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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 72ed200a7e8897544aeddaf3efe6463051e38482 / . / 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 Korobeynikov726d45c2008-03-22 08:36:14 +0000[diff] [blame]766 function, global variable, another alias or bitcast of global value). Aliases
767 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]768 optional <a href="#visibility">visibility style</a>.</p>
769
770 <h5>Syntax:</h5>
771
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]772<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]773<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]774@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]775</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]776</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]777
778</div>
779
780
781
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]782<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]783<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
784<div class="doc_text">
785 <p>The return type and each parameter of a function type may have a set of
786 <i>parameter attributes</i> associated with them. Parameter attributes are
787 used to communicate additional information about the result or parameters of
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]788 a function. Parameter attributes are considered to be part of the function,
789 not of the function type, so functions with different parameter attributes
790 can have the same function type.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]791
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]792 <p>Parameter attributes are simple keywords that follow the type specified. If
793 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]794 example:</p>
795
796<div class="doc_code">
797<pre>
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]798declare i32 @printf(i8* noalias , ...) nounwind
799declare i32 @atoi(i8*) nounwind readonly
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]800</pre>
801</div>
802
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]803 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
804 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]805
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]806 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]807 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]808 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]809 <dd>This indicates that the parameter should be zero extended just before
810 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]811
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]812 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]813 <dd>This indicates that the parameter should be sign extended just before
814 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]815
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]816 <dt><tt>inreg</tt></dt>
817 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]818 possible) during assembling function call. Support for this attribute is
819 target-specific</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]820
821 <dt><tt>byval</tt></dt>
Chris Lattner0747baa2008-01-15 04:34:22 +0000[diff] [blame]822 <dd>This indicates that the pointer parameter should really be passed by
823 value to the function. The attribute implies that a hidden copy of the
824 pointee is made between the caller and the callee, so the callee is unable
825 to modify the value in the callee. This attribute is only valid on llvm
826 pointer arguments. It is generally used to pass structs and arrays by
827 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]828
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]829 <dt><tt>sret</tt></dt>
Duncan Sandse26dec62008-02-18 04:19:38 +0000[diff] [blame]830 <dd>This indicates that the pointer parameter specifies the address of a
831 structure that is the return value of the function in the source program.
Duncan Sandsb7f0c082008-03-17 12:17:41 +0000[diff] [blame]832 Loads and stores to the structure are assumed not to trap.
Duncan Sandse26dec62008-02-18 04:19:38 +0000[diff] [blame]833 May only be applied to the first parameter.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]834
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]835 <dt><tt>noalias</tt></dt>
Owen Anderson117bbd32008-02-18 04:09:01 +0000[diff] [blame]836 <dd>This indicates that the parameter does not alias any global or any other
837 parameter. The caller is responsible for ensuring that this is the case,
838 usually by placing the value in a stack allocation.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]839
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]840 <dt><tt>noreturn</tt></dt>
841 <dd>This function attribute indicates that the function never returns. This
842 indicates to LLVM that every call to this function should be treated as if
843 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]844
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]845 <dt><tt>nounwind</tt></dt>
Duncan Sandsb7f0c082008-03-17 12:17:41 +0000[diff] [blame]846 <dd>This function attribute indicates that no exceptions unwind out of the
847 function. Usually this is because the function makes no use of exceptions,
848 but it may also be that the function catches any exceptions thrown when
849 executing it.</dd>
850
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]851 <dt><tt>nest</tt></dt>
852 <dd>This indicates that the parameter can be excised using the
853 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]854 <dt><tt>readonly</tt></dt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]855 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]856 except for producing a return value or throwing an exception. The value
857 returned must only depend on the function arguments and/or global variables.
858 It may use values obtained by dereferencing pointers.</dd>
859 <dt><tt>readnone</tt></dt>
860 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]861 function, but in addition it is not allowed to dereference any pointer arguments
862 or global variables.
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]863 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]864
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]865</div>
866
867<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]868<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]869 <a name="gc">Garbage Collector Names</a>
870</div>
871
872<div class="doc_text">
873<p>Each function may specify a garbage collector name, which is simply a
874string.</p>
875
876<div class="doc_code"><pre
877>define void @f() gc "name" { ...</pre></div>
878
879<p>The compiler declares the supported values of <i>name</i>. Specifying a
880collector which will cause the compiler to alter its output in order to support
881the named garbage collection algorithm.</p>
882</div>
883
884<!-- ======================================================================= -->
885<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]886 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]887</div>
888
889<div class="doc_text">
890<p>
891Modules may contain "module-level inline asm" blocks, which corresponds to the
892GCC "file scope inline asm" blocks. These blocks are internally concatenated by
893LLVM and treated as a single unit, but may be separated in the .ll file if
894desired. The syntax is very simple:
895</p>
896
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]897<div class="doc_code">
898<pre>
899module asm "inline asm code goes here"
900module asm "more can go here"
901</pre>
902</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]903
904<p>The strings can contain any character by escaping non-printable characters.
905 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
906 for the number.
907</p>
908
909<p>
910 The inline asm code is simply printed to the machine code .s file when
911 assembly code is generated.
912</p>
913</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]914
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]915<!-- ======================================================================= -->
916<div class="doc_subsection">
917 <a name="datalayout">Data Layout</a>
918</div>
919
920<div class="doc_text">
921<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]922data is to be laid out in memory. The syntax for the data layout is simply:</p>
923<pre> target datalayout = "<i>layout specification</i>"</pre>
924<p>The <i>layout specification</i> consists of a list of specifications
925separated by the minus sign character ('-'). Each specification starts with a
926letter and may include other information after the letter to define some
927aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]928<dl>
929 <dt><tt>E</tt></dt>
930 <dd>Specifies that the target lays out data in big-endian form. That is, the
931 bits with the most significance have the lowest address location.</dd>
932 <dt><tt>e</tt></dt>
933 <dd>Specifies that hte target lays out data in little-endian form. That is,
934 the bits with the least significance have the lowest address location.</dd>
935 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
936 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
937 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
938 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
939 too.</dd>
940 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
941 <dd>This specifies the alignment for an integer type of a given bit
942 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
943 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
944 <dd>This specifies the alignment for a vector type of a given bit
945 <i>size</i>.</dd>
946 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
947 <dd>This specifies the alignment for a floating point type of a given bit
948 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
949 (double).</dd>
950 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an aggregate type of a given bit
952 <i>size</i>.</dd>
953</dl>
954<p>When constructing the data layout for a given target, LLVM starts with a
955default set of specifications which are then (possibly) overriden by the
956specifications in the <tt>datalayout</tt> keyword. The default specifications
957are given in this list:</p>
958<ul>
959 <li><tt>E</tt> - big endian</li>
960 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
961 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
962 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
963 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
964 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
965 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
966 alignment of 64-bits</li>
967 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
968 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
969 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
970 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
971 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
972</ul>
973<p>When llvm is determining the alignment for a given type, it uses the
974following rules:
975<ol>
976 <li>If the type sought is an exact match for one of the specifications, that
977 specification is used.</li>
978 <li>If no match is found, and the type sought is an integer type, then the
979 smallest integer type that is larger than the bitwidth of the sought type is
980 used. If none of the specifications are larger than the bitwidth then the the
981 largest integer type is used. For example, given the default specifications
982 above, the i7 type will use the alignment of i8 (next largest) while both
983 i65 and i256 will use the alignment of i64 (largest specified).</li>
984 <li>If no match is found, and the type sought is a vector type, then the
985 largest vector type that is smaller than the sought vector type will be used
986 as a fall back. This happens because <128 x double> can be implemented in
987 terms of 64 <2 x double>, for example.</li>
988</ol>
989</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]990
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]991<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]992<div class="doc_section"> <a name="typesystem">Type System</a> </div>
993<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]995<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]996
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]997<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]998intermediate representation. Being typed enables a number of
999optimizations to be performed on the IR directly, without having to do
1000extra analyses on the side before the transformation. A strong type
1001system makes it easier to read the generated code and enables novel
1002analyses and transformations that are not feasible to perform on normal
1003three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1004
1005</div>
1006
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1007<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1008<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1009Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1010<div class="doc_text">
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1011<p>The types fall into a few useful
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1012classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1013
1014<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1015 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1016 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1018 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1019 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020 </tr>
1021 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1022 <td><a href="#t_floating">floating point</a></td>
1023 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1024 </tr>
1025 <tr>
1026 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1027 <td><a href="#t_integer">integer</a>,
1028 <a href="#t_floating">floating point</a>,
1029 <a href="#t_pointer">pointer</a>,
1030 <a href="#t_vector">vector</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1031 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1032 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1033 <tr>
1034 <td><a href="#t_primitive">primitive</a></td>
1035 <td><a href="#t_label">label</a>,
1036 <a href="#t_void">void</a>,
1037 <a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>.</td>
1039 </tr>
1040 <tr>
1041 <td><a href="#t_derived">derived</a></td>
1042 <td><a href="#t_integer">integer</a>,
1043 <a href="#t_array">array</a>,
1044 <a href="#t_function">function</a>,
1045 <a href="#t_pointer">pointer</a>,
1046 <a href="#t_struct">structure</a>,
1047 <a href="#t_pstruct">packed structure</a>,
1048 <a href="#t_vector">vector</a>,
1049 <a href="#t_opaque">opaque</a>.
1050 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1051 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1052</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1053
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1054<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1055most important. Values of these types are the only ones which can be
1056produced by instructions, passed as arguments, or used as operands to
1057instructions. This means that all structures and arrays must be
1058manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1059</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1060
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1061<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1062<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1063
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1064<div class="doc_text">
1065<p>The primitive types are the fundamental building blocks of the LLVM
1066system.</p>
1067
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1068</div>
1069
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1072
1073<div class="doc_text">
1074 <table>
1075 <tbody>
1076 <tr><th>Type</th><th>Description</th></tr>
1077 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1078 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1079 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1080 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1081 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1082 </tbody>
1083 </table>
1084</div>
1085
1086<!-- _______________________________________________________________________ -->
1087<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1088
1089<div class="doc_text">
1090<h5>Overview:</h5>
1091<p>The void type does not represent any value and has no size.</p>
1092
1093<h5>Syntax:</h5>
1094
1095<pre>
1096 void
1097</pre>
1098</div>
1099
1100<!-- _______________________________________________________________________ -->
1101<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1102
1103<div class="doc_text">
1104<h5>Overview:</h5>
1105<p>The label type represents code labels.</p>
1106
1107<h5>Syntax:</h5>
1108
1109<pre>
1110 label
1111</pre>
1112</div>
1113
1114
1115<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1116<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1117
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1118<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1119
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1120<p>The real power in LLVM comes from the derived types in the system.
