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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 5a15814098702ea301e2f7ef045b12126c808eaf / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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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>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]114 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
117 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
118 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]119 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
120 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
121 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 </ol>
123 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]124 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]125 <ol>
126 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
127 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
129 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
130 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]131 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
132 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
133 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]135 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
136 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]137 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]138 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#otherops">Other Operations</a>
140 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]141 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
142 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]144 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]146 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]147 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]148 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]149 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]150 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]151 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]152 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]153 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
155 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]156 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
158 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 </ol>
160 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]161 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
162 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]163 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
165 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]166 </ol>
167 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]168 <li><a href="#int_codegen">Code Generator Intrinsics</a>
169 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]170 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
172 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
173 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
174 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
175 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
176 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]177 </ol>
178 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]179 <li><a href="#int_libc">Standard C Library Intrinsics</a>
180 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]181 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
185 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]186 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
188 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]189 </ol>
190 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]191 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]192 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]193 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]194 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
196 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]197 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
198 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]199 </ol>
200 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]201 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]202 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]203 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]206 </ol>
207 </li>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]208 <li><a href="#int_atomics">Atomic intrinsics</a>
209 <ol>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]210 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
211 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
212 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
213 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]214 </ol>
215 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]216 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]217 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]218 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]219 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]220 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]221 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]222 <li><a href="#int_trap">
223 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]224 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]225 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]226 </ol>
227 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]228</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
230<div class="doc_author">
231 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
232 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]233</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]235<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]236<div class="doc_section"> <a name="abstract">Abstract </a></div>
237<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]239<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<p>This document is a reference manual for the LLVM assembly language.
241LLVM is an SSA based representation that provides type safety,
242low-level operations, flexibility, and the capability of representing
243'all' high-level languages cleanly. It is the common code
244representation used throughout all phases of the LLVM compilation
245strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]246</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]248<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]249<div class="doc_section"> <a name="introduction">Introduction</a> </div>
250<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]252<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]254<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]255different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256representation (suitable for fast loading by a Just-In-Time compiler),
257and as a human readable assembly language representation. This allows
258LLVM to provide a powerful intermediate representation for efficient
259compiler transformations and analysis, while providing a natural means
260to debug and visualize the transformations. The three different forms
261of LLVM are all equivalent. This document describes the human readable
262representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]263
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]264<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]265while being expressive, typed, and extensible at the same time. It
266aims to be a "universal IR" of sorts, by being at a low enough level
267that high-level ideas may be cleanly mapped to it (similar to how
268microprocessors are "universal IR's", allowing many source languages to
269be mapped to them). By providing type information, LLVM can be used as
270the target of optimizations: for example, through pointer analysis, it
271can be proven that a C automatic variable is never accessed outside of
272the current function... allowing it to be promoted to a simple SSA
273value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]275</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]277<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]278<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]279
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]280<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]282<p>It is important to note that this document describes 'well formed'
283LLVM assembly language. There is a difference between what the parser
284accepts and what is considered 'well formed'. For example, the
285following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]286
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]287<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]288<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]289%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]290</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]293<p>...because the definition of <tt>%x</tt> does not dominate all of
294its uses. The LLVM infrastructure provides a verification pass that may
295be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]296automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]297the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]298by the verifier pass indicate bugs in transformation passes or input to
299the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]300</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]301
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]302<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]304<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]305<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]306<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]307
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]308<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]309
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]310 <p>LLVM identifiers come in two basic types: global and local. Global
311 identifiers (functions, global variables) begin with the @ character. Local
312 identifiers (register names, types) begin with the % character. Additionally,
313 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]316 <li>Named values are represented as a string of characters with their prefix.
317 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
318 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]319 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]320 with quotes. In this way, anything except a <tt>&quot;</tt> character can
321 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]322
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]323 <li>Unnamed values are represented as an unsigned numeric value with their
324 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]326 <li>Constants, which are described in a <a href="#constants">section about
327 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]328</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]330<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331don't need to worry about name clashes with reserved words, and the set of
332reserved words may be expanded in the future without penalty. Additionally,
333unnamed identifiers allow a compiler to quickly come up with a temporary
334variable without having to avoid symbol table conflicts.</p>
335
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]337languages. There are keywords for different opcodes
338('<tt><a href="#i_add">add</a></tt>',
339 '<tt><a href="#i_bitcast">bitcast</a></tt>',
340 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]341href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]343none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344
345<p>Here is an example of LLVM code to multiply the integer variable
346'<tt>%X</tt>' by 8:</p>
347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]348<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]349
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]350<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]353</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]354</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]356<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]357
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]359<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]361</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]363
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]364<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]365
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]366<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]367<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]368<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
369<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
370%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]371</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]373
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
375important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]378
379 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
380 line.</li>
381
382 <li>Unnamed temporaries are created when the result of a computation is not
383 assigned to a named value.</li>
384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]385 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]387</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]388
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]389<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]390demonstrating instructions, we will follow an instruction with a comment that
391defines the type and name of value produced. Comments are shown in italic
392text.</p>
393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]394</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]395
396<!-- *********************************************************************** -->
397<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
398<!-- *********************************************************************** -->
399
400<!-- ======================================================================= -->
401<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
402</div>
403
404<div class="doc_text">
405
406<p>LLVM programs are composed of "Module"s, each of which is a
407translation unit of the input programs. Each module consists of
408functions, global variables, and symbol table entries. Modules may be
409combined together with the LLVM linker, which merges function (and
410global variable) definitions, resolves forward declarations, and merges
411symbol table entries. Here is an example of the "hello world" module:</p>
412
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]413<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]414<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]415<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
416 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]417
418<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]419<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420
421<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]422define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]423 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]424 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]425 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]426
427 <i>; Call puts function to write out the string to stdout...</i>
428 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]429 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]431 href="#i_ret">ret</a> i32 0<br>}<br>
432</pre>
433</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]434
435<p>This example is made up of a <a href="#globalvars">global variable</a>
436named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
437function, and a <a href="#functionstructure">function definition</a>
438for "<tt>main</tt>".</p>
439
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<p>In general, a module is made up of a list of global values,
441where both functions and global variables are global values. Global values are
442represented by a pointer to a memory location (in this case, a pointer to an
443array of char, and a pointer to a function), and have one of the following <a
444href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]445
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</div>
447
448<!-- ======================================================================= -->
449<div class="doc_subsection">
450 <a name="linkage">Linkage Types</a>
451</div>
452
453<div class="doc_text">
454
455<p>
456All Global Variables and Functions have one of the following types of linkage:
457</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]458
459<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]461 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
463 <dd>Global values with internal linkage are only directly accessible by
464 objects in the current module. In particular, linking code into a module with
465 an internal global value may cause the internal to be renamed as necessary to
466 avoid collisions. Because the symbol is internal to the module, all
467 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]468 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]473 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
474 the same name when linkage occurs. This is typically used to implement
475 inline functions, templates, or other code which must be generated in each
476 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
477 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]478 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]479
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
482 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
483 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]484 used for globals that may be emitted in multiple translation units, but that
485 are not guaranteed to be emitted into every translation unit that uses them.
486 One example of this are common globals in C, such as "<tt>int X;</tt>" at
487 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]489
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]491
492 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
493 pointer to array type. When two global variables with appending linkage are
494 linked together, the two global arrays are appended together. This is the
495 LLVM, typesafe, equivalent of having the system linker append together
496 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]498
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]499 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
500 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
501 until linked, if not linked, the symbol becomes null instead of being an
502 undefined reference.
503 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]504
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]506
507 <dd>If none of the above identifiers are used, the global is externally
508 visible, meaning that it participates in linkage and can be used to resolve
509 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]511</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]512
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]513 <p>
514 The next two types of linkage are targeted for Microsoft Windows platform
515 only. They are designed to support importing (exporting) symbols from (to)
516 DLLs.
517 </p>
518
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]519 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
521
522 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
523 or variable via a global pointer to a pointer that is set up by the DLL
524 exporting the symbol. On Microsoft Windows targets, the pointer name is
525 formed by combining <code>_imp__</code> and the function or variable name.
526 </dd>
527
528 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
531 pointer to a pointer in a DLL, so that it can be referenced with the
532 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
533 name is formed by combining <code>_imp__</code> and the function or variable
534 name.
535 </dd>
536
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]537</dl>
538
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]539<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]540variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
541variable and was linked with this one, one of the two would be renamed,
542preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
543external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]544outside of the current module.</p>
545<p>It is illegal for a function <i>declaration</i>
546to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]547or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]548<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
549linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]550</div>
551
552<!-- ======================================================================= -->
553<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]554 <a name="callingconv">Calling Conventions</a>
555</div>
556
557<div class="doc_text">
558
559<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
560and <a href="#i_invoke">invokes</a> can all have an optional calling convention
561specified for the call. The calling convention of any pair of dynamic
562caller/callee must match, or the behavior of the program is undefined. The
563following calling conventions are supported by LLVM, and more may be added in
564the future:</p>
565
566<dl>
567 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
568
569 <dd>This calling convention (the default if no other calling convention is
570 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]571 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]572 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]573 </dd>
574
575 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
576
577 <dd>This calling convention attempts to make calls as fast as possible
578 (e.g. by passing things in registers). This calling convention allows the
579 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]580 without having to conform to an externally specified ABI. Implementations of
581 this convention should allow arbitrary tail call optimization to be supported.
582 This calling convention does not support varargs and requires the prototype of
583 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]584 </dd>
585
586 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
587
588 <dd>This calling convention attempts to make code in the caller as efficient
589 as possible under the assumption that the call is not commonly executed. As
590 such, these calls often preserve all registers so that the call does not break
591 any live ranges in the caller side. This calling convention does not support
592 varargs and requires the prototype of all callees to exactly match the
593 prototype of the function definition.
594 </dd>
595
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]596 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]597
598 <dd>Any calling convention may be specified by number, allowing
599 target-specific calling conventions to be used. Target specific calling
600 conventions start at 64.
601 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]602</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]603
604<p>More calling conventions can be added/defined on an as-needed basis, to
605support pascal conventions or any other well-known target-independent
606convention.</p>
607
608</div>
609
610<!-- ======================================================================= -->
611<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]612 <a name="visibility">Visibility Styles</a>
613</div>
614
615<div class="doc_text">
616
617<p>
618All Global Variables and Functions have one of the following visibility styles:
619</p>
620
621<dl>
622 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
623
624 <dd>On ELF, default visibility means that the declaration is visible to other
625 modules and, in shared libraries, means that the declared entity may be
626 overridden. On Darwin, default visibility means that the declaration is
627 visible to other modules. Default visibility corresponds to "external
628 linkage" in the language.
629 </dd>
630
631 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
632
633 <dd>Two declarations of an object with hidden visibility refer to the same
634 object if they are in the same shared object. Usually, hidden visibility
635 indicates that the symbol will not be placed into the dynamic symbol table,
636 so no other module (executable or shared library) can reference it
637 directly.
638 </dd>
639
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]640 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
641
642 <dd>On ELF, protected visibility indicates that the symbol will be placed in
643 the dynamic symbol table, but that references within the defining module will
644 bind to the local symbol. That is, the symbol cannot be overridden by another
645 module.
646 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]647</dl>
648
649</div>
650
651<!-- ======================================================================= -->
652<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]653 <a name="globalvars">Global Variables</a>
654</div>
655
656<div class="doc_text">
657
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]658<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]659instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]660an explicit section to be placed in, and may have an optional explicit alignment
661specified. A variable may be defined as "thread_local", which means that it
662will not be shared by threads (each thread will have a separated copy of the
663variable). A variable may be defined as a global "constant," which indicates
664that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]665optimization, allowing the global data to be placed in the read-only section of
666an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]667cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]668
669<p>
670LLVM explicitly allows <em>declarations</em> of global variables to be marked
671constant, even if the final definition of the global is not. This capability
672can be used to enable slightly better optimization of the program, but requires
673the language definition to guarantee that optimizations based on the
674'constantness' are valid for the translation units that do not include the
675definition.
676</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677
678<p>As SSA values, global variables define pointer values that are in
679scope (i.e. they dominate) all basic blocks in the program. Global
680variables always define a pointer to their "content" type because they
681describe a region of memory, and all memory objects in LLVM are
682accessed through pointers.</p>
683
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]684<p>A global variable may be declared to reside in a target-specifc numbered
685address space. For targets that support them, address spaces may affect how
686optimizations are performed and/or what target instructions are used to access
Christopher Lambd49e18d2007-12-12 08:44:39 +0000[diff] [blame]687the variable. The default address space is zero. The address space qualifier
688must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]689
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]690<p>LLVM allows an explicit section to be specified for globals. If the target
691supports it, it will emit globals to the section specified.</p>
692
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]693<p>An explicit alignment may be specified for a global. If not present, or if
694the alignment is set to zero, the alignment of the global is set by the target
695to whatever it feels convenient. If an explicit alignment is specified, the
696global is forced to have at least that much alignment. All alignments must be
697a power of 2.</p>
698
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]699<p>For example, the following defines a global in a numbered address space with
700an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]701
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]702<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]703<pre>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]704@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]705</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]706</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]707
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]708</div>
709
710
711<!-- ======================================================================= -->
712<div class="doc_subsection">
713 <a name="functionstructure">Functions</a>
714</div>
715
716<div class="doc_text">
717
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]718<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
719an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]720<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]721<a href="#callingconv">calling convention</a>, a return type, an optional
722<a href="#paramattrs">parameter attribute</a> for the return type, a function
723name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]724<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]725optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]726opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]727
728LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
729optional <a href="#linkage">linkage type</a>, an optional
730<a href="#visibility">visibility style</a>, an optional
731<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]732<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]733name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]734<a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]735
736<p>A function definition contains a list of basic blocks, forming the CFG for
737the function. Each basic block may optionally start with a label (giving the
738basic block a symbol table entry), contains a list of instructions, and ends
739with a <a href="#terminators">terminator</a> instruction (such as a branch or
740function return).</p>
741
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]742<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]743executed on entrance to the function, and it is not allowed to have predecessor
744basic blocks (i.e. there can not be any branches to the entry block of a
745function). Because the block can have no predecessors, it also cannot have any
746<a href="#i_phi">PHI nodes</a>.</p>
747
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]748<p>LLVM allows an explicit section to be specified for functions. If the target
749supports it, it will emit functions to the section specified.</p>
750
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]751<p>An explicit alignment may be specified for a function. If not present, or if
752the alignment is set to zero, the alignment of the function is set by the target
753to whatever it feels convenient. If an explicit alignment is specified, the
754function is forced to have at least that much alignment. All alignments must be
755a power of 2.</p>
756
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]757</div>
758
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]759
760<!-- ======================================================================= -->
761<div class="doc_subsection">
762 <a name="aliasstructure">Aliases</a>
763</div>
764<div class="doc_text">
765 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov726d45c2008-03-22 08:36:14 +0000[diff] [blame]766 function, global variable, another alias or bitcast of global value). Aliases
767 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]768 optional <a href="#visibility">visibility style</a>.</p>
769
770 <h5>Syntax:</h5>
771
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]772<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]773<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]774@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]775</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]776</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]777
778</div>
779
780
781
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]782<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]783<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
784<div class="doc_text">
785 <p>The return type and each parameter of a function type may have a set of
786 <i>parameter attributes</i> associated with them. Parameter attributes are
787 used to communicate additional information about the result or parameters of
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]788 a function. Parameter attributes are considered to be part of the function,
789 not of the function type, so functions with different parameter attributes
790 can have the same function type.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]791
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]792 <p>Parameter attributes are simple keywords that follow the type specified. If
793 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]794 example:</p>
795
796<div class="doc_code">
797<pre>
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]798declare i32 @printf(i8* noalias , ...) nounwind
799declare i32 @atoi(i8*) nounwind readonly
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]800</pre>
801</div>
802
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]803 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
804 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]805
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]806 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]807 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]808 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]809 <dd>This indicates that the parameter should be zero extended just before
810 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]811
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]812 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]813 <dd>This indicates that the parameter should be sign extended just before
814 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]815
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]816 <dt><tt>inreg</tt></dt>
817 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]818 possible) during assembling function call. Support for this attribute is
819 target-specific</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]820
821 <dt><tt>byval</tt></dt>
Chris Lattner0747baa2008-01-15 04:34:22 +0000[diff] [blame]822 <dd>This indicates that the pointer parameter should really be passed by
823 value to the function. The attribute implies that a hidden copy of the
824 pointee is made between the caller and the callee, so the callee is unable
825 to modify the value in the callee. This attribute is only valid on llvm
826 pointer arguments. It is generally used to pass structs and arrays by
827 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]828
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]829 <dt><tt>sret</tt></dt>
Duncan Sandse26dec62008-02-18 04:19:38 +0000[diff] [blame]830 <dd>This indicates that the pointer parameter specifies the address of a
831 structure that is the return value of the function in the source program.
