<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4392<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4393 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4397 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4398 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4399 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4400 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403<p>The '<tt>fptoui</tt>' instruction converts its
4404 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4405 towards zero) unsigned integer value. If the value cannot fit
4406 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4407
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4408<h5>Example:</h5>
4409<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4410 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4411 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]4412 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4414
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4415</div>
4416
4417<!-- _______________________________________________________________________ -->
4418<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4419 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4420</div>
4421<div class="doc_text">
4422
4423<h5>Syntax:</h5>
4424<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4425 &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]4426</pre>
4427
4428<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4429<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4430 <a href="#t_floating">floating point</a> <tt>value</tt> to
4431 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4432
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4433<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4434<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4435 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4436 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4437 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4438 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4439
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4440<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4441<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4442 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4443 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4444 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4445
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]4446<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4447<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4448 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]4449 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4450 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4451</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4452
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4453</div>
4454
4455<!-- _______________________________________________________________________ -->
4456<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4457 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4458</div>
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
4462<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4463 &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]4464</pre>
4465
4466<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4467<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4468 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4469
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4470<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4471<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]4472 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4473 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4474 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4475 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4476
4477<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4478<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479 integer quantity and converts it to the corresponding floating point
4480 value. If the value cannot fit in the floating point value, the results are
4481 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4482
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4483<h5>Example:</h5>
4484<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4485 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4486 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4487</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4488
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4489</div>
4490
4491<!-- _______________________________________________________________________ -->
4492<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4493 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4494</div>
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]4499 &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]4500</pre>
4501
4502<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4503<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4504 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4505
4506<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]4507<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]4508 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4509 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4510 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4511 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4512
4513<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4514<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4515 quantity and converts it to the corresponding floating point value. If the
4516 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4517
4518<h5>Example:</h5>
4519<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4520 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4521 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4522</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4523
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4528 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4529</div>
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
4534 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4535</pre>
4536
4537<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4539 the integer type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4540
4541<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4543 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4544 <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]4545
4546<h5>Semantics:</h5>
4547<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4549 truncating or zero extending that value to the size of the integer type. If
4550 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4551 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4552 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4553 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4554
4555<h5>Example:</h5>
4556<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4557 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4558 %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]4559</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4560
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
4565 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4566</div>
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570<pre>
4571 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4572</pre>
4573
4574<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4576 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]4579<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4580 value to cast, and a type to cast it to, which must be a
4581 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
4584<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4586 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4587 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4588 than the size of a pointer then a zero extension is done. If they are the
4589 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4590
4591<h5>Example:</h5>
4592<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4593 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4594 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4595 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4596</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4597
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]4598</div>
4599
4600<!-- _______________________________________________________________________ -->
4601<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4602 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4603</div>
4604<div class="doc_text">
4605
4606<h5>Syntax:</h5>
4607<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4608 &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]4609</pre>
4610
4611<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4612<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4614
4615<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4617 non-aggregate first class value, and a type to cast it to, which must also be
4618 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4619 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4620 identical. If the source type is a pointer, the destination type must also be
4621 a pointer. This instruction supports bitwise conversion of vectors to
4622 integers and to vectors of other types (as long as they have the same
4623 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]4626<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4627 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4628 this conversion. The conversion is done as if the <tt>value</tt> had been
4629 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4630 be converted to other pointer types with this instruction. To convert
4631 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4632 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]4633
4634<h5>Example:</h5>
4635<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4636 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4637 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4638 %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]4639</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4640
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4641</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4642
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4643<!-- ======================================================================= -->
4644<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4645
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4646<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4647
4648<p>The instructions in this category are the "miscellaneous" instructions, which
4649 defy better classification.</p>
4650
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4651</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4652
4653<!-- _______________________________________________________________________ -->
4654<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4655</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4657<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4659<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4660<pre>
4661 &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]4662</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4663
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4664<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4665<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4666 boolean values based on comparison of its two integer, integer vector, or
4667 pointer operands.</p>
4668
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4669<h5>Arguments:</h5>
4670<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4671 the condition code indicating the kind of comparison to perform. It is not a
4672 value, just a keyword. The possible condition code are:</p>
4673
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4674<ol>
4675 <li><tt>eq</tt>: equal</li>
4676 <li><tt>ne</tt>: not equal </li>
4677 <li><tt>ugt</tt>: unsigned greater than</li>
4678 <li><tt>uge</tt>: unsigned greater or equal</li>
4679 <li><tt>ult</tt>: unsigned less than</li>
4680 <li><tt>ule</tt>: unsigned less or equal</li>
4681 <li><tt>sgt</tt>: signed greater than</li>
4682 <li><tt>sge</tt>: signed greater or equal</li>
4683 <li><tt>slt</tt>: signed less than</li>
4684 <li><tt>sle</tt>: signed less or equal</li>
4685</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4686
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]4687<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4689 typed. They must also be identical types.</p>
4690
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4691<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4692<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4693 condition code given as <tt>cond</tt>. The comparison performed always yields
4694 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4695 result, as follows:</p>
4696
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4697<ol>
4698 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4699 <tt>false</tt> otherwise. No sign interpretation is necessary or
4700 performed.</li>
4701
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4702 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4703 <tt>false</tt> otherwise. No sign interpretation is necessary or
4704 performed.</li>
4705
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4706 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4707 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4708
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4709 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4710 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4711 to <tt>op2</tt>.</li>
4712
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4713 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4715
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4716 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4718
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4719 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4721
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4722 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4723 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4724 to <tt>op2</tt>.</li>
4725
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4726 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4728
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4729 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4730 <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]4731</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4732
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4733<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4734 values are compared as if they were integers.</p>
4735
4736<p>If the operands are integer vectors, then they are compared element by
4737 element. The result is an <tt>i1</tt> vector with the same number of elements
4738 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4739
4740<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4741<pre>
4742 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4743 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4744 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4745 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4747 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4748</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4749
4750<p>Note that the code generator does not yet support vector types with
4751 the <tt>icmp</tt> instruction.</p>
4752
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4753</div>
4754
4755<!-- _______________________________________________________________________ -->
4756<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4757</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4758
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4759<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4761<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4762<pre>
4763 &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]4764</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4765
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4766<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4768 values based on comparison of its operands.</p>
4769
4770<p>If the operands are floating point scalars, then the result type is a boolean
4771(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4772
4773<p>If the operands are floating point vectors, then the result type is a vector
4774 of boolean with the same number of elements as the operands being
4775 compared.</p>
4776
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4777<h5>Arguments:</h5>
4778<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4779 the condition code indicating the kind of comparison to perform. It is not a
4780 value, just a keyword. The possible condition code are:</p>
4781