1121This is what allows a programmer to represent arrays, functions,
1122pointers, and other useful types. Note that these derived types may be
1123recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1124
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1125</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1127<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1128<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1129
1130<div class="doc_text">
1131
1132<h5>Overview:</h5>
1133<p>The integer type is a very simple derived type that simply specifies an
1134arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11352^23-1 (about 8 million) can be specified.</p>
1136
1137<h5>Syntax:</h5>
1138
1139<pre>
1140 iN
1141</pre>
1142
1143<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1144value.</p>
1145
1146<h5>Examples:</h5>
1147<table class="layout">
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1148 <tbody>
1149 <tr>
1150 <td><tt>i1</tt></td>
1151 <td>a single-bit integer.</td>
1152 </tr><tr>
1153 <td><tt>i32</tt></td>
1154 <td>a 32-bit integer.</td>
1155 </tr><tr>
1156 <td><tt>i1942652</tt></td>
1157 <td>a really big integer of over 1 million bits.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1158 </tr>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1159 </tbody>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1160</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1161</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1162
1163<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1164<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1166<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1167
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1168<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1170<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1171sequentially in memory. The array type requires a size (number of
1172elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1173
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1174<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1175
1176<pre>
1177 [&lt;# elements&gt; x &lt;elementtype&gt;]
1178</pre>
1179
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1180<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1181be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1182
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1183<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1184<table class="layout">
1185 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1186 <td class="left"><tt>[40 x i32]</tt></td>
1187 <td class="left">Array of 40 32-bit integer values.</td>
1188 </tr>
1189 <tr class="layout">
1190 <td class="left"><tt>[41 x i32]</tt></td>
1191 <td class="left">Array of 41 32-bit integer values.</td>
1192 </tr>
1193 <tr class="layout">
1194 <td class="left"><tt>[4 x i8]</tt></td>
1195 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1196 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1197</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1198<p>Here are some examples of multidimensional arrays:</p>
1199<table class="layout">
1200 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1201 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1202 <td class="left">3x4 array of 32-bit integer values.</td>
1203 </tr>
1204 <tr class="layout">
1205 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1206 <td class="left">12x10 array of single precision floating point values.</td>
1207 </tr>
1208 <tr class="layout">
1209 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1210 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1211 </tr>
1212</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1213
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1214<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1215length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1216LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1217As a special case, however, zero length arrays are recognized to be variable
1218length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1219type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1220
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1221</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1222
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1223<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1224<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1225<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1227<p>The function type can be thought of as a function signature. It
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1228consists of a return type and a list of formal parameter types. The
Devang Patel7a3ad1a2008-03-24 20:52:42 +0000[diff] [blame]1229return type of a function type is a scalar type or a void type or a struct type.
1230If the return type is a struct type then all struct elements must be of first
Devang Patel3a5bff82008-03-24 18:10:52 +0000[diff] [blame]1231class types. Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1232(which are structures of pointers to functions), for indirect function
1233calls, and when defining a function.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1235<h5>Syntax:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1236<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1237<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]1238specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1239which indicates that the function takes a variable number of arguments.
1240Variable argument functions can access their arguments with the <a
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1241 href="#int_varargs">variable argument handling intrinsic</a> functions.
1242'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1243<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1245<table class="layout">
1246 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1247 <td class="left"><tt>i32 (i32)</tt></td>
1248 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1250 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1251 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1252 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1253 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1254 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1255 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1256 <tt>float</tt>.
1257 </td>
1258 </tr><tr class="layout">
1259 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1260 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1261 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1262 which returns an integer. This is the signature for <tt>printf</tt> in
1263 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1264 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1265 </tr><tr class="layout">
1266 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel3a5bff82008-03-24 18:10:52 +0000[diff] [blame]1267 <td class="left">A function taking an <tt>i32></tt>, returning two
1268 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1269 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1270 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1271</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1273</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1274<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1275<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1276<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1278<p>The structure type is used to represent a collection of data members
1279together in memory. The packing of the field types is defined to match
1280the ABI of the underlying processor. The elements of a structure may
1281be any type that has a size.</p>
1282<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1283and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1284field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1285instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1286<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1287<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1289<table class="layout">
1290 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1291 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1292 <td class="left">A triple of three <tt>i32</tt> values</td>
1293 </tr><tr class="layout">
1294 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1295 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1296 second element is a <a href="#t_pointer">pointer</a> to a
1297 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1298 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1299 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1300</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1301</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1302
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1303<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1304<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1305</div>
1306<div class="doc_text">
1307<h5>Overview:</h5>
1308<p>The packed structure type is used to represent a collection of data members
1309together in memory. There is no padding between fields. Further, the alignment
1310of a packed structure is 1 byte. The elements of a packed structure may
1311be any type that has a size.</p>
1312<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1313and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1314field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1315instruction.</p>
1316<h5>Syntax:</h5>
1317<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1318<h5>Examples:</h5>
1319<table class="layout">
1320 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1321 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1322 <td class="left">A triple of three <tt>i32</tt> values</td>
1323 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1324 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1325 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1326 second element is a <a href="#t_pointer">pointer</a> to a
1327 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1328 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1329 </tr>
1330</table>
1331</div>
1332
1333<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1334<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1335<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1336<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1337<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1338reference to another object, which must live in memory. Pointer types may have
1339an optional address space attribute defining the target-specific numbered
1340address space where the pointed-to object resides. The default address space is
1341zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1342<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1343<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1344<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1345<table class="layout">
1346 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1347 <td class="left"><tt>[4x i32]*</tt></td>
1348 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1349 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1350 </tr>
1351 <tr class="layout">
1352 <td class="left"><tt>i32 (i32 *) *</tt></td>
1353 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1354 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1355 <tt>i32</tt>.</td>
1356 </tr>
1357 <tr class="layout">
1358 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1359 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1360 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1361 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1362</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1364
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1365<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1366<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1368
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1369<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1370
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1371<p>A vector type is a simple derived type that represents a vector
1372of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1373are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1374A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1375elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1376of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1377considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1378
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1379<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1380
1381<pre>
1382 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1383</pre>
1384
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1385<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1386be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1387
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1388<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1389
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1390<table class="layout">
1391 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1392 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1393 <td class="left">Vector of 4 32-bit integer values.</td>
1394 </tr>
1395 <tr class="layout">
1396 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1397 <td class="left">Vector of 8 32-bit floating-point values.</td>
1398 </tr>
1399 <tr class="layout">
1400 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1401 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1402 </tr>
1403</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1404</div>
1405
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1406<!-- _______________________________________________________________________ -->
1407<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411
1412<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1413corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1414In LLVM, opaque types can eventually be resolved to any type (not just a
1415structure type).</p>
1416
1417<h5>Syntax:</h5>
1418
1419<pre>
1420 opaque
1421</pre>
1422
1423<h5>Examples:</h5>
1424
1425<table class="layout">
1426 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1427 <td class="left"><tt>opaque</tt></td>
1428 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1429 </tr>
1430</table>
1431</div>
1432
1433
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1434<!-- *********************************************************************** -->
1435<div class="doc_section"> <a name="constants">Constants</a> </div>
1436<!-- *********************************************************************** -->
1437
1438<div class="doc_text">
1439
1440<p>LLVM has several different basic types of constants. This section describes
1441them all and their syntax.</p>
1442
1443</div>
1444
1445<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1446<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1447
1448<div class="doc_text">
1449
1450<dl>
1451 <dt><b>Boolean constants</b></dt>
1452
1453 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1454 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1455 </dd>
1456
1457 <dt><b>Integer constants</b></dt>
1458
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1459 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1460 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1461 integer types.
1462 </dd>
1463
1464 <dt><b>Floating point constants</b></dt>
1465
1466 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1467 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]1468 notation (see below). The assembler requires the exact decimal value of
1469 a floating-point constant. For example, the assembler accepts 1.25 but
1470 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1471 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1472
1473 <dt><b>Null pointer constants</b></dt>
1474
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1475 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1476 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1477
1478</dl>
1479
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1480<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1481of floating point constants. For example, the form '<tt>double
14820x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14834.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1484(and the only time that they are generated by the disassembler) is when a
1485floating point constant must be emitted but it cannot be represented as a
1486decimal floating point number. For example, NaN's, infinities, and other
1487special values are represented in their IEEE hexadecimal format so that
1488assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1489
1490</div>
1491
1492<!-- ======================================================================= -->
1493<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1494</div>
1495
1496<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1497<p>Aggregate constants arise from aggregation of simple constants
1498and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1499
1500<dl>
1501 <dt><b>Structure constants</b></dt>
1502
1503 <dd>Structure constants are represented with notation similar to structure
1504 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1505 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1506 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1507 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1508 types of elements must match those specified by the type.
1509 </dd>
1510
1511 <dt><b>Array constants</b></dt>
1512
1513 <dd>Array constants are represented with notation similar to array type
1514 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1515 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516 constants must have <a href="#t_array">array type</a>, and the number and
1517 types of elements must match those specified by the type.
1518 </dd>
1519
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1520 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1521
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1522 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1523 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1524 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1525 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1526 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527 match those specified by the type.
1528 </dd>
1529
1530 <dt><b>Zero initialization</b></dt>
1531
1532 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1533 value to zero of <em>any</em> type, including scalar and aggregate types.
1534 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1535 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536 initializers.
1537 </dd>
1538</dl>
1539
1540</div>
1541
1542<!-- ======================================================================= -->
1543<div class="doc_subsection">
1544 <a name="globalconstants">Global Variable and Function Addresses</a>
1545</div>
1546
1547<div class="doc_text">
1548
1549<p>The addresses of <a href="#globalvars">global variables</a> and <a
1550href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1551constants. These constants are explicitly referenced when the <a
1552href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1553href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1554file:</p>
1555
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1556<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1557<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1558@X = global i32 17
1559@Y = global i32 42
1560@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1561</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1562</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1563
1564</div>
1565
1566<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1567<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1568<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1569 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1570 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1571 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1572
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1573 <p>Undefined values indicate to the compiler that the program is well defined
1574 no matter what value is used, giving the compiler more freedom to optimize.
1575 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1576</div>
1577
1578<!-- ======================================================================= -->
1579<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1580</div>
1581
1582<div class="doc_text">
1583
1584<p>Constant expressions are used to allow expressions involving other constants
1585to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1586href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1587that does not have side effects (e.g. load and call are not supported). The
1588following is the syntax for constant expressions:</p>
1589
1590<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1591 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1592 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1593 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1594
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1595 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1596 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1597 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1598
1599 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1600 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1601 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1602
1603 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1604 <dd>Truncate a floating point constant to another floating point type. The
1605 size of CST must be larger than the size of TYPE. Both types must be
1606 floating point.</dd>
1607
1608 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1609 <dd>Floating point extend a constant to another type. The size of CST must be
1610 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1611
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1612 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1613 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1614 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1615 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1616 of the same number of elements. If the value won't fit in the integer type,
1617 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1618
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1619 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1620 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1621 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1622 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1623 of the same number of elements. If the value won't fit in the integer type,
1624 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1625
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1626 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1627 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1628 constant. TYPE must be a scalar or vector floating point type. CST must be of
1629 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1630 of the same number of elements. If the value won't fit in the floating point
1631 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1632
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1633 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1634 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1635 constant. TYPE must be a scalar or vector floating point type. CST must be of
1636 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1637 of the same number of elements. If the value won't fit in the floating point
1638 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1639
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1640 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1641 <dd>Convert a pointer typed constant to the corresponding integer constant
1642 TYPE must be an integer type. CST must be of pointer type. The CST value is
1643 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1644
1645 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1646 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1647 pointer type. CST must be of integer type. The CST value is zero extended,
1648 truncated, or unchanged to make it fit in a pointer size. This one is
1649 <i>really</i> dangerous!</dd>
1650
1651 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1652 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1653 identical (same number of bits). The conversion is done as if the CST value
1654 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1655 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1656 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1657 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1658 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1659
1660 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1661
1662 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1663 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1664 instruction, the index list may have zero or more indexes, which are required
1665 to make sense for the type of "CSTPTR".</dd>
1666
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1667 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1668
1669 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1670 constants.</dd>
1671
1672 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1673 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1674
1675 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1676 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1677
1678 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1679
1680 <dd>Perform the <a href="#i_extractelement">extractelement
1681 operation</a> on constants.
