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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 772fccfe45bd3df54ec48176c83a90f1bc56e72e / . / docs / LangRef.html
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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 Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]766 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]767 optional <a href="#linkage">linkage type</a>, and an
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
1228consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1229Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1230(which are structures of pointers to functions), for indirect function
1231calls, and when defining a function.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1232
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1233<h5>Syntax:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1234<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1235<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]1236specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1237which indicates that the function takes a variable number of arguments.
1238Variable argument functions can access their arguments with the <a
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1239 href="#int_varargs">variable argument handling intrinsic</a> functions.
1240'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1241<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1242<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1243<table class="layout">
1244 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1245 <td class="left"><tt>i32 (i32)</tt></td>
1246 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1247 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1248 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1249 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1250 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1251 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1252 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1253 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1254 <tt>float</tt>.
1255 </td>
1256 </tr><tr class="layout">
1257 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1258 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1259 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1260 which returns an integer. This is the signature for <tt>printf</tt> in
1261 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1262 </td>
1263 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1264</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1266</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1267<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1268<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1269<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1270<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1271<p>The structure type is used to represent a collection of data members
1272together in memory. The packing of the field types is defined to match
1273the ABI of the underlying processor. The elements of a structure may
1274be any type that has a size.</p>
1275<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1276and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1277field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1278instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1279<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1280<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1281<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1282<table class="layout">
1283 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1284 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1285 <td class="left">A triple of three <tt>i32</tt> values</td>
1286 </tr><tr class="layout">
1287 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1288 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1289 second element is a <a href="#t_pointer">pointer</a> to a
1290 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1291 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1292 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1293</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1294</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1296<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1297<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1298</div>
1299<div class="doc_text">
1300<h5>Overview:</h5>
1301<p>The packed structure type is used to represent a collection of data members
1302together in memory. There is no padding between fields. Further, the alignment
1303of a packed structure is 1 byte. The elements of a packed structure may
1304be any type that has a size.</p>
1305<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1306and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1307field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1308instruction.</p>
1309<h5>Syntax:</h5>
1310<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1311<h5>Examples:</h5>
1312<table class="layout">
1313 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1314 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1315 <td class="left">A triple of three <tt>i32</tt> values</td>
1316 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1317 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1318 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1319 second element is a <a href="#t_pointer">pointer</a> to a
1320 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1321 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1322 </tr>
1323</table>
1324</div>
1325
1326<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1327<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1328<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1329<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1330<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1331reference to another object, which must live in memory. Pointer types may have
1332an optional address space attribute defining the target-specific numbered
1333address space where the pointed-to object resides. The default address space is
1334zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1335<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1336<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1337<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1338<table class="layout">
1339 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1340 <td class="left"><tt>[4x i32]*</tt></td>
1341 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1342 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1343 </tr>
1344 <tr class="layout">
1345 <td class="left"><tt>i32 (i32 *) *</tt></td>
1346 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1347 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1348 <tt>i32</tt>.</td>
1349 </tr>
1350 <tr class="layout">
1351 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1352 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1353 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1354 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1355</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1356</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1357
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1358<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1359<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1360<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1361
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1362<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1363
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1364<p>A vector type is a simple derived type that represents a vector
1365of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1366are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1367A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1368elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1369of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1370considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1371
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1372<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1373
1374<pre>
1375 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1376</pre>
1377
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1378<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1379be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1380
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1381<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1382
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1383<table class="layout">
1384 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1385 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1386 <td class="left">Vector of 4 32-bit integer values.</td>
1387 </tr>
1388 <tr class="layout">
1389 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1390 <td class="left">Vector of 8 32-bit floating-point values.</td>
1391 </tr>
1392 <tr class="layout">
1393 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1394 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1395 </tr>
1396</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1397</div>
1398
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1399<!-- _______________________________________________________________________ -->
1400<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1401<div class="doc_text">
1402
1403<h5>Overview:</h5>
1404
1405<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1406corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1407In LLVM, opaque types can eventually be resolved to any type (not just a
1408structure type).</p>
1409
1410<h5>Syntax:</h5>
1411
1412<pre>
1413 opaque
1414</pre>
1415
1416<h5>Examples:</h5>
1417
1418<table class="layout">
1419 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1420 <td class="left"><tt>opaque</tt></td>
1421 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1422 </tr>
1423</table>
1424</div>
1425
1426
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427<!-- *********************************************************************** -->
1428<div class="doc_section"> <a name="constants">Constants</a> </div>
1429<!-- *********************************************************************** -->
1430
1431<div class="doc_text">
1432
1433<p>LLVM has several different basic types of constants. This section describes
1434them all and their syntax.</p>
1435
1436</div>
1437
1438<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1439<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1440
1441<div class="doc_text">
1442
1443<dl>
1444 <dt><b>Boolean constants</b></dt>
1445
1446 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1447 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1448 </dd>
1449
1450 <dt><b>Integer constants</b></dt>
1451
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1452 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1453 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454 integer types.
1455 </dd>
1456
1457 <dt><b>Floating point constants</b></dt>
1458
1459 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1460 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1461 notation (see below). Floating point constants must have a <a
1462 href="#t_floating">floating point</a> type. </dd>
1463
1464 <dt><b>Null pointer constants</b></dt>
1465
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1466 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1468
1469</dl>
1470
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1471<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1472of floating point constants. For example, the form '<tt>double
14730x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14744.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1475(and the only time that they are generated by the disassembler) is when a
1476floating point constant must be emitted but it cannot be represented as a
1477decimal floating point number. For example, NaN's, infinities, and other
1478special values are represented in their IEEE hexadecimal format so that
1479assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1480
1481</div>
1482
1483<!-- ======================================================================= -->
1484<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1485</div>
1486
1487<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1488<p>Aggregate constants arise from aggregation of simple constants
1489and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1490
1491<dl>
1492 <dt><b>Structure constants</b></dt>
1493
1494 <dd>Structure constants are represented with notation similar to structure
1495 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1496 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1497 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]1498 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1499 types of elements must match those specified by the type.
1500 </dd>
1501
1502 <dt><b>Array constants</b></dt>
1503
1504 <dd>Array constants are represented with notation similar to array type
1505 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1506 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1507 constants must have <a href="#t_array">array type</a>, and the number and
1508 types of elements must match those specified by the type.
1509 </dd>
1510
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1511 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1512
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1513 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1514 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1515 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]1516 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1517 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1518 match those specified by the type.
1519 </dd>
1520
1521 <dt><b>Zero initialization</b></dt>
1522
1523 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1524 value to zero of <em>any</em> type, including scalar and aggregate types.
1525 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]1526 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527 initializers.
1528 </dd>
1529</dl>
1530
1531</div>
1532
1533<!-- ======================================================================= -->
1534<div class="doc_subsection">
1535 <a name="globalconstants">Global Variable and Function Addresses</a>
1536</div>
1537
1538<div class="doc_text">
1539
1540<p>The addresses of <a href="#globalvars">global variables</a> and <a
1541href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1542constants. These constants are explicitly referenced when the <a
1543href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1544href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1545file:</p>
1546
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1547<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1548<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1549@X = global i32 17
1550@Y = global i32 42
1551@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1552</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1553</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1554
1555</div>
1556
1557<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1558<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1559<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1560 <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]1561 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1562 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1563
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1564 <p>Undefined values indicate to the compiler that the program is well defined
1565 no matter what value is used, giving the compiler more freedom to optimize.
1566 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1567</div>
1568
1569<!-- ======================================================================= -->
1570<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1571</div>
1572
1573<div class="doc_text">
1574
1575<p>Constant expressions are used to allow expressions involving other constants
1576to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1577href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1578that does not have side effects (e.g. load and call are not supported). The
1579following is the syntax for constant expressions:</p>
1580
1581<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1582 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1583 <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]1584 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1585
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1586 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1587 <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]1588 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]1589
1590 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1591 <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]1592 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]1593
1594 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1595 <dd>Truncate a floating point constant to another floating point type. The
1596 size of CST must be larger than the size of TYPE. Both types must be
1597 floating point.</dd>
1598
1599 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1600 <dd>Floating point extend a constant to another type. The size of CST must be
1601 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1602
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1603 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1604 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1605 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1606 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1607 of the same number of elements. If the value won't fit in the integer type,
1608 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1609
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1610 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1611 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1612 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1613 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1614 of the same number of elements. If the value won't fit in the integer type,
1615 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1616
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1617 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1618 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1619 constant. TYPE must be a scalar or vector floating point type. CST must be of
1620 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1621 of the same number of elements. If the value won't fit in the floating point
1622 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1623
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1624 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1625 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1626 constant. TYPE must be a scalar or vector floating point type. CST must be of
1627 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1628 of the same number of elements. If the value won't fit in the floating point
1629 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1630
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1631 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1632 <dd>Convert a pointer typed constant to the corresponding integer constant
1633 TYPE must be an integer type. CST must be of pointer type. The CST value is
1634 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1635
1636 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1637 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1638 pointer type. CST must be of integer type. The CST value is zero extended,
1639 truncated, or unchanged to make it fit in a pointer size. This one is
1640 <i>really</i> dangerous!</dd>
1641
1642 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1643 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1644 identical (same number of bits). The conversion is done as if the CST value
1645 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]1646 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1647 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]1648 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1649 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1650
1651 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1652
1653 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1654 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1655 instruction, the index list may have zero or more indexes, which are required
1656 to make sense for the type of "CSTPTR".</dd>
1657
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1658 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1659
1660 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1661 constants.</dd>
1662
1663 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1664 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1665
1666 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1667 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1668
1669 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1670
1671 <dd>Perform the <a href="#i_extractelement">extractelement
1672 operation</a> on constants.
1673
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1674 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1675
1676 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1677 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1678
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1679
1680 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1681
1682 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1683 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1684
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1685 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1686
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1687 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1688 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1689 binary</a> operations. The constraints on operands are the same as those for
1690 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1691 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1692</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1693</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1695<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1696<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1697<!-- *********************************************************************** -->
1698
1699<!-- ======================================================================= -->
1700<div class="doc_subsection">
1701<a name="inlineasm">Inline Assembler Expressions</a>
1702</div>
1703
1704<div class="doc_text">
1705
1706<p>
1707LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1708Module-Level Inline Assembly</a>) through the use of a special value. This
1709value represents the inline assembler as a string (containing the instructions
1710to emit), a list of operand constraints (stored as a string), and a flag that
1711indicates whether or not the inline asm expression has side effects. An example
1712inline assembler expression is:
1713</p>
1714
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1715<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1716<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1717i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1718</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1719</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1720
1721<p>
1722Inline assembler expressions may <b>only</b> be used as the callee operand of
1723a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1724</p>
1725
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1726<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1727<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1728%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]1729</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1730</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1731
1732<p>
1733Inline asms with side effects not visible in the constraint list must be marked
1734as having side effects. This is done through the use of the
1735'<tt>sideeffect</tt>' keyword, like so:
1736</p>
1737
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1738<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1739<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1740call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1741</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1742</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1743
1744<p>TODO: The format of the asm and constraints string still need to be
1745documented here. Constraints on what can be done (e.g. duplication, moving, etc
1746need to be documented).