Duncan Sandsb7f0c082008-03-17 12:17:41 +0000[diff] [blame]832 Loads and stores to the structure are assumed not to trap.
Duncan Sandse26dec62008-02-18 04:19:38 +0000[diff] [blame]833 May only be applied to the first parameter.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]834
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]835 <dt><tt>noalias</tt></dt>
Owen Anderson117bbd32008-02-18 04:09:01 +0000[diff] [blame]836 <dd>This indicates that the parameter does not alias any global or any other
837 parameter. The caller is responsible for ensuring that this is the case,
838 usually by placing the value in a stack allocation.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]839
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]840 <dt><tt>noreturn</tt></dt>
841 <dd>This function attribute indicates that the function never returns. This
842 indicates to LLVM that every call to this function should be treated as if
843 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]844
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]845 <dt><tt>nounwind</tt></dt>
Duncan Sandsb7f0c082008-03-17 12:17:41 +0000[diff] [blame]846 <dd>This function attribute indicates that no exceptions unwind out of the
847 function. Usually this is because the function makes no use of exceptions,
848 but it may also be that the function catches any exceptions thrown when
849 executing it.</dd>
850
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]851 <dt><tt>nest</tt></dt>
852 <dd>This indicates that the parameter can be excised using the
853 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]854 <dt><tt>readonly</tt></dt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]855 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]856 except for producing a return value or throwing an exception. The value
857 returned must only depend on the function arguments and/or global variables.
858 It may use values obtained by dereferencing pointers.</dd>
859 <dt><tt>readnone</tt></dt>
860 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]861 function, but in addition it is not allowed to dereference any pointer arguments
862 or global variables.
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]863 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]864
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]865</div>
866
867<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]868<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]869 <a name="gc">Garbage Collector Names</a>
870</div>
871
872<div class="doc_text">
873<p>Each function may specify a garbage collector name, which is simply a
874string.</p>
875
876<div class="doc_code"><pre
877>define void @f() gc "name" { ...</pre></div>
878
879<p>The compiler declares the supported values of <i>name</i>. Specifying a
880collector which will cause the compiler to alter its output in order to support
881the named garbage collection algorithm.</p>
882</div>
883
884<!-- ======================================================================= -->
885<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]886 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]887</div>
888
889<div class="doc_text">
890<p>
891Modules may contain "module-level inline asm" blocks, which corresponds to the
892GCC "file scope inline asm" blocks. These blocks are internally concatenated by
893LLVM and treated as a single unit, but may be separated in the .ll file if
894desired. The syntax is very simple:
895</p>
896
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]897<div class="doc_code">
898<pre>
899module asm "inline asm code goes here"
900module asm "more can go here"
901</pre>
902</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]903
904<p>The strings can contain any character by escaping non-printable characters.
905 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
906 for the number.
907</p>
908
909<p>
910 The inline asm code is simply printed to the machine code .s file when
911 assembly code is generated.
912</p>
913</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]914
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]915<!-- ======================================================================= -->
916<div class="doc_subsection">
917 <a name="datalayout">Data Layout</a>
918</div>
919
920<div class="doc_text">
921<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]922data is to be laid out in memory. The syntax for the data layout is simply:</p>
923<pre> target datalayout = "<i>layout specification</i>"</pre>
924<p>The <i>layout specification</i> consists of a list of specifications
925separated by the minus sign character ('-'). Each specification starts with a
926letter and may include other information after the letter to define some
927aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]928<dl>
929 <dt><tt>E</tt></dt>
930 <dd>Specifies that the target lays out data in big-endian form. That is, the
931 bits with the most significance have the lowest address location.</dd>
932 <dt><tt>e</tt></dt>
933 <dd>Specifies that hte target lays out data in little-endian form. That is,
934 the bits with the least significance have the lowest address location.</dd>
935 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
936 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
937 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
938 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
939 too.</dd>
940 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
941 <dd>This specifies the alignment for an integer type of a given bit
942 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
943 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
944 <dd>This specifies the alignment for a vector type of a given bit
945 <i>size</i>.</dd>
946 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
947 <dd>This specifies the alignment for a floating point type of a given bit
948 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
949 (double).</dd>
950 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an aggregate type of a given bit
952 <i>size</i>.</dd>
953</dl>
954<p>When constructing the data layout for a given target, LLVM starts with a
955default set of specifications which are then (possibly) overriden by the
956specifications in the <tt>datalayout</tt> keyword. The default specifications
957are given in this list:</p>
958<ul>
959 <li><tt>E</tt> - big endian</li>
960 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
961 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
962 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
963 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
964 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
965 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
966 alignment of 64-bits</li>
967 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
968 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
969 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
970 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
971 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
972</ul>
973<p>When llvm is determining the alignment for a given type, it uses the
974following rules:
975<ol>
976 <li>If the type sought is an exact match for one of the specifications, that
977 specification is used.</li>
978 <li>If no match is found, and the type sought is an integer type, then the
979 smallest integer type that is larger than the bitwidth of the sought type is
980 used. If none of the specifications are larger than the bitwidth then the the
981 largest integer type is used. For example, given the default specifications
982 above, the i7 type will use the alignment of i8 (next largest) while both
983 i65 and i256 will use the alignment of i64 (largest specified).</li>
984 <li>If no match is found, and the type sought is a vector type, then the
985 largest vector type that is smaller than the sought vector type will be used
986 as a fall back. This happens because <128 x double> can be implemented in
987 terms of 64 <2 x double>, for example.</li>
988</ol>
989</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]990
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]991<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]992<div class="doc_section"> <a name="typesystem">Type System</a> </div>
993<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]995<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]997<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]998intermediate representation. Being typed enables a number of
999optimizations to be performed on the IR directly, without having to do
1000extra analyses on the side before the transformation. A strong type
1001system makes it easier to read the generated code and enables novel
1002analyses and transformations that are not feasible to perform on normal
1003three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1004
1005</div>
1006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1007<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1008<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1009Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1010<div class="doc_text">
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1011<p>The types fall into a few useful
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1012classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1013
1014<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1015 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1016 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1018 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1019 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020 </tr>
1021 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1022 <td><a href="#t_floating">floating point</a></td>
1023 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1024 </tr>
1025 <tr>
1026 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1027 <td><a href="#t_integer">integer</a>,
1028 <a href="#t_floating">floating point</a>,
1029 <a href="#t_pointer">pointer</a>,
1030 <a href="#t_vector">vector</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1031 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1032 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1033 <tr>
1034 <td><a href="#t_primitive">primitive</a></td>
1035 <td><a href="#t_label">label</a>,
1036 <a href="#t_void">void</a>,
1037 <a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>.</td>
1039 </tr>
1040 <tr>
1041 <td><a href="#t_derived">derived</a></td>
1042 <td><a href="#t_integer">integer</a>,
1043 <a href="#t_array">array</a>,
1044 <a href="#t_function">function</a>,
1045 <a href="#t_pointer">pointer</a>,
1046 <a href="#t_struct">structure</a>,
1047 <a href="#t_pstruct">packed structure</a>,
1048 <a href="#t_vector">vector</a>,
1049 <a href="#t_opaque">opaque</a>.
1050 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1051 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1052</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1053
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1054<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1055most important. Values of these types are the only ones which can be
1056produced by instructions, passed as arguments, or used as operands to
1057instructions. This means that all structures and arrays must be
1058manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1059</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1061<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1062<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1063
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1064<div class="doc_text">
1065<p>The primitive types are the fundamental building blocks of the LLVM
1066system.</p>
1067
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1068</div>
1069
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1072
1073<div class="doc_text">
1074 <table>
1075 <tbody>
1076 <tr><th>Type</th><th>Description</th></tr>
1077 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1078 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1079 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1080 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1081 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1082 </tbody>
1083 </table>
1084</div>
1085
1086<!-- _______________________________________________________________________ -->
1087<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1088
1089<div class="doc_text">
1090<h5>Overview:</h5>
1091<p>The void type does not represent any value and has no size.</p>
1092
1093<h5>Syntax:</h5>
1094
1095<pre>
1096 void
1097</pre>
1098</div>
1099
1100<!-- _______________________________________________________________________ -->
1101<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1102
1103<div class="doc_text">
1104<h5>Overview:</h5>
1105<p>The label type represents code labels.</p>
1106
1107<h5>Syntax:</h5>
1108
1109<pre>
1110 label
1111</pre>
1112</div>
1113
1114
1115<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1116<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1117
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1118<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1119
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1120<p>The real power in LLVM comes from the derived types in the system.
1121This is what allows a programmer to represent arrays, functions,
1122pointers, and other useful types. Note that these derived types may be
1123recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1124
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1125</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1127<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1128<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1129
1130<div class="doc_text">
1131
1132<h5>Overview:</h5>
1133<p>The integer type is a very simple derived type that simply specifies an
1134arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11352^23-1 (about 8 million) can be specified.</p>
1136
1137<h5>Syntax:</h5>
1138
1139<pre>
1140 iN
1141</pre>
1142
1143<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1144value.</p>
1145
1146<h5>Examples:</h5>
1147<table class="layout">
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1148 <tbody>
1149 <tr>
1150 <td><tt>i1</tt></td>
1151 <td>a single-bit integer.</td>
1152 </tr><tr>
1153 <td><tt>i32</tt></td>
1154 <td>a 32-bit integer.</td>
1155 </tr><tr>
1156 <td><tt>i1942652</tt></td>
1157 <td>a really big integer of over 1 million bits.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1158 </tr>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1159 </tbody>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1160</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1161</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1162
1163<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1164<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1166<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1167
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1168<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1170<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1171sequentially in memory. The array type requires a size (number of
1172elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1173
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1174<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1175
1176<pre>
1177 [&lt;# elements&gt; x &lt;elementtype&gt;]
1178</pre>
1179
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1180<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1181be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1182
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1183<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1184<table class="layout">
1185 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1186 <td class="left"><tt>[40 x i32]</tt></td>
1187 <td class="left">Array of 40 32-bit integer values.</td>
1188 </tr>
1189 <tr class="layout">
1190 <td class="left"><tt>[41 x i32]</tt></td>
1191 <td class="left">Array of 41 32-bit integer values.</td>
1192 </tr>
1193 <tr class="layout">
1194 <td class="left"><tt>[4 x i8]</tt></td>
1195 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1196 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1197</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1198<p>Here are some examples of multidimensional arrays:</p>
1199<table class="layout">
1200 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1201 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1202 <td class="left">3x4 array of 32-bit integer values.</td>
1203 </tr>
1204 <tr class="layout">
1205 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1206 <td class="left">12x10 array of single precision floating point values.</td>
1207 </tr>
1208 <tr class="layout">
1209 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1210 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1211 </tr>
1212</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1213
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1214<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1215length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1216LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1217As a special case, however, zero length arrays are recognized to be variable
1218length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1219type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1221</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1223<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1224<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1225<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1227<p>The function type can be thought of as a function signature. It
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1228consists of a return type and a list of formal parameter types. The
Devang Patel7a3ad1a2008-03-24 20:52:42 +0000[diff] [blame]1229return type of a function type is a scalar type or a void type or a struct type.
1230If the return type is a struct type then all struct elements must be of first
Devang Patel3a5bff82008-03-24 18:10:52 +0000[diff] [blame]1231class types. Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232(which are structures of pointers to functions), for indirect function
1233calls, and when defining a function.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1235<h5>Syntax:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1236<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1237<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]1238specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1239which indicates that the function takes a variable number of arguments.
1240Variable argument functions can access their arguments with the <a
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1241 href="#int_varargs">variable argument handling intrinsic</a> functions.
1242'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1243<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1245<table class="layout">
1246 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1247 <td class="left"><tt>i32 (i32)</tt></td>
1248 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1250 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1251 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1252 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1253 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1254 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1255 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1256 <tt>float</tt>.