1682
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1683 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1684
1685 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1686 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1687
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1688
1689 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1690
1691 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1692 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1693
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1694 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1695
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1696 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1697 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1698 binary</a> operations. The constraints on operands are the same as those for
1699 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1700 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1701</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1702</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1703
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1705<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1706<!-- *********************************************************************** -->
1707
1708<!-- ======================================================================= -->
1709<div class="doc_subsection">
1710<a name="inlineasm">Inline Assembler Expressions</a>
1711</div>
1712
1713<div class="doc_text">
1714
1715<p>
1716LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1717Module-Level Inline Assembly</a>) through the use of a special value. This
1718value represents the inline assembler as a string (containing the instructions
1719to emit), a list of operand constraints (stored as a string), and a flag that
1720indicates whether or not the inline asm expression has side effects. An example
1721inline assembler expression is:
1722</p>
1723
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1724<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1725<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1726i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1727</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1728</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1729
1730<p>
1731Inline assembler expressions may <b>only</b> be used as the callee operand of
1732a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1733</p>
1734
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1735<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1736<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1737%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1738</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1739</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1740
1741<p>
1742Inline asms with side effects not visible in the constraint list must be marked
1743as having side effects. This is done through the use of the
1744'<tt>sideeffect</tt>' keyword, like so:
1745</p>
1746
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1747<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1748<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1749call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1750</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1751</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1752
1753<p>TODO: The format of the asm and constraints string still need to be
1754documented here. Constraints on what can be done (e.g. duplication, moving, etc
1755need to be documented).
1756</p>
1757
1758</div>
1759
1760<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1761<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1762<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1763
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1764<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1765
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766<p>The LLVM instruction set consists of several different
1767classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1768instructions</a>, <a href="#binaryops">binary instructions</a>,
1769<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1770 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1771instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1772
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1773</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1775<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1776<div class="doc_subsection"> <a name="terminators">Terminator
1777Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1779<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1780
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1781<p>As mentioned <a href="#functionstructure">previously</a>, every
1782basic block in a program ends with a "Terminator" instruction, which
1783indicates which block should be executed after the current block is
1784finished. These terminator instructions typically yield a '<tt>void</tt>'
1785value: they produce control flow, not values (the one exception being
1786the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1787<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1788 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1789instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1790the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1791 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1792 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1793
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1794</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1795
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1796<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1797<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1798Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1802 ret void <i>; Return from void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1803 ret &lt;type&gt; &lt;value&gt;, &lt;type&gt; &lt;value&gt; <i>; Return two values from a non-void function </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1804</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1806<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1807value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1808<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809returns a value and then causes control flow, and one that just causes
1810control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Arguments:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1812<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1813type of each return value must be a '<a href="#t_firstclass">first class</a>'
1814 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1815if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1816returns values that do not match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1817<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1818<p>When the '<tt>ret</tt>' instruction is executed, control flow
1819returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1820 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1821the instruction after the call. If the caller was an "<a
1822 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1823at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824returns a value, that value shall set the call or invoke instruction's
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1825return value. If the instruction returns multiple values then these
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1826values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1827</a>' instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1829<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1830 ret void <i>; Return from a void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1831 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1833</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1834<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1835<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1836<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1838<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1840<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1841<p>The '<tt>br</tt>' instruction is used to cause control flow to
1842transfer to a different basic block in the current function. There are
1843two forms of this instruction, corresponding to a conditional branch
1844and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1846<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1847single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1848unconditional form of the '<tt>br</tt>' instruction takes a single
1849'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1850<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1851<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852argument is evaluated. If the value is <tt>true</tt>, control flows
1853to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1854control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1856<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1857 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1858</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1859<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1860<div class="doc_subsubsection">
1861 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1862</div>
1863
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1866
1867<pre>
1868 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1869</pre>
1870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1871<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1872
1873<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1874several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1875instruction, allowing a branch to occur to one of many possible
1876destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1877
1878
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1879<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1880
1881<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1882comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1883an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1884table is not allowed to contain duplicate constant entries.</p>
1885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1887
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1888<p>The <tt>switch</tt> instruction specifies a table of values and
1889destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1890table is searched for the given value. If the value is found, control flow is
1891transfered to the corresponding destination; otherwise, control flow is
1892transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1894<h5>Implementation:</h5>
1895
1896<p>Depending on properties of the target machine and the particular
1897<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1898ways. For example, it could be generated as a series of chained conditional
1899branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1900
1901<h5>Example:</h5>
1902
1903<pre>
1904 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1905 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1906 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1907
1908 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1909 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1910
1911 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1912 switch i32 %val, label %otherwise [ i32 0, label %onzero
1913 i32 1, label %onone
1914 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1915</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1916</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1917
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1919<div class="doc_subsubsection">
1920 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1921</div>
1922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1923<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1924
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1925<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1926
1927<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1928 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1929 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1930</pre>
1931
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1932<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1933
1934<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1935function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1936'<tt>normal</tt>' label or the
1937'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1938"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1939"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1940href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1941continued at the dynamically nearest "exception" label. If the callee function
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1942returns multiple values then individual return values are only accessible through
1943a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1945<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1947<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1950 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1951 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1952 convention</a> the call should use. If none is specified, the call defaults
1953 to using C calling conventions.
1954 </li>
1955 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1956 function value being invoked. In most cases, this is a direct function
1957 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1958 an arbitrary pointer to function value.
1959 </li>
1960
1961 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1962 function to be invoked. </li>
1963
1964 <li>'<tt>function args</tt>': argument list whose types match the function
1965 signature argument types. If the function signature indicates the function
1966 accepts a variable number of arguments, the extra arguments can be
1967 specified. </li>
1968
1969 <li>'<tt>normal label</tt>': the label reached when the called function
1970 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1971
1972 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1973 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1974
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1975</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1976
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1978
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1979<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1980href="#i_call">call</a></tt>' instruction in most regards. The primary
1981difference is that it establishes an association with a label, which is used by
1982the runtime library to unwind the stack.</p>
1983
1984<p>This instruction is used in languages with destructors to ensure that proper
1985cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1986exception. Additionally, this is important for implementation of
1987'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1989<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1990<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1991 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1992 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1993 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1994 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1996</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1997
1998
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1999<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2000
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2002Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2003
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2005
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2006<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2007<pre>
2008 unwind
2009</pre>
2010
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2011<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2012
2013<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2014at the first callee in the dynamic call stack which used an <a
2015href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2016primarily used to implement exception handling.</p>
2017
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2018<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2019
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2020<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2021immediately halt. The dynamic call stack is then searched for the first <a
2022href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2023execution continues at the "exceptional" destination block specified by the
2024<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2025dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2026</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2027
2028<!-- _______________________________________________________________________ -->
2029
2030<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2031Instruction</a> </div>
2032
2033<div class="doc_text">
2034
2035<h5>Syntax:</h5>
2036<pre>
2037 unreachable
2038</pre>
2039
2040<h5>Overview:</h5>
2041
2042<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2043instruction is used to inform the optimizer that a particular portion of the
2044code is not reachable. This can be used to indicate that the code after a
2045no-return function cannot be reached, and other facts.</p>
2046
2047<h5>Semantics:</h5>
2048
2049<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2050</div>
2051
2052
2053
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2054<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2056<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2057<p>Binary operators are used to do most of the computation in a
Chris Lattner5a158142008-04-01 18:47:32 +0000[diff] [blame]2058program. They require two operands of the same type, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2059produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2060multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner5a158142008-04-01 18:47:32 +0000[diff] [blame]2061The result value has the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2062<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2063</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2064<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2065<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2066Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2067<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2069<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2071<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2072<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2073<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2074<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2075 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2076 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2077Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2079<p>The value produced is the integer or floating point sum of the two
2080operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2081<p>If an integer sum has unsigned overflow, the result returned is the
2082mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2083the result.</p>
2084<p>Because LLVM integers use a two's complement representation, this
2085instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2087<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2089</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2090<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2091<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2092Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2093<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2095<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2096</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2097<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2098<p>The '<tt>sub</tt>' instruction returns the difference of its two
2099operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2100<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2101instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2102<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2103<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2104 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2105values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2106This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2107Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2109<p>The value produced is the integer or floating point difference of
2110the two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2111<p>If an integer difference has unsigned overflow, the result returned is the
2112mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2113the result.</p>
2114<p>Because LLVM integers use a two's complement representation, this
2115instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2116<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2117<pre>
2118 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2119 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2120</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2121</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2122<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2123<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2124Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2125<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2126<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2127<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2128</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2130<p>The '<tt>mul</tt>' instruction returns the product of its two
2131operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2132<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2133<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2134 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2135values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2136This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2137Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2138<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2139<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2141<p>If the result of an integer multiplication has unsigned overflow,
2142the result returned is the mathematical result modulo
21432<sup>n</sup>, where n is the bit width of the result.</p>
2144<p>Because LLVM integers use a two's complement representation, and the
2145result is the same width as the operands, this instruction returns the
2146correct result for both signed and unsigned integers. If a full product
2147(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2148should be sign-extended or zero-extended as appropriate to the
2149width of the full product.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2150<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2151<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2152</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2153</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2154<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2155<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2156</a></div>
2157<div class="doc_text">
2158<h5>Syntax:</h5>
2159<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2160</pre>
2161<h5>Overview:</h5>
2162<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2163operands.</p>
2164<h5>Arguments:</h5>
2165<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2166<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2167types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2168of the values in which case the elements must be integers.</p>
2169<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2170<p>The value produced is the unsigned integer quotient of the two operands.</p>
2171<p>Note that unsigned integer division and signed integer division are distinct
2172operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2173<p>Division by zero leads to undefined behavior.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2174<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2175<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2176</pre>
2177</div>
2178<!-- _______________________________________________________________________ -->
2179<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2180</a> </div>
2181<div class="doc_text">
2182<h5>Syntax:</h5>
2183<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2184</pre>
2185<h5>Overview:</h5>
2186<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2187operands.</p>
2188<h5>Arguments:</h5>
2189<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2190<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2191types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2192of the values in which case the elements must be integers.</p>
2193<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2194<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2195<p>Note that signed integer division and unsigned integer division are distinct
2196operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2197<p>Division by zero leads to undefined behavior. Overflow also leads to
2198undefined behavior; this is a rare case, but can occur, for example,
2199by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2200<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2201<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2202</pre>
2203</div>
2204<!-- _______________________________________________________________________ -->
2205<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2206Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2207<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2208<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2209<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2210</pre>
2211<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2212<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213operands.</p>
2214<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2215<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2216<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2217identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2218versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2219<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2220<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2221<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2222<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2223</pre>
2224</div>
2225<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2226<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2227</div>
2228<div class="doc_text">
2229<h5>Syntax:</h5>
2230<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2231</pre>
2232<h5>Overview:</h5>
2233<p>The '<tt>urem</tt>' instruction returns the remainder from the
2234unsigned division of its two arguments.</p>
2235<h5>Arguments:</h5>
2236<p>The two arguments to the '<tt>urem</tt>' instruction must be
2237<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2238types. This instruction can also take <a href="#t_vector">vector</a> versions
2239of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2240<h5>Semantics:</h5>
2241<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2242This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2243<p>Note that unsigned integer remainder and signed integer remainder are
2244distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2245<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2246<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2247<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2248</pre>
2249
2250</div>
2251<!-- _______________________________________________________________________ -->
2252<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2253Instruction</a> </div>
2254<div class="doc_text">
2255<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2256<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2257</pre>
2258<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2259<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2260signed division of its two operands. This instruction can also take
2261<a href="#t_vector">vector</a> versions of the values in which case
2262the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2263
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2264<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2265<p>The two arguments to the '<tt>srem</tt>' instruction must be
2266<a href="#t_integer">integer</a> values. Both arguments must have identical
2267types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2268<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2269<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2270has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2271operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2272a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2273 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2274Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2275please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2276Wikipedia: modulo operation</a>.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2277<p>Note that signed integer remainder and unsigned integer remainder are
2278distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2279<p>Taking the remainder of a division by zero leads to undefined behavior.