1747</p>
1748
1749</div>
1750
1751<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1752<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1753<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1755<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1756
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1757<p>The LLVM instruction set consists of several different
1758classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1759instructions</a>, <a href="#binaryops">binary instructions</a>,
1760<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1761 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1762instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1764</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1765
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1766<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1767<div class="doc_subsection"> <a name="terminators">Terminator
1768Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1769
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1770<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1771
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1772<p>As mentioned <a href="#functionstructure">previously</a>, every
1773basic block in a program ends with a "Terminator" instruction, which
1774indicates which block should be executed after the current block is
1775finished. These terminator instructions typically yield a '<tt>void</tt>'
1776value: they produce control flow, not values (the one exception being
1777the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1778<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1779 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1780instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1781the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1782 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1783 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1785</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1787<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1788<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1789Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1790<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1791<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1792<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]1793 ret void <i>; Return from void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1794 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]1795</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1796<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1797<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1798value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1799<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1800returns a value and then causes control flow, and one that just causes
1801control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1802<h5>Arguments:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1803<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1804type of each return value must be a '<a href="#t_firstclass">first class</a>'
1805 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1806if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1807returns values that do not match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809<p>When the '<tt>ret</tt>' instruction is executed, control flow
1810returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1811 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1812the instruction after the call. If the caller was an "<a
1813 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1814at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1815returns a value, that value shall set the call or invoke instruction's
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1816return value. If the instruction returns multiple values then these
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1817values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1818</a>' instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1820<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1821 ret void <i>; Return from a void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1822 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1825<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1826<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1827<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1829<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]1830</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1831<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1832<p>The '<tt>br</tt>' instruction is used to cause control flow to
1833transfer to a different basic block in the current function. There are
1834two forms of this instruction, corresponding to a conditional branch
1835and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1836<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1837<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1838single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1839unconditional form of the '<tt>br</tt>' instruction takes a single
1840'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1842<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1843argument is evaluated. If the value is <tt>true</tt>, control flows
1844to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1845control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1846<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1847<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]1848 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]1849</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1850<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1851<div class="doc_subsubsection">
1852 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1853</div>
1854
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1855<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1856<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1857
1858<pre>
1859 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1860</pre>
1861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1862<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1863
1864<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1865several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1866instruction, allowing a branch to occur to one of many possible
1867destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1868
1869
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1870<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1871
1872<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1873comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1874an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1875table is not allowed to contain duplicate constant entries.</p>
1876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1878
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1879<p>The <tt>switch</tt> instruction specifies a table of values and
1880destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1881table is searched for the given value. If the value is found, control flow is
1882transfered to the corresponding destination; otherwise, control flow is
1883transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1884
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1885<h5>Implementation:</h5>
1886
1887<p>Depending on properties of the target machine and the particular
1888<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1889ways. For example, it could be generated as a series of chained conditional
1890branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1891
1892<h5>Example:</h5>
1893
1894<pre>
1895 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1896 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1897 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1898
1899 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1900 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1901
1902 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1903 switch i32 %val, label %otherwise [ i32 0, label %onzero
1904 i32 1, label %onone
1905 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1906</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1907</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1910<div class="doc_subsubsection">
1911 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1912</div>
1913
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1914<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1915
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1917
1918<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1919 &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]1920 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1921</pre>
1922
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1923<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1924
1925<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1926function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1927'<tt>normal</tt>' label or the
1928'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1929"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1930"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1931href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1932continued at the dynamically nearest "exception" label. If the callee function
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1933returns multiple values then individual return values are only accessible through
1934a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1935
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1936<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1941 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1942 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1943 convention</a> the call should use. If none is specified, the call defaults
1944 to using C calling conventions.
1945 </li>
1946 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1947 function value being invoked. In most cases, this is a direct function
1948 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1949 an arbitrary pointer to function value.
1950 </li>
1951
1952 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1953 function to be invoked. </li>
1954
1955 <li>'<tt>function args</tt>': argument list whose types match the function
1956 signature argument types. If the function signature indicates the function
1957 accepts a variable number of arguments, the extra arguments can be
1958 specified. </li>
1959
1960 <li>'<tt>normal label</tt>': the label reached when the called function
1961 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1962
1963 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1964 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1965
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1966</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1967
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1968<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1970<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1971href="#i_call">call</a></tt>' instruction in most regards. The primary
1972difference is that it establishes an association with a label, which is used by
1973the runtime library to unwind the stack.</p>
1974
1975<p>This instruction is used in languages with destructors to ensure that proper
1976cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1977exception. Additionally, this is important for implementation of
1978'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1979
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1980<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1981<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1982 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1983 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1984 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1985 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1986</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1987</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1988
1989
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1990<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1991
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1992<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1993Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1995<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1996
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1997<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1998<pre>
1999 unwind
2000</pre>
2001
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2002<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2003
2004<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2005at the first callee in the dynamic call stack which used an <a
2006href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2007primarily used to implement exception handling.</p>
2008
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2009<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2010
2011<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
2012immediately halt. The dynamic call stack is then searched for the first <a
2013href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2014execution continues at the "exceptional" destination block specified by the
2015<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2016dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2017</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2018
2019<!-- _______________________________________________________________________ -->
2020
2021<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2022Instruction</a> </div>
2023
2024<div class="doc_text">
2025
2026<h5>Syntax:</h5>
2027<pre>
2028 unreachable
2029</pre>
2030
2031<h5>Overview:</h5>
2032
2033<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2034instruction is used to inform the optimizer that a particular portion of the
2035code is not reachable. This can be used to indicate that the code after a
2036no-return function cannot be reached, and other facts.</p>
2037
2038<h5>Semantics:</h5>
2039
2040<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2041</div>
2042
2043
2044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2046<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2047<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2048<p>Binary operators are used to do most of the computation in a
2049program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2050produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2051multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2052The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2053necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2054<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2055</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2056<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2057<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2058Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2059<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2060<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2061<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]2062</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2063<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2064<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2066<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2067 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2068 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]2069Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2071<p>The value produced is the integer or floating point sum of the two
2072operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2073<p>If an integer sum has unsigned overflow, the result returned is the
2074mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2075the result.</p>
2076<p>Because LLVM integers use a two's complement representation, this
2077instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2079<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]2080</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2081</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2082<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2083<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2084Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2085<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2087<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]2088</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2089<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2090<p>The '<tt>sub</tt>' instruction returns the difference of its two
2091operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2092<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2093instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2095<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2096 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2097values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2098This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2099Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2100<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2101<p>The value produced is the integer or floating point difference of
2102the two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2103<p>If an integer difference has unsigned overflow, the result returned is the
2104mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2105the result.</p>
2106<p>Because LLVM integers use a two's complement representation, this
2107instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2109<pre>
2110 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2111 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2112</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2113</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2114<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2115<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2116Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2117<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2118<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2119<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]2120</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2122<p>The '<tt>mul</tt>' instruction returns the product of its two
2123operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2125<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2126 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2127values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2128This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2129Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2130<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2131<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2132two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2133<p>If the result of an integer multiplication has unsigned overflow,
2134the result returned is the mathematical result modulo
21352<sup>n</sup>, where n is the bit width of the result.</p>
2136<p>Because LLVM integers use a two's complement representation, and the
2137result is the same width as the operands, this instruction returns the
2138correct result for both signed and unsigned integers. If a full product
2139(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2140should be sign-extended or zero-extended as appropriate to the
2141width of the full product.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2142<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2143<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]2144</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2145</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2146<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2147<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2148</a></div>
2149<div class="doc_text">
2150<h5>Syntax:</h5>
2151<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2152</pre>
2153<h5>Overview:</h5>
2154<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2155operands.</p>
2156<h5>Arguments:</h5>
2157<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2158<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2159types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2160of the values in which case the elements must be integers.</p>
2161<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2162<p>The value produced is the unsigned integer quotient of the two operands.</p>
2163<p>Note that unsigned integer division and signed integer division are distinct
2164operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2165<p>Division by zero leads to undefined behavior.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2166<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2167<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]2168</pre>
2169</div>
2170<!-- _______________________________________________________________________ -->
2171<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2172</a> </div>
2173<div class="doc_text">
2174<h5>Syntax:</h5>
2175<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2176</pre>
2177<h5>Overview:</h5>
2178<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2179operands.</p>
2180<h5>Arguments:</h5>
2181<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2182<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2183types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2184of the values in which case the elements must be integers.</p>
2185<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2186<p>The value produced is the signed integer quotient of the two operands.</p>
2187<p>Note that signed integer division and unsigned integer division are distinct
2188operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2189<p>Division by zero leads to undefined behavior. Overflow also leads to
2190undefined behavior; this is a rare case, but can occur, for example,
2191by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2192<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2193<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]2194</pre>
2195</div>
2196<!-- _______________________________________________________________________ -->
2197<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2198Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2199<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2201<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]2202</pre>
2203<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2204<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2205operands.</p>
2206<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2207<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2208<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2209identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2210versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2211<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2212<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2214<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]2215</pre>
2216</div>
2217<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2218<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2219</div>
2220<div class="doc_text">
2221<h5>Syntax:</h5>
2222<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2223</pre>
2224<h5>Overview:</h5>
2225<p>The '<tt>urem</tt>' instruction returns the remainder from the
2226unsigned division of its two arguments.</p>
2227<h5>Arguments:</h5>
2228<p>The two arguments to the '<tt>urem</tt>' instruction must be
2229<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2230types. This instruction can also take <a href="#t_vector">vector</a> versions
2231of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2232<h5>Semantics:</h5>
2233<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2234This instruction always performs an unsigned division to get the remainder,
2235regardless of whether the arguments are unsigned or not.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2236<p>Note that unsigned integer remainder and signed integer remainder are
2237distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2238<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2239<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2240<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]2241</pre>
2242
2243</div>
2244<!-- _______________________________________________________________________ -->
2245<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2246Instruction</a> </div>
2247<div class="doc_text">
2248<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2249<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]2250</pre>
2251<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2252<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2253signed division of its two operands. This instruction can also take
2254<a href="#t_vector">vector</a> versions of the values in which case
2255the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2256
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2257<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2258<p>The two arguments to the '<tt>srem</tt>' instruction must be
2259<a href="#t_integer">integer</a> values. Both arguments must have identical
2260types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2261<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2262<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2263has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2264operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2265a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2266 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2267Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2268please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2269Wikipedia: modulo operation</a>.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2270<p>Note that signed integer remainder and unsigned integer remainder are
2271distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2272<p>Taking the remainder of a division by zero leads to undefined behavior.