1257 </td>
1258 </tr><tr class="layout">
1259 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1260 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1261 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1262 which returns an integer. This is the signature for <tt>printf</tt> in
1263 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1264 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1265 </tr><tr class="layout">
1266 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel3a5bff82008-03-24 18:10:52 +0000[diff] [blame]1267 <td class="left">A function taking an <tt>i32></tt>, returning two
1268 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1269 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1270 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1271</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1273</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1274<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1275<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1276<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1278<p>The structure type is used to represent a collection of data members
1279together in memory. The packing of the field types is defined to match
1280the ABI of the underlying processor. The elements of a structure may
1281be any type that has a size.</p>
1282<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1283and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1284field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1285instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1286<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1287<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1289<table class="layout">
1290 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1291 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1292 <td class="left">A triple of three <tt>i32</tt> values</td>
1293 </tr><tr class="layout">
1294 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1295 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1296 second element is a <a href="#t_pointer">pointer</a> to a
1297 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1298 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1299 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1300</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1301</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1302
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1303<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1304<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1305</div>
1306<div class="doc_text">
1307<h5>Overview:</h5>
1308<p>The packed structure type is used to represent a collection of data members
1309together in memory. There is no padding between fields. Further, the alignment
1310of a packed structure is 1 byte. The elements of a packed structure may
1311be any type that has a size.</p>
1312<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1313and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1314field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1315instruction.</p>
1316<h5>Syntax:</h5>
1317<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1318<h5>Examples:</h5>
1319<table class="layout">
1320 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1321 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1322 <td class="left">A triple of three <tt>i32</tt> values</td>
1323 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1324 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1325 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1326 second element is a <a href="#t_pointer">pointer</a> to a
1327 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1328 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1329 </tr>
1330</table>
1331</div>
1332
1333<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1334<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1335<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1336<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1337<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1338reference to another object, which must live in memory. Pointer types may have
1339an optional address space attribute defining the target-specific numbered
1340address space where the pointed-to object resides. The default address space is
1341zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1342<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1343<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1344<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1345<table class="layout">
1346 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1347 <td class="left"><tt>[4x i32]*</tt></td>
1348 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1349 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1350 </tr>
1351 <tr class="layout">
1352 <td class="left"><tt>i32 (i32 *) *</tt></td>
1353 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1354 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1355 <tt>i32</tt>.</td>
1356 </tr>
1357 <tr class="layout">
1358 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1359 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1360 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1361 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1362</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1364
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1365<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1366<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1368
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1369<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1370
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1371<p>A vector type is a simple derived type that represents a vector
1372of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1373are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1374A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1375elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1376of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1377considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1378
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1379<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1380
1381<pre>
1382 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1383</pre>
1384
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1385<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1386be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1387
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1388<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1389
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1390<table class="layout">
1391 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1392 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1393 <td class="left">Vector of 4 32-bit integer values.</td>
1394 </tr>
1395 <tr class="layout">
1396 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1397 <td class="left">Vector of 8 32-bit floating-point values.</td>
1398 </tr>
1399 <tr class="layout">
1400 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1401 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1402 </tr>
1403</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1404</div>
1405
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1406<!-- _______________________________________________________________________ -->
1407<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411
1412<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1413corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1414In LLVM, opaque types can eventually be resolved to any type (not just a
1415structure type).</p>
1416
1417<h5>Syntax:</h5>
1418
1419<pre>
1420 opaque
1421</pre>
1422
1423<h5>Examples:</h5>
1424
1425<table class="layout">
1426 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1427 <td class="left"><tt>opaque</tt></td>
1428 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1429 </tr>
1430</table>
1431</div>
1432
1433
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1434<!-- *********************************************************************** -->
1435<div class="doc_section"> <a name="constants">Constants</a> </div>
1436<!-- *********************************************************************** -->
1437
1438<div class="doc_text">
1439
1440<p>LLVM has several different basic types of constants. This section describes
1441them all and their syntax.</p>
1442
1443</div>
1444
1445<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1446<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1447
1448<div class="doc_text">
1449
1450<dl>
1451 <dt><b>Boolean constants</b></dt>
1452
1453 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1454 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1455 </dd>
1456
1457 <dt><b>Integer constants</b></dt>
1458
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1459 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1460 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1461 integer types.
1462 </dd>
1463
1464 <dt><b>Floating point constants</b></dt>
1465
1466 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1467 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]1468 notation (see below). The assembler requires the exact decimal value of
1469 a floating-point constant. For example, the assembler accepts 1.25 but
1470 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1471 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1472
1473 <dt><b>Null pointer constants</b></dt>
1474
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1475 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1476 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1477
1478</dl>
1479
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1480<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1481of floating point constants. For example, the form '<tt>double
14820x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14834.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1484(and the only time that they are generated by the disassembler) is when a
1485floating point constant must be emitted but it cannot be represented as a
1486decimal floating point number. For example, NaN's, infinities, and other
1487special values are represented in their IEEE hexadecimal format so that
1488assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1489
1490</div>
1491
1492<!-- ======================================================================= -->
1493<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1494</div>
1495
1496<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1497<p>Aggregate constants arise from aggregation of simple constants
1498and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1499
1500<dl>
1501 <dt><b>Structure constants</b></dt>
1502
1503 <dd>Structure constants are represented with notation similar to structure
1504 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1505 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1506 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1507 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1508 types of elements must match those specified by the type.
1509 </dd>
1510
1511 <dt><b>Array constants</b></dt>
1512
1513 <dd>Array constants are represented with notation similar to array type
1514 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1515 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516 constants must have <a href="#t_array">array type</a>, and the number and
1517 types of elements must match those specified by the type.
1518 </dd>
1519
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1520 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1521
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1522 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1523 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1524 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1525 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1526 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527 match those specified by the type.
1528 </dd>
1529
1530 <dt><b>Zero initialization</b></dt>
1531
1532 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1533 value to zero of <em>any</em> type, including scalar and aggregate types.
1534 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1535 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536 initializers.
1537 </dd>
1538</dl>
1539
1540</div>
1541
1542<!-- ======================================================================= -->
1543<div class="doc_subsection">
1544 <a name="globalconstants">Global Variable and Function Addresses</a>
1545</div>
1546
1547<div class="doc_text">
1548
1549<p>The addresses of <a href="#globalvars">global variables</a> and <a
1550href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1551constants. These constants are explicitly referenced when the <a
1552href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1553href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1554file:</p>
1555
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1556<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1557<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1558@X = global i32 17
1559@Y = global i32 42
1560@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1561</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1562</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1563
1564</div>
1565
1566<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1567<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1568<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1569 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1570 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1571 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1572
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1573 <p>Undefined values indicate to the compiler that the program is well defined
1574 no matter what value is used, giving the compiler more freedom to optimize.
1575 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1576</div>
1577
1578<!-- ======================================================================= -->
1579<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1580</div>
1581
1582<div class="doc_text">
1583
1584<p>Constant expressions are used to allow expressions involving other constants
1585to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1586href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1587that does not have side effects (e.g. load and call are not supported). The
1588following is the syntax for constant expressions:</p>
1589
1590<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1591 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1592 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1593 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1594
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1595 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1596 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1597 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1598
1599 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1600 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1601 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1602
1603 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1604 <dd>Truncate a floating point constant to another floating point type. The
1605 size of CST must be larger than the size of TYPE. Both types must be
1606 floating point.</dd>
1607
1608 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1609 <dd>Floating point extend a constant to another type. The size of CST must be
1610 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1611
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1612 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1613 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1614 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1615 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1616 of the same number of elements. If the value won't fit in the integer type,
1617 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1618
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1619 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1620 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1621 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1622 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1623 of the same number of elements. If the value won't fit in the integer type,
1624 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1625
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1626 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1627 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1628 constant. TYPE must be a scalar or vector floating point type. CST must be of
1629 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1630 of the same number of elements. If the value won't fit in the floating point
1631 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1632
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1633 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1634 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1635 constant. TYPE must be a scalar or vector floating point type. CST must be of
1636 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1637 of the same number of elements. If the value won't fit in the floating point
1638 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1639
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1640 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1641 <dd>Convert a pointer typed constant to the corresponding integer constant
1642 TYPE must be an integer type. CST must be of pointer type. The CST value is
1643 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1644
1645 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1646 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1647 pointer type. CST must be of integer type. The CST value is zero extended,
1648 truncated, or unchanged to make it fit in a pointer size. This one is
1649 <i>really</i> dangerous!</dd>
1650
1651 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1652 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1653 identical (same number of bits). The conversion is done as if the CST value
1654 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1655 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1656 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1657 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1658 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1659
1660 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1661
1662 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1663 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1664 instruction, the index list may have zero or more indexes, which are required
1665 to make sense for the type of "CSTPTR".</dd>
1666
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1667 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1668
1669 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1670 constants.</dd>
1671
1672 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1673 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1674
1675 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1676 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1677
1678 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1679
1680 <dd>Perform the <a href="#i_extractelement">extractelement
1681 operation</a> on constants.
1682
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1683 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1684
1685 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1686 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1687
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1688
1689 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1690
1691 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1692 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1693
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1695
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1696 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1697 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1698 binary</a> operations. The constraints on operands are the same as those for
1699 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1700 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1701</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1702</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1703
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1705<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1706<!-- *********************************************************************** -->
1707
1708<!-- ======================================================================= -->
1709<div class="doc_subsection">
1710<a name="inlineasm">Inline Assembler Expressions</a>
1711</div>
1712
1713<div class="doc_text">
1714
1715<p>
1716LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1717Module-Level Inline Assembly</a>) through the use of a special value. This
1718value represents the inline assembler as a string (containing the instructions
1719to emit), a list of operand constraints (stored as a string), and a flag that
1720indicates whether or not the inline asm expression has side effects. An example
1721inline assembler expression is:
1722</p>
1723
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1724<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1725<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1726i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1727</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1728</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1729
1730<p>
1731Inline assembler expressions may <b>only</b> be used as the callee operand of
1732a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1733</p>
1734
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1735<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1736<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1737%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]1738</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1739</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1740
1741<p>
1742Inline asms with side effects not visible in the constraint list must be marked
1743as having side effects. This is done through the use of the
1744'<tt>sideeffect</tt>' keyword, like so:
1745</p>
1746
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1747<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1748<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1749call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1750</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1751</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1752
1753<p>TODO: The format of the asm and constraints string still need to be
1754documented here. Constraints on what can be done (e.g. duplication, moving, etc
1755need to be documented).
1756</p>
1757
1758</div>
1759
1760<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1761<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1762<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1764<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1765
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766<p>The LLVM instruction set consists of several different
1767classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1768instructions</a>, <a href="#binaryops">binary instructions</a>,
1769<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1770 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1771instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1772
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1773</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1775<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1776<div class="doc_subsection"> <a name="terminators">Terminator
1777Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1779<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1780
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1781<p>As mentioned <a href="#functionstructure">previously</a>, every
1782basic block in a program ends with a "Terminator" instruction, which
1783indicates which block should be executed after the current block is
1784finished. These terminator instructions typically yield a '<tt>void</tt>'
1785value: they produce control flow, not values (the one exception being
1786the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1787<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1788 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1789instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1790the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1791 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1792 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1795
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1796<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1797<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1798Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801<pre> 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]1802 ret void <i>; Return from void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1803 ret &lt;type&gt; &lt;value&gt;, &lt;type&gt; &lt;value&gt; <i>; Return two values from a non-void function </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1804</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1806<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1807value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1808<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809returns a value and then causes control flow, and one that just causes
1810control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Arguments:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1812<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1813type of each return value must be a '<a href="#t_firstclass">first class</a>'
1814 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1815if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1816returns values that do not match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1817<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1818<p>When the '<tt>ret</tt>' instruction is executed, control flow
1819returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1820 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1821the instruction after the call. If the caller was an "<a
1822 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1823at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824returns a value, that value shall set the call or invoke instruction's
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1825return value. If the instruction returns multiple values then these
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1826values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1827</a>' instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1829<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1830 ret void <i>; Return from a void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1831 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1833</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1834<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1835<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1836<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1838<pre> 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]1839</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1840<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1841<p>The '<tt>br</tt>' instruction is used to cause control flow to
1842transfer to a different basic block in the current function. There are
1843two forms of this instruction, corresponding to a conditional branch
1844and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1846<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1847single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1848unconditional form of the '<tt>br</tt>' instruction takes a single
1849'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1850<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1851<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852argument is evaluated. If the value is <tt>true</tt>, control flows
1853to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1854control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1856<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1857 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1858</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1859<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1860<div class="doc_subsubsection">
1861 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1862</div>
1863
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1866
1867<pre>
1868 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1869</pre>
1870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1871<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1872
1873<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1874several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1875instruction, allowing a branch to occur to one of many possible
1876destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1877
1878
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1879<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1880
1881<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1882comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1883an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1884table is not allowed to contain duplicate constant entries.</p>
1885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1887
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888<p>The <tt>switch</tt> instruction specifies a table of values and
1889destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1890table is searched for the given value. If the value is found, control flow is
1891transfered to the corresponding destination; otherwise, control flow is
1892transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1894<h5>Implementation:</h5>
1895
1896<p>Depending on properties of the target machine and the particular
1897<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1898ways. For example, it could be generated as a series of chained conditional
1899branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1900
1901<h5>Example:</h5>
1902
1903<pre>
1904 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1905 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1906 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1907
1908 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1909 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1910
1911 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1912 switch i32 %val, label %otherwise [ i32 0, label %onzero
1913 i32 1, label %onone
1914 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1915</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1916</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1919<div class="doc_subsubsection">
1920 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1921</div>
1922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1923<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1925<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1926
1927<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1928 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1929 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1930</pre>
1931
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1932<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1933
1934<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1935function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1936'<tt>normal</tt>' label or the
1937'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1938"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1939"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1940href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1941continued at the dynamically nearest "exception" label. If the callee function
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1942returns multiple values then individual return values are only accessible through
1943a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1945<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1947<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1950 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1951 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1952 convention</a> the call should use. If none is specified, the call defaults
1953 to using C calling conventions.
1954 </li>
1955 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1956 function value being invoked. In most cases, this is a direct function
1957 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1958 an arbitrary pointer to function value.