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4782<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4783 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4784 <li><tt>oeq</tt>: ordered and equal</li>
4785 <li><tt>ogt</tt>: ordered and greater than </li>
4786 <li><tt>oge</tt>: ordered and greater than or equal</li>
4787 <li><tt>olt</tt>: ordered and less than </li>
4788 <li><tt>ole</tt>: ordered and less than or equal</li>
4789 <li><tt>one</tt>: ordered and not equal</li>
4790 <li><tt>ord</tt>: ordered (no nans)</li>
4791 <li><tt>ueq</tt>: unordered or equal</li>
4792 <li><tt>ugt</tt>: unordered or greater than </li>
4793 <li><tt>uge</tt>: unordered or greater than or equal</li>
4794 <li><tt>ult</tt>: unordered or less than </li>
4795 <li><tt>ule</tt>: unordered or less than or equal</li>
4796 <li><tt>une</tt>: unordered or not equal</li>
4797 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4798 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4799</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4800
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4801<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4802 <i>unordered</i> means that either operand may be a QNAN.</p>
4803
4804<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4805 a <a href="#t_floating">floating point</a> type or
4806 a <a href="#t_vector">vector</a> of floating point type. They must have
4807 identical types.</p>
4808
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4809<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4810<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4811 according to the condition code given as <tt>cond</tt>. If the operands are
4812 vectors, then the vectors are compared element by element. Each comparison
4813 performed always yields an <a href="#t_primitive">i1</a> result, as
4814 follows:</p>
4815
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4816<ol>
4817 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4818
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4819 <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]4820 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4821
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4822 <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]4823 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4824
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4825 <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]4826 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4827
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4828 <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]4829 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4830
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4831 <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]4832 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4833
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4834 <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]4835 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4836
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4837 <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]4838
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4841
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4844
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4847
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4850
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4851 <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]4852 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4853
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4854 <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]4855 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4856
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]4857 <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]4858
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4859 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4860</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4861
4862<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4863<pre>
4864 &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]4865 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4866 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4867 &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]4868</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4869
4870<p>Note that the code generator does not yet support vector types with
4871 the <tt>fcmp</tt> instruction.</p>
4872
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]4873</div>
4874
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4875<!-- _______________________________________________________________________ -->
Nate Begemanac80ade2008-05-12 19:01:56 +0000[diff] [blame]4876<div class="doc_subsubsection">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4877 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4878</div>
4879
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4880<div class="doc_text">
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4881
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4882<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4883<pre>
4884 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4885</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4886
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4887<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4889 SSA graph representing the function.</p>
4890
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4891<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4892<p>The type of the incoming values is specified with the first type field. After
4893 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4894 one pair for each predecessor basic block of the current block. Only values
4895 of <a href="#t_firstclass">first class</a> type may be used as the value
4896 arguments to the PHI node. Only labels may be used as the label
4897 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4898
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4899<p>There must be no non-phi instructions between the start of a basic block and
4900 the PHI instructions: i.e. PHI instructions must be first in a basic
4901 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4902
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4903<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4904 occur on the edge from the corresponding predecessor block to the current
4905 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4906 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]4907
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4908<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4909<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4910 specified by the pair corresponding to the predecessor basic block that
4911 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4912
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4913<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4914<pre>
4915Loop: ; Infinite loop that counts from 0 on up...
4916 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4917 %nextindvar = add i32 %indvar, 1
4918 br label %Loop
4919</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4920
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]4921</div>
4922
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4923<!-- _______________________________________________________________________ -->
4924<div class="doc_subsubsection">
4925 <a name="i_select">'<tt>select</tt>' Instruction</a>
4926</div>
4927
4928<div class="doc_text">
4929
4930<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4931<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]4932 &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>
4933
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]4934 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4938<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4939 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4940
4941
4942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4943<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4944 values indicating the condition, and two values of the
4945 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4946 vectors and the condition is a scalar, then entire vectors are selected, not
4947 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4948
4949<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4950<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4951 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4952
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4953<p>If the condition is a vector of i1, then the value arguments must be vectors
4954 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4955
4956<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4957<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]4958 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4959</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]4960
4961<p>Note that the code generator does not yet support conditions
4962 with vector type.</p>
4963
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]4964</div>
4965
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4968 <a name="i_call">'<tt>call</tt>' Instruction</a>
4969</div>
4970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4971<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4972
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4973<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4974<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]4975 &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]4976</pre>
4977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4978<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4979<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4980
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4981<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4982<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]4983
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]4984<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4985 <li>The optional "tail" marker indicates whether the callee function accesses
4986 any allocas or varargs in the caller. If the "tail" marker is present,
4987 the function call is eligible for tail call optimization. Note that calls
4988 may be marked "tail" even if they do not occur before
4989 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4990
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4991 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4992 convention</a> the call should use. If none is specified, the call
4993 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]4994
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4996 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4997 '<tt>inreg</tt>' attributes are valid here.</li>
4998
4999 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5000 type of the return value. Functions that return no value are marked
5001 <tt><a href="#t_void">void</a></tt>.</li>
5002
5003 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5004 being invoked. The argument types must match the types implied by this
5005 signature. This type can be omitted if the function is not varargs and if
5006 the function type does not return a pointer to a function.</li>
5007
5008 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5009 be invoked. In most cases, this is a direct function invocation, but
5010 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5011 to function value.</li>
5012
5013 <li>'<tt>function args</tt>': argument list whose types match the function
5014 signature argument types. All arguments must be of
5015 <a href="#t_firstclass">first class</a> type. If the function signature
5016 indicates the function accepts a variable number of arguments, the extra
5017 arguments can be specified.</li>
5018
5019 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5020 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5021 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5022</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5024<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5025<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5026 a specified function, with its incoming arguments bound to the specified
5027 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5028 function, control flow continues with the instruction after the function
5029 call, and the return value of the function is bound to the result
5030 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5031
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5032<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5033<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]5034 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]5035 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5036 %X = tail call i32 @foo() <i>; yields i32</i>
5037 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5038 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]5039
5040 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]5041 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]5042 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5043 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]5044 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]5045 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]5046</pre>
5047
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5048<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame^]5049standard C99 library as being the C99 library functions, and may perform
5050optimizations or generate code for them under that assumption. This is
5051something we'd like to change in the future to provide better support for
5052freestanding environments and non-C-based langauges.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]5053
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5054</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5055
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5056<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5057<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]5058 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5059</div>
5060
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5061<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5062
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5063<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5064<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5065 &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]5066</pre>
5067
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5068<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5069<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5070 the "variable argument" area of a function call. It is used to implement the
5071 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5072
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5073<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5074<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5075 argument. It returns a value of the specified argument type and increments
5076 the <tt>va_list</tt> to point to the next argument. The actual type
5077 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5078
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5079<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5081 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5082 to the next argument. For more information, see the variable argument
5083 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5084
5085<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]5086 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5087 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5088
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5089<p><tt>va_arg</tt> is an LLVM instruction instead of
5090 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5091 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5092
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]5093<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]5094<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5095
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5096<p>Note that the code generator does not yet fully support va_arg on many
5097 targets. Also, it does not currently support va_arg with aggregate types on
5098 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]5099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5100</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5101
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5102<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]5103<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5104<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5105
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5106<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5107
5108<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5109 well known names and semantics and are required to follow certain
5110 restrictions. Overall, these intrinsics represent an extension mechanism for