2280Overflow also leads to undefined behavior; this is a rare case, but can occur,
2281for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2282(The remainder doesn't actually overflow, but this rule lets srem be
2283implemented using instructions that return both the result of the division
2284and the remainder.)</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2285<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2286<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2287</pre>
2288
2289</div>
2290<!-- _______________________________________________________________________ -->
2291<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2292Instruction</a> </div>
2293<div class="doc_text">
2294<h5>Syntax:</h5>
2295<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2296</pre>
2297<h5>Overview:</h5>
2298<p>The '<tt>frem</tt>' instruction returns the remainder from the
2299division of its two operands.</p>
2300<h5>Arguments:</h5>
2301<p>The two arguments to the '<tt>frem</tt>' instruction must be
2302<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2303identical types. This instruction can also take <a href="#t_vector">vector</a>
2304versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2305<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2306<p>This instruction returns the <i>remainder</i> of a division.
2307The remainder has the same sign as the dividend.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2308<h5>Example:</h5>
2309<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2310</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2311</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2312
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2313<!-- ======================================================================= -->
2314<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2315Operations</a> </div>
2316<div class="doc_text">
2317<p>Bitwise binary operators are used to do various forms of
2318bit-twiddling in a program. They are generally very efficient
2319instructions and can commonly be strength reduced from other
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2320instructions. They require two operands of the same type, execute an operation on them,
2321and produce a single value. The resulting value is the same type as its operands.</p>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2322</div>
2323
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2324<!-- _______________________________________________________________________ -->
2325<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2326Instruction</a> </div>
2327<div class="doc_text">
2328<h5>Syntax:</h5>
2329<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2330</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2331
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2332<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2333
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2334<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2335the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2336
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2337<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2339<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2340 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2341unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2342
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2343<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2344
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2345<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2346where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2347equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2348
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2349<h5>Example:</h5><pre>
2350 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2351 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2352 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2353 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2354</pre>
2355</div>
2356<!-- _______________________________________________________________________ -->
2357<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2358Instruction</a> </div>
2359<div class="doc_text">
2360<h5>Syntax:</h5>
2361<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2362</pre>
2363
2364<h5>Overview:</h5>
2365<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2366operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2367
2368<h5>Arguments:</h5>
2369<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2370<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2371unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2372
2373<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2374
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2375<p>This instruction always performs a logical shift right operation. The most
2376significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2377shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2378the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2379
2380<h5>Example:</h5>
2381<pre>
2382 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2383 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2384 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2385 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2386 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2387</pre>
2388</div>
2389
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2390<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2391<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2392Instruction</a> </div>
2393<div class="doc_text">
2394
2395<h5>Syntax:</h5>
2396<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2397</pre>
2398
2399<h5>Overview:</h5>
2400<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2401operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2402
2403<h5>Arguments:</h5>
2404<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2405<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2406unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2407
2408<h5>Semantics:</h5>
2409<p>This instruction always performs an arithmetic shift right operation,
2410The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2411of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2412larger than the number of bits in <tt>var1</tt>, the result is undefined.
2413</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2414
2415<h5>Example:</h5>
2416<pre>
2417 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2418 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2419 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2420 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2421 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2422</pre>
2423</div>
2424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2425<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2426<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2427Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2430<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]2431</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2433<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2434its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2435<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2436<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2437 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2438identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2439<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2440<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2441<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2442<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2443<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2444 <tbody>
2445 <tr>
2446 <td>In0</td>
2447 <td>In1</td>
2448 <td>Out</td>
2449 </tr>
2450 <tr>
2451 <td>0</td>
2452 <td>0</td>
2453 <td>0</td>
2454 </tr>
2455 <tr>
2456 <td>0</td>
2457 <td>1</td>
2458 <td>0</td>
2459 </tr>
2460 <tr>
2461 <td>1</td>
2462 <td>0</td>
2463 <td>0</td>
2464 </tr>
2465 <tr>
2466 <td>1</td>
2467 <td>1</td>
2468 <td>1</td>
2469 </tr>
2470 </tbody>
2471</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2472</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2473<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2474<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2475 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2476 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2477</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2478</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2480<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2481<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2483<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]2484</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2485<h5>Overview:</h5>
2486<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2487or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2488<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2489<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2490 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2491identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2492<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2493<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2494<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2495<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2496<table border="1" cellspacing="0" cellpadding="4">
2497 <tbody>
2498 <tr>
2499 <td>In0</td>
2500 <td>In1</td>
2501 <td>Out</td>
2502 </tr>
2503 <tr>
2504 <td>0</td>
2505 <td>0</td>
2506 <td>0</td>
2507 </tr>
2508 <tr>
2509 <td>0</td>
2510 <td>1</td>
2511 <td>1</td>
2512 </tr>
2513 <tr>
2514 <td>1</td>
2515 <td>0</td>
2516 <td>1</td>
2517 </tr>
2518 <tr>
2519 <td>1</td>
2520 <td>1</td>
2521 <td>1</td>
2522 </tr>
2523 </tbody>
2524</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2525</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2526<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2527<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2528 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2529 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2530</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2531</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2532<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2533<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2534Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2535<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2536<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2537<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]2538</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2539<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2540<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2541or of its two operands. The <tt>xor</tt> is used to implement the
2542"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2543<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2544<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2545 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2546identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2547<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2548<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2549<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2550<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2551<table border="1" cellspacing="0" cellpadding="4">
2552 <tbody>
2553 <tr>
2554 <td>In0</td>
2555 <td>In1</td>
2556 <td>Out</td>
2557 </tr>
2558 <tr>
2559 <td>0</td>
2560 <td>0</td>
2561 <td>0</td>
2562 </tr>
2563 <tr>
2564 <td>0</td>
2565 <td>1</td>
2566 <td>1</td>
2567 </tr>
2568 <tr>
2569 <td>1</td>
2570 <td>0</td>
2571 <td>1</td>
2572 </tr>
2573 <tr>
2574 <td>1</td>
2575 <td>1</td>
2576 <td>0</td>
2577 </tr>
2578 </tbody>
2579</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2580</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2581<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2583<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2584 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2585 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2586 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2587</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2588</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2589
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2590<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2591<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2592 <a name="vectorops">Vector Operations</a>
2593</div>
2594
2595<div class="doc_text">
2596
2597<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2598target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2599vector-specific operations needed to process vectors effectively. While LLVM
2600does directly support these vector operations, many sophisticated algorithms
2601will want to use target-specific intrinsics to take full advantage of a specific
2602target.</p>
2603
2604</div>
2605
2606<!-- _______________________________________________________________________ -->
2607<div class="doc_subsubsection">
2608 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2609</div>
2610
2611<div class="doc_text">
2612
2613<h5>Syntax:</h5>
2614
2615<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2616 &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]2617</pre>
2618
2619<h5>Overview:</h5>
2620
2621<p>
2622The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2623element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2624</p>
2625
2626
2627<h5>Arguments:</h5>
2628
2629<p>
2630The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2631value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2632an index indicating the position from which to extract the element.
2633The index may be a variable.</p>
2634
2635<h5>Semantics:</h5>
2636
2637<p>
2638The result is a scalar of the same type as the element type of
2639<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2640<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2641results are undefined.
2642</p>
2643
2644<h5>Example:</h5>
2645
2646<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2647 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2648</pre>
2649</div>
2650
2651
2652<!-- _______________________________________________________________________ -->
2653<div class="doc_subsubsection">
2654 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2655</div>
2656
2657<div class="doc_text">
2658
2659<h5>Syntax:</h5>
2660
2661<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2662 &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]2663</pre>
2664
2665<h5>Overview:</h5>
2666
2667<p>
2668The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2669element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2670</p>
2671
2672
2673<h5>Arguments:</h5>
2674
2675<p>
2676The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2677value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2678scalar value whose type must equal the element type of the first
2679operand. The third operand is an index indicating the position at
2680which to insert the value. The index may be a variable.</p>
2681
2682<h5>Semantics:</h5>
2683
2684<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2685The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2686element values are those of <tt>val</tt> except at position
2687<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2688exceeds the length of <tt>val</tt>, the results are undefined.
2689</p>
2690
2691<h5>Example:</h5>
2692
2693<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2694 %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]2695</pre>
2696</div>
2697
2698<!-- _______________________________________________________________________ -->
2699<div class="doc_subsubsection">
2700 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<h5>Syntax:</h5>
2706
2707<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2708 &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]2709</pre>
2710
2711<h5>Overview:</h5>
2712
2713<p>
2714The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2715from two input vectors, returning a vector of the same type.
2716</p>
2717
2718<h5>Arguments:</h5>
2719
2720<p>
2721The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2722with types that match each other and types that match the result of the
2723instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2724of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2725</p>
2726
2727<p>
2728The shuffle mask operand is required to be a constant vector with either
2729constant integer or undef values.
2730</p>
2731
2732<h5>Semantics:</h5>
2733
2734<p>
2735The elements of the two input vectors are numbered from left to right across
2736both of the vectors. The shuffle mask operand specifies, for each element of
2737the result vector, which element of the two input registers the result element
2738gets. The element selector may be undef (meaning "don't care") and the second
2739operand may be undef if performing a shuffle from only one vector.