1959 </li>
1960
1961 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1962 function to be invoked. </li>
1963
1964 <li>'<tt>function args</tt>': argument list whose types match the function
1965 signature argument types. If the function signature indicates the function
1966 accepts a variable number of arguments, the extra arguments can be
1967 specified. </li>
1968
1969 <li>'<tt>normal label</tt>': the label reached when the called function
1970 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1971
1972 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1973 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1978
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1979<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1980href="#i_call">call</a></tt>' instruction in most regards. The primary
1981difference is that it establishes an association with a label, which is used by
1982the runtime library to unwind the stack.</p>
1983
1984<p>This instruction is used in languages with destructors to ensure that proper
1985cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1986exception. Additionally, this is important for implementation of
1987'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1990<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1991 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1992 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1993 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1994 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1996</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1997
1998
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1999<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2000
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2002Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2003
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2005
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2006<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2007<pre>
2008 unwind
2009</pre>
2010
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2011<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2012
2013<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2014at the first callee in the dynamic call stack which used an <a
2015href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2016primarily used to implement exception handling.</p>
2017
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2018<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2019
2020<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
2021immediately halt. The dynamic call stack is then searched for the first <a
2022href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2023execution continues at the "exceptional" destination block specified by the
2024<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2025dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2026</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2027
2028<!-- _______________________________________________________________________ -->
2029
2030<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2031Instruction</a> </div>
2032
2033<div class="doc_text">
2034
2035<h5>Syntax:</h5>
2036<pre>
2037 unreachable
2038</pre>
2039
2040<h5>Overview:</h5>
2041
2042<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2043instruction is used to inform the optimizer that a particular portion of the
2044code is not reachable. This can be used to indicate that the code after a
2045no-return function cannot be reached, and other facts.</p>
2046
2047<h5>Semantics:</h5>
2048
2049<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2050</div>
2051
2052
2053
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2054<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2056<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2057<p>Binary operators are used to do most of the computation in a
Chris Lattner5a158142008-04-01 18:47:32 +0000[diff] [blame^]2058program. They require two operands of the same type, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2059produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2060multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner5a158142008-04-01 18:47:32 +0000[diff] [blame^]2061The result value has the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2062<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2063</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2064<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2065<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2066Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2067<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2069<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2071<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2072<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2074<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2075 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2076 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2077Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2079<p>The value produced is the integer or floating point sum of the two
2080operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2081<p>If an integer sum has unsigned overflow, the result returned is the
2082mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2083the result.</p>
2084<p>Because LLVM integers use a two's complement representation, this
2085instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2087<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2089</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2090<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2091<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2092Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2093<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2095<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2097<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2098<p>The '<tt>sub</tt>' instruction returns the difference of its two
2099operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2100<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2101instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2102<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2103<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2104 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2105values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2106This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2107Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2109<p>The value produced is the integer or floating point difference of
2110the two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2111<p>If an integer difference has unsigned overflow, the result returned is the
2112mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2113the result.</p>
2114<p>Because LLVM integers use a two's complement representation, this
2115instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2116<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2117<pre>
2118 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2119 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2120</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2121</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2122<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2123<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2124Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2125<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2126<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2127<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2128</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2130<p>The '<tt>mul</tt>' instruction returns the product of its two
2131operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2132<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2133<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2134 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2135values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2136This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2137Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2138<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2139<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2141<p>If the result of an integer multiplication has unsigned overflow,
2142the result returned is the mathematical result modulo
21432<sup>n</sup>, where n is the bit width of the result.</p>
2144<p>Because LLVM integers use a two's complement representation, and the
2145result is the same width as the operands, this instruction returns the
2146correct result for both signed and unsigned integers. If a full product
2147(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2148should be sign-extended or zero-extended as appropriate to the
2149width of the full product.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2150<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2151<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2152</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2153</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2154<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2155<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2156</a></div>
2157<div class="doc_text">
2158<h5>Syntax:</h5>
2159<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2160</pre>
2161<h5>Overview:</h5>
2162<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2163operands.</p>
2164<h5>Arguments:</h5>
2165<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2166<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2167types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2168of the values in which case the elements must be integers.</p>
2169<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2170<p>The value produced is the unsigned integer quotient of the two operands.</p>
2171<p>Note that unsigned integer division and signed integer division are distinct
2172operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2173<p>Division by zero leads to undefined behavior.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2174<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2175<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2176</pre>
2177</div>
2178<!-- _______________________________________________________________________ -->
2179<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2180</a> </div>
2181<div class="doc_text">
2182<h5>Syntax:</h5>
2183<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2184</pre>
2185<h5>Overview:</h5>
2186<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2187operands.</p>
2188<h5>Arguments:</h5>
2189<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2190<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2191types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2192of the values in which case the elements must be integers.</p>
2193<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2194<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2195<p>Note that signed integer division and unsigned integer division are distinct
2196operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2197<p>Division by zero leads to undefined behavior. Overflow also leads to
2198undefined behavior; this is a rare case, but can occur, for example,
2199by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2200<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2201<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2202</pre>
2203</div>
2204<!-- _______________________________________________________________________ -->
2205<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2206Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2207<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2208<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2209<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2210</pre>
2211<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2212<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213operands.</p>
2214<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2215<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2216<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2217identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2218versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2219<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2220<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2221<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2222<pre> &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]2223</pre>
2224</div>
2225<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2226<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2227</div>
2228<div class="doc_text">
2229<h5>Syntax:</h5>
2230<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2231</pre>
2232<h5>Overview:</h5>
2233<p>The '<tt>urem</tt>' instruction returns the remainder from the
2234unsigned division of its two arguments.</p>
2235<h5>Arguments:</h5>
2236<p>The two arguments to the '<tt>urem</tt>' instruction must be
2237<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2238types. This instruction can also take <a href="#t_vector">vector</a> versions
2239of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2240<h5>Semantics:</h5>
2241<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2242This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2243<p>Note that unsigned integer remainder and signed integer remainder are
2244distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2245<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2246<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2247<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2248</pre>
2249
2250</div>
2251<!-- _______________________________________________________________________ -->
2252<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2253Instruction</a> </div>
2254<div class="doc_text">
2255<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2256<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2257</pre>
2258<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2259<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2260signed division of its two operands. This instruction can also take
2261<a href="#t_vector">vector</a> versions of the values in which case
2262the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2263
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2264<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2265<p>The two arguments to the '<tt>srem</tt>' instruction must be
2266<a href="#t_integer">integer</a> values. Both arguments must have identical
2267types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2268<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2269<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2270has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2271operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2272a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2273 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2274Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2275please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2276Wikipedia: modulo operation</a>.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2277<p>Note that signed integer remainder and unsigned integer remainder are
2278distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2279<p>Taking the remainder of a division by zero leads to undefined behavior.
2280Overflow also leads to undefined behavior; this is a rare case, but can occur,
2281for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2282(The remainder doesn't actually overflow, but this rule lets srem be
2283implemented using instructions that return both the result of the division
2284and the remainder.)</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2285<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2286<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2287</pre>
2288
2289</div>
2290<!-- _______________________________________________________________________ -->
2291<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2292Instruction</a> </div>
2293<div class="doc_text">
2294<h5>Syntax:</h5>
2295<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2296</pre>
2297<h5>Overview:</h5>
2298<p>The '<tt>frem</tt>' instruction returns the remainder from the
2299division of its two operands.</p>
2300<h5>Arguments:</h5>
2301<p>The two arguments to the '<tt>frem</tt>' instruction must be
2302<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2303identical types. This instruction can also take <a href="#t_vector">vector</a>
2304versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2305<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2306<p>This instruction returns the <i>remainder</i> of a division.
2307The remainder has the same sign as the dividend.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2308<h5>Example:</h5>
2309<pre> &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]2310</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2311</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2312
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2313<!-- ======================================================================= -->
2314<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2315Operations</a> </div>
2316<div class="doc_text">
2317<p>Bitwise binary operators are used to do various forms of
2318bit-twiddling in a program. They are generally very efficient
2319instructions and can commonly be strength reduced from other
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2320instructions. They require two operands of the same type, execute an operation on them,
2321and produce a single value. The resulting value is the same type as its operands.</p>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2322</div>
2323
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2324<!-- _______________________________________________________________________ -->
2325<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2326Instruction</a> </div>
2327<div class="doc_text">
2328<h5>Syntax:</h5>
2329<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2330</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2331
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2332<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2333
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2334<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2335the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2336
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2337<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2339<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2340 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2341
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2342<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2343
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2344<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2345where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2346equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2347
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2348<h5>Example:</h5><pre>
2349 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2350 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2351 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2352 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2353</pre>
2354</div>
2355<!-- _______________________________________________________________________ -->
2356<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2357Instruction</a> </div>
2358<div class="doc_text">
2359<h5>Syntax:</h5>
2360<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2361</pre>
2362
2363<h5>Overview:</h5>
2364<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2365operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2366
2367<h5>Arguments:</h5>
2368<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2369<a href="#t_integer">integer</a> type.</p>
2370
2371<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2372
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2373<p>This instruction always performs a logical shift right operation. The most
2374significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2375shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2376the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2377
2378<h5>Example:</h5>
2379<pre>
2380 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2381 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2382 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2383 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2384 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2385</pre>
2386</div>
2387
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2388<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2389<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2390Instruction</a> </div>
2391<div class="doc_text">
2392
2393<h5>Syntax:</h5>
2394<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2395</pre>
2396
2397<h5>Overview:</h5>
2398<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2399operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2400
2401<h5>Arguments:</h5>
2402<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2403<a href="#t_integer">integer</a> type.</p>
2404
2405<h5>Semantics:</h5>
2406<p>This instruction always performs an arithmetic shift right operation,
2407The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2408of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2409larger than the number of bits in <tt>var1</tt>, the result is undefined.
2410</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2411
2412<h5>Example:</h5>
2413<pre>
2414 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2415 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2416 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2417 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2418 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2419</pre>
2420</div>
2421
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2423<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2424Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2425<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2426<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2427<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2428</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2430<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2431its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2433<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2434 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2435identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2436<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2437<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2438<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2439<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2440<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2441 <tbody>
2442 <tr>
2443 <td>In0</td>
2444 <td>In1</td>
2445 <td>Out</td>
2446 </tr>
2447 <tr>
2448 <td>0</td>
2449 <td>0</td>
2450 <td>0</td>
2451 </tr>
2452 <tr>
2453 <td>0</td>
2454 <td>1</td>
2455 <td>0</td>
2456 </tr>
2457 <tr>
2458 <td>1</td>
2459 <td>0</td>
2460 <td>0</td>
2461 </tr>
2462 <tr>
2463 <td>1</td>
2464 <td>1</td>
2465 <td>1</td>
2466 </tr>
2467 </tbody>
2468</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2469</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2470<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2471<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2472 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2473 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2474</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2475</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2476<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2477<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2478<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2480<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2481</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2482<h5>Overview:</h5>
2483<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2484or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2485<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2486<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2487 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2488identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2489<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2490<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2491<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2492<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2493<table border="1" cellspacing="0" cellpadding="4">
2494 <tbody>
2495 <tr>
2496 <td>In0</td>
2497 <td>In1</td>
2498 <td>Out</td>
2499 </tr>
2500 <tr>
2501 <td>0</td>
2502 <td>0</td>
2503 <td>0</td>
2504 </tr>
2505 <tr>
2506 <td>0</td>
2507 <td>1</td>
2508 <td>1</td>
2509 </tr>
2510 <tr>
2511 <td>1</td>
2512 <td>0</td>
2513 <td>1</td>
2514 </tr>
2515 <tr>
2516 <td>1</td>
2517 <td>1</td>
2518 <td>1</td>
2519 </tr>
2520 </tbody>
2521</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2522</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2523<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2524<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2525 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2526 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2528</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2529<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2530<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2531Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2532<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2533<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2534<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2536<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2537<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2538or of its two operands. The <tt>xor</tt> is used to implement the
2539"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2540<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2541<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2542 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2543identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2544<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2545<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2546<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2547<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2548<table border="1" cellspacing="0" cellpadding="4">
2549 <tbody>
2550 <tr>
2551 <td>In0</td>
2552 <td>In1</td>
2553 <td>Out</td>
2554 </tr>
2555 <tr>
2556 <td>0</td>
2557 <td>0</td>
2558 <td>0</td>
2559 </tr>
2560 <tr>
2561 <td>0</td>
2562 <td>1</td>
2563 <td>1</td>
2564 </tr>
2565 <tr>
2566 <td>1</td>
2567 <td>0</td>
2568 <td>1</td>
2569 </tr>
2570 <tr>
2571 <td>1</td>
2572 <td>1</td>
2573 <td>0</td>
2574 </tr>
2575 </tbody>
2576</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2577</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2578<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2580<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2581 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2582 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2583 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2584</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2585</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2588<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2589 <a name="vectorops">Vector Operations</a>
2590</div>
2591
2592<div class="doc_text">
2593
2594<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2595target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2596vector-specific operations needed to process vectors effectively. While LLVM
2597does directly support these vector operations, many sophisticated algorithms
2598will want to use target-specific intrinsics to take full advantage of a specific
2599target.</p>
2600
2601</div>
2602
2603<!-- _______________________________________________________________________ -->
2604<div class="doc_subsubsection">
2605 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2606</div>
2607
2608<div class="doc_text">
2609
2610<h5>Syntax:</h5>
2611
2612<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2613 &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]2614</pre>
2615
2616<h5>Overview:</h5>
2617
2618<p>
2619The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2620element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2621</p>
2622
2623
2624<h5>Arguments:</h5>
2625
2626<p>
2627The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2628value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2629an index indicating the position from which to extract the element.
2630The index may be a variable.</p>
2631
2632<h5>Semantics:</h5>
2633
2634<p>
2635The result is a scalar of the same type as the element type of
2636<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2637<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2638results are undefined.
2639</p>
2640
2641<h5>Example:</h5>
2642
2643<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2644 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2645</pre>
2646</div>
2647
2648
2649<!-- _______________________________________________________________________ -->
2650<div class="doc_subsubsection">
2651 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2652</div>
2653
2654<div class="doc_text">
2655
2656<h5>Syntax:</h5>
2657
2658<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2659 &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]2660</pre>
2661
2662<h5>Overview:</h5>
2663
2664<p>
2665The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2666element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2667</p>
2668
2669
2670<h5>Arguments:</h5>
2671
2672<p>
2673The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2674value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2675scalar value whose type must equal the element type of the first
2676operand. The third operand is an index indicating the position at
2677which to insert the value. The index may be a variable.</p>
2678
2679<h5>Semantics:</h5>
2680
2681<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2682The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2683element values are those of <tt>val</tt> except at position
2684<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2685exceeds the length of <tt>val</tt>, the results are undefined.
2686</p>
2687
2688<h5>Example:</h5>
2689
2690<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2691 %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]2692</pre>
2693</div>
2694
2695<!-- _______________________________________________________________________ -->
2696<div class="doc_subsubsection">
2697 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2698</div>
2699
2700<div class="doc_text">
2701
2702<h5>Syntax:</h5>
2703
2704<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2705 &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;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2706</pre>
2707
2708<h5>Overview:</h5>
2709
2710<p>
2711The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2712from two input vectors, returning a vector of the same type.
2713</p>
2714
2715<h5>Arguments:</h5>
2716
2717<p>
2718The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2719with types that match each other and types that match the result of the
2720instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2721of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2722</p>
2723
2724<p>
2725The shuffle mask operand is required to be a constant vector with either
2726constant integer or undef values.
2727</p>
2728
2729<h5>Semantics:</h5>
2730
2731<p>
2732The elements of the two input vectors are numbered from left to right across
2733both of the vectors. The shuffle mask operand specifies, for each element of
2734the result vector, which element of the two input registers the result element
2735gets. The element selector may be undef (meaning "don't care") and the second
2736operand may be undef if performing a shuffle from only one vector.
2737</p>
2738
2739<h5>Example:</h5>
2740
2741<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2742 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2743 &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]2744 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2745 &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.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2746</pre>
2747</div>
2748
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2749
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2750<!-- ======================================================================= -->
2751<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2752 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2753</div>
2754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2755<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2756
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2757<p>A key design point of an SSA-based representation is how it
2758represents memory. In LLVM, no memory locations are in SSA form, which
2759makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2760allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2762</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2764<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2765<div class="doc_subsubsection">
2766 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2767</div>
2768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2769<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2770
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2771<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2772
2773<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2774 &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]2775</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2777<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2778
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2779<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2780heap and returns a pointer to it. The object is always allocated in the generic
2781address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2783<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2784
2785<p>The '<tt>malloc</tt>' instruction allocates
2786<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2787bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2788appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2789number of elements allocated, otherwise "NumElements" is defaulted to be one.