5111 the LLVM language that does not require changing all of the transformations
5112 in LLVM when adding to the language (or the bitcode reader/writer, the
5113 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5114
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]5115<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5116 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5117 begin with this prefix. Intrinsic functions must always be external
5118 functions: you cannot define the body of intrinsic functions. Intrinsic
5119 functions may only be used in call or invoke instructions: it is illegal to
5120 take the address of an intrinsic function. Additionally, because intrinsic
5121 functions are part of the LLVM language, it is required if any are added that
5122 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5123
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5124<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5125 family of functions that perform the same operation but on different data
5126 types. Because LLVM can represent over 8 million different integer types,
5127 overloading is used commonly to allow an intrinsic function to operate on any
5128 integer type. One or more of the argument types or the result type can be
5129 overloaded to accept any integer type. Argument types may also be defined as
5130 exactly matching a previous argument's type or the result type. This allows
5131 an intrinsic function which accepts multiple arguments, but needs all of them
5132 to be of the same type, to only be overloaded with respect to a single
5133 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5135<p>Overloaded intrinsics will have the names of its overloaded argument types
5136 encoded into its function name, each preceded by a period. Only those types
5137 which are overloaded result in a name suffix. Arguments whose type is matched
5138 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5139 can take an integer of any width and returns an integer of exactly the same
5140 integer width. This leads to a family of functions such as
5141 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5142 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5143 suffix is required. Because the argument's type is matched against the return
5144 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5145
5146<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5147 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5148
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5149</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5150
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5151<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5152<div class="doc_subsection">
5153 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5154</div>
5155
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5156<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5157
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5158<p>Variable argument support is defined in LLVM with
5159 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5160 intrinsic functions. These functions are related to the similarly named
5161 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5162
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5163<p>All of these functions operate on arguments that use a target-specific value
5164 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5165 not define what this type is, so all transformations should be prepared to
5166 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5167
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]5168<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]5169 instruction and the variable argument handling intrinsic functions are
5170 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5171
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5172<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5173<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5174define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5175 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5176 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5177 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5178 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5179
5180 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5181 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5182
5183 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5184 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5185 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5186 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5187 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5188
5189 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5190 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5191 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5192}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]5193
5194declare void @llvm.va_start(i8*)
5195declare void @llvm.va_copy(i8*, i8*)
5196declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5197</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5198</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5199
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5200</div>
5201
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5202<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5203<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5204 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5205</div>
5206
5207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5208<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5209
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5210<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5211<pre>
5212 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5213</pre>
5214
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5215<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5216<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5217 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]5218
5219<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5220<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]5221
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5222<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5223<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]5224 macro available in C. In a target-dependent way, it initializes
5225 the <tt>va_list</tt> element to which the argument points, so that the next
5226 call to <tt>va_arg</tt> will produce the first variable argument passed to
5227 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5228 need to know the last argument of the function as the compiler can figure
5229 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5230
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5231</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5232
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5233<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5234<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5235 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5236</div>
5237
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5238<div class="doc_text">
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5239
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5240<h5>Syntax:</h5>
5241<pre>
5242 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5243</pre>
5244
5245<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5246<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5247 which has been initialized previously
5248 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5249 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5250
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5251<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5252<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]5253
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5254<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5255<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]5256 macro available in C. In a target-dependent way, it destroys
5257 the <tt>va_list</tt> element to which the argument points. Calls
5258 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5259 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5260 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]5261
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5262</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5263
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5264<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5265<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5266 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5267</div>
5268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5269<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5270
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5271<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5272<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5273 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5274</pre>
5275
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5276<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5277<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5278 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5279
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5280<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]5281<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]5282 The second argument is a pointer to a <tt>va_list</tt> element to copy
5283 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5284
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]5285<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5286<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]5287 macro available in C. In a target-dependent way, it copies the
5288 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5289 element. This intrinsic is necessary because
5290 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5291 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5292
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5293</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5294
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5295<!-- ======================================================================= -->
5296<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5297 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5298</div>
5299
5300<div class="doc_text">
5301
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5302<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]5303Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5304intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5305roots on the stack</a>, as well as garbage collector implementations that
5306require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5307barriers. Front-ends for type-safe garbage collected languages should generate
5308these intrinsics to make use of the LLVM garbage collectors. For more details,
5309see <a href="GarbageCollection.html">Accurate Garbage Collection with
5310LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5312<p>The garbage collection intrinsics only operate on objects in the generic
5313 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]5314
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5315</div>
5316
5317<!-- _______________________________________________________________________ -->
5318<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5319 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5320</div>
5321
5322<div class="doc_text">
5323
5324<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5325<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5326 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5327</pre>
5328
5329<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]5330<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]5331 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5332
5333<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5334<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5335 root pointer. The second pointer (which must be either a constant or a
5336 global value address) contains the meta-data to be associated with the
5337 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5338
5339<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]5340<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]5341 location. At compile-time, the code generator generates information to allow
5342 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5343 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5344 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5345
5346</div>
5347
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5348<!-- _______________________________________________________________________ -->
5349<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5350 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5351</div>
5352
5353<div class="doc_text">
5354
5355<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5356<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5357 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5358</pre>
5359
5360<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5361<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5362 locations, allowing garbage collector implementations that require read
5363 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5364
5365<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5366<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]5367 allocated from the garbage collector. The first object is a pointer to the
5368 start of the referenced object, if needed by the language runtime (otherwise
5369 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5370
5371<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5372<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5373 instruction, but may be replaced with substantially more complex code by the
5374 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5375 may only be used in a function which <a href="#gc">specifies a GC
5376 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5377
5378</div>
5379
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5380<!-- _______________________________________________________________________ -->
5381<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5382 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5383</div>
5384
5385<div class="doc_text">
5386
5387<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5388<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5389 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5390</pre>
5391
5392<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5393<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394 locations, allowing garbage collector implementations that require write
5395 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5396
5397<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]5398<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]5399 object to store it to, and the third is the address of the field of Obj to
5400 store to. If the runtime does not require a pointer to the object, Obj may
5401 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5402
5403<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5404<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5405 instruction, but may be replaced with substantially more complex code by the
5406 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5407 may only be used in a function which <a href="#gc">specifies a GC
5408 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5409
5410</div>
5411
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]5412<!-- ======================================================================= -->
5413<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5414 <a name="int_codegen">Code Generator Intrinsics</a>
5415</div>
5416
5417<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5418
5419<p>These intrinsics are provided by LLVM to expose special features that may
5420 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5421
5422</div>
5423
5424<!-- _______________________________________________________________________ -->
5425<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5426 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5427</div>
5428
5429<div class="doc_text">
5430
5431<h5>Syntax:</h5>
5432<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5433 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5434</pre>
5435
5436<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5437<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5438 target-specific value indicating the return address of the current function
5439 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5440
5441<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442<p>The argument to this intrinsic indicates which function to return the address
5443 for. Zero indicates the calling function, one indicates its caller, etc.