2740</p>
2741
2742<h5>Example:</h5>
2743
2744<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2745 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2746 &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]2747 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2748 &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]2749</pre>
2750</div>
2751
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2752
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2753<!-- ======================================================================= -->
2754<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2755 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2756</div>
2757
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2758<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2759
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2760<p>A key design point of an SSA-based representation is how it
2761represents memory. In LLVM, no memory locations are in SSA form, which
2762makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2763allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2764
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2765</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2766
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2767<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2768<div class="doc_subsubsection">
2769 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2770</div>
2771
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2772<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2774<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2775
2776<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2777 &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]2778</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2780<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2781
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2782<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2783heap and returns a pointer to it. The object is always allocated in the generic
2784address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2786<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2787
2788<p>The '<tt>malloc</tt>' instruction allocates
2789<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2790bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2791appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2792number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2793If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2794be aligned to at least that boundary. If not specified, or if zero, the target can
2795choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2797<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2798
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2799<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2800
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2801<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2802a pointer is returned. The result of a zero byte allocattion is undefined. The
2803result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2804
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2805<h5>Example:</h5>
2806
2807<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2808 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2809
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2810 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2811 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2812 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2813 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2814 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2815</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2816</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2817
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2818<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2819<div class="doc_subsubsection">
2820 <a name="i_free">'<tt>free</tt>' Instruction</a>
2821</div>
2822
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2823<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2826
2827<pre>
2828 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2829</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2830
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2831<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2832
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2833<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2834memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2835
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2837
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2838<p>'<tt>value</tt>' shall be a pointer value that points to a value
2839that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2840instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2843
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2844<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2845after this instruction executes. If the pointer is null, the behavior is
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2846undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2847
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2848<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2849
2850<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2851 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2852 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2853</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2854</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2856<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2857<div class="doc_subsubsection">
2858 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2859</div>
2860
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2861<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2863<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2864
2865<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2866 &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]2867</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2869<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2870
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2871<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2872currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2873returns to its caller. The object is always allocated in the generic address
2874space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2877
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2878<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2879bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2880appropriate type to the program. If "NumElements" is specified, it is the
2881number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2882If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2883to be aligned to at least that boundary. If not specified, or if zero, the target
2884can choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2886<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2887
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2888<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2889
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame^]2890<p>Memory is allocated; a pointer is returned. The operation is undefiend if
2891there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2892memory is automatically released when the function returns. The '<tt>alloca</tt>'
2893instruction is commonly used to represent automatic variables that must
2894have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2895 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2896instructions), the memory is reclaimed. Allocating zero bytes
2897is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2900
2901<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2902 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2903 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2904 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2905 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2906</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2907</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2908
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2909<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2910<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2911Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2912<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2913<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2914<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]2915<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2916<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2917<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2918<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2919address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2920 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2921marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2922the number or order of execution of this <tt>load</tt> with other
2923volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2924instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2925<p>
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2926The optional constant "align" argument specifies the alignment of the operation
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2927(that is, the alignment of the memory address). A value of 0 or an
2928omitted "align" argument means that the operation has the preferential
2929alignment for the target. It is the responsibility of the code emitter
2930to ensure that the alignment information is correct. Overestimating
2931the alignment results in an undefined behavior. Underestimating the
2932alignment may produce less efficient code. An alignment of 1 is always
2933safe.
2934</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2935<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2936<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2937<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2938<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2939 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2940 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2941 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2942</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2943</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2944<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2945<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2946Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2947<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2948<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2949<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2950 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]2951</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2952<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2953<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2954<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2955<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2956to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2957operand must be a pointer to the <a href="#t_firstclass">first class</a> type
2958of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2959operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2960optimizer is not allowed to modify the number or order of execution of
2961this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2962 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2963<p>
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2964The optional constant "align" argument specifies the alignment of the operation
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2965(that is, the alignment of the memory address). A value of 0 or an
2966omitted "align" argument means that the operation has the preferential
2967alignment for the target. It is the responsibility of the code emitter
2968to ensure that the alignment information is correct. Overestimating
2969the alignment results in an undefined behavior. Underestimating the
2970alignment may produce less efficient code. An alignment of 1 is always
2971safe.
2972</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2973<h5>Semantics:</h5>
2974<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2975at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2976<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2977<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2978 store i32 3, i32* %ptr <i>; yields {void}</i>
2979 %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]2980</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2981</div>
2982
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2983<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2984<div class="doc_subsubsection">
2985 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2986</div>
2987
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2988<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2989<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2990<pre>
2991 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2992</pre>
2993
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2994<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2995
2996<p>
2997The '<tt>getelementptr</tt>' instruction is used to get the address of a
2998subelement of an aggregate data structure.</p>
2999
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3000<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3001
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3002<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3003elements of the aggregate object to index to. The actual types of the arguments
3004provided depend on the type of the first pointer argument. The
3005'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3006levels 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]3007structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3008into an array or pointer, only integers of 32 or 64 bits are allowed, and will
3009be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3010
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3011<p>For example, let's consider a C code fragment and how it gets
3012compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3013
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3014<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3015<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3016struct RT {
3017 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3018 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3019 char C;
3020};
3021struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3022 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3023 double Y;
3024 struct RT Z;
3025};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3026
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3027int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3028 return &amp;s[1].Z.B[5][13];
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
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3033<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3034
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3035<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3036<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3037%RT = type { i8 , [10 x [20 x i32]], i8 }
3038%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3039
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3040define i32* %foo(%ST* %s) {
3041entry:
3042 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3043 ret i32* %reg
3044}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3045</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3046</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3047
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3048<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3049
3050<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]3051on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3052and <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]3053<a href="#t_integer">integer</a> type but the value will always be sign extended
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]3054to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3055structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3056
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3057<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]3058type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3059}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3060the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3061i8 }</tt>' type, another structure. The third index indexes into the second
3062element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3063array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3064'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3065to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3066
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3067<p>Note that it is perfectly legal to index partially through a
3068structure, returning a pointer to an inner element. Because of this,
3069the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3070
3071<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3072 define i32* %foo(%ST* %s) {
3073 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3074 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3075 %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]3076 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3077 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3078 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3079 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3080</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3081
3082<p>Note that it is undefined to access an array out of bounds: array and
3083pointer indexes must always be within the defined bounds of the array type.
3084The one exception for this rules is zero length arrays. These arrays are
3085defined to be accessible as variable length arrays, which requires access
3086beyond the zero'th element.</p>
3087
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3088<p>The getelementptr instruction is often confusing. For some more insight
3089into how it works, see <a href="GetElementPtr.html">the getelementptr
3090FAQ</a>.</p>
3091
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3092<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3093
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3094<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3095 <i>; yields [12 x i8]*:aptr</i>
3096 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3097</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3098</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3099
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3100<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3101<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3102</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3103<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3104<p>The instructions in this category are the conversion instructions (casting)
3105which all take a single operand and a type. They perform various bit conversions
3106on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3107</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3108
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3109<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3110<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3112</div>
3113<div class="doc_text">
3114
3115<h5>Syntax:</h5>
3116<pre>
3117 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3118</pre>
3119
3120<h5>Overview:</h5>
3121<p>
3122The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3123</p>
3124
3125<h5>Arguments:</h5>
3126<p>
3127The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3128be 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]3129and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3130type. The bit size of <tt>value</tt> must be larger than the bit size of
3131<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3132
3133<h5>Semantics:</h5>
3134<p>
3135The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3136and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3137larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3138It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3139
3140<h5>Example:</h5>
3141<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3142 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3143 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3144 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3145</pre>
3146</div>
3147
3148<!-- _______________________________________________________________________ -->
3149<div class="doc_subsubsection">
3150 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3151</div>
3152<div class="doc_text">
3153
3154<h5>Syntax:</h5>
3155<pre>
3156 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3157</pre>
3158
3159<h5>Overview:</h5>
3160<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3161<tt>ty2</tt>.</p>
3162
3163
3164<h5>Arguments:</h5>
3165<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]3166<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3167also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3168<tt>value</tt> must be smaller than the bit size of the destination type,
3169<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3170
3171<h5>Semantics:</h5>
3172<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]3173bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3174
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3175<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]3176
3177<h5>Example:</h5>
3178<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3179 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3180 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3181</pre>
3182</div>
3183
3184<!-- _______________________________________________________________________ -->
3185<div class="doc_subsubsection">
3186 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3187</div>
3188<div class="doc_text">
3189
3190<h5>Syntax:</h5>
3191<pre>
3192 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3193</pre>
3194
3195<h5>Overview:</h5>
3196<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3197
3198<h5>Arguments:</h5>
3199<p>
3200The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3201<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3202also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3203<tt>value</tt> must be smaller than the bit size of the destination type,
3204<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3205
3206<h5>Semantics:</h5>
3207<p>
3208The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3209bit (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]3210the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3211
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3212<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]3213
3214<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3215<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3216 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3217 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3218</pre>
3219</div>
3220
3221<!-- _______________________________________________________________________ -->
3222<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3223 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3224</div>
3225
3226<div class="doc_text">
3227
3228<h5>Syntax:</h5>
3229
3230<pre>
3231 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3232</pre>
3233
3234<h5>Overview:</h5>
3235<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3236<tt>ty2</tt>.</p>
3237
3238
3239<h5>Arguments:</h5>
3240<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3241 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3242cast it to. The size of <tt>value</tt> must be larger than the size of
3243<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3244<i>no-op cast</i>.</p>
3245
3246<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3247<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3248<a href="#t_floating">floating point</a> type to a smaller
3249<a href="#t_floating">floating point</a> type. If the value cannot fit within
3250the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3251
3252<h5>Example:</h5>
3253<pre>
3254 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3255 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3256</pre>
3257</div>
3258
3259<!-- _______________________________________________________________________ -->
3260<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3261 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3262</div>
3263<div class="doc_text">
3264
3265<h5>Syntax:</h5>
3266<pre>
3267 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3268</pre>
3269
3270<h5>Overview:</h5>
3271<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3272floating point value.</p>
3273
3274<h5>Arguments:</h5>
3275<p>The '<tt>fpext</tt>' instruction takes a
3276<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3277and a <a href="#t_floating">floating point</a> type to cast it to. The source
3278type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3279
3280<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3281<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3282<a href="#t_floating">floating point</a> type to a larger
3283<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3284used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3285<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]3286
3287<h5>Example:</h5>
3288<pre>
3289 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3290 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3291</pre>
3292</div>
3293
3294<!-- _______________________________________________________________________ -->
3295<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3296 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3297</div>
3298<div class="doc_text">
3299
3300<h5>Syntax:</h5>
3301<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3302 &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]3303</pre>
3304
3305<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3306<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3307unsigned integer equivalent of type <tt>ty2</tt>.