2790If an alignment is specified, the value result of the allocation is guaranteed to
2791be aligned to at least that boundary. If not specified, or if zero, the target can
2792choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2794<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2795
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2796<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2797
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2798<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2799a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2800
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2801<h5>Example:</h5>
2802
2803<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2804 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2805
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2806 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2807 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2808 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2809 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2810 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2811</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2812</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2815<div class="doc_subsubsection">
2816 <a name="i_free">'<tt>free</tt>' Instruction</a>
2817</div>
2818
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2819<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2820
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2821<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2822
2823<pre>
2824 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2826
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2827<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2828
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2829<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2830memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2831
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2832<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2833
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2834<p>'<tt>value</tt>' shall be a pointer value that points to a value
2835that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2836instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2837
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2838<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2839
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2840<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2841after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2842
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2843<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2844
2845<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2846 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2847 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2848</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2849</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2851<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2852<div class="doc_subsubsection">
2853 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2854</div>
2855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2856<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2858<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2859
2860<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2861 &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]2862</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2864<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2865
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2866<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2867currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2868returns to its caller. The object is always allocated in the generic address
2869space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2871<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2872
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2873<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2874bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2875appropriate type to the program. If "NumElements" is specified, it is the
2876number of elements allocated, otherwise "NumElements" is defaulted to be one.
2877If an alignment is specified, the value result of the allocation is guaranteed
2878to be aligned to at least that boundary. If not specified, or if zero, the target
2879can choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2880
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2881<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2884
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2885<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2886memory is automatically released when the function returns. The '<tt>alloca</tt>'
2887instruction is commonly used to represent automatic variables that must
2888have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2889 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2890instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2892<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2893
2894<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2895 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2896 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2897 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2898 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2899</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2900</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2901
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2902<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2903<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2904Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2905<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2906<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2907<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2908<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2909<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2910<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2911<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2912address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2913 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2914marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2915the number or order of execution of this <tt>load</tt> with other
2916volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2917instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2918<p>
2919The optional "align" argument specifies the alignment of the operation
2920(that is, the alignment of the memory address). A value of 0 or an
2921omitted "align" argument means that the operation has the preferential
2922alignment for the target. It is the responsibility of the code emitter
2923to ensure that the alignment information is correct. Overestimating
2924the alignment results in an undefined behavior. Underestimating the
2925alignment may produce less efficient code. An alignment of 1 is always
2926safe.
2927</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2928<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2929<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2930<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2931<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2932 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2933 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2934 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2935</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2936</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2937<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2938<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2939Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2940<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2941<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2942<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2943 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]2944</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2945<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2946<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2947<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2948<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2949to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2950operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2951operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2952optimizer is not allowed to modify the number or order of execution of
2953this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2954 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2955<p>
2956The optional "align" argument specifies the alignment of the operation
2957(that is, the alignment of the memory address). A value of 0 or an
2958omitted "align" argument means that the operation has the preferential
2959alignment for the target. It is the responsibility of the code emitter
2960to ensure that the alignment information is correct. Overestimating
2961the alignment results in an undefined behavior. Underestimating the
2962alignment may produce less efficient code. An alignment of 1 is always
2963safe.
2964</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2965<h5>Semantics:</h5>
2966<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2967at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2968<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2969<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2970 store i32 3, i32* %ptr <i>; yields {void}</i>
2971 %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]2972</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2973</div>
2974
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2975<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2976<div class="doc_subsubsection">
2977 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2978</div>
2979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2980<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2981<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2982<pre>
2983 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2984</pre>
2985
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2986<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2987
2988<p>
2989The '<tt>getelementptr</tt>' instruction is used to get the address of a
2990subelement of an aggregate data structure.</p>
2991
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2992<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2993
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2994<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2995elements of the aggregate object to index to. The actual types of the arguments
2996provided depend on the type of the first pointer argument. The
2997'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2998levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2999structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3000into an array or pointer, only integers of 32 or 64 bits are allowed, and will
3001be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3002
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3003<p>For example, let's consider a C code fragment and how it gets
3004compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3005
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3006<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3007<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3008struct RT {
3009 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3010 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3011 char C;
3012};
3013struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3014 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3015 double Y;
3016 struct RT Z;
3017};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3018
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3019int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3020 return &amp;s[1].Z.B[5][13];
3021}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3022</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3023</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3024
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3025<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3026
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3027<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3028<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3029%RT = type { i8 , [10 x [20 x i32]], i8 }
3030%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3031
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3032define i32* %foo(%ST* %s) {
3033entry:
3034 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3035 ret i32* %reg
3036}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3037</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3038</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3039
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3040<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3041
3042<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]3043on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3044and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]3045<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3046to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]3047<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3048
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3049<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3050type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3051}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3052the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3053i8 }</tt>' type, another structure. The third index indexes into the second
3054element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3055array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3056'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3057to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3058
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3059<p>Note that it is perfectly legal to index partially through a
3060structure, returning a pointer to an inner element. Because of this,
3061the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3062
3063<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3064 define i32* %foo(%ST* %s) {
3065 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3066 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3067 %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]3068 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3069 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3070 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3071 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3072</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3073
3074<p>Note that it is undefined to access an array out of bounds: array and
3075pointer indexes must always be within the defined bounds of the array type.
3076The one exception for this rules is zero length arrays. These arrays are
3077defined to be accessible as variable length arrays, which requires access
3078beyond the zero'th element.</p>
3079
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3080<p>The getelementptr instruction is often confusing. For some more insight
3081into how it works, see <a href="GetElementPtr.html">the getelementptr
3082FAQ</a>.</p>
3083
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3084<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3085
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3086<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3087 <i>; yields [12 x i8]*:aptr</i>
3088 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3089</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3090</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3091
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3092<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3093<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3094</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3095<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3096<p>The instructions in this category are the conversion instructions (casting)
3097which all take a single operand and a type. They perform various bit conversions
3098on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3099</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3100
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3101<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3102<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3103 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3104</div>
3105<div class="doc_text">
3106
3107<h5>Syntax:</h5>
3108<pre>
3109 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3110</pre>
3111
3112<h5>Overview:</h5>
3113<p>
3114The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3115</p>
3116
3117<h5>Arguments:</h5>
3118<p>
3119The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3120be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3121and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3122type. The bit size of <tt>value</tt> must be larger than the bit size of
3123<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Semantics:</h5>
3126<p>
3127The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3128and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3129larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3130It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3131
3132<h5>Example:</h5>
3133<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3134 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3135 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3136 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3137</pre>
3138</div>
3139
3140<!-- _______________________________________________________________________ -->
3141<div class="doc_subsubsection">
3142 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3143</div>
3144<div class="doc_text">
3145
3146<h5>Syntax:</h5>
3147<pre>
3148 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3149</pre>
3150
3151<h5>Overview:</h5>
3152<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3153<tt>ty2</tt>.</p>
3154
3155
3156<h5>Arguments:</h5>
3157<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3158<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3159also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3160<tt>value</tt> must be smaller than the bit size of the destination type,
3161<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3162
3163<h5>Semantics:</h5>
3164<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]3165bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3166
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3167<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]3168
3169<h5>Example:</h5>
3170<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3171 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3172 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3173</pre>
3174</div>
3175
3176<!-- _______________________________________________________________________ -->
3177<div class="doc_subsubsection">
3178 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3179</div>
3180<div class="doc_text">
3181
3182<h5>Syntax:</h5>
3183<pre>
3184 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3185</pre>
3186
3187<h5>Overview:</h5>
3188<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3189
3190<h5>Arguments:</h5>
3191<p>
3192The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3193<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3194also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3195<tt>value</tt> must be smaller than the bit size of the destination type,
3196<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3197
3198<h5>Semantics:</h5>
3199<p>
3200The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3201bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]3202the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3203
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3204<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]3205
3206<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3207<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3208 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3209 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3215 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3216</div>
3217
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221
3222<pre>
3223 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3224</pre>
3225
3226<h5>Overview:</h5>
3227<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3228<tt>ty2</tt>.</p>
3229
3230
3231<h5>Arguments:</h5>
3232<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3233 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3234cast it to. The size of <tt>value</tt> must be larger than the size of
3235<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3236<i>no-op cast</i>.</p>
3237
3238<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3239<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3240<a href="#t_floating">floating point</a> type to a smaller
3241<a href="#t_floating">floating point</a> type. If the value cannot fit within
3242the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3243
3244<h5>Example:</h5>
3245<pre>
3246 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3247 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3248</pre>
3249</div>
3250
3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3253 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3254</div>
3255<div class="doc_text">
3256
3257<h5>Syntax:</h5>
3258<pre>
3259 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3260</pre>
3261
3262<h5>Overview:</h5>
3263<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3264floating point value.</p>
3265
3266<h5>Arguments:</h5>
3267<p>The '<tt>fpext</tt>' instruction takes a
3268<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3269and a <a href="#t_floating">floating point</a> type to cast it to. The source
3270type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3271
3272<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3273<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3274<a href="#t_floating">floating point</a> type to a larger
3275<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3276used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3277<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]3278
3279<h5>Example:</h5>
3280<pre>
3281 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3282 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3283</pre>
3284</div>
3285
3286<!-- _______________________________________________________________________ -->
3287<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3288 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3289</div>
3290<div class="doc_text">
3291
3292<h5>Syntax:</h5>
3293<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3294 &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]3295</pre>
3296
3297<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3298<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3299unsigned integer equivalent of type <tt>ty2</tt>.
3300</p>
3301
3302<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3303<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3304scalar or vector <a href="#t_floating">floating point</a> value, and a type
3305to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3306type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3307vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3308
3309<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3310<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3311<a href="#t_floating">floating point</a> operand into the nearest (rounding
3312towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3313the results are undefined.</p>
3314
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3315<h5>Example:</h5>
3316<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3317 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3318 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3319 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3320</pre>
3321</div>
3322
3323<!-- _______________________________________________________________________ -->
3324<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3325 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3326</div>
3327<div class="doc_text">
3328
3329<h5>Syntax:</h5>
3330<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3331 &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]3332</pre>
3333
3334<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3335<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3336<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3337</p>
3338
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3339<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3340<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3341scalar or vector <a href="#t_floating">floating point</a> value, and a type
3342to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3343type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3344vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3345
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3346<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3347<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3348<a href="#t_floating">floating point</a> operand into the nearest (rounding
3349towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3350the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3351
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3352<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3353<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3354 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3355 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3356 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3357</pre>
3358</div>
3359
3360<!-- _______________________________________________________________________ -->
3361<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3362 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3363</div>
3364<div class="doc_text">
3365
3366<h5>Syntax:</h5>
3367<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3368 &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]3369</pre>
3370
3371<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3372<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3373integer and converts that value to the <tt>ty2</tt> type.</p>
3374
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3375<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3376<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3377scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3378to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3379type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3380floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3381
3382<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3383<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3384integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3385the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3386
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3387<h5>Example:</h5>
3388<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3389 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3390 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3391</pre>
3392</div>
3393
3394<!-- _______________________________________________________________________ -->
3395<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3396 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3397</div>
3398<div class="doc_text">
3399
3400<h5>Syntax:</h5>
3401<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3402 &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]3403</pre>
3404
3405<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3406<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3407integer and converts that value to the <tt>ty2</tt> type.</p>
3408
3409<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3410<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3411scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3412to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3413type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3414floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3415
3416<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3417<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3418integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3419the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3420
3421<h5>Example:</h5>
3422<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3423 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3424 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3425</pre>
3426</div>
3427
3428<!-- _______________________________________________________________________ -->
3429<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3430 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3431</div>
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
3435<pre>
3436 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3437</pre>
3438
3439<h5>Overview:</h5>
3440<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3441the integer type <tt>ty2</tt>.</p>
3442
3443<h5>Arguments:</h5>
3444<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3445must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3446<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3447
3448<h5>Semantics:</h5>
3449<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3450<tt>ty2</tt> by interpreting the pointer value as an integer and either
3451truncating or zero extending that value to the size of the integer type. If
3452<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3453<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3454are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3455change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3456
3457<h5>Example:</h5>
3458<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3459 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3460 %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]3461</pre>
3462</div>
3463
3464<!-- _______________________________________________________________________ -->
3465<div class="doc_subsubsection">
3466 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3467</div>
3468<div class="doc_text">
3469
3470<h5>Syntax:</h5>
3471<pre>
3472 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3473</pre>
3474
3475<h5>Overview:</h5>
3476<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3477a pointer type, <tt>ty2</tt>.</p>
3478
3479<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3480<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3481value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3482<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3483
3484<h5>Semantics:</h5>
3485<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3486<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3487the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3488size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3489the size of a pointer then a zero extension is done. If they are the same size,
3490nothing is done (<i>no-op cast</i>).</p>
3491
3492<h5>Example:</h5>
3493<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3494 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3495 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3496 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3497</pre>
3498</div>
3499
3500<!-- _______________________________________________________________________ -->
3501<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3502 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3503</div>
3504<div class="doc_text">
3505
3506<h5>Syntax:</h5>
3507<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3508 &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]3509</pre>
3510
3511<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3512<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3513<tt>ty2</tt> without changing any bits.</p>
3514
3515<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3516<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3517a first class value, and a type to cast it to, which must also be a <a
3518 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3519and the destination type, <tt>ty2</tt>, must be identical. If the source
3520type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3521
3522<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3523<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3524<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3525this conversion. The conversion is done as if the <tt>value</tt> had been
3526stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3527converted to other pointer types with this instruction. To convert pointers to
3528other types, use the <a href="#i_inttoptr">inttoptr</a> or
3529<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3530
3531<h5>Example:</h5>
3532<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3533 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3534 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3535 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3536</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3537</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3538
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3539<!-- ======================================================================= -->
3540<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3541<div class="doc_text">
3542<p>The instructions in this category are the "miscellaneous"
3543instructions, which defy better classification.</p>
3544</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3545
3546<!-- _______________________________________________________________________ -->
3547<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3548</div>
3549<div class="doc_text">
3550<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3551<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3552</pre>
3553<h5>Overview:</h5>
3554<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3555of its two integer operands.</p>
3556<h5>Arguments:</h5>
3557<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3558the condition code indicating the kind of comparison to perform. It is not
3559a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3560<ol>
3561 <li><tt>eq</tt>: equal</li>
3562 <li><tt>ne</tt>: not equal </li>
3563 <li><tt>ugt</tt>: unsigned greater than</li>
3564 <li><tt>uge</tt>: unsigned greater or equal</li>
3565 <li><tt>ult</tt>: unsigned less than</li>
3566 <li><tt>ule</tt>: unsigned less or equal</li>
3567 <li><tt>sgt</tt>: signed greater than</li>
3568 <li><tt>sge</tt>: signed greater or equal</li>
3569 <li><tt>slt</tt>: signed less than</li>
3570 <li><tt>sle</tt>: signed less or equal</li>
3571</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3572<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3573<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3576the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3577yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3578<ol>
3579 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3580 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3581 </li>
3582 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3583 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3584 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3585 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3586 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3587 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3588 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3589 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3590 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3591 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3592 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3593 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3594 <li><tt>sge</tt>: interprets the operands as signed values and yields
3595 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3596 <li><tt>slt</tt>: interprets the operands as signed values and yields
3597 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3598 <li><tt>sle</tt>: interprets the operands as signed values and yields
3599 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3600</ol>
3601<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3602values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3603
3604<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3605<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3606 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3607 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3608 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3609 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3610 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3611</pre>
3612</div>
3613
3614<!-- _______________________________________________________________________ -->
3615<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3616</div>
3617<div class="doc_text">
3618<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3619<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3620</pre>
3621<h5>Overview:</h5>
3622<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3623of its floating point operands.</p>
3624<h5>Arguments:</h5>
3625<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3626the condition code indicating the kind of comparison to perform. It is not
3627a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3628<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3629 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3630 <li><tt>oeq</tt>: ordered and equal</li>
3631 <li><tt>ogt</tt>: ordered and greater than </li>
3632 <li><tt>oge</tt>: ordered and greater than or equal</li>
3633 <li><tt>olt</tt>: ordered and less than </li>
3634 <li><tt>ole</tt>: ordered and less than or equal</li>
3635 <li><tt>one</tt>: ordered and not equal</li>
3636 <li><tt>ord</tt>: ordered (no nans)</li>
3637 <li><tt>ueq</tt>: unordered or equal</li>
3638 <li><tt>ugt</tt>: unordered or greater than </li>
3639 <li><tt>uge</tt>: unordered or greater than or equal</li>
3640 <li><tt>ult</tt>: unordered or less than </li>
3641 <li><tt>ule</tt>: unordered or less than or equal</li>
3642 <li><tt>une</tt>: unordered or not equal</li>
3643 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3644 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3645</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3646<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3647<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3648<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3649<a href="#t_floating">floating point</a> typed. They must have identical
3650types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3651<h5>Semantics:</h5>
3652<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3653the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3654yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3655<ol>
3656 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3657 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3658 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3659 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3660 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3661 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3662 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3663 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3664 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3665 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3666 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3667 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3668 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3669 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3670 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3671 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3672 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3673 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3674 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3675 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3676 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3677 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3678 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3679 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3680 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3681 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3682 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3683 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3684</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3685
3686<h5>Example:</h5>
3687<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3688 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3689 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3690 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3691</pre>
3692</div>
3693
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3696Instruction</a> </div>
3697<div class="doc_text">
3698<h5>Syntax:</h5>
3699<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3700<h5>Overview:</h5>
3701<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3702the SSA graph representing the function.</p>
3703<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3704<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3705field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3706as arguments, with one pair for each predecessor basic block of the
3707current block. Only values of <a href="#t_firstclass">first class</a>
3708type may be used as the value arguments to the PHI node. Only labels
3709may be used as the label arguments.</p>
3710<p>There must be no non-phi instructions between the start of a basic
3711block and the PHI instructions: i.e. PHI instructions must be first in
3712a basic block.</p>
3713<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3714<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3715specified by the pair corresponding to the predecessor basic block that executed
3716just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3717<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3718<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3719</div>
3720
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3721<!-- _______________________________________________________________________ -->
3722<div class="doc_subsubsection">
3723 <a name="i_select">'<tt>select</tt>' Instruction</a>
3724</div>
3725
3726<div class="doc_text">
3727
3728<h5>Syntax:</h5>
3729
3730<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3731 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3732</pre>
3733
3734<h5>Overview:</h5>
3735
3736<p>
3737The '<tt>select</tt>' instruction is used to choose one value based on a
3738condition, without branching.