5444 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5445
5446<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5448 indicating the return address of the specified call frame, or zero if it
5449 cannot be identified. The value returned by this intrinsic is likely to be
5450 incorrect or 0 for arguments other than zero, so it should only be used for
5451 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5452
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5453<p>Note that calling this intrinsic does not prevent function inlining or other
5454 aggressive transformations, so the value returned may not be that of the
5455 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5456
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5457</div>
5458
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5459<!-- _______________________________________________________________________ -->
5460<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5461 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5462</div>
5463
5464<div class="doc_text">
5465
5466<h5>Syntax:</h5>
5467<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5468 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5469</pre>
5470
5471<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5472<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5473 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5474
5475<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5476<p>The argument to this intrinsic indicates which function to return the frame
5477 pointer for. Zero indicates the calling function, one indicates its caller,
5478 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5479
5480<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5481<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5482 indicating the frame address of the specified call frame, or zero if it
5483 cannot be identified. The value returned by this intrinsic is likely to be
5484 incorrect or 0 for arguments other than zero, so it should only be used for
5485 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5486
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5487<p>Note that calling this intrinsic does not prevent function inlining or other
5488 aggressive transformations, so the value returned may not be that of the
5489 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5490
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5491</div>
5492
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5493<!-- _______________________________________________________________________ -->
5494<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5495 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5496</div>
5497
5498<div class="doc_text">
5499
5500<h5>Syntax:</h5>
5501<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5502 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5503</pre>
5504
5505<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5506<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5507 of the function stack, for use
5508 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5509 useful for implementing language features like scoped automatic variable
5510 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5511
5512<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5513<p>This intrinsic returns a opaque pointer value that can be passed
5514 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5515 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5516 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5517 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5518 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5519 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5520
5521</div>
5522
5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5525 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5526</div>
5527
5528<div class="doc_text">
5529
5530<h5>Syntax:</h5>
5531<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5532 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5533</pre>
5534
5535<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5536<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5537 the function stack to the state it was in when the
5538 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5539 executed. This is useful for implementing language features like scoped
5540 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5541
5542<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5543<p>See the description
5544 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5545
5546</div>
5547
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]5548<!-- _______________________________________________________________________ -->
5549<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5550 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5551</div>
5552
5553<div class="doc_text">
5554
5555<h5>Syntax:</h5>
5556<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5557 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]5558</pre>
5559
5560<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5561<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5562 insert a prefetch instruction if supported; otherwise, it is a noop.
5563 Prefetches have no effect on the behavior of the program but can change its
5564 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5565
5566<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5567<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5568 specifier determining if the fetch should be for a read (0) or write (1),
5569 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5570 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5571 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5572
5573<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5574<p>This intrinsic does not modify the behavior of the program. In particular,
5575 prefetches cannot trap and do not produce a value. On targets that support
5576 this intrinsic, the prefetch can provide hints to the processor cache for
5577 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]5578
5579</div>
5580
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5583 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]5590 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5594<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5595 Counter (PC) in a region of code to simulators and other tools. The method
5596 is target specific, but it is expected that the marker will use exported
5597 symbols to transmit the PC of the marker. The marker makes no guarantees
5598 that it will remain with any specific instruction after optimizations. It is
5599 possible that the presence of a marker will inhibit optimizations. The
5600 intended use is to be inserted after optimizations to allow correlations of
5601 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5604<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5605
5606<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5607<p>This intrinsic does not modify the behavior of the program. Backends that do
5608 not support this intrinisic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]5609
5610</div>
5611
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5614 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
5620<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5621 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5622</pre>
5623
5624<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5625<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5626 counter register (or similar low latency, high accuracy clocks) on those
5627 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5628 should map to RPCC. As the backing counters overflow quickly (on the order
5629 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5630
5631<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632<p>When directly supported, reading the cycle counter should not modify any
5633 memory. Implementations are allowed to either return a application specific
5634 value or a system wide value. On backends without support, this is lowered
5635 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]5636
5637</div>
5638
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5639<!-- ======================================================================= -->
5640<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5641 <a name="int_libc">Standard C Library Intrinsics</a>
5642</div>
5643
5644<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5645
5646<p>LLVM provides intrinsics for a few important standard C library functions.
5647 These intrinsics allow source-language front-ends to pass information about
5648 the alignment of the pointer arguments to the code generator, providing
5649 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5650
5651</div>
5652
5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5655 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5661<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5662 integer bit width. Not all targets support all bit widths however.</p>
5663
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5664<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5665 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5666 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5668 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5669 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5670 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5671 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5672 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5673</pre>
5674
5675<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5677 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5678
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5679<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5680 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5681
5682<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5683<p>The first argument is a pointer to the destination, the second is a pointer
5684 to the source. The third argument is an integer argument specifying the
5685 number of bytes to copy, and the fourth argument is the alignment of the
5686 source and destination locations.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5687
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5688<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5689 then the caller guarantees that both the source and destination pointers are
5690 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5691
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5692<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5694 source location to the destination location, which are not allowed to
5695 overlap. It copies "len" bytes of memory over. If the argument is known to
5696 be aligned to some boundary, this can be specified as the fourth argument,
5697 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5698
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]5699</div>
5700
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5701<!-- _______________________________________________________________________ -->
5702<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5703 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5704</div>
5705
5706<div class="doc_text">
5707
5708<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5709<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]5710 width. Not all targets support all bit widths however.</p>
5711
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5712<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5713 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5715 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5716 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5717 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5718 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5719 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5720 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5721</pre>
5722
5723<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5724<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5725 source location to the destination location. It is similar to the
5726 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5727 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5728
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5729<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5730 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5731
5732<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5733<p>The first argument is a pointer to the destination, the second is a pointer
5734 to the source. The third argument is an integer argument specifying the
5735 number of bytes to copy, and the fourth argument is the alignment of the
5736 source and destination locations.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5737
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5738<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5739 then the caller guarantees that the source and destination pointers are
5740 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]5741
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5742<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5743<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5744 source location to the destination location, which may overlap. It copies
5745 "len" bytes of memory over. If the argument is known to be aligned to some
5746 boundary, this can be specified as the fourth argument, otherwise it should
5747 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5748
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]5749</div>
5750
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5751<!-- _______________________________________________________________________ -->
5752<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5753 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5754</div>
5755
5756<div class="doc_text">
5757
5758<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5759<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]5760 width. Not all targets support all bit widths however.</p>
5761
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5762<pre>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5763 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]5765 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5766 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5767 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5768 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5769 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5770 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5771</pre>
5772
5773<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5775 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5776
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5778 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The first argument is a pointer to the destination to fill, the second is the
5782 byte value to fill it with, the third argument is an integer argument
5783 specifying the number of bytes to fill, and the fourth argument is the known
5784 alignment of destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5785
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5786<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5787 then the caller guarantees that the destination pointer is aligned to that
5788 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5789
5790<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5791<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5792 at the destination location. If the argument is known to be aligned to some
5793 boundary, this can be specified as the fourth argument, otherwise it should
5794 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5795
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]5796</div>
5797