2273Overflow also leads to undefined behavior; this is a rare case, but can occur,
2274for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2275(The remainder doesn't actually overflow, but this rule lets srem be
2276implemented using instructions that return both the result of the division
2277and the remainder.)</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2278<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2279<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]2280</pre>
2281
2282</div>
2283<!-- _______________________________________________________________________ -->
2284<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2285Instruction</a> </div>
2286<div class="doc_text">
2287<h5>Syntax:</h5>
2288<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2289</pre>
2290<h5>Overview:</h5>
2291<p>The '<tt>frem</tt>' instruction returns the remainder from the
2292division of its two operands.</p>
2293<h5>Arguments:</h5>
2294<p>The two arguments to the '<tt>frem</tt>' instruction must be
2295<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2296identical types. This instruction can also take <a href="#t_vector">vector</a>
2297versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2298<h5>Semantics:</h5>
2299<p>This instruction returns the <i>remainder</i> of a division.</p>
2300<h5>Example:</h5>
2301<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]2302</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2303</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2304
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2305<!-- ======================================================================= -->
2306<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2307Operations</a> </div>
2308<div class="doc_text">
2309<p>Bitwise binary operators are used to do various forms of
2310bit-twiddling in a program. They are generally very efficient
2311instructions and can commonly be strength reduced from other
2312instructions. They require two operands, execute an operation on them,
2313and produce a single value. The resulting value of the bitwise binary
2314operators is always the same type as its first operand.</p>
2315</div>
2316
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2317<!-- _______________________________________________________________________ -->
2318<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2319Instruction</a> </div>
2320<div class="doc_text">
2321<h5>Syntax:</h5>
2322<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2323</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2324
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2325<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2326
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2327<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2328the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2329
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2330<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2331
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2332<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2333 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2334
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2335<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2336
2337<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2338<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2339of bits in <tt>var1</tt>, the result is undefined.</p>
2340
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2341<h5>Example:</h5><pre>
2342 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2343 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2344 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2345 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2346</pre>
2347</div>
2348<!-- _______________________________________________________________________ -->
2349<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2350Instruction</a> </div>
2351<div class="doc_text">
2352<h5>Syntax:</h5>
2353<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2354</pre>
2355
2356<h5>Overview:</h5>
2357<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2358operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2359
2360<h5>Arguments:</h5>
2361<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2362<a href="#t_integer">integer</a> type.</p>
2363
2364<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2365
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2366<p>This instruction always performs a logical shift right operation. The most
2367significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2368shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2369the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2370
2371<h5>Example:</h5>
2372<pre>
2373 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2374 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2375 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2376 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2377 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2378</pre>
2379</div>
2380
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2381<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2382<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2383Instruction</a> </div>
2384<div class="doc_text">
2385
2386<h5>Syntax:</h5>
2387<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2388</pre>
2389
2390<h5>Overview:</h5>
2391<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2392operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2393
2394<h5>Arguments:</h5>
2395<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2396<a href="#t_integer">integer</a> type.</p>
2397
2398<h5>Semantics:</h5>
2399<p>This instruction always performs an arithmetic shift right operation,
2400The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2401of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2402larger than the number of bits in <tt>var1</tt>, the result is undefined.
2403</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2404
2405<h5>Example:</h5>
2406<pre>
2407 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2408 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2409 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2410 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2411 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2412</pre>
2413</div>
2414
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2415<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2416<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2417Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2418<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2419<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2420<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]2421</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2423<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2424its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2425<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2426<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2427 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2428identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2430<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2431<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2432<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2433<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2434 <tbody>
2435 <tr>
2436 <td>In0</td>
2437 <td>In1</td>
2438 <td>Out</td>
2439 </tr>
2440 <tr>
2441 <td>0</td>
2442 <td>0</td>
2443 <td>0</td>
2444 </tr>
2445 <tr>
2446 <td>0</td>
2447 <td>1</td>
2448 <td>0</td>
2449 </tr>
2450 <tr>
2451 <td>1</td>
2452 <td>0</td>
2453 <td>0</td>
2454 </tr>
2455 <tr>
2456 <td>1</td>
2457 <td>1</td>
2458 <td>1</td>
2459 </tr>
2460 </tbody>
2461</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2462</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2463<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2464<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2465 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2466 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2467</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2468</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2470<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2471<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2472<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2473<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]2474</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2475<h5>Overview:</h5>
2476<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2477or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2479<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2480 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2481identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2483<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2484<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2485<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2486<table border="1" cellspacing="0" cellpadding="4">
2487 <tbody>
2488 <tr>
2489 <td>In0</td>
2490 <td>In1</td>
2491 <td>Out</td>
2492 </tr>
2493 <tr>
2494 <td>0</td>
2495 <td>0</td>
2496 <td>0</td>
2497 </tr>
2498 <tr>
2499 <td>0</td>
2500 <td>1</td>
2501 <td>1</td>
2502 </tr>
2503 <tr>
2504 <td>1</td>
2505 <td>0</td>
2506 <td>1</td>
2507 </tr>
2508 <tr>
2509 <td>1</td>
2510 <td>1</td>
2511 <td>1</td>
2512 </tr>
2513 </tbody>
2514</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2515</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2516<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2517<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2518 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2519 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2520</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2521</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2522<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2523<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2524Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2525<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2526<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2527<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]2528</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2529<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2530<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2531or of its two operands. The <tt>xor</tt> is used to implement the
2532"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2533<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2534<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2535 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2536identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2537<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2538<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2539<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2540<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2541<table border="1" cellspacing="0" cellpadding="4">
2542 <tbody>
2543 <tr>
2544 <td>In0</td>
2545 <td>In1</td>
2546 <td>Out</td>
2547 </tr>
2548 <tr>
2549 <td>0</td>
2550 <td>0</td>
2551 <td>0</td>
2552 </tr>
2553 <tr>
2554 <td>0</td>
2555 <td>1</td>
2556 <td>1</td>
2557 </tr>
2558 <tr>
2559 <td>1</td>
2560 <td>0</td>
2561 <td>1</td>
2562 </tr>
2563 <tr>
2564 <td>1</td>
2565 <td>1</td>
2566 <td>0</td>
2567 </tr>
2568 </tbody>
2569</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2570</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2571<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2572<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2573<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2574 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2575 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2576 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2577</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2578</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2579
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2580<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2581<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2582 <a name="vectorops">Vector Operations</a>
2583</div>
2584
2585<div class="doc_text">
2586
2587<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2588target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2589vector-specific operations needed to process vectors effectively. While LLVM
2590does directly support these vector operations, many sophisticated algorithms
2591will want to use target-specific intrinsics to take full advantage of a specific
2592target.</p>
2593
2594</div>
2595
2596<!-- _______________________________________________________________________ -->
2597<div class="doc_subsubsection">
2598 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2599</div>
2600
2601<div class="doc_text">
2602
2603<h5>Syntax:</h5>
2604
2605<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2606 &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]2607</pre>
2608
2609<h5>Overview:</h5>
2610
2611<p>
2612The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2613element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2614</p>
2615
2616
2617<h5>Arguments:</h5>
2618
2619<p>
2620The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2621value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2622an index indicating the position from which to extract the element.
2623The index may be a variable.</p>
2624
2625<h5>Semantics:</h5>
2626
2627<p>
2628The result is a scalar of the same type as the element type of
2629<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2630<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2631results are undefined.
2632</p>
2633
2634<h5>Example:</h5>
2635
2636<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2637 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2638</pre>
2639</div>
2640
2641
2642<!-- _______________________________________________________________________ -->
2643<div class="doc_subsubsection">
2644 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2645</div>
2646
2647<div class="doc_text">
2648
2649<h5>Syntax:</h5>
2650
2651<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2652 &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]2653</pre>
2654
2655<h5>Overview:</h5>
2656
2657<p>
2658The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2659element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2660</p>
2661
2662
2663<h5>Arguments:</h5>
2664
2665<p>
2666The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2667value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2668scalar value whose type must equal the element type of the first
2669operand. The third operand is an index indicating the position at
2670which to insert the value. The index may be a variable.</p>
2671
2672<h5>Semantics:</h5>
2673
2674<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2675The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2676element values are those of <tt>val</tt> except at position
2677<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2678exceeds the length of <tt>val</tt>, the results are undefined.
2679</p>
2680
2681<h5>Example:</h5>
2682
2683<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2684 %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]2685</pre>
2686</div>
2687
2688<!-- _______________________________________________________________________ -->
2689<div class="doc_subsubsection">
2690 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2691</div>
2692
2693<div class="doc_text">
2694
2695<h5>Syntax:</h5>
2696
2697<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2698 &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]2699</pre>
2700
2701<h5>Overview:</h5>
2702
2703<p>
2704The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2705from two input vectors, returning a vector of the same type.
2706</p>
2707
2708<h5>Arguments:</h5>
2709
2710<p>
2711The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2712with types that match each other and types that match the result of the
2713instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2714of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2715</p>
2716
2717<p>
2718The shuffle mask operand is required to be a constant vector with either
2719constant integer or undef values.
2720</p>
2721
2722<h5>Semantics:</h5>
2723
2724<p>
2725The elements of the two input vectors are numbered from left to right across
2726both of the vectors. The shuffle mask operand specifies, for each element of
2727the result vector, which element of the two input registers the result element
2728gets. The element selector may be undef (meaning "don't care") and the second
2729operand may be undef if performing a shuffle from only one vector.
2730</p>
2731
2732<h5>Example:</h5>
2733
2734<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2735 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2736 &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]2737 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2738 &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]2739</pre>
2740</div>
2741
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2742
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2743<!-- ======================================================================= -->
2744<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2745 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2746</div>
2747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2748<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2749
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2750<p>A key design point of an SSA-based representation is how it
2751represents memory. In LLVM, no memory locations are in SSA form, which
2752makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2753allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2754
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2755</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2758<div class="doc_subsubsection">
2759 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2760</div>
2761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2762<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2764<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2765
2766<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2767 &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]2768</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2769
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2770<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2771
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2772<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2773heap and returns a pointer to it. The object is always allocated in the generic
2774address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2775
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2776<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2777
2778<p>The '<tt>malloc</tt>' instruction allocates
2779<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2780bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2781appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2782number of elements allocated, otherwise "NumElements" is defaulted to be one.
2783If an alignment is specified, the value result of the allocation is guaranteed to
2784be aligned to at least that boundary. If not specified, or if zero, the target can
2785choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2787<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2789<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2790
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2791<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2792a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2793
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2794<h5>Example:</h5>
2795
2796<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2797 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2798
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2799 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2800 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2801 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2802 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2803 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2804</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2805</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2806
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2807<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2808<div class="doc_subsubsection">
2809 <a name="i_free">'<tt>free</tt>' Instruction</a>
2810</div>
2811
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2812<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2815
2816<pre>
2817 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2818</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2819
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2820<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2821
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2822<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2823memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2826
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2827<p>'<tt>value</tt>' shall be a pointer value that points to a value
2828that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2829instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2832
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2833<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2834after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2837
2838<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2839 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2840 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2841</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2842</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2843
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2845<div class="doc_subsubsection">
2846 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2847</div>
2848
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2849<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2852
2853<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2854 &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]2855</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2857<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2858
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2859<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2860currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2861returns to its caller. The object is always allocated in the generic address
2862space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2863
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2864<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2865
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2866<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2867bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2868appropriate type to the program. If "NumElements" is specified, it is the
2869number of elements allocated, otherwise "NumElements" is defaulted to be one.
2870If an alignment is specified, the value result of the allocation is guaranteed
2871to be aligned to at least that boundary. If not specified, or if zero, the target
2872can choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2873
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2874<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2877
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2878<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2879memory is automatically released when the function returns. The '<tt>alloca</tt>'
2880instruction is commonly used to represent automatic variables that must
2881have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2882 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]2883instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2884
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2885<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2886
2887<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2888 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2889 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2890 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2891 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2892</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2893</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2894
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2895<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2896<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2897Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2898<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2899<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2900<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]2901<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2902<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2903<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2904<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2905address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2906 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2907marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2908the number or order of execution of this <tt>load</tt> with other
2909volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2910instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2911<p>
2912The optional "align" argument specifies the alignment of the operation
2913(that is, the alignment of the memory address). A value of 0 or an
2914omitted "align" argument means that the operation has the preferential
2915alignment for the target. It is the responsibility of the code emitter
2916to ensure that the alignment information is correct. Overestimating
2917the alignment results in an undefined behavior. Underestimating the
2918alignment may produce less efficient code. An alignment of 1 is always
2919safe.
2920</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2921<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2923<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2924<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2925 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2926 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2927 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2928</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2929</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2930<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2931<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2932Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2933<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2934<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2935<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2936 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]2937</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2938<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2939<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2940<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2941<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2942to 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]2943operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2944operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2945optimizer is not allowed to modify the number or order of execution of
2946this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2947 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2948<p>
2949The optional "align" argument specifies the alignment of the operation
2950(that is, the alignment of the memory address). A value of 0 or an
2951omitted "align" argument means that the operation has the preferential
2952alignment for the target. It is the responsibility of the code emitter
2953to ensure that the alignment information is correct. Overestimating
2954the alignment results in an undefined behavior. Underestimating the
2955alignment may produce less efficient code. An alignment of 1 is always
2956safe.