3739</p>
3740
3741
3742<h5>Arguments:</h5>
3743
3744<p>
3745The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
3746</p>
3747
3748<h5>Semantics:</h5>
3749
3750<p>
3751If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3752value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3753</p>
3754
3755<h5>Example:</h5>
3756
3757<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3758 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3759</pre>
3760</div>
3761
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3762
3763<!-- _______________________________________________________________________ -->
3764<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3765 <a name="i_call">'<tt>call</tt>' Instruction</a>
3766</div>
3767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3768<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3769
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3770<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3771<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3772 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3773</pre>
3774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3775<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3776
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3777<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3778
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3779<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3781<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3782
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3783<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3784 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3785 <p>The optional "tail" marker indicates whether the callee function accesses
3786 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3787 function call is eligible for tail call optimization. Note that calls may
3788 be marked "tail" even if they do not occur before a <a
3789 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3790 </li>
3791 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3792 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3793 convention</a> the call should use. If none is specified, the call defaults
3794 to using C calling conventions.
3795 </li>
3796 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3797 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3798 the type of the return value. Functions that return no value are marked
3799 <tt><a href="#t_void">void</a></tt>.</p>
3800 </li>
3801 <li>
3802 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3803 value being invoked. The argument types must match the types implied by
3804 this signature. This type can be omitted if the function is not varargs
3805 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3806 </li>
3807 <li>
3808 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3809 be invoked. In most cases, this is a direct function invocation, but
3810 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3811 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3812 </li>
3813 <li>
3814 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3815 function signature argument types. All arguments must be of
3816 <a href="#t_firstclass">first class</a> type. If the function signature
3817 indicates the function accepts a variable number of arguments, the extra
3818 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3819 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3820</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3821
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3822<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3823
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3824<p>The '<tt>call</tt>' instruction is used to cause control flow to
3825transfer to a specified function, with its incoming arguments bound to
3826the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3827instruction in the called function, control flow continues with the
3828instruction after the function call, and the return value of the
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3829function is bound to the result argument. If the callee returns multiple
3830values then the return values of the function are only accessible through
3831the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3833<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3834
3835<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3836 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3837 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
3838 %X = tail call i32 @foo() <i>; yields i32</i>
3839 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
3840 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3841
3842 %struct.A = type { i32, i8 }
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3843 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
3844 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
3845 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3846</pre>
3847
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3848</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3849
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3850<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3851<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3852 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3853</div>
3854
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3855<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3856
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3857<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3858
3859<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3860 &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]3861</pre>
3862
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3863<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3864
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3865<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3866the "variable argument" area of a function call. It is used to implement the
3867<tt>va_arg</tt> macro in C.</p>
3868
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3869<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3870
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3871<p>This instruction takes a <tt>va_list*</tt> value and the type of
3872the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3873increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3874actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3875
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3876<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3877
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3878<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3879type from the specified <tt>va_list</tt> and causes the
3880<tt>va_list</tt> to point to the next argument. For more information,
3881see the variable argument handling <a href="#int_varargs">Intrinsic
3882Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3883
3884<p>It is legal for this instruction to be called in a function which does not
3885take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3886function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3887
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3888<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3889href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3890argument.</p>
3891
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3892<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3893
3894<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3895
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3896</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3897
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3898<!-- _______________________________________________________________________ -->
3899<div class="doc_subsubsection">
3900 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3901</div>
3902
3903<div class="doc_text">
3904
3905<h5>Syntax:</h5>
3906<pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3907 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3908</pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3909
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3910<h5>Overview:</h5>
3911
3912<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3913from a '<tt><a href="#i_call">call</a></tt>'
3914or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
3915results.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3916
3917<h5>Arguments:</h5>
3918
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3919<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
3920first argument. The value must have <a href="#t_struct">structure type</a>.
3921The second argument is an unsigned index value which must be in range for
3922the number of values returned by the call.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3923
3924<h5>Semantics:</h5>
3925
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3926<p>The '<tt>getresult</tt>' instruction extracts the element identified by
3927'<tt>index</tt>' from the aggregate value.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3928
3929<h5>Example:</h5>
3930
3931<pre>
3932 %struct.A = type { i32, i8 }
3933
3934 %r = call %struct.A @foo()
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3935 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
3936 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3937 add i32 %gr, 42
3938 add i8 %gr1, 41
3939</pre>
3940
3941</div>
3942
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3943<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3944<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3945<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3947<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3948
3949<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3950well known names and semantics and are required to follow certain restrictions.
3951Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3952language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3953adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3954
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3955<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3956prefix is reserved in LLVM for intrinsic names; thus, function names may not
3957begin with this prefix. Intrinsic functions must always be external functions:
3958you cannot define the body of intrinsic functions. Intrinsic functions may
3959only be used in call or invoke instructions: it is illegal to take the address
3960of an intrinsic function. Additionally, because intrinsic functions are part
3961of the LLVM language, it is required if any are added that they be documented
3962here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3963
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3964<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3965a family of functions that perform the same operation but on different data
3966types. Because LLVM can represent over 8 million different integer types,
3967overloading is used commonly to allow an intrinsic function to operate on any
3968integer type. One or more of the argument types or the result type can be
3969overloaded to accept any integer type. Argument types may also be defined as
3970exactly matching a previous argument's type or the result type. This allows an
3971intrinsic function which accepts multiple arguments, but needs all of them to
3972be of the same type, to only be overloaded with respect to a single argument or
3973the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3974
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3975<p>Overloaded intrinsics will have the names of its overloaded argument types
3976encoded into its function name, each preceded by a period. Only those types
3977which are overloaded result in a name suffix. Arguments whose type is matched
3978against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3979take an integer of any width and returns an integer of exactly the same integer
3980width. This leads to a family of functions such as
3981<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3982Only one type, the return type, is overloaded, and only one type suffix is
3983required. Because the argument's type is matched against the return type, it
3984does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3985
3986<p>To learn how to add an intrinsic function, please see the
3987<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3988</p>
3989
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3990</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3991
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3992<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3993<div class="doc_subsection">
3994 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3995</div>
3996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3997<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3998
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3999<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]4000 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4001intrinsic functions. These functions are related to the similarly
4002named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4003
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4004<p>All of these functions operate on arguments that use a
4005target-specific value type "<tt>va_list</tt>". The LLVM assembly
4006language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4007transformations should be prepared to handle these functions regardless of
4008the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4009
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]4010<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4011instruction and the variable argument handling intrinsic functions are
4012used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4013
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4014<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4015<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4016define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4017 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4018 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4019 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4020 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4021
4022 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4023 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4024
4025 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4026 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4027 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4028 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4029 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4030
4031 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4032 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4033 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4034}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4035
4036declare void @llvm.va_start(i8*)
4037declare void @llvm.va_copy(i8*, i8*)
4038declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4039</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4040</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4041
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4042</div>
4043
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4044<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4045<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4046 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4047</div>
4048
4049
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4050<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4051<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4052<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4053<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4054<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4055<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4056href="#i_va_arg">va_arg</a></tt>.</p>
4057
4058<h5>Arguments:</h5>
4059
4060<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4061
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4062<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4063
4064<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4065macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4066<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4067<tt>va_arg</tt> will produce the first variable argument passed to the function.
4068Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4069last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4070
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4071</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4072
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4073<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4074<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4075 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4076</div>
4077
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4078<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4079<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4080<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4081<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4082
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4083<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4084which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4085or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4086
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4087<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4088
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4089<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]4090
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4091<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4092
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4093<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4094macro available in C. In a target-dependent way, it destroys the
4095<tt>va_list</tt> element to which the argument points. Calls to <a
4096href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4097<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4098<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4100</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4101
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4102<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4103<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4104 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4105</div>
4106
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4107<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4108
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4109<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4110
4111<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4112 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4113</pre>
4114
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4115<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4116
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4117<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4118from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4119
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4120<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4121
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4122<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]4123The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4124
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4125
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4126<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4127
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4128<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4129macro available in C. In a target-dependent way, it copies the source
4130<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4131intrinsic is necessary because the <tt><a href="#int_va_start">
4132llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4133example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4134
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4135</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4136
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4137<!-- ======================================================================= -->
4138<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4139 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4140</div>
4141
4142<div class="doc_text">
4143
4144<p>
4145LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4146Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4147These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4148stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4149href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4150Front-ends for type-safe garbage collected languages should generate these
4151intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4152href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4153</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4154
4155<p>The garbage collection intrinsics only operate on objects in the generic
4156 address space (address space zero).</p>
4157
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4158</div>
4159
4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4162 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4163</div>
4164
4165<div class="doc_text">
4166
4167<h5>Syntax:</h5>
4168
4169<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4170 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4171</pre>
4172
4173<h5>Overview:</h5>
4174
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4175<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4176the code generator, and allows some metadata to be associated with it.</p>
4177
4178<h5>Arguments:</h5>
4179
4180<p>The first argument specifies the address of a stack object that contains the
4181root pointer. The second pointer (which must be either a constant or a global
4182value address) contains the meta-data to be associated with the root.</p>
4183
4184<h5>Semantics:</h5>
4185
4186<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4187location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4188the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4189intrinsic may only be used in a function which <a href="#gc">specifies a GC
4190algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4191
4192</div>
4193
4194
4195<!-- _______________________________________________________________________ -->
4196<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4197 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4198</div>
4199
4200<div class="doc_text">
4201
4202<h5>Syntax:</h5>
4203
4204<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4205 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4206</pre>
4207
4208<h5>Overview:</h5>
4209
4210<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4211locations, allowing garbage collector implementations that require read
4212barriers.</p>
4213
4214<h5>Arguments:</h5>
4215
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4216<p>The second argument is the address to read from, which should be an address
4217allocated from the garbage collector. The first object is a pointer to the
4218start of the referenced object, if needed by the language runtime (otherwise
4219null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4220
4221<h5>Semantics:</h5>
4222
4223<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4224instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4225garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4226may only be used in a function which <a href="#gc">specifies a GC
4227algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4228
4229</div>
4230
4231
4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4234 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4235</div>
4236
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240
4241<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4242 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4243</pre>
4244
4245<h5>Overview:</h5>
4246
4247<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4248locations, allowing garbage collector implementations that require write
4249barriers (such as generational or reference counting collectors).</p>
4250
4251<h5>Arguments:</h5>
4252
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4253<p>The first argument is the reference to store, the second is the start of the
4254object to store it to, and the third is the address of the field of Obj to
4255store to. If the runtime does not require a pointer to the object, Obj may be
4256null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4257
4258<h5>Semantics:</h5>
4259
4260<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4261instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4262garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4263may only be used in a function which <a href="#gc">specifies a GC
4264algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4265
4266</div>
4267
4268
4269
4270<!-- ======================================================================= -->
4271<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4272 <a name="int_codegen">Code Generator Intrinsics</a>
4273</div>
4274
4275<div class="doc_text">
4276<p>
4277These intrinsics are provided by LLVM to expose special features that may only
4278be implemented with code generator support.
4279</p>
4280
4281</div>
4282
4283<!-- _______________________________________________________________________ -->
4284<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4285 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4286</div>
4287
4288<div class="doc_text">
4289
4290<h5>Syntax:</h5>
4291<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4292 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4293</pre>
4294
4295<h5>Overview:</h5>
4296
4297<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4298The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4299target-specific value indicating the return address of the current function
4300or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4301</p>
4302
4303<h5>Arguments:</h5>
4304
4305<p>
4306The argument to this intrinsic indicates which function to return the address
4307for. Zero indicates the calling function, one indicates its caller, etc. The
4308argument is <b>required</b> to be a constant integer value.
4309</p>
4310
4311<h5>Semantics:</h5>
4312
4313<p>
4314The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4315the return address of the specified call frame, or zero if it cannot be
4316identified. The value returned by this intrinsic is likely to be incorrect or 0
4317for arguments other than zero, so it should only be used for debugging purposes.
4318</p>
4319
4320<p>
4321Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4322aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4323source-language caller.