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5800 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5806<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5807 floating point or vector of floating point type. Not all targets support all
5808 types however.</p>
5809
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5810<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5811 declare float @llvm.sqrt.f32(float %Val)
5812 declare double @llvm.sqrt.f64(double %Val)
5813 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5814 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5815 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5816</pre>
5817
5818<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5820 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5821 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5822 behavior for negative numbers other than -0.0 (which allows for better
5823 optimization, because there is no need to worry about errno being
5824 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]5825
5826<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827<p>The argument and return value are floating point numbers of the same
5828 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5829
5830<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5831<p>This function returns the sqrt of the specified operand if it is a
5832 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5833
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]5834</div>
5835
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5836<!-- _______________________________________________________________________ -->
5837<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5838 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5839</div>
5840
5841<div class="doc_text">
5842
5843<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5844<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5845 floating point or vector of floating point type. Not all targets support all
5846 types however.</p>
5847
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5848<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]5849 declare float @llvm.powi.f32(float %Val, i32 %power)
5850 declare double @llvm.powi.f64(double %Val, i32 %power)
5851 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5852 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5853 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5854</pre>
5855
5856<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5858 specified (positive or negative) power. The order of evaluation of
5859 multiplications is not defined. When a vector of floating point type is
5860 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5861
5862<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5863<p>The second argument is an integer power, and the first is a value to raise to
5864 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5865
5866<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5867<p>This function returns the first value raised to the second power with an
5868 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5869
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]5870</div>
5871
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5872<!-- _______________________________________________________________________ -->
5873<div class="doc_subsubsection">
5874 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5875</div>
5876
5877<div class="doc_text">
5878
5879<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5880<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5881 floating point or vector of floating point type. Not all targets support all
5882 types however.</p>
5883
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5884<pre>
5885 declare float @llvm.sin.f32(float %Val)
5886 declare double @llvm.sin.f64(double %Val)
5887 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5888 declare fp128 @llvm.sin.f128(fp128 %Val)
5889 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5890</pre>
5891
5892<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5894
5895<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5896<p>The argument and return value are floating point numbers of the same
5897 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5898
5899<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5900<p>This function returns the sine of the specified operand, returning the same
5901 values as the libm <tt>sin</tt> functions would, and handles error conditions
5902 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5903
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5904</div>
5905
5906<!-- _______________________________________________________________________ -->
5907<div class="doc_subsubsection">
5908 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5909</div>
5910
5911<div class="doc_text">
5912
5913<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5914<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5915 floating point or vector of floating point type. Not all targets support all
5916 types however.</p>
5917
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5918<pre>
5919 declare float @llvm.cos.f32(float %Val)
5920 declare double @llvm.cos.f64(double %Val)
5921 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5922 declare fp128 @llvm.cos.f128(fp128 %Val)
5923 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5924</pre>
5925
5926<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5927<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5928
5929<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5930<p>The argument and return value are floating point numbers of the same
5931 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5932
5933<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5934<p>This function returns the cosine of the specified operand, returning the same
5935 values as the libm <tt>cos</tt> functions would, and handles error conditions
5936 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5937
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5938</div>
5939
5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
5942 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5948<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5949 floating point or vector of floating point type. Not all targets support all
5950 types however.</p>
5951
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5952<pre>
5953 declare float @llvm.pow.f32(float %Val, float %Power)
5954 declare double @llvm.pow.f64(double %Val, double %Power)
5955 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5956 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5957 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5958</pre>
5959
5960<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5961<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5962 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5963
5964<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965<p>The second argument is a floating point power, and the first is a value to
5966 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5967
5968<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5969<p>This function returns the first value raised to the second power, returning
5970 the same values as the libm <tt>pow</tt> functions would, and handles error
5971 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5972
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]5973</div>
5974
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5975<!-- ======================================================================= -->
5976<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5977 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5978</div>
5979
5980<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5981
5982<p>LLVM provides intrinsics for a few important bit manipulation operations.
5983 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5984
5985</div>
5986
5987<!-- _______________________________________________________________________ -->
5988<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5989 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5990</div>
5991
5992<div class="doc_text">
5993
5994<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5995<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5996 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5997
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5998<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5999 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6000 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6001 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6002</pre>
6003
6004<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6006 values with an even number of bytes (positive multiple of 16 bits). These
6007 are useful for performing operations on data that is not in the target's
6008 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6009
6010<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6011<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6012 and low byte of the input i16 swapped. Similarly,
6013 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6014 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6015 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6016 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6017 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6018 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]6019
6020</div>
6021
6022<!-- _______________________________________________________________________ -->
6023<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]6024 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6025</div>
6026
6027<div class="doc_text">
6028
6029<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6030<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]6031 width. Not all targets support all bit widths however.</p>
6032
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6033<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6034 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6035 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6036 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6037 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6038 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6039</pre>
6040
6041<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6042<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6043 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6044
6045<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6046<p>The only argument is the value to be counted. The argument may be of any
6047 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6048
6049<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6050<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]6051
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6052</div>
6053
6054<!-- _______________________________________________________________________ -->
6055<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6056 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6057</div>
6058
6059<div class="doc_text">
6060
6061<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6062<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6063 integer bit width. Not all targets support all bit widths however.</p>
6064
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6065<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6066 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6067 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6068 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6069 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6070 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6071</pre>
6072
6073<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6075 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6076
6077<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6078<p>The only argument is the value to be counted. The argument may be of any
6079 integer type. The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6080
6081<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6082<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6083 zeros in a variable. If the src == 0 then the result is the size in bits of
6084 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6085
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]6086</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6087
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6088<!-- _______________________________________________________________________ -->
6089<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]6090 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6096<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6097 integer bit width. Not all targets support all bit widths however.</p>
6098
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6099<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6100 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6101 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6102 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]6103 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6104 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6105</pre>
6106
6107<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6108<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6109 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6110
6111<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6112<p>The only argument is the value to be counted. The argument may be of any
6113 integer type. The return type must match the argument type.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6114
6115<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6116<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6117 zeros in a variable. If the src == 0 then the result is the size in bits of
6118 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6119
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]6120</div>
6121
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6122<!-- ======================================================================= -->
6123<div class="doc_subsection">
6124 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6125</div>
6126
6127<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6128
6129<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6130
6131</div>
6132
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6133<!-- _______________________________________________________________________ -->
6134<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6135 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6136</div>
6137
6138<div class="doc_text">
6139
6140<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6141<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]6142 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6143
6144<pre>
6145 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6146 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6147 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6148</pre>
6149
6150<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6151<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6152 a signed addition of the two arguments, and indicate whether an overflow
6153 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6156<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]6157 be of integer types of any bit width, but they must have the same bit
6158 width. The second element of the result structure must be of
6159 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6160 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6163<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6164 a signed addition of the two variables. They return a structure &mdash; the
6165 first element of which is the signed summation, and the second element of
6166 which is a bit specifying if the signed summation resulted in an
6167 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6168