2957</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2958<h5>Semantics:</h5>
2959<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2960at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2961<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2962<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2963 store i32 3, i32* %ptr <i>; yields {void}</i>
2964 %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]2965</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2966</div>
2967
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2968<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2969<div class="doc_subsubsection">
2970 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2971</div>
2972
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2973<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2974<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2975<pre>
2976 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2977</pre>
2978
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2979<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2980
2981<p>
2982The '<tt>getelementptr</tt>' instruction is used to get the address of a
2983subelement of an aggregate data structure.</p>
2984
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2985<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2986
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2987<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2988elements of the aggregate object to index to. The actual types of the arguments
2989provided depend on the type of the first pointer argument. The
2990'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2991levels 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]2992structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2993into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2994be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2995
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2996<p>For example, let's consider a C code fragment and how it gets
2997compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2998
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2999<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3000<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3001struct RT {
3002 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3003 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3004 char C;
3005};
3006struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3007 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3008 double Y;
3009 struct RT Z;
3010};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3011
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3012int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3013 return &amp;s[1].Z.B[5][13];
3014}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3015</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3016</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3017
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3018<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3019
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3020<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3021<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3022%RT = type { i8 , [10 x [20 x i32]], i8 }
3023%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3024
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3025define i32* %foo(%ST* %s) {
3026entry:
3027 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3028 ret i32* %reg
3029}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3030</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3031</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3032
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3033<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3034
3035<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]3036on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3037and <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]3038<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]3039to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]3040<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3041
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3042<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]3043type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3044}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3045the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3046i8 }</tt>' type, another structure. The third index indexes into the second
3047element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3048array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3049'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3050to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3051
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3052<p>Note that it is perfectly legal to index partially through a
3053structure, returning a pointer to an inner element. Because of this,
3054the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3055
3056<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3057 define i32* %foo(%ST* %s) {
3058 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3059 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3060 %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]3061 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3062 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3063 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3064 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3065</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3066
3067<p>Note that it is undefined to access an array out of bounds: array and
3068pointer indexes must always be within the defined bounds of the array type.
3069The one exception for this rules is zero length arrays. These arrays are
3070defined to be accessible as variable length arrays, which requires access
3071beyond the zero'th element.</p>
3072
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3073<p>The getelementptr instruction is often confusing. For some more insight
3074into how it works, see <a href="GetElementPtr.html">the getelementptr
3075FAQ</a>.</p>
3076
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3077<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3078
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3079<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3080 <i>; yields [12 x i8]*:aptr</i>
3081 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3082</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3083</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3084
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3085<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3086<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3087</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3088<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3089<p>The instructions in this category are the conversion instructions (casting)
3090which all take a single operand and a type. They perform various bit conversions
3091on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3092</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3093
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3094<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3095<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3096 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3097</div>
3098<div class="doc_text">
3099
3100<h5>Syntax:</h5>
3101<pre>
3102 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3103</pre>
3104
3105<h5>Overview:</h5>
3106<p>
3107The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3108</p>
3109
3110<h5>Arguments:</h5>
3111<p>
3112The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3113be 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]3114and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3115type. The bit size of <tt>value</tt> must be larger than the bit size of
3116<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3117
3118<h5>Semantics:</h5>
3119<p>
3120The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3121and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3122larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3123It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Example:</h5>
3126<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3127 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3128 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3129 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3130</pre>
3131</div>
3132
3133<!-- _______________________________________________________________________ -->
3134<div class="doc_subsubsection">
3135 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3136</div>
3137<div class="doc_text">
3138
3139<h5>Syntax:</h5>
3140<pre>
3141 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3142</pre>
3143
3144<h5>Overview:</h5>
3145<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3146<tt>ty2</tt>.</p>
3147
3148
3149<h5>Arguments:</h5>
3150<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]3151<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3152also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3153<tt>value</tt> must be smaller than the bit size of the destination type,
3154<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3155
3156<h5>Semantics:</h5>
3157<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]3158bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3159
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3160<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]3161
3162<h5>Example:</h5>
3163<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3164 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3165 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3166</pre>
3167</div>
3168
3169<!-- _______________________________________________________________________ -->
3170<div class="doc_subsubsection">
3171 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3172</div>
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3178</pre>
3179
3180<h5>Overview:</h5>
3181<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3182
3183<h5>Arguments:</h5>
3184<p>
3185The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3186<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3187also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3188<tt>value</tt> must be smaller than the bit size of the destination type,
3189<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3190
3191<h5>Semantics:</h5>
3192<p>
3193The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3194bit (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]3195the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3196
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3197<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]3198
3199<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3200<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3201 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3202 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3203</pre>
3204</div>
3205
3206<!-- _______________________________________________________________________ -->
3207<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3208 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3209</div>
3210
3211<div class="doc_text">
3212
3213<h5>Syntax:</h5>
3214
3215<pre>
3216 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3217</pre>
3218
3219<h5>Overview:</h5>
3220<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3221<tt>ty2</tt>.</p>
3222
3223
3224<h5>Arguments:</h5>
3225<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3226 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3227cast it to. The size of <tt>value</tt> must be larger than the size of
3228<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3229<i>no-op cast</i>.</p>
3230
3231<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3232<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3233<a href="#t_floating">floating point</a> type to a smaller
3234<a href="#t_floating">floating point</a> type. If the value cannot fit within
3235the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3236
3237<h5>Example:</h5>
3238<pre>
3239 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3240 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3241</pre>
3242</div>
3243
3244<!-- _______________________________________________________________________ -->
3245<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3246 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3247</div>
3248<div class="doc_text">
3249
3250<h5>Syntax:</h5>
3251<pre>
3252 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3253</pre>
3254
3255<h5>Overview:</h5>
3256<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3257floating point value.</p>
3258
3259<h5>Arguments:</h5>
3260<p>The '<tt>fpext</tt>' instruction takes a
3261<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3262and a <a href="#t_floating">floating point</a> type to cast it to. The source
3263type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3264
3265<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3266<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3267<a href="#t_floating">floating point</a> type to a larger
3268<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3269used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3270<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]3271
3272<h5>Example:</h5>
3273<pre>
3274 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3275 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3276</pre>
3277</div>
3278
3279<!-- _______________________________________________________________________ -->
3280<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3281 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3282</div>
3283<div class="doc_text">
3284
3285<h5>Syntax:</h5>
3286<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3287 &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]3288</pre>
3289
3290<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3291<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3292unsigned integer equivalent of type <tt>ty2</tt>.
3293</p>
3294
3295<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3296<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]3297scalar or vector <a href="#t_floating">floating point</a> value, and a type
3298to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3299type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3300vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3301
3302<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3303<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3304<a href="#t_floating">floating point</a> operand into the nearest (rounding
3305towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3306the results are undefined.</p>
3307
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3308<h5>Example:</h5>
3309<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3310 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3311 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3312 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3313</pre>
3314</div>
3315
3316<!-- _______________________________________________________________________ -->
3317<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3318 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3319</div>
3320<div class="doc_text">
3321
3322<h5>Syntax:</h5>
3323<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3324 &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]3325</pre>
3326
3327<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3328<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3329<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]3330</p>
3331
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3332<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3333<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]3334scalar or vector <a href="#t_floating">floating point</a> value, and a type
3335to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3336type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3337vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3338
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3339<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3340<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3341<a href="#t_floating">floating point</a> operand into the nearest (rounding
3342towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3343the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3344
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3345<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3346<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3347 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3348 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3349 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3350</pre>
3351</div>
3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3355 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3356</div>
3357<div class="doc_text">
3358
3359<h5>Syntax:</h5>
3360<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3361 &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]3362</pre>
3363
3364<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3365<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3366integer and converts that value to the <tt>ty2</tt> type.</p>
3367
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3368<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3369<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3370scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3371to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3372type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3373floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3374
3375<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3376<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3377integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3378the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3379
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3380<h5>Example:</h5>
3381<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3382 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3383 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3384</pre>
3385</div>
3386
3387<!-- _______________________________________________________________________ -->
3388<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3389 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3390</div>
3391<div class="doc_text">
3392
3393<h5>Syntax:</h5>
3394<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3395 &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]3396</pre>
3397
3398<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3399<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3400integer and converts that value to the <tt>ty2</tt> type.</p>
3401
3402<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3403<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3404scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3405to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3406type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3407floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3408
3409<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3410<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3411integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3412the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3413
3414<h5>Example:</h5>
3415<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3416 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3417 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3423 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3424</div>
3425<div class="doc_text">
3426
3427<h5>Syntax:</h5>
3428<pre>
3429 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3430</pre>
3431
3432<h5>Overview:</h5>
3433<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3434the integer type <tt>ty2</tt>.</p>
3435
3436<h5>Arguments:</h5>
3437<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3438must 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]3439<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3440
3441<h5>Semantics:</h5>
3442<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3443<tt>ty2</tt> by interpreting the pointer value as an integer and either
3444truncating or zero extending that value to the size of the integer type. If
3445<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3446<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]3447are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3448change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3449
3450<h5>Example:</h5>
3451<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3452 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3453 %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]3454</pre>
3455</div>
3456
3457<!-- _______________________________________________________________________ -->
3458<div class="doc_subsubsection">
3459 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3460</div>
3461<div class="doc_text">
3462
3463<h5>Syntax:</h5>
3464<pre>
3465 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3466</pre>
3467
3468<h5>Overview:</h5>
3469<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3470a pointer type, <tt>ty2</tt>.</p>
3471
3472<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3473<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3474value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3475<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3476
3477<h5>Semantics:</h5>
3478<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3479<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3480the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3481size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3482the size of a pointer then a zero extension is done. If they are the same size,
3483nothing is done (<i>no-op cast</i>).</p>
3484
3485<h5>Example:</h5>
3486<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3487 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3488 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3489 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3490</pre>
3491</div>
3492
3493<!-- _______________________________________________________________________ -->
3494<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3495 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3496</div>
3497<div class="doc_text">
3498
3499<h5>Syntax:</h5>
3500<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3501 &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]3502</pre>
3503
3504<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3505<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3506<tt>ty2</tt> without changing any bits.</p>
3507
3508<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3509<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3510a first class value, and a type to cast it to, which must also be a <a
3511 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3512and the destination type, <tt>ty2</tt>, must be identical. If the source
3513type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3514
3515<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3516<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3517<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3518this conversion. The conversion is done as if the <tt>value</tt> had been
3519stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3520converted to other pointer types with this instruction. To convert pointers to
3521other types, use the <a href="#i_inttoptr">inttoptr</a> or
3522<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3523
3524<h5>Example:</h5>
3525<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3526 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3527 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3528 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3529</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3530</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3531
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3532<!-- ======================================================================= -->
3533<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3534<div class="doc_text">
3535<p>The instructions in this category are the "miscellaneous"
3536instructions, which defy better classification.</p>
3537</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3538
3539<!-- _______________________________________________________________________ -->
3540<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3541</div>
3542<div class="doc_text">
3543<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3544<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]3545</pre>
3546<h5>Overview:</h5>
3547<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3548of its two integer operands.</p>
3549<h5>Arguments:</h5>
3550<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3551the condition code indicating the kind of comparison to perform. It is not