3308</p>
3309
3310<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3311<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]3312scalar or vector <a href="#t_floating">floating point</a> value, and a type
3313to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3314type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3315vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3316
3317<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3318<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3319<a href="#t_floating">floating point</a> operand into the nearest (rounding
3320towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3321the results are undefined.</p>
3322
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3323<h5>Example:</h5>
3324<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3325 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3326 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3327 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3328</pre>
3329</div>
3330
3331<!-- _______________________________________________________________________ -->
3332<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3333 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3334</div>
3335<div class="doc_text">
3336
3337<h5>Syntax:</h5>
3338<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3339 &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]3340</pre>
3341
3342<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3343<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3344<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]3345</p>
3346
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3347<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3348<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]3349scalar or vector <a href="#t_floating">floating point</a> value, and a type
3350to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3351type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3352vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3353
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3354<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3355<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3356<a href="#t_floating">floating point</a> operand into the nearest (rounding
3357towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3358the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3359
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3360<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3361<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3362 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3363 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3364 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3365</pre>
3366</div>
3367
3368<!-- _______________________________________________________________________ -->
3369<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3370 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3371</div>
3372<div class="doc_text">
3373
3374<h5>Syntax:</h5>
3375<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3376 &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]3377</pre>
3378
3379<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3380<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3381integer and converts that value to the <tt>ty2</tt> type.</p>
3382
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3383<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3384<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3385scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3386to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3387type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3388floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3389
3390<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3391<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3392integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3393the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3394
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3395<h5>Example:</h5>
3396<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3397 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3398 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3399</pre>
3400</div>
3401
3402<!-- _______________________________________________________________________ -->
3403<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3404 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3405</div>
3406<div class="doc_text">
3407
3408<h5>Syntax:</h5>
3409<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3410 &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]3411</pre>
3412
3413<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3414<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3415integer and converts that value to the <tt>ty2</tt> type.</p>
3416
3417<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3418<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3419scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3420to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3421type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3422floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3423
3424<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3425<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3426integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3427the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3428
3429<h5>Example:</h5>
3430<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3431 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3432 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3433</pre>
3434</div>
3435
3436<!-- _______________________________________________________________________ -->
3437<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3438 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3439</div>
3440<div class="doc_text">
3441
3442<h5>Syntax:</h5>
3443<pre>
3444 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3445</pre>
3446
3447<h5>Overview:</h5>
3448<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3449the integer type <tt>ty2</tt>.</p>
3450
3451<h5>Arguments:</h5>
3452<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3453must 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]3454<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3455
3456<h5>Semantics:</h5>
3457<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3458<tt>ty2</tt> by interpreting the pointer value as an integer and either
3459truncating or zero extending that value to the size of the integer type. If
3460<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3461<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]3462are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3463change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3464
3465<h5>Example:</h5>
3466<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3467 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3468 %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]3469</pre>
3470</div>
3471
3472<!-- _______________________________________________________________________ -->
3473<div class="doc_subsubsection">
3474 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3475</div>
3476<div class="doc_text">
3477
3478<h5>Syntax:</h5>
3479<pre>
3480 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3481</pre>
3482
3483<h5>Overview:</h5>
3484<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3485a pointer type, <tt>ty2</tt>.</p>
3486
3487<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3488<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3489value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3490<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3491
3492<h5>Semantics:</h5>
3493<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3494<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3495the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3496size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3497the size of a pointer then a zero extension is done. If they are the same size,
3498nothing is done (<i>no-op cast</i>).</p>
3499
3500<h5>Example:</h5>
3501<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3502 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3503 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3504 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3505</pre>
3506</div>
3507
3508<!-- _______________________________________________________________________ -->
3509<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3510 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3511</div>
3512<div class="doc_text">
3513
3514<h5>Syntax:</h5>
3515<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3516 &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]3517</pre>
3518
3519<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3520<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3521<tt>ty2</tt> without changing any bits.</p>
3522
3523<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3524<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3525a first class value, and a type to cast it to, which must also be a <a
3526 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3527and the destination type, <tt>ty2</tt>, must be identical. If the source
3528type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3529
3530<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3531<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3532<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3533this conversion. The conversion is done as if the <tt>value</tt> had been
3534stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3535converted to other pointer types with this instruction. To convert pointers to
3536other types, use the <a href="#i_inttoptr">inttoptr</a> or
3537<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3538
3539<h5>Example:</h5>
3540<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3541 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3542 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3543 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3544</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3545</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3546
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3547<!-- ======================================================================= -->
3548<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3549<div class="doc_text">
3550<p>The instructions in this category are the "miscellaneous"
3551instructions, which defy better classification.</p>
3552</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3553
3554<!-- _______________________________________________________________________ -->
3555<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3556</div>
3557<div class="doc_text">
3558<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3559<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]3560</pre>
3561<h5>Overview:</h5>
3562<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]3563of its two integer or pointer operands.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3564<h5>Arguments:</h5>
3565<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3566the condition code indicating the kind of comparison to perform. It is not
3567a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3568<ol>
3569 <li><tt>eq</tt>: equal</li>
3570 <li><tt>ne</tt>: not equal </li>
3571 <li><tt>ugt</tt>: unsigned greater than</li>
3572 <li><tt>uge</tt>: unsigned greater or equal</li>
3573 <li><tt>ult</tt>: unsigned less than</li>
3574 <li><tt>ule</tt>: unsigned less or equal</li>
3575 <li><tt>sgt</tt>: signed greater than</li>
3576 <li><tt>sge</tt>: signed greater or equal</li>
3577 <li><tt>slt</tt>: signed less than</li>
3578 <li><tt>sle</tt>: signed less or equal</li>
3579</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3580<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3581<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3582<h5>Semantics:</h5>
3583<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3584the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3585yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3586<ol>
3587 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3588 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3589 </li>
3590 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3591 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3592 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3593 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3594 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3595 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3596 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3597 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3598 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3599 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3600 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3601 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3602 <li><tt>sge</tt>: interprets the operands as signed values and yields
3603 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3604 <li><tt>slt</tt>: interprets the operands as signed values and yields
3605 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3606 <li><tt>sle</tt>: interprets the operands as signed values and yields
3607 <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]3608</ol>
3609<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3610values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3611
3612<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3613<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3614 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3615 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3616 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3617 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3618 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3619</pre>
3620</div>
3621
3622<!-- _______________________________________________________________________ -->
3623<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3624</div>
3625<div class="doc_text">
3626<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3627<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]3628</pre>
3629<h5>Overview:</h5>
3630<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3631of its floating point operands.</p>
3632<h5>Arguments:</h5>
3633<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3634the condition code indicating the kind of comparison to perform. It is not
3635a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3636<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3637 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3638 <li><tt>oeq</tt>: ordered and equal</li>
3639 <li><tt>ogt</tt>: ordered and greater than </li>
3640 <li><tt>oge</tt>: ordered and greater than or equal</li>
3641 <li><tt>olt</tt>: ordered and less than </li>
3642 <li><tt>ole</tt>: ordered and less than or equal</li>
3643 <li><tt>one</tt>: ordered and not equal</li>
3644 <li><tt>ord</tt>: ordered (no nans)</li>
3645 <li><tt>ueq</tt>: unordered or equal</li>
3646 <li><tt>ugt</tt>: unordered or greater than </li>
3647 <li><tt>uge</tt>: unordered or greater than or equal</li>
3648 <li><tt>ult</tt>: unordered or less than </li>
3649 <li><tt>ule</tt>: unordered or less than or equal</li>
3650 <li><tt>une</tt>: unordered or not equal</li>
3651 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3652 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3653</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3654<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3655<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3656<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3657<a href="#t_floating">floating point</a> typed. They must have identical
3658types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3659<h5>Semantics:</h5>
3660<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3661the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3662yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3663<ol>
3664 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3665 <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]3666 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3667 <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]3668 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3669 <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]3670 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3671 <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]3672 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3673 <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]3674 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3675 <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]3676 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3677 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3678 <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]3679 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3680 <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]3681 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3682 <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]3683 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3684 <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]3685 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3686 <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]3687 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3688 <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]3689 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3690 <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]3691 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3692</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3693
3694<h5>Example:</h5>
3695<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3696 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3697 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3698 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3699</pre>
3700</div>
3701
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3702<!-- _______________________________________________________________________ -->
3703<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3704Instruction</a> </div>
3705<div class="doc_text">
3706<h5>Syntax:</h5>
3707<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3708<h5>Overview:</h5>
3709<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3710the SSA graph representing the function.</p>
3711<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3712<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3713field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3714as arguments, with one pair for each predecessor basic block of the
3715current block. Only values of <a href="#t_firstclass">first class</a>
3716type may be used as the value arguments to the PHI node. Only labels
3717may be used as the label arguments.</p>
3718<p>There must be no non-phi instructions between the start of a basic
3719block and the PHI instructions: i.e. PHI instructions must be first in
3720a basic block.</p>
3721<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3722<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3723specified by the pair corresponding to the predecessor basic block that executed
3724just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3725<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3726<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]3727</div>
3728
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3729<!-- _______________________________________________________________________ -->
3730<div class="doc_subsubsection">
3731 <a name="i_select">'<tt>select</tt>' Instruction</a>
3732</div>
3733
3734<div class="doc_text">
3735
3736<h5>Syntax:</h5>
3737
3738<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3739 &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]3740</pre>
3741
3742<h5>Overview:</h5>
3743
3744<p>
3745The '<tt>select</tt>' instruction is used to choose one value based on a
3746condition, without branching.
3747</p>
3748
3749
3750<h5>Arguments:</h5>
3751
3752<p>
3753The '<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.
3754</p>
3755
3756<h5>Semantics:</h5>
3757
3758<p>
3759If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3760value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3761</p>
3762
3763<h5>Example:</h5>
3764
3765<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3766 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3767</pre>
3768</div>
3769
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3770
3771<!-- _______________________________________________________________________ -->
3772<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3773 <a name="i_call">'<tt>call</tt>' Instruction</a>
3774</div>
3775
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3776<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3777
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3778<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3779<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3780 &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]3781</pre>
3782
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3785<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3787<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3788
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3789<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3790
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3791<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3792 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3793 <p>The optional "tail" marker indicates whether the callee function accesses
3794 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3795 function call is eligible for tail call optimization. Note that calls may
3796 be marked "tail" even if they do not occur before a <a
3797 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3798 </li>
3799 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3800 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3801 convention</a> the call should use. If none is specified, the call defaults
3802 to using C calling conventions.