4324</p>
4325</div>
4326
4327
4328<!-- _______________________________________________________________________ -->
4329<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4330 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4331</div>
4332
4333<div class="doc_text">
4334
4335<h5>Syntax:</h5>
4336<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4337 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4338</pre>
4339
4340<h5>Overview:</h5>
4341
4342<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4343The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4344target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4345</p>
4346
4347<h5>Arguments:</h5>
4348
4349<p>
4350The argument to this intrinsic indicates which function to return the frame
4351pointer for. Zero indicates the calling function, one indicates its caller,
4352etc. The argument is <b>required</b> to be a constant integer value.
4353</p>
4354
4355<h5>Semantics:</h5>
4356
4357<p>
4358The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4359the frame address of the specified call frame, or zero if it cannot be
4360identified. The value returned by this intrinsic is likely to be incorrect or 0
4361for arguments other than zero, so it should only be used for debugging purposes.
4362</p>
4363
4364<p>
4365Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4366aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4367source-language caller.
4368</p>
4369</div>
4370
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4371<!-- _______________________________________________________________________ -->
4372<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4373 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4374</div>
4375
4376<div class="doc_text">
4377
4378<h5>Syntax:</h5>
4379<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4380 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
4386The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4387the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4388<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4389features like scoped automatic variable sized arrays in C99.
4390</p>
4391
4392<h5>Semantics:</h5>
4393
4394<p>
4395This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4396href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4397<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4398<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4399state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4400practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4401that were allocated after the <tt>llvm.stacksave</tt> was executed.
4402</p>
4403
4404</div>
4405
4406<!-- _______________________________________________________________________ -->
4407<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4408 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4409</div>
4410
4411<div class="doc_text">
4412
4413<h5>Syntax:</h5>
4414<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4415 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4416</pre>
4417
4418<h5>Overview:</h5>
4419
4420<p>
4421The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4422the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4423href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4424useful for implementing language features like scoped automatic variable sized
4425arrays in C99.
4426</p>
4427
4428<h5>Semantics:</h5>
4429
4430<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4431See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4432</p>
4433
4434</div>
4435
4436
4437<!-- _______________________________________________________________________ -->
4438<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4439 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4440</div>
4441
4442<div class="doc_text">
4443
4444<h5>Syntax:</h5>
4445<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4446 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]4447</pre>
4448
4449<h5>Overview:</h5>
4450
4451
4452<p>
4453The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4454a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4455no
4456effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4457characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4458</p>
4459
4460<h5>Arguments:</h5>
4461
4462<p>
4463<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4464determining if the fetch should be for a read (0) or write (1), and
4465<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4466locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4467<tt>locality</tt> arguments must be constant integers.
4468</p>
4469
4470<h5>Semantics:</h5>
4471
4472<p>
4473This intrinsic does not modify the behavior of the program. In particular,
4474prefetches cannot trap and do not produce a value. On targets that support this
4475intrinsic, the prefetch can provide hints to the processor cache for better
4476performance.
4477</p>
4478
4479</div>
4480
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4481<!-- _______________________________________________________________________ -->
4482<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4483 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4484</div>
4485
4486<div class="doc_text">
4487
4488<h5>Syntax:</h5>
4489<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4490 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4491</pre>
4492
4493<h5>Overview:</h5>
4494
4495
4496<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4497The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4498(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4499code to simulators and other tools. The method is target specific, but it is
4500expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4501The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4502after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4503optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4504correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4505</p>
4506
4507<h5>Arguments:</h5>
4508
4509<p>
4510<tt>id</tt> is a numerical id identifying the marker.
4511</p>
4512
4513<h5>Semantics:</h5>
4514
4515<p>
4516This intrinsic does not modify the behavior of the program. Backends that do not
4517support this intrinisic may ignore it.
4518</p>
4519
4520</div>
4521
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4522<!-- _______________________________________________________________________ -->
4523<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4524 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4525</div>
4526
4527<div class="doc_text">
4528
4529<h5>Syntax:</h5>
4530<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4531 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4532</pre>
4533
4534<h5>Overview:</h5>
4535
4536
4537<p>
4538The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4539counter register (or similar low latency, high accuracy clocks) on those targets
4540that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4541As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4542should only be used for small timings.
4543</p>
4544
4545<h5>Semantics:</h5>
4546
4547<p>
4548When directly supported, reading the cycle counter should not modify any memory.
4549Implementations are allowed to either return a application specific value or a
4550system wide value. On backends without support, this is lowered to a constant 0.
4551</p>
4552
4553</div>
4554
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4555<!-- ======================================================================= -->
4556<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4557 <a name="int_libc">Standard C Library Intrinsics</a>
4558</div>
4559
4560<div class="doc_text">
4561<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4562LLVM provides intrinsics for a few important standard C library functions.
4563These intrinsics allow source-language front-ends to pass information about the
4564alignment of the pointer arguments to the code generator, providing opportunity
4565for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4566</p>
4567
4568</div>
4569
4570<!-- _______________________________________________________________________ -->
4571<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4572 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4573</div>
4574
4575<div class="doc_text">
4576
4577<h5>Syntax:</h5>
4578<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4579 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4580 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4581 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4582 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4583</pre>
4584
4585<h5>Overview:</h5>
4586
4587<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4588The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4589location to the destination location.
4590</p>
4591
4592<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4593Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4594intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4595</p>
4596
4597<h5>Arguments:</h5>
4598
4599<p>
4600The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4601the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4602specifying the number of bytes to copy, and the fourth argument is the alignment
4603of the source and destination locations.
4604</p>
4605
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4606<p>
4607If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4608the caller guarantees that both the source and destination pointers are aligned
4609to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4610</p>
4611
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4612<h5>Semantics:</h5>
4613
4614<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4615The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4616location to the destination location, which are not allowed to overlap. It
4617copies "len" bytes of memory over. If the argument is known to be aligned to
4618some boundary, this can be specified as the fourth argument, otherwise it should
4619be set to 0 or 1.
4620</p>
4621</div>
4622
4623
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4624<!-- _______________________________________________________________________ -->
4625<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4626 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4627</div>
4628
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
4632<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4633 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4634 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4635 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4636 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4637</pre>
4638
4639<h5>Overview:</h5>
4640
4641<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4642The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4643location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4644'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4645</p>
4646
4647<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4648Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4649intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4650</p>
4651
4652<h5>Arguments:</h5>
4653
4654<p>
4655The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4656the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4657specifying the number of bytes to copy, and the fourth argument is the alignment
4658of the source and destination locations.
4659</p>
4660
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4661<p>
4662If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4663the caller guarantees that the source and destination pointers are aligned to
4664that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4665</p>
4666
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4667<h5>Semantics:</h5>
4668
4669<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4670The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4671location to the destination location, which may overlap. It
4672copies "len" bytes of memory over. If the argument is known to be aligned to
4673some boundary, this can be specified as the fourth argument, otherwise it should
4674be set to 0 or 1.
4675</p>
4676</div>
4677
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4678
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4679<!-- _______________________________________________________________________ -->
4680<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4681 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4682</div>
4683
4684<div class="doc_text">
4685
4686<h5>Syntax:</h5>
4687<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4688 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4689 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4690 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4691 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4692</pre>
4693
4694<h5>Overview:</h5>
4695
4696<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4697The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4698byte value.
4699</p>
4700
4701<p>
4702Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4703does not return a value, and takes an extra alignment argument.
4704</p>
4705
4706<h5>Arguments:</h5>
4707
4708<p>
4709The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4710byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4711argument specifying the number of bytes to fill, and the fourth argument is the
4712known alignment of destination location.
4713</p>
4714
4715<p>
4716If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4717the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4718</p>
4719
4720<h5>Semantics:</h5>
4721
4722<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4723The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4724the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4725destination location. If the argument is known to be aligned to some boundary,
4726this can be specified as the fourth argument, otherwise it should be set to 0 or
47271.
4728</p>
4729</div>
4730
4731
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4732<!-- _______________________________________________________________________ -->
4733<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4734 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4735</div>
4736
4737<div class="doc_text">
4738
4739<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4740<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4741floating point or vector of floating point type. Not all targets support all
4742types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4743<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4744 declare float @llvm.sqrt.f32(float %Val)
4745 declare double @llvm.sqrt.f64(double %Val)
4746 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4747 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4748 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4749</pre>
4750
4751<h5>Overview:</h5>
4752
4753<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4754The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4755returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4756<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner103e2d72008-01-29 07:00:44 +0000[diff] [blame]4757negative numbers other than -0.0 (which allows for better optimization, because
4758there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4759defined to return -0.0 like IEEE sqrt.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4760</p>
4761
4762<h5>Arguments:</h5>
4763
4764<p>
4765The argument and return value are floating point numbers of the same type.
4766</p>
4767
4768<h5>Semantics:</h5>
4769
4770<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4771This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4772floating point number.
4773</p>
4774</div>
4775
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4776<!-- _______________________________________________________________________ -->
4777<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4778 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4779</div>
4780
4781<div class="doc_text">
4782
4783<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4784<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4785floating point or vector of floating point type. Not all targets support all
4786types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4787<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4788 declare float @llvm.powi.f32(float %Val, i32 %power)
4789 declare double @llvm.powi.f64(double %Val, i32 %power)
4790 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4791 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4792 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4793</pre>
4794
4795<h5>Overview:</h5>
4796
4797<p>
4798The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4799specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4800multiplications is not defined. When a vector of floating point type is
4801used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4802</p>
4803
4804<h5>Arguments:</h5>
4805
4806<p>
4807The second argument is an integer power, and the first is a value to raise to
4808that power.
4809</p>
4810
4811<h5>Semantics:</h5>
4812
4813<p>
4814This function returns the first value raised to the second power with an
4815unspecified sequence of rounding operations.</p>
4816</div>
4817
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4818<!-- _______________________________________________________________________ -->
4819<div class="doc_subsubsection">
4820 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4821</div>
4822
4823<div class="doc_text">
4824
4825<h5>Syntax:</h5>
4826<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4827floating point or vector of floating point type. Not all targets support all
4828types however.
4829<pre>
4830 declare float @llvm.sin.f32(float %Val)
4831 declare double @llvm.sin.f64(double %Val)
4832 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4833 declare fp128 @llvm.sin.f128(fp128 %Val)
4834 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4835</pre>
4836
4837<h5>Overview:</h5>
4838
4839<p>
4840The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4841</p>
4842
4843<h5>Arguments:</h5>
4844
4845<p>
4846The argument and return value are floating point numbers of the same type.
4847</p>
4848
4849<h5>Semantics:</h5>
4850
4851<p>
4852This function returns the sine of the specified operand, returning the
4853same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4854conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4855</div>
4856
4857<!-- _______________________________________________________________________ -->
4858<div class="doc_subsubsection">
4859 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4860</div>
4861
4862<div class="doc_text">
4863
4864<h5>Syntax:</h5>
4865<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4866floating point or vector of floating point type. Not all targets support all
4867types however.
4868<pre>
4869 declare float @llvm.cos.f32(float %Val)
4870 declare double @llvm.cos.f64(double %Val)
4871 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4872 declare fp128 @llvm.cos.f128(fp128 %Val)
4873 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4874</pre>
4875
4876<h5>Overview:</h5>
4877
4878<p>
4879The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4880</p>
4881
4882<h5>Arguments:</h5>
4883
4884<p>
4885The argument and return value are floating point numbers of the same type.
4886</p>
4887
4888<h5>Semantics:</h5>
4889
4890<p>
4891This function returns the cosine of the specified operand, returning the
4892same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4893conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4894</div>
4895
4896<!-- _______________________________________________________________________ -->
4897<div class="doc_subsubsection">
4898 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4899</div>
4900
4901<div class="doc_text">
4902
4903<h5>Syntax:</h5>
4904<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4905floating point or vector of floating point type. Not all targets support all
4906types however.
4907<pre>
4908 declare float @llvm.pow.f32(float %Val, float %Power)
4909 declare double @llvm.pow.f64(double %Val, double %Power)
4910 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4911 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4912 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4913</pre>
4914
4915<h5>Overview:</h5>
4916
4917<p>
4918The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4919specified (positive or negative) power.
4920</p>
4921
4922<h5>Arguments:</h5>
4923
4924<p>
4925The second argument is a floating point power, and the first is a value to
4926raise to that power.
4927</p>
4928
4929<h5>Semantics:</h5>
4930
4931<p>
4932This function returns the first value raised to the second power,
4933returning the
4934same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4935conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4936</div>
4937
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4938
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4939<!-- ======================================================================= -->
4940<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4941 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4942</div>
4943
4944<div class="doc_text">
4945<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4946LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4947These allow efficient code generation for some algorithms.
4948</p>
4949
4950</div>
4951
4952<!-- _______________________________________________________________________ -->
4953<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4954 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4955</div>
4956
4957<div class="doc_text">
4958
4959<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4960<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4961type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4962<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4963 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4964 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4965 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4966</pre>
4967
4968<h5>Overview:</h5>
4969
4970<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4971The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4972values with an even number of bytes (positive multiple of 16 bits). These are
4973useful for performing operations on data that is not in the target's native
4974byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4975</p>
4976
4977<h5>Semantics:</h5>
4978
4979<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4980The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4981and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4982intrinsic returns an i32 value that has the four bytes of the input i32
4983swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4984i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4985<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4986additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4987</p>
4988
4989</div>
4990
4991<!-- _______________________________________________________________________ -->
4992<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4993 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4994</div>
4995
4996<div class="doc_text">
4997
4998<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4999<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5000width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5001<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5002 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5003 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5004 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5005 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5006 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5007</pre>
5008
5009<h5>Overview:</h5>
5010
5011<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]5012The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5013value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5014</p>
5015
5016<h5>Arguments:</h5>
5017
5018<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5019The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5020integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5021</p>
5022
5023<h5>Semantics:</h5>
5024
5025<p>
5026The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5027</p>
5028</div>
5029
5030<!-- _______________________________________________________________________ -->
5031<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5032 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5033</div>
5034
5035<div class="doc_text">
5036
5037<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5038<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5039integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5040<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5041 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5042 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5043 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5044 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5045 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5046</pre>
5047
5048<h5>Overview:</h5>
5049
5050<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5051The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5052leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5053</p>
5054
5055<h5>Arguments:</h5>
5056
5057<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5058The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5059integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5060</p>
5061
5062<h5>Semantics:</h5>
5063
5064<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5065The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5066in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5067of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5068</p>
5069</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5070
5071
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5072
5073<!-- _______________________________________________________________________ -->
5074<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5075 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5076</div>
5077
5078<div class="doc_text">
5079
5080<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5081<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5082integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5083<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5084 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5085 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5086 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5087 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5088 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5089</pre>
5090
5091<h5>Overview:</h5>
5092
5093<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5094The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5095trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5096</p>
5097
5098<h5>Arguments:</h5>
5099
5100<p>
5101The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5102integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5103</p>
5104
5105<h5>Semantics:</h5>
5106
5107<p>
5108The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5109in a variable. If the src == 0 then the result is the size in bits of the type
5110of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5111</p>
5112</div>
5113
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5114<!-- _______________________________________________________________________ -->
5115<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5116 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5117</div>
5118
5119<div class="doc_text">
5120
5121<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5122<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5123on any integer bit width.