3552a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3553<ol>
3554 <li><tt>eq</tt>: equal</li>
3555 <li><tt>ne</tt>: not equal </li>
3556 <li><tt>ugt</tt>: unsigned greater than</li>
3557 <li><tt>uge</tt>: unsigned greater or equal</li>
3558 <li><tt>ult</tt>: unsigned less than</li>
3559 <li><tt>ule</tt>: unsigned less or equal</li>
3560 <li><tt>sgt</tt>: signed greater than</li>
3561 <li><tt>sge</tt>: signed greater or equal</li>
3562 <li><tt>slt</tt>: signed less than</li>
3563 <li><tt>sle</tt>: signed less or equal</li>
3564</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3565<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3566<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3567<h5>Semantics:</h5>
3568<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3569the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3570yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3571<ol>
3572 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3573 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3574 </li>
3575 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3576 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3577 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3578 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3579 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3580 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3581 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3582 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3583 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3584 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3585 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3586 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3587 <li><tt>sge</tt>: interprets the operands as signed values and yields
3588 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3589 <li><tt>slt</tt>: interprets the operands as signed values and yields
3590 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3591 <li><tt>sle</tt>: interprets the operands as signed values and yields
3592 <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]3593</ol>
3594<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3595values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3596
3597<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3598<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3599 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3600 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3601 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3602 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3603 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3604</pre>
3605</div>
3606
3607<!-- _______________________________________________________________________ -->
3608<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3609</div>
3610<div class="doc_text">
3611<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3612<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]3613</pre>
3614<h5>Overview:</h5>
3615<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3616of its floating point operands.</p>
3617<h5>Arguments:</h5>
3618<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3619the condition code indicating the kind of comparison to perform. It is not
3620a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3621<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3622 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3623 <li><tt>oeq</tt>: ordered and equal</li>
3624 <li><tt>ogt</tt>: ordered and greater than </li>
3625 <li><tt>oge</tt>: ordered and greater than or equal</li>
3626 <li><tt>olt</tt>: ordered and less than </li>
3627 <li><tt>ole</tt>: ordered and less than or equal</li>
3628 <li><tt>one</tt>: ordered and not equal</li>
3629 <li><tt>ord</tt>: ordered (no nans)</li>
3630 <li><tt>ueq</tt>: unordered or equal</li>
3631 <li><tt>ugt</tt>: unordered or greater than </li>
3632 <li><tt>uge</tt>: unordered or greater than or equal</li>
3633 <li><tt>ult</tt>: unordered or less than </li>
3634 <li><tt>ule</tt>: unordered or less than or equal</li>
3635 <li><tt>une</tt>: unordered or not equal</li>
3636 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3637 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3638</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3639<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3640<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3641<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3642<a href="#t_floating">floating point</a> typed. They must have identical
3643types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3644<h5>Semantics:</h5>
3645<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3646the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3647yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3648<ol>
3649 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3650 <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]3651 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3652 <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]3653 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3654 <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]3655 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3656 <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]3657 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3658 <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]3659 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3660 <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]3661 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3662 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3663 <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]3664 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3665 <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]3666 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3667 <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]3668 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3669 <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]3670 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3671 <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]3672 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3673 <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]3674 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3675 <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]3676 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3677</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3678
3679<h5>Example:</h5>
3680<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3681 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3682 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3683 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3684</pre>
3685</div>
3686
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3687<!-- _______________________________________________________________________ -->
3688<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3689Instruction</a> </div>
3690<div class="doc_text">
3691<h5>Syntax:</h5>
3692<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3693<h5>Overview:</h5>
3694<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3695the SSA graph representing the function.</p>
3696<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3697<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3698field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3699as arguments, with one pair for each predecessor basic block of the
3700current block. Only values of <a href="#t_firstclass">first class</a>
3701type may be used as the value arguments to the PHI node. Only labels
3702may be used as the label arguments.</p>
3703<p>There must be no non-phi instructions between the start of a basic
3704block and the PHI instructions: i.e. PHI instructions must be first in
3705a basic block.</p>
3706<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3707<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3708specified by the pair corresponding to the predecessor basic block that executed
3709just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3710<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3711<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]3712</div>
3713
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_select">'<tt>select</tt>' Instruction</a>
3717</div>
3718
3719<div class="doc_text">
3720
3721<h5>Syntax:</h5>
3722
3723<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3724 &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]3725</pre>
3726
3727<h5>Overview:</h5>
3728
3729<p>
3730The '<tt>select</tt>' instruction is used to choose one value based on a
3731condition, without branching.
3732</p>
3733
3734
3735<h5>Arguments:</h5>
3736
3737<p>
3738The '<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.
3739</p>
3740
3741<h5>Semantics:</h5>
3742
3743<p>
3744If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3745value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3746</p>
3747
3748<h5>Example:</h5>
3749
3750<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3751 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3752</pre>
3753</div>
3754
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3755
3756<!-- _______________________________________________________________________ -->
3757<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3758 <a name="i_call">'<tt>call</tt>' Instruction</a>
3759</div>
3760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3761<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3762
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3763<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3764<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3765 &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]3766</pre>
3767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3768<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3769
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3770<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3772<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3773
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3774<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3775
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3776<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3777 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3778 <p>The optional "tail" marker indicates whether the callee function accesses
3779 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3780 function call is eligible for tail call optimization. Note that calls may
3781 be marked "tail" even if they do not occur before a <a
3782 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3783 </li>
3784 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3785 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3786 convention</a> the call should use. If none is specified, the call defaults
3787 to using C calling conventions.
3788 </li>
3789 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3790 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3791 the type of the return value. Functions that return no value are marked
3792 <tt><a href="#t_void">void</a></tt>.</p>
3793 </li>
3794 <li>
3795 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3796 value being invoked. The argument types must match the types implied by
3797 this signature. This type can be omitted if the function is not varargs
3798 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3799 </li>
3800 <li>
3801 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3802 be invoked. In most cases, this is a direct function invocation, but
3803 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3804 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3805 </li>
3806 <li>
3807 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3808 function signature argument types. All arguments must be of
3809 <a href="#t_firstclass">first class</a> type. If the function signature
3810 indicates the function accepts a variable number of arguments, the extra
3811 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3812 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3813</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3814
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3815<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3816
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3817<p>The '<tt>call</tt>' instruction is used to cause control flow to
3818transfer to a specified function, with its incoming arguments bound to
3819the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3820instruction in the called function, control flow continues with the
3821instruction after the function call, and the return value of the
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame^]3822function is bound to the result argument. If the callee returns multiple
3823values then the return values of the function are only accessible through
3824the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3826<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3827
3828<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3829 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame^]3830 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
3831 %X = tail call i32 @foo() <i>; yields i32</i>
3832 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
3833 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3834
3835 %struct.A = type { i32, i8 }
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame^]3836 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
3837 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
3838 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3839</pre>
3840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3841</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3842
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3843<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3844<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3845 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3846</div>
3847
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3848<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3849
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3850<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3851
3852<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3853 &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]3854</pre>
3855
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3856<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3857
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3858<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3859the "variable argument" area of a function call. It is used to implement the
3860<tt>va_arg</tt> macro in C.</p>
3861
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3862<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3863
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3864<p>This instruction takes a <tt>va_list*</tt> value and the type of
3865the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3866increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3867actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3868
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3869<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3870
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3871<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3872type from the specified <tt>va_list</tt> and causes the
3873<tt>va_list</tt> to point to the next argument. For more information,
3874see the variable argument handling <a href="#int_varargs">Intrinsic
3875Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3876
3877<p>It is legal for this instruction to be called in a function which does not
3878take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3879function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3880
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3881<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3882href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3883argument.</p>
3884
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3885<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3886
3887<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3888
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3889</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3890
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
3892<div class="doc_subsubsection">
3893 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3894</div>
3895
3896<div class="doc_text">
3897
3898<h5>Syntax:</h5>
3899<pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3900 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3901</pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3902
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3903<h5>Overview:</h5>
3904
3905<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3906from a '<tt><a href="#i_call">call</a></tt>'
3907or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
3908results.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3909
3910<h5>Arguments:</h5>
3911
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3912<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
3913first argument. The value must have <a href="#t_struct">structure type</a>.
3914The second argument is an unsigned index value which must be in range for
3915the number of values returned by the call.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3916
3917<h5>Semantics:</h5>
3918
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3919<p>The '<tt>getresult</tt>' instruction extracts the element identified by
3920'<tt>index</tt>' from the aggregate value.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3921
3922<h5>Example:</h5>
3923
3924<pre>
3925 %struct.A = type { i32, i8 }
3926
3927 %r = call %struct.A @foo()
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3928 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
3929 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3930 add i32 %gr, 42
3931 add i8 %gr1, 41
3932</pre>
3933
3934</div>
3935
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3936<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3937<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3938<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3939
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3940<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3941
3942<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3943well known names and semantics and are required to follow certain restrictions.
3944Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3945language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3946adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3947
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3948<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3949prefix is reserved in LLVM for intrinsic names; thus, function names may not
3950begin with this prefix. Intrinsic functions must always be external functions:
3951you cannot define the body of intrinsic functions. Intrinsic functions may
3952only be used in call or invoke instructions: it is illegal to take the address
3953of an intrinsic function. Additionally, because intrinsic functions are part
3954of the LLVM language, it is required if any are added that they be documented
3955here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3956
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3957<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3958a family of functions that perform the same operation but on different data
3959types. Because LLVM can represent over 8 million different integer types,
3960overloading is used commonly to allow an intrinsic function to operate on any
3961integer type. One or more of the argument types or the result type can be
3962overloaded to accept any integer type. Argument types may also be defined as
3963exactly matching a previous argument's type or the result type. This allows an
3964intrinsic function which accepts multiple arguments, but needs all of them to
3965be of the same type, to only be overloaded with respect to a single argument or
3966the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3967
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3968<p>Overloaded intrinsics will have the names of its overloaded argument types
3969encoded into its function name, each preceded by a period. Only those types
3970which are overloaded result in a name suffix. Arguments whose type is matched
3971against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3972take an integer of any width and returns an integer of exactly the same integer
3973width. This leads to a family of functions such as
3974<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3975Only one type, the return type, is overloaded, and only one type suffix is
3976required. Because the argument's type is matched against the return type, it
3977does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3978
3979<p>To learn how to add an intrinsic function, please see the
3980<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3981</p>
3982
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3983</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3984
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3985<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3986<div class="doc_subsection">
3987 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3988</div>
3989
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3990<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3991
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3992<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3993 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3994intrinsic functions. These functions are related to the similarly
3995named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3996
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3997<p>All of these functions operate on arguments that use a
3998target-specific value type "<tt>va_list</tt>". The LLVM assembly
3999language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4000transformations should be prepared to handle these functions regardless of
4001the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4002
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]4003<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]4004instruction and the variable argument handling intrinsic functions are
4005used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4006
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4007<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4008<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4009define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4010 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4011 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4012 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4013 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4014
4015 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4016 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4017
4018 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4019 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4020 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4021 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4022 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4023
4024 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4025 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4026 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4027}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4028
4029declare void @llvm.va_start(i8*)
4030declare void @llvm.va_copy(i8*, i8*)
4031declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4032</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4033</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4034
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4035</div>
4036
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4037<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4038<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4039 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4040</div>
4041
4042
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4043<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4044<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4045<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4046<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4047<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4048<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4049href="#i_va_arg">va_arg</a></tt>.</p>
4050
4051<h5>Arguments:</h5>
4052
4053<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4054
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4055<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4056
4057<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4058macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4059<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]4060<tt>va_arg</tt> will produce the first variable argument passed to the function.