6169<h5>Examples:</h5>
6170<pre>
6171 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6172 %sum = extractvalue {i32, i1} %res, 0
6173 %obit = extractvalue {i32, i1} %res, 1
6174 br i1 %obit, label %overflow, label %normal
6175</pre>
6176
6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6181 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6187<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]6188 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<pre>
6191 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6192 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6193 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6194</pre>
6195
6196<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6197<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6198 an unsigned addition of the two arguments, and indicate whether a carry
6199 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6202<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]6203 be of integer types of any bit width, but they must have the same bit
6204 width. The second element of the result structure must be of
6205 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6206 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6207
6208<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6209<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6210 an unsigned addition of the two arguments. They return a structure &mdash;
6211 the first element of which is the sum, and the second element of which is a
6212 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6213
6214<h5>Examples:</h5>
6215<pre>
6216 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6217 %sum = extractvalue {i32, i1} %res, 0
6218 %obit = extractvalue {i32, i1} %res, 1
6219 br i1 %obit, label %carry, label %normal
6220</pre>
6221
6222</div>
6223
6224<!-- _______________________________________________________________________ -->
6225<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6226 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6227</div>
6228
6229<div class="doc_text">
6230
6231<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6232<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]6233 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6234
6235<pre>
6236 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6237 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6238 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6239</pre>
6240
6241<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6242<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6243 a signed subtraction of the two arguments, and indicate whether an overflow
6244 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6247<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]6248 be of integer types of any bit width, but they must have the same bit
6249 width. The second element of the result structure must be of
6250 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6251 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6254<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6255 a signed subtraction of the two arguments. They return a structure &mdash;
6256 the first element of which is the subtraction, and the second element of
6257 which is a bit specifying if the signed subtraction resulted in an
6258 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6259
6260<h5>Examples:</h5>
6261<pre>
6262 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6263 %sum = extractvalue {i32, i1} %res, 0
6264 %obit = extractvalue {i32, i1} %res, 1
6265 br i1 %obit, label %overflow, label %normal
6266</pre>
6267
6268</div>
6269
6270<!-- _______________________________________________________________________ -->
6271<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6272 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6273</div>
6274
6275<div class="doc_text">
6276
6277<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6278<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]6279 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<pre>
6282 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6283 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6284 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6285</pre>
6286
6287<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6288<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6289 an unsigned subtraction of the two arguments, and indicate whether an
6290 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6291
6292<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6293<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]6294 be of integer types of any bit width, but they must have the same bit
6295 width. The second element of the result structure must be of
6296 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6297 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6298
6299<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6300<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6301 an unsigned subtraction of the two arguments. They return a structure &mdash;
6302 the first element of which is the subtraction, and the second element of
6303 which is a bit specifying if the unsigned subtraction resulted in an
6304 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6305
6306<h5>Examples:</h5>
6307<pre>
6308 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6309 %sum = extractvalue {i32, i1} %res, 0
6310 %obit = extractvalue {i32, i1} %res, 1
6311 br i1 %obit, label %overflow, label %normal
6312</pre>
6313
6314</div>
6315
6316<!-- _______________________________________________________________________ -->
6317<div class="doc_subsubsection">
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]6318 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6319</div>
6320
6321<div class="doc_text">
6322
6323<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6324<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]6325 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6326
6327<pre>
6328 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6329 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6330 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6331</pre>
6332
6333<h5>Overview:</h5>
6334
6335<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6336 a signed multiplication of the two arguments, and indicate whether an
6337 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6340<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]6341 be of integer types of any bit width, but they must have the same bit
6342 width. The second element of the result structure must be of
6343 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6344 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6347<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6348 a signed multiplication of the two arguments. They return a structure &mdash;
6349 the first element of which is the multiplication, and the second element of
6350 which is a bit specifying if the signed multiplication resulted in an
6351 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]6352
6353<h5>Examples:</h5>
6354<pre>
6355 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6356 %sum = extractvalue {i32, i1} %res, 0
6357 %obit = extractvalue {i32, i1} %res, 1
6358 br i1 %obit, label %overflow, label %normal
6359</pre>
6360
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]6361</div>
6362
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6363<!-- _______________________________________________________________________ -->
6364<div class="doc_subsubsection">
6365 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6366</div>
6367
6368<div class="doc_text">
6369
6370<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6371<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]6372 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6373
6374<pre>
6375 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6376 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6377 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6378</pre>
6379
6380<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6381<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6382 a unsigned multiplication of the two arguments, and indicate whether an
6383 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6384
6385<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6386<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]6387 be of integer types of any bit width, but they must have the same bit
6388 width. The second element of the result structure must be of
6389 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6390 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6393<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6394 an unsigned multiplication of the two arguments. They return a structure
6395 &mdash; the first element of which is the multiplication, and the second
6396 element of which is a bit specifying if the unsigned multiplication resulted
6397 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]6398
6399<h5>Examples:</h5>
6400<pre>
6401 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6402 %sum = extractvalue {i32, i1} %res, 0
6403 %obit = extractvalue {i32, i1} %res, 1
6404 br i1 %obit, label %overflow, label %normal
6405</pre>
6406
6407</div>
6408
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6409<!-- ======================================================================= -->
6410<div class="doc_subsection">
6411 <a name="int_debugger">Debugger Intrinsics</a>
6412</div>
6413
6414<div class="doc_text">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6415
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6416<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6417 prefix), are described in
6418 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6419 Level Debugging</a> document.</p>
6420
6421</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6422
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6423<!-- ======================================================================= -->
6424<div class="doc_subsection">
6425 <a name="int_eh">Exception Handling Intrinsics</a>
6426</div>
6427
6428<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6429
6430<p>The LLVM exception handling intrinsics (which all start with
6431 <tt>llvm.eh.</tt> prefix), are described in
6432 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6433 Handling</a> document.</p>
6434
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]6435</div>
6436
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6437<!-- ======================================================================= -->
6438<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6439 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6440</div>
6441
6442<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6443
6444<p>This intrinsic makes it possible to excise one parameter, marked with
6445 the <tt>nest</tt> attribute, from a function. The result is a callable
6446 function pointer lacking the nest parameter - the caller does not need to
6447 provide a value for it. Instead, the value to use is stored in advance in a
6448 "trampoline", a block of memory usually allocated on the stack, which also
6449 contains code to splice the nest value into the argument list. This is used
6450 to implement the GCC nested function address extension.</p>
6451
6452<p>For example, if the function is
6453 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6454 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6455 follows:</p>
6456
6457<div class="doc_code">
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6458<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]6459 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6460 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6461 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6462 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6463</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464</div>
6465
6466<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6467 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6468
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6469</div>
6470
6471<!-- _______________________________________________________________________ -->
6472<div class="doc_subsubsection">
6473 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6474</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6475
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6476<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6477
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6478<h5>Syntax:</h5>
6479<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6480 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]6481</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6482
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6483<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6484<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6485 function pointer suitable for executing it.</p>
6486
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6487<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6488<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6489 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6490 sufficiently aligned block of memory; this memory is written to by the
6491 intrinsic. Note that the size and the alignment are target-specific - LLVM
6492 currently provides no portable way of determining them, so a front-end that
6493 generates this intrinsic needs to have some target-specific knowledge.
6494 The <tt>func</tt> argument must hold a function bitcast to
6495 an <tt>i8*</tt>.</p>
6496
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6497<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6498<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6499 dependent code, turning it into a function. A pointer to this function is
6500 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6501 function pointer type</a> before being called. The new function's signature
6502 is the same as that of <tt>func</tt> with any arguments marked with
6503 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6504 is allowed, and it must be of pointer type. Calling the new function is
6505 equivalent to calling <tt>func</tt> with the same argument list, but
6506 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6507 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6508 by <tt>tramp</tt> is modified, then the effect of any later call to the
6509 returned function pointer is undefined.</p>
6510
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]6511</div>
6512
6513<!-- ======================================================================= -->
6514<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6515 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6516</div>
6517
6518<div class="doc_text">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6519
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6520<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6521 hardware constructs for atomic operations and memory synchronization. This
6522 provides an interface to the hardware, not an interface to the programmer. It
6523 is aimed at a low enough level to allow any programming models or APIs
6524 (Application Programming Interfaces) which need atomic behaviors to map
6525 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6526 hardware provides a "universal IR" for source languages, it also provides a
6527 starting point for developing a "universal" atomic operation and
6528 synchronization IR.</p>
6529
6530<p>These do <em>not</em> form an API such as high-level threading libraries,
6531 software transaction memory systems, atomic primitives, and intrinsic
6532 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6533 application libraries. The hardware interface provided by LLVM should allow
6534 a clean implementation of all of these APIs and parallel programming models.