5124<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5125 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5126 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5127</pre>
5128
5129<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5130<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5131range of bits from an integer value and returns them in the same bit width as
5132the original value.</p>
5133
5134<h5>Arguments:</h5>
5135<p>The first argument, <tt>%val</tt> and the result may be integer types of
5136any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5137arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5138
5139<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5140<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5141of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5142<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5143operates in forward mode.</p>
5144<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5145right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5146only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5147<ol>
5148 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5149 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5150 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5151 to determine the number of bits to retain.</li>
5152 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5153 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5154</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5155<p>In reverse mode, a similar computation is made except that the bits are
5156returned in the reverse order. So, for example, if <tt>X</tt> has the value
5157<tt>i16 0x0ACF (101011001111)</tt> and we apply
5158<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5159<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5160</div>
5161
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5162<div class="doc_subsubsection">
5163 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5164</div>
5165
5166<div class="doc_text">
5167
5168<h5>Syntax:</h5>
5169<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5170on any integer bit width.
5171<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5172 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5173 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5174</pre>
5175
5176<h5>Overview:</h5>
5177<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5178of bits in an integer value with another integer value. It returns the integer
5179with the replaced bits.</p>
5180
5181<h5>Arguments:</h5>
5182<p>The first argument, <tt>%val</tt> and the result may be integer types of
5183any bit width but they must have the same bit width. <tt>%val</tt> is the value
5184whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5185integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5186type since they specify only a bit index.</p>
5187
5188<h5>Semantics:</h5>
5189<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5190of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5191<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5192operates in forward mode.</p>
5193<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5194truncating it down to the size of the replacement area or zero extending it
5195up to that size.</p>
5196<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5197are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5198in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5199to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5200<p>In reverse mode, a similar computation is made except that the bits are
5201reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5202<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5203<h5>Examples:</h5>
5204<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5205 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5206 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5207 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5208 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5209 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5210</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5211</div>
5212
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5213<!-- ======================================================================= -->
5214<div class="doc_subsection">
5215 <a name="int_debugger">Debugger Intrinsics</a>
5216</div>
5217
5218<div class="doc_text">
5219<p>
5220The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5221are described in the <a
5222href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5223Debugging</a> document.
5224</p>
5225</div>
5226
5227
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5228<!-- ======================================================================= -->
5229<div class="doc_subsection">
5230 <a name="int_eh">Exception Handling Intrinsics</a>
5231</div>
5232
5233<div class="doc_text">
5234<p> The LLVM exception handling intrinsics (which all start with
5235<tt>llvm.eh.</tt> prefix), are described in the <a
5236href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5237Handling</a> document. </p>
5238</div>
5239
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5240<!-- ======================================================================= -->
5241<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5242 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5243</div>
5244
5245<div class="doc_text">
5246<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5247 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5248 the <tt>nest</tt> attribute, from a function. The result is a callable
5249 function pointer lacking the nest parameter - the caller does not need
5250 to provide a value for it. Instead, the value to use is stored in
5251 advance in a "trampoline", a block of memory usually allocated
5252 on the stack, which also contains code to splice the nest value into the
5253 argument list. This is used to implement the GCC nested function address
5254 extension.
5255</p>
5256<p>
5257 For example, if the function is
5258 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5259 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5260<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5261 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5262 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5263 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5264 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5265</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5266 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5267 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5268</div>
5269
5270<!-- _______________________________________________________________________ -->
5271<div class="doc_subsubsection">
5272 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5273</div>
5274<div class="doc_text">
5275<h5>Syntax:</h5>
5276<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5277declare 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]5278</pre>
5279<h5>Overview:</h5>
5280<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5281 This fills the memory pointed to by <tt>tramp</tt> with code
5282 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5283</p>
5284<h5>Arguments:</h5>
5285<p>
5286 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5287 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5288 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5289 intrinsic. Note that the size and the alignment are target-specific - LLVM
5290 currently provides no portable way of determining them, so a front-end that
5291 generates this intrinsic needs to have some target-specific knowledge.
5292 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5293</p>
5294<h5>Semantics:</h5>
5295<p>
5296 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5297 dependent code, turning it into a function. A pointer to this function is
5298 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5299 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5300 before being called. The new function's signature is the same as that of
5301 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5302 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5303 of pointer type. Calling the new function is equivalent to calling
5304 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5305 missing <tt>nest</tt> argument. If, after calling
5306 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5307 modified, then the effect of any later call to the returned function pointer is
5308 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5309</p>
5310</div>
5311
5312<!-- ======================================================================= -->
5313<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5314 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5315</div>
5316
5317<div class="doc_text">
5318<p>
5319 These intrinsic functions expand the "universal IR" of LLVM to represent
5320 hardware constructs for atomic operations and memory synchronization. This
5321 provides an interface to the hardware, not an interface to the programmer. It
5322 is aimed at a low enough level to allow any programming models or APIs which
5323 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5324 hardware behavior. Just as hardware provides a "universal IR" for source
5325 languages, it also provides a starting point for developing a "universal"
5326 atomic operation and synchronization IR.
5327</p>
5328<p>
5329 These do <em>not</em> form an API such as high-level threading libraries,
5330 software transaction memory systems, atomic primitives, and intrinsic
5331 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5332 application libraries. The hardware interface provided by LLVM should allow
5333 a clean implementation of all of these APIs and parallel programming models.
5334 No one model or paradigm should be selected above others unless the hardware
5335 itself ubiquitously does so.
5336
5337</p>
5338</div>
5339
5340<!-- _______________________________________________________________________ -->
5341<div class="doc_subsubsection">
5342 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5343</div>
5344<div class="doc_text">
5345<h5>Syntax:</h5>
5346<pre>
5347declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5348i1 &lt;device&gt; )
5349
5350</pre>
5351<h5>Overview:</h5>
5352<p>
5353 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5354 specific pairs of memory access types.
5355</p>
5356<h5>Arguments:</h5>
5357<p>
5358 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5359 The first four arguments enables a specific barrier as listed below. The fith
5360 argument specifies that the barrier applies to io or device or uncached memory.
5361
5362</p>
5363 <ul>
5364 <li><tt>ll</tt>: load-load barrier</li>
5365 <li><tt>ls</tt>: load-store barrier</li>
5366 <li><tt>sl</tt>: store-load barrier</li>
5367 <li><tt>ss</tt>: store-store barrier</li>
5368 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5369 </ul>
5370<h5>Semantics:</h5>
5371<p>
5372 This intrinsic causes the system to enforce some ordering constraints upon
5373 the loads and stores of the program. This barrier does not indicate
5374 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5375 which they occur. For any of the specified pairs of load and store operations
5376 (f.ex. load-load, or store-load), all of the first operations preceding the
5377 barrier will complete before any of the second operations succeeding the
5378 barrier begin. Specifically the semantics for each pairing is as follows:
5379</p>
5380 <ul>
5381 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5382 after the barrier begins.</li>
5383
5384 <li><tt>ls</tt>: All loads before the barrier must complete before any
5385 store after the barrier begins.</li>
5386 <li><tt>ss</tt>: All stores before the barrier must complete before any
5387 store after the barrier begins.</li>
5388 <li><tt>sl</tt>: All stores before the barrier must complete before any
5389 load after the barrier begins.</li>
5390 </ul>
5391<p>
5392 These semantics are applied with a logical "and" behavior when more than one
5393 is enabled in a single memory barrier intrinsic.
5394</p>
5395<p>
5396 Backends may implement stronger barriers than those requested when they do not
5397 support as fine grained a barrier as requested. Some architectures do not
5398 need all types of barriers and on such architectures, these become noops.
5399</p>
5400<h5>Example:</h5>
5401<pre>
5402%ptr = malloc i32
5403 store i32 4, %ptr
5404
5405%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5406 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5407 <i>; guarantee the above finishes</i>
5408 store i32 8, %ptr <i>; before this begins</i>
5409</pre>
5410</div>
5411
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]5412<!-- _______________________________________________________________________ -->
5413<div class="doc_subsubsection">
5414 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5415</div>
5416<div class="doc_text">
5417<h5>Syntax:</h5>
5418<p>
5419 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5420 integer bit width. Not all targets support all bit widths however.</p>
5421
5422<pre>
5423declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5424declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5425declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5426declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5427
5428</pre>
5429<h5>Overview:</h5>
5430<p>
5431 This loads a value in memory and compares it to a given value. If they are
5432 equal, it stores a new value into the memory.
5433</p>
5434<h5>Arguments:</h5>
5435<p>
5436 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5437 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5438 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5439 this integer type. While any bit width integer may be used, targets may only
5440 lower representations they support in hardware.
5441
5442</p>
5443<h5>Semantics:</h5>
5444<p>
5445 This entire intrinsic must be executed atomically. It first loads the value
5446 in memory pointed to by <tt>ptr</tt> and compares it with the value
5447 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5448 loaded value is yielded in all cases. This provides the equivalent of an
5449 atomic compare-and-swap operation within the SSA framework.
5450</p>
5451<h5>Examples:</h5>
5452
5453<pre>
5454%ptr = malloc i32
5455 store i32 4, %ptr
5456
5457%val1 = add i32 4, 4
5458%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5459 <i>; yields {i32}:result1 = 4</i>
5460%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5461%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5462
5463%val2 = add i32 1, 1
5464%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5465 <i>; yields {i32}:result2 = 8</i>
5466%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5467
5468%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5469</pre>
5470</div>
5471
5472<!-- _______________________________________________________________________ -->
5473<div class="doc_subsubsection">
5474 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5475</div>
5476<div class="doc_text">
5477<h5>Syntax:</h5>
5478
5479<p>
5480 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5481 integer bit width. Not all targets support all bit widths however.</p>
5482<pre>
5483declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5484declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5485declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5486declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5487
5488</pre>
5489<h5>Overview:</h5>
5490<p>
5491 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5492 the value from memory. It then stores the value in <tt>val</tt> in the memory
5493 at <tt>ptr</tt>.
5494</p>
5495<h5>Arguments:</h5>
5496
5497<p>
5498 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5499 <tt>val</tt> argument and the result must be integers of the same bit width.
5500 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5501 integer type. The targets may only lower integer representations they
5502 support.
5503</p>
5504<h5>Semantics:</h5>
5505<p>
5506 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5507 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5508 equivalent of an atomic swap operation within the SSA framework.
5509
5510</p>
5511<h5>Examples:</h5>
5512<pre>
5513%ptr = malloc i32
5514 store i32 4, %ptr
5515
5516%val1 = add i32 4, 4
5517%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5518 <i>; yields {i32}:result1 = 4</i>
5519%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5520%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5521
5522%val2 = add i32 1, 1
5523%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5524 <i>; yields {i32}:result2 = 8</i>
5525
5526%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5527%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5528</pre>
5529</div>
5530
5531<!-- _______________________________________________________________________ -->
5532<div class="doc_subsubsection">
5533 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5534
5535</div>
5536<div class="doc_text">
5537<h5>Syntax:</h5>
5538<p>
5539 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5540 integer bit width. Not all targets support all bit widths however.</p>
5541<pre>
5542declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5543declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5544declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5545declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5546
5547</pre>
5548<h5>Overview:</h5>
5549<p>
5550 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5551 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5552</p>
5553<h5>Arguments:</h5>
5554<p>
5555
5556 The intrinsic takes two arguments, the first a pointer to an integer value
5557 and the second an integer value. The result is also an integer value. These
5558 integer types can have any bit width, but they must all have the same bit
5559 width. The targets may only lower integer representations they support.
5560</p>
5561<h5>Semantics:</h5>
5562<p>
5563 This intrinsic does a series of operations atomically. It first loads the
5564 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5565 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5566</p>
5567
5568<h5>Examples:</h5>
5569<pre>
5570%ptr = malloc i32
5571 store i32 4, %ptr
5572%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5573 <i>; yields {i32}:result1 = 4</i>
5574%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5575 <i>; yields {i32}:result2 = 8</i>
5576%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5577 <i>; yields {i32}:result3 = 10</i>
5578%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5579</pre>
5580</div>
5581
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5582
5583<!-- ======================================================================= -->
5584<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5585 <a name="int_general">General Intrinsics</a>
5586</div>
5587
5588<div class="doc_text">
5589<p> This class of intrinsics is designed to be generic and has
5590no specific purpose. </p>
5591</div>
5592
5593<!-- _______________________________________________________________________ -->
5594<div class="doc_subsubsection">
5595 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5596</div>
5597
5598<div class="doc_text">
5599
5600<h5>Syntax:</h5>
5601<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5602 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]5603</pre>
5604
5605<h5>Overview:</h5>
5606
5607<p>
5608The '<tt>llvm.var.annotation</tt>' intrinsic
5609</p>
5610
5611<h5>Arguments:</h5>
5612
5613<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5614The first argument is a pointer to a value, the second is a pointer to a
5615global string, the third is a pointer to a global string which is the source
5616file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5617</p>
5618
5619<h5>Semantics:</h5>
5620
5621<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5622This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5623This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5624annotations. These have no other defined use, they are ignored by code
5625generation and optimization.
5626</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5627</div>
5628
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5629<!-- _______________________________________________________________________ -->
5630<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5631 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5632</div>
5633
5634<div class="doc_text">
5635
5636<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5637<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5638any integer bit width.
5639</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5640<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5641 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5642 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5643 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5644 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5645 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]5646</pre>
5647
5648<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5649
5650<p>
5651The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5652</p>
5653
5654<h5>Arguments:</h5>
5655
5656<p>
5657The first argument is an integer value (result of some expression),
5658the second is a pointer to a global string, the third is a pointer to a global
5659string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5660It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5661</p>
5662
5663<h5>Semantics:</h5>
5664
5665<p>
5666This intrinsic allows annotations to be put on arbitrary expressions
5667with arbitrary strings. This can be useful for special purpose optimizations
5668that want to look for these annotations. These have no other defined use, they
5669are ignored by code generation and optimization.
5670</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5671
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5672<!-- _______________________________________________________________________ -->
5673<div class="doc_subsubsection">
5674 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5675</div>
5676
5677<div class="doc_text">
5678
5679<h5>Syntax:</h5>
5680<pre>
5681 declare void @llvm.trap()
5682</pre>
5683
5684<h5>Overview:</h5>
5685
5686<p>
5687The '<tt>llvm.trap</tt>' intrinsic
5688</p>
5689
5690<h5>Arguments:</h5>
5691
5692<p>
5693None
5694</p>
5695
5696<h5>Semantics:</h5>
5697
5698<p>
5699This intrinsics is lowered to the target dependent trap instruction. If the
5700target does not have a trap instruction, this intrinsic will be lowered to the
5701call of the abort() function.
5702</p>
5703</div>
5704
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5705<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5706<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5707<address>
5708 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5709 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5710 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5711 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5712
5713 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5714 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5715 Last modified: $Date$
5716</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5717
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