4061Unlike 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]4062last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4063
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4064</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4065
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4066<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4067<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4068 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4069</div>
4070
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4071<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4072<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4073<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4074<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4075
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4076<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4077which 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]4078or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4079
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4080<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4081
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4082<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]4083
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4084<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4085
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4086<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]4087macro available in C. In a target-dependent way, it destroys the
4088<tt>va_list</tt> element to which the argument points. Calls to <a
4089href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4090<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4091<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4092
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4093</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4094
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4095<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4096<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4097 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4098</div>
4099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4100<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4101
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4102<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4103
4104<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4105 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4106</pre>
4107
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4108<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4109
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4110<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4111from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4112
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4113<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4114
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4115<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]4116The 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]4117
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4118
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4119<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4120
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4121<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4122macro available in C. In a target-dependent way, it copies the source
4123<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4124intrinsic is necessary because the <tt><a href="#int_va_start">
4125llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4126example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4127
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4128</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4129
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4130<!-- ======================================================================= -->
4131<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4132 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4133</div>
4134
4135<div class="doc_text">
4136
4137<p>
4138LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4139Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4140These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4141stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4142href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4143Front-ends for type-safe garbage collected languages should generate these
4144intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4145href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4146</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4147
4148<p>The garbage collection intrinsics only operate on objects in the generic
4149 address space (address space zero).</p>
4150
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4151</div>
4152
4153<!-- _______________________________________________________________________ -->
4154<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4155 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4156</div>
4157
4158<div class="doc_text">
4159
4160<h5>Syntax:</h5>
4161
4162<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4163 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4164</pre>
4165
4166<h5>Overview:</h5>
4167
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4168<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]4169the code generator, and allows some metadata to be associated with it.</p>
4170
4171<h5>Arguments:</h5>
4172
4173<p>The first argument specifies the address of a stack object that contains the
4174root pointer. The second pointer (which must be either a constant or a global
4175value address) contains the meta-data to be associated with the root.</p>
4176
4177<h5>Semantics:</h5>
4178
4179<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4180location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4181the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4182intrinsic may only be used in a function which <a href="#gc">specifies a GC
4183algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4184
4185</div>
4186
4187
4188<!-- _______________________________________________________________________ -->
4189<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4190 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4191</div>
4192
4193<div class="doc_text">
4194
4195<h5>Syntax:</h5>
4196
4197<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4198 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4199</pre>
4200
4201<h5>Overview:</h5>
4202
4203<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4204locations, allowing garbage collector implementations that require read
4205barriers.</p>
4206
4207<h5>Arguments:</h5>
4208
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4209<p>The second argument is the address to read from, which should be an address
4210allocated from the garbage collector. The first object is a pointer to the
4211start of the referenced object, if needed by the language runtime (otherwise
4212null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4213
4214<h5>Semantics:</h5>
4215
4216<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4217instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4218garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4219may only be used in a function which <a href="#gc">specifies a GC
4220algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4221
4222</div>
4223
4224
4225<!-- _______________________________________________________________________ -->
4226<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4227 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4228</div>
4229
4230<div class="doc_text">
4231
4232<h5>Syntax:</h5>
4233
4234<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4235 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4236</pre>
4237
4238<h5>Overview:</h5>
4239
4240<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4241locations, allowing garbage collector implementations that require write
4242barriers (such as generational or reference counting collectors).</p>
4243
4244<h5>Arguments:</h5>
4245
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4246<p>The first argument is the reference to store, the second is the start of the
4247object to store it to, and the third is the address of the field of Obj to
4248store to. If the runtime does not require a pointer to the object, Obj may be
4249null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4250
4251<h5>Semantics:</h5>
4252
4253<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4254instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4255garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4256may only be used in a function which <a href="#gc">specifies a GC
4257algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4258
4259</div>
4260
4261
4262
4263<!-- ======================================================================= -->
4264<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4265 <a name="int_codegen">Code Generator Intrinsics</a>
4266</div>
4267
4268<div class="doc_text">
4269<p>
4270These intrinsics are provided by LLVM to expose special features that may only
4271be implemented with code generator support.
4272</p>
4273
4274</div>
4275
4276<!-- _______________________________________________________________________ -->
4277<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4278 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4279</div>
4280
4281<div class="doc_text">
4282
4283<h5>Syntax:</h5>
4284<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4285 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4286</pre>
4287
4288<h5>Overview:</h5>
4289
4290<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4291The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4292target-specific value indicating the return address of the current function
4293or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4294</p>
4295
4296<h5>Arguments:</h5>
4297
4298<p>
4299The argument to this intrinsic indicates which function to return the address
4300for. Zero indicates the calling function, one indicates its caller, etc. The
4301argument is <b>required</b> to be a constant integer value.
4302</p>
4303
4304<h5>Semantics:</h5>
4305
4306<p>
4307The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4308the return address of the specified call frame, or zero if it cannot be
4309identified. The value returned by this intrinsic is likely to be incorrect or 0
4310for arguments other than zero, so it should only be used for debugging purposes.
4311</p>
4312
4313<p>
4314Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4315aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4316source-language caller.
4317</p>
4318</div>
4319
4320
4321<!-- _______________________________________________________________________ -->
4322<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4323 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4324</div>
4325
4326<div class="doc_text">
4327
4328<h5>Syntax:</h5>
4329<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4330 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4331</pre>
4332
4333<h5>Overview:</h5>
4334
4335<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4336The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4337target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4338</p>
4339
4340<h5>Arguments:</h5>
4341
4342<p>
4343The argument to this intrinsic indicates which function to return the frame
4344pointer for. Zero indicates the calling function, one indicates its caller,
4345etc. The argument is <b>required</b> to be a constant integer value.
4346</p>
4347
4348<h5>Semantics:</h5>
4349
4350<p>
4351The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4352the frame address of the specified call frame, or zero if it cannot be
4353identified. The value returned by this intrinsic is likely to be incorrect or 0
4354for arguments other than zero, so it should only be used for debugging purposes.
4355</p>
4356
4357<p>
4358Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4359aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4360source-language caller.
4361</p>
4362</div>
4363
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4364<!-- _______________________________________________________________________ -->
4365<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4366 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4367</div>
4368
4369<div class="doc_text">
4370
4371<h5>Syntax:</h5>
4372<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4373 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4374</pre>
4375
4376<h5>Overview:</h5>
4377
4378<p>
4379The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4380the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4381<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4382features like scoped automatic variable sized arrays in C99.
4383</p>
4384
4385<h5>Semantics:</h5>
4386
4387<p>
4388This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4389href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4390<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4391<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4392state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4393practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4394that were allocated after the <tt>llvm.stacksave</tt> was executed.
4395</p>
4396
4397</div>
4398
4399<!-- _______________________________________________________________________ -->
4400<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4401 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4402</div>
4403
4404<div class="doc_text">
4405
4406<h5>Syntax:</h5>
4407<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4408 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4409</pre>
4410
4411<h5>Overview:</h5>
4412
4413<p>
4414The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4415the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4416href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4417useful for implementing language features like scoped automatic variable sized
4418arrays in C99.
4419</p>
4420
4421<h5>Semantics:</h5>
4422
4423<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4424See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4425</p>
4426
4427</div>
4428
4429
4430<!-- _______________________________________________________________________ -->
4431<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4432 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4433</div>
4434
4435<div class="doc_text">
4436
4437<h5>Syntax:</h5>
4438<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4439 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]4440</pre>
4441
4442<h5>Overview:</h5>
4443
4444
4445<p>
4446The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4447a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4448no
4449effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4450characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4451</p>
4452
4453<h5>Arguments:</h5>
4454
4455<p>
4456<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4457determining if the fetch should be for a read (0) or write (1), and
4458<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4459locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4460<tt>locality</tt> arguments must be constant integers.
4461</p>
4462
4463<h5>Semantics:</h5>
4464
4465<p>
4466This intrinsic does not modify the behavior of the program. In particular,
4467prefetches cannot trap and do not produce a value. On targets that support this
4468intrinsic, the prefetch can provide hints to the processor cache for better
4469performance.
4470</p>
4471
4472</div>
4473
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4474<!-- _______________________________________________________________________ -->
4475<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4476 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4477</div>
4478
4479<div class="doc_text">
4480
4481<h5>Syntax:</h5>
4482<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4483 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4484</pre>
4485
4486<h5>Overview:</h5>
4487
4488
4489<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4490The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4491(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4492code to simulators and other tools. The method is target specific, but it is
4493expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4494The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4495after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4496optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4497correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4498</p>
4499
4500<h5>Arguments:</h5>
4501
4502<p>
4503<tt>id</tt> is a numerical id identifying the marker.
4504</p>
4505
4506<h5>Semantics:</h5>
4507
4508<p>
4509This intrinsic does not modify the behavior of the program. Backends that do not
4510support this intrinisic may ignore it.
4511</p>
4512
4513</div>
4514
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4517 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4518</div>
4519
4520<div class="doc_text">
4521
4522<h5>Syntax:</h5>
4523<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4524 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4525</pre>
4526
4527<h5>Overview:</h5>
4528
4529
4530<p>
4531The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4532counter register (or similar low latency, high accuracy clocks) on those targets
4533that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4534As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4535should only be used for small timings.
4536</p>
4537
4538<h5>Semantics:</h5>
4539
4540<p>
4541When directly supported, reading the cycle counter should not modify any memory.
4542Implementations are allowed to either return a application specific value or a
4543system wide value. On backends without support, this is lowered to a constant 0.
4544</p>
4545
4546</div>
4547
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4548<!-- ======================================================================= -->
4549<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4550 <a name="int_libc">Standard C Library Intrinsics</a>
4551</div>
4552
4553<div class="doc_text">
4554<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4555LLVM provides intrinsics for a few important standard C library functions.
4556These intrinsics allow source-language front-ends to pass information about the
4557alignment of the pointer arguments to the code generator, providing opportunity
4558for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4559</p>
4560
4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4565 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4566</div>
4567
4568<div class="doc_text">
4569
4570<h5>Syntax:</h5>
4571<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4572 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4573 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4574 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4575 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4576</pre>
4577
4578<h5>Overview:</h5>
4579
4580<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4581The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4582location to the destination location.
4583</p>
4584
4585<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4586Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4587intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4588</p>
4589
4590<h5>Arguments:</h5>
4591
4592<p>
4593The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4594the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4595specifying the number of bytes to copy, and the fourth argument is the alignment
4596of the source and destination locations.
4597</p>
4598
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4599<p>
4600If 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]4601the caller guarantees that both the source and destination pointers are aligned
4602to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4603</p>
4604
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4605<h5>Semantics:</h5>
4606
4607<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4608The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4609location to the destination location, which are not allowed to overlap. It
4610copies "len" bytes of memory over. If the argument is known to be aligned to
4611some boundary, this can be specified as the fourth argument, otherwise it should
4612be set to 0 or 1.
4613</p>
4614</div>
4615
4616
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4617<!-- _______________________________________________________________________ -->
4618<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4619 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4620</div>
4621
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
4625<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4626 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4627 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4628 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4629 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4630</pre>
4631
4632<h5>Overview:</h5>
4633
4634<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4635The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4636location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4637'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4638</p>
4639
4640<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4641Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4642intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4643</p>
4644
4645<h5>Arguments:</h5>
4646
4647<p>
4648The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4649the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4650specifying the number of bytes to copy, and the fourth argument is the alignment
4651of the source and destination locations.
4652</p>
4653
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4654<p>
4655If 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]4656the caller guarantees that the source and destination pointers are aligned to
4657that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4658</p>
4659
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4660<h5>Semantics:</h5>
4661
4662<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4663The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4664location to the destination location, which may overlap. It
4665copies "len" bytes of memory over. If the argument is known to be aligned to
4666some boundary, this can be specified as the fourth argument, otherwise it should
4667be set to 0 or 1.