6535 No one model or paradigm should be selected above others unless the hardware
6536 itself ubiquitously does so.</p>
6537
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6538</div>
6539
6540<!-- _______________________________________________________________________ -->
6541<div class="doc_subsubsection">
6542 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6543</div>
6544<div class="doc_text">
6545<h5>Syntax:</h5>
6546<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6547 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]6548</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6549
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6550<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6551<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6552 specific pairs of memory access types.</p>
6553
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6554<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6556 The first four arguments enables a specific barrier as listed below. The
6557 fith argument specifies that the barrier applies to io or device or uncached
6558 memory.</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6559
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6560<ul>
6561 <li><tt>ll</tt>: load-load barrier</li>
6562 <li><tt>ls</tt>: load-store barrier</li>
6563 <li><tt>sl</tt>: store-load barrier</li>
6564 <li><tt>ss</tt>: store-store barrier</li>
6565 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6566</ul>
6567
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6568<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6569<p>This intrinsic causes the system to enforce some ordering constraints upon
6570 the loads and stores of the program. This barrier does not
6571 indicate <em>when</em> any events will occur, it only enforces
6572 an <em>order</em> in which they occur. For any of the specified pairs of load
6573 and store operations (f.ex. load-load, or store-load), all of the first
6574 operations preceding the barrier will complete before any of the second
6575 operations succeeding the barrier begin. Specifically the semantics for each
6576 pairing is as follows:</p>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6577
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6578<ul>
6579 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6580 after the barrier begins.</li>
6581 <li><tt>ls</tt>: All loads before the barrier must complete before any
6582 store after the barrier begins.</li>
6583 <li><tt>ss</tt>: All stores before the barrier must complete before any
6584 store after the barrier begins.</li>
6585 <li><tt>sl</tt>: All stores before the barrier must complete before any
6586 load after the barrier begins.</li>
6587</ul>
6588
6589<p>These semantics are applied with a logical "and" behavior when more than one
6590 is enabled in a single memory barrier intrinsic.</p>
6591
6592<p>Backends may implement stronger barriers than those requested when they do
6593 not support as fine grained a barrier as requested. Some architectures do
6594 not need all types of barriers and on such architectures, these become
6595 noops.</p>
6596
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6597<h5>Example:</h5>
6598<pre>
6599%ptr = malloc i32
6600 store i32 4, %ptr
6601
6602%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6603 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6604 <i>; guarantee the above finishes</i>
6605 store i32 8, %ptr <i>; before this begins</i>
6606</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6607
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6608</div>
6609
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6610<!-- _______________________________________________________________________ -->
6611<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6612 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6613</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6614
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6615<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6617<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6618<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6619 any integer bit width and for different address spaces. Not all targets
6620 support all bit widths however.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6621
6622<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6623 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6624 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6625 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6626 declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6627</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6628
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6629<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6630<p>This loads a value in memory and compares it to a given value. If they are
6631 equal, it stores a new value into the memory.</p>
6632
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6633<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6634<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6635 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6636 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6637 this integer type. While any bit width integer may be used, targets may only
6638 lower representations they support in hardware.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6639
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6640<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6641<p>This entire intrinsic must be executed atomically. It first loads the value
6642 in memory pointed to by <tt>ptr</tt> and compares it with the
6643 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6644 memory. The loaded value is yielded in all cases. This provides the
6645 equivalent of an atomic compare-and-swap operation within the SSA
6646 framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6647
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6648<h5>Examples:</h5>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6649<pre>
6650%ptr = malloc i32
6651 store i32 4, %ptr
6652
6653%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6654%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6655 <i>; yields {i32}:result1 = 4</i>
6656%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6657%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6658
6659%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6660%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6661 <i>; yields {i32}:result2 = 8</i>
6662%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6663
6664%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6665</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6666
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6667</div>
6668
6669<!-- _______________________________________________________________________ -->
6670<div class="doc_subsubsection">
6671 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6672</div>
6673<div class="doc_text">
6674<h5>Syntax:</h5>
6675
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6676<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6677 integer bit width. Not all targets support all bit widths however.</p>
6678
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6679<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6680 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6681 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6682 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6683 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]6684</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6685
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6686<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6687<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6688 the value from memory. It then stores the value in <tt>val</tt> in the memory
6689 at <tt>ptr</tt>.</p>
6690
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6691<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6692<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6693 the <tt>val</tt> argument and the result must be integers of the same bit
6694 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6695 integer type. The targets may only lower integer representations they
6696 support.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6697
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6698<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6699<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6700 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6701 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6702
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6703<h5>Examples:</h5>
6704<pre>
6705%ptr = malloc i32
6706 store i32 4, %ptr
6707
6708%val1 = add i32 4, 4
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6709%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6710 <i>; yields {i32}:result1 = 4</i>
6711%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6712%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6713
6714%val2 = add i32 1, 1
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6715%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6716 <i>; yields {i32}:result2 = 8</i>
6717
6718%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6719%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6720</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6721
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6722</div>
6723
6724<!-- _______________________________________________________________________ -->
6725<div class="doc_subsubsection">
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6726 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6727
6728</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6729
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6730<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6731
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6732<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6733<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6734 any integer bit width. Not all targets support all bit widths however.</p>
6735
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6736<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6737 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6738 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6739 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6740 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]6741</pre>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6742
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6743<h5>Overview:</h5>
6744<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6745 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6746
6747<h5>Arguments:</h5>
6748<p>The intrinsic takes two arguments, the first a pointer to an integer value
6749 and the second an integer value. The result is also an integer value. These
6750 integer types can have any bit width, but they must all have the same bit
6751 width. The targets may only lower integer representations they support.</p>
6752
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6753<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6754<p>This intrinsic does a series of operations atomically. It first loads the
6755 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6756 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]6757
6758<h5>Examples:</h5>
6759<pre>
6760%ptr = malloc i32
6761 store i32 4, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6762%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6763 <i>; yields {i32}:result1 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6764%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6766%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6767 <i>; yields {i32}:result3 = 10</i>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6768%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6769</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6770
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]6771</div>
6772
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6773<!-- _______________________________________________________________________ -->
6774<div class="doc_subsubsection">
6775 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6776
6777</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6778
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6779<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6780
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6781<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6782<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6783 any integer bit width and for different address spaces. Not all targets
6784 support all bit widths however.</p>
6785
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6786<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6787 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6788 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6789 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6790 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]6791</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6792
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6793<h5>Overview:</h5>
6794<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6795 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6796
6797<h5>Arguments:</h5>
6798<p>The intrinsic takes two arguments, the first a pointer to an integer value
6799 and the second an integer value. The result is also an integer value. These
6800 integer types can have any bit width, but they must all have the same bit
6801 width. The targets may only lower integer representations they support.</p>
6802
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6803<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6804<p>This intrinsic does a series of operations atomically. It first loads the
6805 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6806 result to <tt>ptr</tt>. It yields the original value stored
6807 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6808
6809<h5>Examples:</h5>
6810<pre>
6811%ptr = malloc i32
6812 store i32 8, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6813%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6814 <i>; yields {i32}:result1 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6815%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6816 <i>; yields {i32}:result2 = 4</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6817%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6818 <i>; yields {i32}:result3 = 2</i>
6819%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6820</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6821
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6822</div>
6823
6824<!-- _______________________________________________________________________ -->