3803 </li>
3804 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3805 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3806 the type of the return value. Functions that return no value are marked
3807 <tt><a href="#t_void">void</a></tt>.</p>
3808 </li>
3809 <li>
3810 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3811 value being invoked. The argument types must match the types implied by
3812 this signature. This type can be omitted if the function is not varargs
3813 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3814 </li>
3815 <li>
3816 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3817 be invoked. In most cases, this is a direct function invocation, but
3818 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3819 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3820 </li>
3821 <li>
3822 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3823 function signature argument types. All arguments must be of
3824 <a href="#t_firstclass">first class</a> type. If the function signature
3825 indicates the function accepts a variable number of arguments, the extra
3826 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3827 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3828</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3829
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3830<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3831
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3832<p>The '<tt>call</tt>' instruction is used to cause control flow to
3833transfer to a specified function, with its incoming arguments bound to
3834the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3835instruction in the called function, control flow continues with the
3836instruction after the function call, and the return value of the
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3837function is bound to the result argument. If the callee returns multiple
3838values then the return values of the function are only accessible through
3839the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3841<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3842
3843<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3844 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3845 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
3846 %X = tail call i32 @foo() <i>; yields i32</i>
3847 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
3848 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3849
3850 %struct.A = type { i32, i8 }
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3851 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
3852 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
3853 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3854</pre>
3855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3856</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3857
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3858<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3859<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3860 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3861</div>
3862
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3863<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3864
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3865<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3866
3867<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3868 &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]3869</pre>
3870
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3871<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3872
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3873<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3874the "variable argument" area of a function call. It is used to implement the
3875<tt>va_arg</tt> macro in C.</p>
3876
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3877<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3878
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3879<p>This instruction takes a <tt>va_list*</tt> value and the type of
3880the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3881increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3882actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3883
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3884<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3885
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3886<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3887type from the specified <tt>va_list</tt> and causes the
3888<tt>va_list</tt> to point to the next argument. For more information,
3889see the variable argument handling <a href="#int_varargs">Intrinsic
3890Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3891
3892<p>It is legal for this instruction to be called in a function which does not
3893take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3894function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3895
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3896<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3897href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3898argument.</p>
3899
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3900<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3901
3902<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3903
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3904</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3905
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3906<!-- _______________________________________________________________________ -->
3907<div class="doc_subsubsection">
3908 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3909</div>
3910
3911<div class="doc_text">
3912
3913<h5>Syntax:</h5>
3914<pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3915 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3916</pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3917
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3918<h5>Overview:</h5>
3919
3920<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3921from a '<tt><a href="#i_call">call</a></tt>'
3922or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
3923results.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3924
3925<h5>Arguments:</h5>
3926
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3927<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
3928first argument. The value must have <a href="#t_struct">structure type</a>.
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]3929The second argument is a constant unsigned index value which must be in range for
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3930the number of values returned by the call.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3931
3932<h5>Semantics:</h5>
3933
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3934<p>The '<tt>getresult</tt>' instruction extracts the element identified by
3935'<tt>index</tt>' from the aggregate value.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3936
3937<h5>Example:</h5>
3938
3939<pre>
3940 %struct.A = type { i32, i8 }
3941
3942 %r = call %struct.A @foo()
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3943 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
3944 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3945 add i32 %gr, 42
3946 add i8 %gr1, 41
3947</pre>
3948
3949</div>
3950
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3951<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3952<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3953<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3955<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3956
3957<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3958well known names and semantics and are required to follow certain restrictions.
3959Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3960language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3961adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3962
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3963<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3964prefix is reserved in LLVM for intrinsic names; thus, function names may not
3965begin with this prefix. Intrinsic functions must always be external functions:
3966you cannot define the body of intrinsic functions. Intrinsic functions may
3967only be used in call or invoke instructions: it is illegal to take the address
3968of an intrinsic function. Additionally, because intrinsic functions are part
3969of the LLVM language, it is required if any are added that they be documented
3970here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3971
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3972<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3973a family of functions that perform the same operation but on different data
3974types. Because LLVM can represent over 8 million different integer types,
3975overloading is used commonly to allow an intrinsic function to operate on any
3976integer type. One or more of the argument types or the result type can be
3977overloaded to accept any integer type. Argument types may also be defined as
3978exactly matching a previous argument's type or the result type. This allows an
3979intrinsic function which accepts multiple arguments, but needs all of them to
3980be of the same type, to only be overloaded with respect to a single argument or
3981the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3982
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3983<p>Overloaded intrinsics will have the names of its overloaded argument types
3984encoded into its function name, each preceded by a period. Only those types
3985which are overloaded result in a name suffix. Arguments whose type is matched
3986against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3987take an integer of any width and returns an integer of exactly the same integer
3988width. This leads to a family of functions such as
3989<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3990Only one type, the return type, is overloaded, and only one type suffix is
3991required. Because the argument's type is matched against the return type, it
3992does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3993
3994<p>To learn how to add an intrinsic function, please see the
3995<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3996</p>
3997
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3998</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3999
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4000<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4001<div class="doc_subsection">
4002 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4003</div>
4004
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4005<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4006
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4007<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]4008 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4009intrinsic functions. These functions are related to the similarly
4010named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4011
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4012<p>All of these functions operate on arguments that use a
4013target-specific value type "<tt>va_list</tt>". The LLVM assembly
4014language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4015transformations should be prepared to handle these functions regardless of
4016the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4017
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]4018<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]4019instruction and the variable argument handling intrinsic functions are
4020used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4021
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4022<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4023<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4024define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4025 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4026 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4027 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4028 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4029
4030 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4031 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4032
4033 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4034 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4035 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4036 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4037 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4038
4039 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4040 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4041 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4042}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4043
4044declare void @llvm.va_start(i8*)
4045declare void @llvm.va_copy(i8*, i8*)
4046declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4047</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4048</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4049
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4050</div>
4051
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4052<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4053<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4054 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4055</div>
4056
4057
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4058<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4059<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4060<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4061<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4062<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4063<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4064href="#i_va_arg">va_arg</a></tt>.</p>
4065
4066<h5>Arguments:</h5>
4067
4068<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4069
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4070<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4071
4072<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4073macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4074<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]4075<tt>va_arg</tt> will produce the first variable argument passed to the function.
4076Unlike 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]4077last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4078
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4079</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4080
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4081<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4082<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4083 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4084</div>
4085
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4086<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4087<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4088<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4089<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4090
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4091<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4092which 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]4093or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4094
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4095<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4096
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4097<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]4098
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4099<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4100
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4101<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]4102macro available in C. In a target-dependent way, it destroys the
4103<tt>va_list</tt> element to which the argument points. Calls to <a
4104href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4105<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4106<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4107
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4108</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4109
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4110<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4111<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4112 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4113</div>
4114
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4115<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4116
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4117<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4118
4119<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4120 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4121</pre>
4122
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4123<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4124
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4125<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4126from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4127
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4128<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4129
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4130<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]4131The 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]4132
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4133
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4134<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4135
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4136<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4137macro available in C. In a target-dependent way, it copies the source
4138<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4139intrinsic is necessary because the <tt><a href="#int_va_start">
4140llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4141example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4142
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4143</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4144
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4145<!-- ======================================================================= -->
4146<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4147 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4148</div>
4149
4150<div class="doc_text">
4151
4152<p>
4153LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4154Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4155These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4156stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4157href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4158Front-ends for type-safe garbage collected languages should generate these
4159intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4160href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4161</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4162
4163<p>The garbage collection intrinsics only operate on objects in the generic
4164 address space (address space zero).</p>
4165
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4166</div>
4167
4168<!-- _______________________________________________________________________ -->
4169<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4170 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4171</div>
4172
4173<div class="doc_text">
4174
4175<h5>Syntax:</h5>
4176
4177<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4178 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4179</pre>
4180
4181<h5>Overview:</h5>
4182
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4183<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]4184the code generator, and allows some metadata to be associated with it.</p>
4185
4186<h5>Arguments:</h5>
4187
4188<p>The first argument specifies the address of a stack object that contains the
4189root pointer. The second pointer (which must be either a constant or a global
4190value address) contains the meta-data to be associated with the root.</p>
4191
4192<h5>Semantics:</h5>
4193
4194<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4195location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4196the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4197intrinsic may only be used in a function which <a href="#gc">specifies a GC
4198algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4199
4200</div>
4201
4202
4203<!-- _______________________________________________________________________ -->
4204<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4205 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4206</div>
4207
4208<div class="doc_text">
4209
4210<h5>Syntax:</h5>
4211
4212<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4213 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4214</pre>
4215
4216<h5>Overview:</h5>
4217
4218<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4219locations, allowing garbage collector implementations that require read
4220barriers.</p>
4221
4222<h5>Arguments:</h5>
4223
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4224<p>The second argument is the address to read from, which should be an address
4225allocated from the garbage collector. The first object is a pointer to the
4226start of the referenced object, if needed by the language runtime (otherwise
4227null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4228
4229<h5>Semantics:</h5>
4230
4231<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4232instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4233garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4234may only be used in a function which <a href="#gc">specifies a GC
4235algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4236
4237</div>
4238
4239
4240<!-- _______________________________________________________________________ -->
4241<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4242 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4243</div>
4244
4245<div class="doc_text">
4246
4247<h5>Syntax:</h5>
4248
4249<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4250 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4251</pre>
4252
4253<h5>Overview:</h5>
4254
4255<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4256locations, allowing garbage collector implementations that require write
4257barriers (such as generational or reference counting collectors).</p>
4258
4259<h5>Arguments:</h5>
4260
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4261<p>The first argument is the reference to store, the second is the start of the
4262object to store it to, and the third is the address of the field of Obj to
4263store to. If the runtime does not require a pointer to the object, Obj may be
4264null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4265
4266<h5>Semantics:</h5>
4267
4268<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4269instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4270garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4271may only be used in a function which <a href="#gc">specifies a GC
4272algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4273
4274</div>
4275
4276
4277
4278<!-- ======================================================================= -->
4279<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4280 <a name="int_codegen">Code Generator Intrinsics</a>
4281</div>
4282
4283<div class="doc_text">
4284<p>
4285These intrinsics are provided by LLVM to expose special features that may only
4286be implemented with code generator support.
4287</p>
4288
4289</div>
4290
4291<!-- _______________________________________________________________________ -->
4292<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4293 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4294</div>
4295
4296<div class="doc_text">
4297
4298<h5>Syntax:</h5>
4299<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4300 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4301</pre>
4302
4303<h5>Overview:</h5>
4304
4305<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4306The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4307target-specific value indicating the return address of the current function
4308or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4309</p>
4310
4311<h5>Arguments:</h5>
4312
4313<p>
4314The argument to this intrinsic indicates which function to return the address
4315for. Zero indicates the calling function, one indicates its caller, etc. The
4316argument is <b>required</b> to be a constant integer value.
4317</p>
4318
4319<h5>Semantics:</h5>
4320
4321<p>
4322The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4323the return address of the specified call frame, or zero if it cannot be
4324identified. The value returned by this intrinsic is likely to be incorrect or 0
4325for arguments other than zero, so it should only be used for debugging purposes.
4326</p>
4327
4328<p>
4329Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4330aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4331source-language caller.
4332</p>
4333</div>
4334
4335
4336<!-- _______________________________________________________________________ -->
4337<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4338 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4339</div>
4340
4341<div class="doc_text">
4342
4343<h5>Syntax:</h5>
4344<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4345 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4346</pre>
4347
4348<h5>Overview:</h5>
4349
4350<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4351The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4352target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4353</p>
4354
4355<h5>Arguments:</h5>
4356
4357<p>
4358The argument to this intrinsic indicates which function to return the frame
4359pointer for. Zero indicates the calling function, one indicates its caller,
4360etc. The argument is <b>required</b> to be a constant integer value.