4668</p>
4669</div>
4670
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4671
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4672<!-- _______________________________________________________________________ -->
4673<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4674 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4675</div>
4676
4677<div class="doc_text">
4678
4679<h5>Syntax:</h5>
4680<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4681 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4682 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4683 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4684 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4685</pre>
4686
4687<h5>Overview:</h5>
4688
4689<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4690The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4691byte value.
4692</p>
4693
4694<p>
4695Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4696does not return a value, and takes an extra alignment argument.
4697</p>
4698
4699<h5>Arguments:</h5>
4700
4701<p>
4702The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4703byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4704argument specifying the number of bytes to fill, and the fourth argument is the
4705known alignment of destination location.
4706</p>
4707
4708<p>
4709If 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]4710the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4711</p>
4712
4713<h5>Semantics:</h5>
4714
4715<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4716The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4717the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4718destination location. If the argument is known to be aligned to some boundary,
4719this can be specified as the fourth argument, otherwise it should be set to 0 or
47201.
4721</p>
4722</div>
4723
4724
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4725<!-- _______________________________________________________________________ -->
4726<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4727 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4728</div>
4729
4730<div class="doc_text">
4731
4732<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4733<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]4734floating point or vector of floating point type. Not all targets support all
4735types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4736<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4737 declare float @llvm.sqrt.f32(float %Val)
4738 declare double @llvm.sqrt.f64(double %Val)
4739 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4740 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4741 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4742</pre>
4743
4744<h5>Overview:</h5>
4745
4746<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4747The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4748returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4749<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner103e2d72008-01-29 07:00:44 +0000[diff] [blame]4750negative numbers other than -0.0 (which allows for better optimization, because
4751there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4752defined to return -0.0 like IEEE sqrt.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4753</p>
4754
4755<h5>Arguments:</h5>
4756
4757<p>
4758The argument and return value are floating point numbers of the same type.
4759</p>
4760
4761<h5>Semantics:</h5>
4762
4763<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4764This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4765floating point number.
4766</p>
4767</div>
4768
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4769<!-- _______________________________________________________________________ -->
4770<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4771 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4772</div>
4773
4774<div class="doc_text">
4775
4776<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4777<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]4778floating point or vector of floating point type. Not all targets support all
4779types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4780<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4781 declare float @llvm.powi.f32(float %Val, i32 %power)
4782 declare double @llvm.powi.f64(double %Val, i32 %power)
4783 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4784 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4785 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4786</pre>
4787
4788<h5>Overview:</h5>
4789
4790<p>
4791The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4792specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4793multiplications is not defined. When a vector of floating point type is
4794used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4795</p>
4796
4797<h5>Arguments:</h5>
4798
4799<p>
4800The second argument is an integer power, and the first is a value to raise to
4801that power.
4802</p>
4803
4804<h5>Semantics:</h5>
4805
4806<p>
4807This function returns the first value raised to the second power with an
4808unspecified sequence of rounding operations.</p>
4809</div>
4810
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4811<!-- _______________________________________________________________________ -->
4812<div class="doc_subsubsection">
4813 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4814</div>
4815
4816<div class="doc_text">
4817
4818<h5>Syntax:</h5>
4819<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4820floating point or vector of floating point type. Not all targets support all
4821types however.
4822<pre>
4823 declare float @llvm.sin.f32(float %Val)
4824 declare double @llvm.sin.f64(double %Val)
4825 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4826 declare fp128 @llvm.sin.f128(fp128 %Val)
4827 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4828</pre>
4829
4830<h5>Overview:</h5>
4831
4832<p>
4833The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4834</p>
4835
4836<h5>Arguments:</h5>
4837
4838<p>
4839The argument and return value are floating point numbers of the same type.
4840</p>
4841
4842<h5>Semantics:</h5>
4843
4844<p>
4845This function returns the sine of the specified operand, returning the
4846same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4847conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4848</div>
4849
4850<!-- _______________________________________________________________________ -->
4851<div class="doc_subsubsection">
4852 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4853</div>
4854
4855<div class="doc_text">
4856
4857<h5>Syntax:</h5>
4858<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4859floating point or vector of floating point type. Not all targets support all
4860types however.
4861<pre>
4862 declare float @llvm.cos.f32(float %Val)
4863 declare double @llvm.cos.f64(double %Val)
4864 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4865 declare fp128 @llvm.cos.f128(fp128 %Val)
4866 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4867</pre>
4868
4869<h5>Overview:</h5>
4870
4871<p>
4872The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4873</p>
4874
4875<h5>Arguments:</h5>
4876
4877<p>
4878The argument and return value are floating point numbers of the same type.
4879</p>
4880
4881<h5>Semantics:</h5>
4882
4883<p>
4884This function returns the cosine of the specified operand, returning the
4885same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4886conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4887</div>
4888
4889<!-- _______________________________________________________________________ -->
4890<div class="doc_subsubsection">
4891 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4892</div>
4893
4894<div class="doc_text">
4895
4896<h5>Syntax:</h5>
4897<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4898floating point or vector of floating point type. Not all targets support all
4899types however.
4900<pre>
4901 declare float @llvm.pow.f32(float %Val, float %Power)
4902 declare double @llvm.pow.f64(double %Val, double %Power)
4903 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4904 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4905 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4906</pre>
4907
4908<h5>Overview:</h5>
4909
4910<p>
4911The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4912specified (positive or negative) power.
4913</p>
4914
4915<h5>Arguments:</h5>
4916
4917<p>
4918The second argument is a floating point power, and the first is a value to
4919raise to that power.
4920</p>
4921
4922<h5>Semantics:</h5>
4923
4924<p>
4925This function returns the first value raised to the second power,
4926returning the
4927same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4928conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4929</div>
4930
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4931
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4932<!-- ======================================================================= -->
4933<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4934 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4935</div>
4936
4937<div class="doc_text">
4938<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4939LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4940These allow efficient code generation for some algorithms.
4941</p>
4942
4943</div>
4944
4945<!-- _______________________________________________________________________ -->
4946<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4947 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4948</div>
4949
4950<div class="doc_text">
4951
4952<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4953<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4954type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4955<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4956 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4957 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4958 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4959</pre>
4960
4961<h5>Overview:</h5>
4962
4963<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4964The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4965values with an even number of bytes (positive multiple of 16 bits). These are
4966useful for performing operations on data that is not in the target's native
4967byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4968</p>
4969
4970<h5>Semantics:</h5>
4971
4972<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4973The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4974and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4975intrinsic returns an i32 value that has the four bytes of the input i32
4976swapped, 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]4977i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4978<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4979additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4980</p>
4981
4982</div>
4983
4984<!-- _______________________________________________________________________ -->
4985<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4986 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4987</div>
4988
4989<div class="doc_text">
4990
4991<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4992<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4993width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4994<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4995 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4996 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4997 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4998 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4999 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5000</pre>
5001
5002<h5>Overview:</h5>
5003
5004<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]5005The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5006value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5007</p>
5008
5009<h5>Arguments:</h5>
5010
5011<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5012The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5013integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5014</p>
5015
5016<h5>Semantics:</h5>
5017
5018<p>
5019The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5020</p>
5021</div>
5022
5023<!-- _______________________________________________________________________ -->
5024<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5025 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5026</div>
5027
5028<div class="doc_text">
5029
5030<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5031<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5032integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5033<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5034 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5035 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5036 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5037 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5038 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5039</pre>
5040
5041<h5>Overview:</h5>
5042
5043<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5044The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5045leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5046</p>
5047
5048<h5>Arguments:</h5>
5049
5050<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5051The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5052integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5053</p>
5054
5055<h5>Semantics:</h5>
5056
5057<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5058The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5059in 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]5060of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5061</p>
5062</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5063
5064
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5068 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5069</div>
5070
5071<div class="doc_text">
5072
5073<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5074<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5075integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5076<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5077 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5078 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5079 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5080 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5081 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5082</pre>
5083
5084<h5>Overview:</h5>
5085
5086<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5087The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5088trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5089</p>
5090
5091<h5>Arguments:</h5>
5092
5093<p>
5094The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5095integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5096</p>
5097
5098<h5>Semantics:</h5>
5099
5100<p>
5101The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5102in a variable. If the src == 0 then the result is the size in bits of the type
5103of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5104</p>
5105</div>
5106
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5107<!-- _______________________________________________________________________ -->
5108<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5109 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5110</div>
5111
5112<div class="doc_text">
5113
5114<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5115<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5116on any integer bit width.
5117<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5118 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5119 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5120</pre>
5121
5122<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5123<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5124range of bits from an integer value and returns them in the same bit width as
5125the original value.</p>
5126
5127<h5>Arguments:</h5>
5128<p>The first argument, <tt>%val</tt> and the result may be integer types of
5129any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5130arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5131
5132<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5133<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5134of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5135<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5136operates in forward mode.</p>
5137<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5138right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5139only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5140<ol>
5141 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5142 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5143 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5144 to determine the number of bits to retain.</li>
5145 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5146 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5147</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5148<p>In reverse mode, a similar computation is made except that the bits are
5149returned in the reverse order. So, for example, if <tt>X</tt> has the value
5150<tt>i16 0x0ACF (101011001111)</tt> and we apply
5151<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5152<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5153</div>
5154
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5155<div class="doc_subsubsection">
5156 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5157</div>
5158
5159<div class="doc_text">
5160
5161<h5>Syntax:</h5>
5162<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5163on any integer bit width.
5164<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5165 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5166 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]5167</pre>
5168
5169<h5>Overview:</h5>
5170<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5171of bits in an integer value with another integer value. It returns the integer
5172with the replaced bits.</p>
5173
5174<h5>Arguments:</h5>
5175<p>The first argument, <tt>%val</tt> and the result may be integer types of
5176any bit width but they must have the same bit width. <tt>%val</tt> is the value
5177whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5178integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5179type since they specify only a bit index.</p>
5180
5181<h5>Semantics:</h5>
5182<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5183of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5184<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5185operates in forward mode.</p>
5186<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5187truncating it down to the size of the replacement area or zero extending it
5188up to that size.</p>
5189<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5190are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5191in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5192to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5193<p>In reverse mode, a similar computation is made except that the bits are
5194reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5195<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]5196<h5>Examples:</h5>
5197<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5198 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5199 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5200 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5201 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5202 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5203</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5204</div>
5205
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5206<!-- ======================================================================= -->
5207<div class="doc_subsection">
5208 <a name="int_debugger">Debugger Intrinsics</a>
5209</div>
5210
5211<div class="doc_text">
5212<p>
5213The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5214are described in the <a
5215href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5216Debugging</a> document.
5217</p>
5218</div>
5219
5220
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5221<!-- ======================================================================= -->
5222<div class="doc_subsection">
5223 <a name="int_eh">Exception Handling Intrinsics</a>
5224</div>
5225
5226<div class="doc_text">
5227<p> The LLVM exception handling intrinsics (which all start with
5228<tt>llvm.eh.</tt> prefix), are described in the <a
5229href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5230Handling</a> document. </p>
5231</div>
5232
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5233<!-- ======================================================================= -->
5234<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5235 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5236</div>
5237
5238<div class="doc_text">
5239<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5240 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5241 the <tt>nest</tt> attribute, from a function. The result is a callable
5242 function pointer lacking the nest parameter - the caller does not need
5243 to provide a value for it. Instead, the value to use is stored in
5244 advance in a "trampoline", a block of memory usually allocated
5245 on the stack, which also contains code to splice the nest value into the
5246 argument list. This is used to implement the GCC nested function address
5247 extension.