6825<div class="doc_subsubsection">
6826 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6827 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6828 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6829 <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]6830</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6831
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6832<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6833
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6834<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6835<p>These are overloaded intrinsics. You can
6836 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6837 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6838 bit width and for different address spaces. Not all targets support all bit
6839 widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6840
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6841<pre>
6842 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6843 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6844 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6845 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]6846</pre>
6847
6848<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6849 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6850 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6851 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6852 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]6853</pre>
6854
6855<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6856 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859 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]6860</pre>
6861
6862<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6863 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6864 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6865 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6866 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]6867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6868
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6869<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6871 the value stored in memory at <tt>ptr</tt>. It yields the original value
6872 at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6873
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6874<h5>Arguments:</h5>
6875<p>These intrinsics take two arguments, the first a pointer to an integer value
6876 and the second an integer value. The result is also an integer value. These
6877 integer types can have any bit width, but they must all have the same bit
6878 width. The targets may only lower integer representations they support.</p>
6879
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6880<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6881<p>These intrinsics does a series of operations atomically. They first load the
6882 value stored at <tt>ptr</tt>. They then do the bitwise
6883 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6884 original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6885
6886<h5>Examples:</h5>
6887<pre>
6888%ptr = malloc i32
6889 store i32 0x0F0F, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6890%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6891 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6892%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6893 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6894%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6895 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6896%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result3 = FF</i>
6898%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6899</pre>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6900
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6901</div>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6902
6903<!-- _______________________________________________________________________ -->
6904<div class="doc_subsubsection">
6905 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6906 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6907 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6908 <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]6909</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6910
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6911<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6912
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6913<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6914<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6915 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6916 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6917 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6918
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6919<pre>
6920 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6921 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6922 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6923 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]6924</pre>
6925
6926<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6927 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 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]6931</pre>
6932
6933<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 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]6938</pre>
6939
6940<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6941 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6942 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6943 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6944 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]6945</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6946
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6947<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6948<p>These intrinsics takes the signed or unsigned minimum or maximum of
6949 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6950 original value at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6951
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6952<h5>Arguments:</h5>
6953<p>These intrinsics take two arguments, the first a pointer to an integer value
6954 and the second an integer value. The result is also an integer value. These
6955 integer types can have any bit width, but they must all have the same bit
6956 width. The targets may only lower integer representations they support.</p>
6957
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6958<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6959<p>These intrinsics does a series of operations atomically. They first load the
6960 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6961 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6962 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6963
6964<h5>Examples:</h5>
6965<pre>
6966%ptr = malloc i32
6967 store i32 7, %ptr
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6968%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6969 <i>; yields {i32}:result0 = 7</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6970%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6971 <i>; yields {i32}:result1 = -2</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6972%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6973 <i>; yields {i32}:result2 = 8</i>
Mon P Wange3b3a722008-07-30 04:36:53 +0000[diff] [blame]6974%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6975 <i>; yields {i32}:result3 = 8</i>
6976%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6977</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6978
Mon P Wang28873102008-06-25 08:15:39 +0000[diff] [blame]6979</div>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]6980
6981<!-- ======================================================================= -->
6982<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6983 <a name="int_general">General Intrinsics</a>
6984</div>
6985
6986<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6987
6988<p>This class of intrinsics is designed to be generic and has no specific
6989 purpose.</p>
6990
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]6991</div>
6992
6993<!-- _______________________________________________________________________ -->
6994<div class="doc_subsubsection">
6995 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6996</div>
6997
6998<div class="doc_text">
6999
7000<h5>Syntax:</h5>
7001<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]7002 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]7003</pre>
7004
7005<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7006<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7007
7008<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7009<p>The first argument is a pointer to a value, the second is a pointer to a
7010 global string, the third is a pointer to a global string which is the source
7011 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7012
7013<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7014<p>This intrinsic allows annotation of local variables with arbitrary strings.
7015 This can be useful for special purpose optimizations that want to look for
7016 these annotations. These have no other defined use, they are ignored by code
7017 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7018
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7019</div>
7020
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7021<!-- _______________________________________________________________________ -->
7022<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]7023 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7024</div>
7025
7026<div class="doc_text">
7027
7028<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7029<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7030 any integer bit width.</p>
7031
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7032<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]7033 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7034 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7035 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7036 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7037 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]7038</pre>
7039
7040<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7041<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7042
7043<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7044<p>The first argument is an integer value (result of some expression), the
7045 second is a pointer to a global string, the third is a pointer to a global
7046 string which is the source file name, and the last argument is the line
7047 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7048
7049<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7050<p>This intrinsic allows annotations to be put on arbitrary expressions with
7051 arbitrary strings. This can be useful for special purpose optimizations that
7052 want to look for these annotations. These have no other defined use, they
7053 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7054
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]7055</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7056
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7057<!-- _______________________________________________________________________ -->
7058<div class="doc_subsubsection">
7059 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7060</div>
7061
7062<div class="doc_text">
7063
7064<h5>Syntax:</h5>
7065<pre>
7066 declare void @llvm.trap()
7067</pre>
7068
7069<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7070<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7071
7072<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7073<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7074
7075<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7076<p>This intrinsics is lowered to the target dependent trap instruction. If the
7077 target does not have a trap instruction, this intrinsic will be lowered to
7078 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7079
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]7080</div>
7081
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7082<!-- _______________________________________________________________________ -->
7083<div class="doc_subsubsection">
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]7084 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7085</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7086
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7087<div class="doc_text">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7088
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7089<h5>Syntax:</h5>
7090<pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7091 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7092</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7093
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7094<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7095<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7096 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7097 ensure that it is placed on the stack before local variables.</p>
7098
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7099<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7100<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7101 arguments. The first argument is the value loaded from the stack
7102 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7103 that has enough space to hold the value of the guard.</p>
7104
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7105<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7106<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7107 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7108 stack. This is to ensure that if a local variable on the stack is
7109 overwritten, it will destroy the value of the guard. When the function exits,
7110 the guard on the stack is checked against the original guard. If they're
7111 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7112 function.</p>
7113
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]7114</div>
7115
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7116<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]7117<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7118<address>
7119 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7120 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7121 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]7122 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]7123
7124 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]7125 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]7126 Last modified: $Date$
7127</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]7128
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]7129</body>
7130</html>