5248</p>
5249<p>
5250 For example, if the function is
5251 <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]5252 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]5253<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5254 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5255 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5256 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5257 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5258</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5259 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5260 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5261</div>
5262
5263<!-- _______________________________________________________________________ -->
5264<div class="doc_subsubsection">
5265 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5266</div>
5267<div class="doc_text">
5268<h5>Syntax:</h5>
5269<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5270declare 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]5271</pre>
5272<h5>Overview:</h5>
5273<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5274 This fills the memory pointed to by <tt>tramp</tt> with code
5275 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5276</p>
5277<h5>Arguments:</h5>
5278<p>
5279 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5280 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5281 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5282 intrinsic. Note that the size and the alignment are target-specific - LLVM
5283 currently provides no portable way of determining them, so a front-end that
5284 generates this intrinsic needs to have some target-specific knowledge.
5285 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]5286</p>
5287<h5>Semantics:</h5>
5288<p>
5289 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5290 dependent code, turning it into a function. A pointer to this function is
5291 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5292 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5293 before being called. The new function's signature is the same as that of
5294 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5295 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5296 of pointer type. Calling the new function is equivalent to calling
5297 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5298 missing <tt>nest</tt> argument. If, after calling
5299 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5300 modified, then the effect of any later call to the returned function pointer is
5301 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5302</p>
5303</div>
5304
5305<!-- ======================================================================= -->
5306<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5307 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5308</div>
5309
5310<div class="doc_text">
5311<p>
5312 These intrinsic functions expand the "universal IR" of LLVM to represent
5313 hardware constructs for atomic operations and memory synchronization. This
5314 provides an interface to the hardware, not an interface to the programmer. It
5315 is aimed at a low enough level to allow any programming models or APIs which
5316 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5317 hardware behavior. Just as hardware provides a "universal IR" for source
5318 languages, it also provides a starting point for developing a "universal"
5319 atomic operation and synchronization IR.
5320</p>
5321<p>
5322 These do <em>not</em> form an API such as high-level threading libraries,
5323 software transaction memory systems, atomic primitives, and intrinsic
5324 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5325 application libraries. The hardware interface provided by LLVM should allow
5326 a clean implementation of all of these APIs and parallel programming models.
5327 No one model or paradigm should be selected above others unless the hardware
5328 itself ubiquitously does so.
5329
5330</p>
5331</div>
5332
5333<!-- _______________________________________________________________________ -->
5334<div class="doc_subsubsection">
5335 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5336</div>
5337<div class="doc_text">
5338<h5>Syntax:</h5>
5339<pre>
5340declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5341i1 &lt;device&gt; )
5342
5343</pre>
5344<h5>Overview:</h5>
5345<p>
5346 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5347 specific pairs of memory access types.
5348</p>
5349<h5>Arguments:</h5>
5350<p>
5351 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5352 The first four arguments enables a specific barrier as listed below. The fith
5353 argument specifies that the barrier applies to io or device or uncached memory.
5354
5355</p>
5356 <ul>
5357 <li><tt>ll</tt>: load-load barrier</li>
5358 <li><tt>ls</tt>: load-store barrier</li>
5359 <li><tt>sl</tt>: store-load barrier</li>
5360 <li><tt>ss</tt>: store-store barrier</li>
5361 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5362 </ul>
5363<h5>Semantics:</h5>
5364<p>
5365 This intrinsic causes the system to enforce some ordering constraints upon
5366 the loads and stores of the program. This barrier does not indicate
5367 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5368 which they occur. For any of the specified pairs of load and store operations
5369 (f.ex. load-load, or store-load), all of the first operations preceding the
5370 barrier will complete before any of the second operations succeeding the
5371 barrier begin. Specifically the semantics for each pairing is as follows:
5372</p>
5373 <ul>
5374 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5375 after the barrier begins.</li>
5376
5377 <li><tt>ls</tt>: All loads before the barrier must complete before any
5378 store after the barrier begins.</li>
5379 <li><tt>ss</tt>: All stores before the barrier must complete before any
5380 store after the barrier begins.</li>
5381 <li><tt>sl</tt>: All stores before the barrier must complete before any
5382 load after the barrier begins.</li>
5383 </ul>
5384<p>
5385 These semantics are applied with a logical "and" behavior when more than one
5386 is enabled in a single memory barrier intrinsic.
5387</p>
5388<p>
5389 Backends may implement stronger barriers than those requested when they do not
5390 support as fine grained a barrier as requested. Some architectures do not
5391 need all types of barriers and on such architectures, these become noops.
5392</p>
5393<h5>Example:</h5>
5394<pre>
5395%ptr = malloc i32
5396 store i32 4, %ptr
5397
5398%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5399 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5400 <i>; guarantee the above finishes</i>
5401 store i32 8, %ptr <i>; before this begins</i>
5402</pre>
5403</div>
5404
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]5405<!-- _______________________________________________________________________ -->
5406<div class="doc_subsubsection">
5407 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5408</div>
5409<div class="doc_text">
5410<h5>Syntax:</h5>
5411<p>
5412 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5413 integer bit width. Not all targets support all bit widths however.</p>
5414
5415<pre>
5416declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5417declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5418declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5419declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5420
5421</pre>
5422<h5>Overview:</h5>
5423<p>
5424 This loads a value in memory and compares it to a given value. If they are
5425 equal, it stores a new value into the memory.
5426</p>
5427<h5>Arguments:</h5>
5428<p>
5429 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5430 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5431 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5432 this integer type. While any bit width integer may be used, targets may only
5433 lower representations they support in hardware.
5434
5435</p>
5436<h5>Semantics:</h5>
5437<p>
5438 This entire intrinsic must be executed atomically. It first loads the value
5439 in memory pointed to by <tt>ptr</tt> and compares it with the value
5440 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5441 loaded value is yielded in all cases. This provides the equivalent of an
5442 atomic compare-and-swap operation within the SSA framework.
5443</p>
5444<h5>Examples:</h5>
5445
5446<pre>
5447%ptr = malloc i32
5448 store i32 4, %ptr
5449
5450%val1 = add i32 4, 4
5451%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5452 <i>; yields {i32}:result1 = 4</i>
5453%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5454%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5455
5456%val2 = add i32 1, 1
5457%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5458 <i>; yields {i32}:result2 = 8</i>
5459%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5460
5461%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5462</pre>
5463</div>
5464
5465<!-- _______________________________________________________________________ -->
5466<div class="doc_subsubsection">
5467 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5468</div>
5469<div class="doc_text">
5470<h5>Syntax:</h5>
5471
5472<p>
5473 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5474 integer bit width. Not all targets support all bit widths however.</p>
5475<pre>
5476declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5477declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5478declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5479declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5480
5481</pre>
5482<h5>Overview:</h5>
5483<p>
5484 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5485 the value from memory. It then stores the value in <tt>val</tt> in the memory
5486 at <tt>ptr</tt>.
5487</p>
5488<h5>Arguments:</h5>
5489
5490<p>
5491 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5492 <tt>val</tt> argument and the result must be integers of the same bit width.
5493 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5494 integer type. The targets may only lower integer representations they
5495 support.
5496</p>
5497<h5>Semantics:</h5>
5498<p>
5499 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5500 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5501 equivalent of an atomic swap operation within the SSA framework.
5502
5503</p>
5504<h5>Examples:</h5>
5505<pre>
5506%ptr = malloc i32
5507 store i32 4, %ptr
5508
5509%val1 = add i32 4, 4
5510%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5511 <i>; yields {i32}:result1 = 4</i>
5512%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5513%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5514
5515%val2 = add i32 1, 1
5516%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5517 <i>; yields {i32}:result2 = 8</i>
5518
5519%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5520%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5521</pre>
5522</div>
5523
5524<!-- _______________________________________________________________________ -->
5525<div class="doc_subsubsection">
5526 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5527
5528</div>
5529<div class="doc_text">
5530<h5>Syntax:</h5>
5531<p>
5532 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5533 integer bit width. Not all targets support all bit widths however.</p>
5534<pre>
5535declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5536declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5537declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5538declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5539
5540</pre>
5541<h5>Overview:</h5>
5542<p>
5543 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5544 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5545</p>
5546<h5>Arguments:</h5>
5547<p>
5548
5549 The intrinsic takes two arguments, the first a pointer to an integer value
5550 and the second an integer value. The result is also an integer value. These
5551 integer types can have any bit width, but they must all have the same bit
5552 width. The targets may only lower integer representations they support.
5553</p>
5554<h5>Semantics:</h5>
5555<p>
5556 This intrinsic does a series of operations atomically. It first loads the
5557 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5558 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5559</p>
5560
5561<h5>Examples:</h5>
5562<pre>
5563%ptr = malloc i32
5564 store i32 4, %ptr
5565%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5566 <i>; yields {i32}:result1 = 4</i>
5567%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5568 <i>; yields {i32}:result2 = 8</i>
5569%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5570 <i>; yields {i32}:result3 = 10</i>
5571%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5572</pre>
5573</div>
5574
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5575
5576<!-- ======================================================================= -->
5577<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5578 <a name="int_general">General Intrinsics</a>
5579</div>
5580
5581<div class="doc_text">
5582<p> This class of intrinsics is designed to be generic and has
5583no specific purpose. </p>
5584</div>
5585
5586<!-- _______________________________________________________________________ -->
5587<div class="doc_subsubsection">
5588 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5589</div>
5590
5591<div class="doc_text">
5592
5593<h5>Syntax:</h5>
5594<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5595 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]5596</pre>
5597
5598<h5>Overview:</h5>
5599
5600<p>
5601The '<tt>llvm.var.annotation</tt>' intrinsic
5602</p>
5603
5604<h5>Arguments:</h5>
5605
5606<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5607The first argument is a pointer to a value, the second is a pointer to a
5608global string, the third is a pointer to a global string which is the source
5609file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5610</p>
5611
5612<h5>Semantics:</h5>
5613
5614<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5615This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5616This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5617annotations. These have no other defined use, they are ignored by code
5618generation and optimization.
5619</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5620</div>
5621
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5622<!-- _______________________________________________________________________ -->
5623<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5624 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5625</div>
5626
5627<div class="doc_text">
5628
5629<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5630<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5631any integer bit width.
5632</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5633<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5634 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5635 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5636 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5637 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5638 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]5639</pre>
5640
5641<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5642
5643<p>
5644The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5645</p>
5646
5647<h5>Arguments:</h5>
5648
5649<p>
5650The first argument is an integer value (result of some expression),
5651the second is a pointer to a global string, the third is a pointer to a global
5652string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5653It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5654</p>
5655
5656<h5>Semantics:</h5>
5657
5658<p>
5659This intrinsic allows annotations to be put on arbitrary expressions
5660with arbitrary strings. This can be useful for special purpose optimizations
5661that want to look for these annotations. These have no other defined use, they
5662are ignored by code generation and optimization.
5663</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5664
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5665<!-- _______________________________________________________________________ -->
5666<div class="doc_subsubsection">
5667 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5668</div>
5669
5670<div class="doc_text">
5671
5672<h5>Syntax:</h5>
5673<pre>
5674 declare void @llvm.trap()
5675</pre>
5676
5677<h5>Overview:</h5>
5678
5679<p>
5680The '<tt>llvm.trap</tt>' intrinsic
5681</p>
5682
5683<h5>Arguments:</h5>
5684
5685<p>
5686None
5687</p>
5688
5689<h5>Semantics:</h5>
5690
5691<p>
5692This intrinsics is lowered to the target dependent trap instruction. If the
5693target does not have a trap instruction, this intrinsic will be lowered to the
5694call of the abort() function.
5695</p>
5696</div>
5697
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5698<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5699<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5700<address>
5701 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5705
5706 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5707 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5708 Last modified: $Date$
5709</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5710
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