4361</p>
4362
4363<h5>Semantics:</h5>
4364
4365<p>
4366The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4367the frame address of the specified call frame, or zero if it cannot be
4368identified. The value returned by this intrinsic is likely to be incorrect or 0
4369for arguments other than zero, so it should only be used for debugging purposes.
4370</p>
4371
4372<p>
4373Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4374aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4375source-language caller.
4376</p>
4377</div>
4378
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4379<!-- _______________________________________________________________________ -->
4380<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4381 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4382</div>
4383
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4388 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4389</pre>
4390
4391<h5>Overview:</h5>
4392
4393<p>
4394The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4395the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4396<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4397features like scoped automatic variable sized arrays in C99.
4398</p>
4399
4400<h5>Semantics:</h5>
4401
4402<p>
4403This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4404href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4405<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4406<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4407state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4408practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4409that were allocated after the <tt>llvm.stacksave</tt> was executed.
4410</p>
4411
4412</div>
4413
4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4416 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4417</div>
4418
4419<div class="doc_text">
4420
4421<h5>Syntax:</h5>
4422<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4423 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4424</pre>
4425
4426<h5>Overview:</h5>
4427
4428<p>
4429The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4430the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4431href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4432useful for implementing language features like scoped automatic variable sized
4433arrays in C99.
4434</p>
4435
4436<h5>Semantics:</h5>
4437
4438<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4439See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4440</p>
4441
4442</div>
4443
4444
4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4447 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4448</div>
4449
4450<div class="doc_text">
4451
4452<h5>Syntax:</h5>
4453<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4454 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]4455</pre>
4456
4457<h5>Overview:</h5>
4458
4459
4460<p>
4461The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4462a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4463no
4464effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4465characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4466</p>
4467
4468<h5>Arguments:</h5>
4469
4470<p>
4471<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4472determining if the fetch should be for a read (0) or write (1), and
4473<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4474locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4475<tt>locality</tt> arguments must be constant integers.
4476</p>
4477
4478<h5>Semantics:</h5>
4479
4480<p>
4481This intrinsic does not modify the behavior of the program. In particular,
4482prefetches cannot trap and do not produce a value. On targets that support this
4483intrinsic, the prefetch can provide hints to the processor cache for better
4484performance.
4485</p>
4486
4487</div>
4488
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4489<!-- _______________________________________________________________________ -->
4490<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4491 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4492</div>
4493
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
4497<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4498 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4499</pre>
4500
4501<h5>Overview:</h5>
4502
4503
4504<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4505The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4506(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4507code to simulators and other tools. The method is target specific, but it is
4508expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4509The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4510after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4511optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4512correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4513</p>
4514
4515<h5>Arguments:</h5>
4516
4517<p>
4518<tt>id</tt> is a numerical id identifying the marker.
4519</p>
4520
4521<h5>Semantics:</h5>
4522
4523<p>
4524This intrinsic does not modify the behavior of the program. Backends that do not
4525support this intrinisic may ignore it.
4526</p>
4527
4528</div>
4529
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4530<!-- _______________________________________________________________________ -->
4531<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4532 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4533</div>
4534
4535<div class="doc_text">
4536
4537<h5>Syntax:</h5>
4538<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4539 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4540</pre>
4541
4542<h5>Overview:</h5>
4543
4544
4545<p>
4546The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4547counter register (or similar low latency, high accuracy clocks) on those targets
4548that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4549As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4550should only be used for small timings.
4551</p>
4552
4553<h5>Semantics:</h5>
4554
4555<p>
4556When directly supported, reading the cycle counter should not modify any memory.
4557Implementations are allowed to either return a application specific value or a
4558system wide value. On backends without support, this is lowered to a constant 0.
4559</p>
4560
4561</div>
4562
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4563<!-- ======================================================================= -->
4564<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4565 <a name="int_libc">Standard C Library Intrinsics</a>
4566</div>
4567
4568<div class="doc_text">
4569<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4570LLVM provides intrinsics for a few important standard C library functions.
4571These intrinsics allow source-language front-ends to pass information about the
4572alignment of the pointer arguments to the code generator, providing opportunity
4573for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4574</p>
4575
4576</div>
4577
4578<!-- _______________________________________________________________________ -->
4579<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4580 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4581</div>
4582
4583<div class="doc_text">
4584
4585<h5>Syntax:</h5>
4586<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4587 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4588 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4589 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4590 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4591</pre>
4592
4593<h5>Overview:</h5>
4594
4595<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4596The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4597location to the destination location.
4598</p>
4599
4600<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4601Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4602intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4603</p>
4604
4605<h5>Arguments:</h5>
4606
4607<p>
4608The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4609the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4610specifying the number of bytes to copy, and the fourth argument is the alignment
4611of the source and destination locations.
4612</p>
4613
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4614<p>
4615If 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]4616the caller guarantees that both the source and destination pointers are aligned
4617to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4618</p>
4619
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4620<h5>Semantics:</h5>
4621
4622<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4623The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4624location to the destination location, which are not allowed to overlap. It
4625copies "len" bytes of memory over. If the argument is known to be aligned to
4626some boundary, this can be specified as the fourth argument, otherwise it should
4627be set to 0 or 1.
4628</p>
4629</div>
4630
4631
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4632<!-- _______________________________________________________________________ -->
4633<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4634 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4635</div>
4636
4637<div class="doc_text">
4638
4639<h5>Syntax:</h5>
4640<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4641 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4642 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4643 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4644 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4645</pre>
4646
4647<h5>Overview:</h5>
4648
4649<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4650The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4651location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4652'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4653</p>
4654
4655<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4656Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4657intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4658</p>
4659
4660<h5>Arguments:</h5>
4661
4662<p>
4663The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4664the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4665specifying the number of bytes to copy, and the fourth argument is the alignment
4666of the source and destination locations.
4667</p>
4668
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4669<p>
4670If 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]4671the caller guarantees that the source and destination pointers are aligned to
4672that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4673</p>
4674
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4675<h5>Semantics:</h5>
4676
4677<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4678The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4679location to the destination location, which may overlap. It
4680copies "len" bytes of memory over. If the argument is known to be aligned to
4681some boundary, this can be specified as the fourth argument, otherwise it should
4682be set to 0 or 1.
4683</p>
4684</div>
4685
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4686
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4687<!-- _______________________________________________________________________ -->
4688<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4689 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4690</div>
4691
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4696 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4697 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4698 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4699 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4700</pre>
4701
4702<h5>Overview:</h5>
4703
4704<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4705The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4706byte value.
4707</p>
4708
4709<p>
4710Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4711does not return a value, and takes an extra alignment argument.
4712</p>
4713
4714<h5>Arguments:</h5>
4715
4716<p>
4717The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4718byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4719argument specifying the number of bytes to fill, and the fourth argument is the
4720known alignment of destination location.
4721</p>
4722
4723<p>
4724If 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]4725the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4726</p>
4727
4728<h5>Semantics:</h5>
4729
4730<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4731The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4732the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4733destination location. If the argument is known to be aligned to some boundary,
4734this can be specified as the fourth argument, otherwise it should be set to 0 or
47351.
4736</p>
4737</div>
4738
4739
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4740<!-- _______________________________________________________________________ -->
4741<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4742 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4743</div>
4744
4745<div class="doc_text">
4746
4747<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4748<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]4749floating point or vector of floating point type. Not all targets support all
4750types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4751<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4752 declare float @llvm.sqrt.f32(float %Val)
4753 declare double @llvm.sqrt.f64(double %Val)
4754 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4755 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4756 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4757</pre>
4758
4759<h5>Overview:</h5>
4760
4761<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4762The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4763returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4764<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner103e2d72008-01-29 07:00:44 +0000[diff] [blame]4765negative numbers other than -0.0 (which allows for better optimization, because
4766there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4767defined to return -0.0 like IEEE sqrt.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4768</p>
4769
4770<h5>Arguments:</h5>
4771
4772<p>
4773The argument and return value are floating point numbers of the same type.
4774</p>
4775
4776<h5>Semantics:</h5>
4777
4778<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4779This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4780floating point number.
4781</p>
4782</div>
4783
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4784<!-- _______________________________________________________________________ -->
4785<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4786 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4787</div>
4788
4789<div class="doc_text">
4790
4791<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4792<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]4793floating point or vector of floating point type. Not all targets support all
4794types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4795<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4796 declare float @llvm.powi.f32(float %Val, i32 %power)
4797 declare double @llvm.powi.f64(double %Val, i32 %power)
4798 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4799 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4800 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4801</pre>
4802
4803<h5>Overview:</h5>
4804
4805<p>
4806The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4807specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4808multiplications is not defined. When a vector of floating point type is
4809used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4810</p>
4811
4812<h5>Arguments:</h5>
4813
4814<p>
4815The second argument is an integer power, and the first is a value to raise to
4816that power.
4817</p>
4818
4819<h5>Semantics:</h5>
4820
4821<p>
4822This function returns the first value raised to the second power with an
4823unspecified sequence of rounding operations.</p>
4824</div>
4825
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4826<!-- _______________________________________________________________________ -->
4827<div class="doc_subsubsection">
4828 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4829</div>
4830
4831<div class="doc_text">
4832
4833<h5>Syntax:</h5>
4834<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4835floating point or vector of floating point type. Not all targets support all
4836types however.
4837<pre>
4838 declare float @llvm.sin.f32(float %Val)
4839 declare double @llvm.sin.f64(double %Val)
4840 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4841 declare fp128 @llvm.sin.f128(fp128 %Val)
4842 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4843</pre>
4844
4845<h5>Overview:</h5>
4846
4847<p>
4848The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4849</p>
4850
4851<h5>Arguments:</h5>
4852
4853<p>
4854The argument and return value are floating point numbers of the same type.
4855</p>
4856
4857<h5>Semantics:</h5>
4858
4859<p>
4860This function returns the sine of the specified operand, returning the
4861same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4862conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
4867 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4868</div>
4869
4870<div class="doc_text">
4871
4872<h5>Syntax:</h5>
4873<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4874floating point or vector of floating point type. Not all targets support all
4875types however.
4876<pre>
4877 declare float @llvm.cos.f32(float %Val)
4878 declare double @llvm.cos.f64(double %Val)
4879 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4880 declare fp128 @llvm.cos.f128(fp128 %Val)
4881 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4882</pre>
4883
4884<h5>Overview:</h5>
4885
4886<p>
4887The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4888</p>
4889
4890<h5>Arguments:</h5>
4891
4892<p>
4893The argument and return value are floating point numbers of the same type.
4894</p>
4895
4896<h5>Semantics:</h5>
4897
4898<p>
4899This function returns the cosine of the specified operand, returning the
4900same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4901conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4902</div>
4903
4904<!-- _______________________________________________________________________ -->
4905<div class="doc_subsubsection">
4906 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4907</div>
4908
4909<div class="doc_text">
4910
4911<h5>Syntax:</h5>
4912<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4913floating point or vector of floating point type. Not all targets support all
4914types however.
4915<pre>
4916 declare float @llvm.pow.f32(float %Val, float %Power)
4917 declare double @llvm.pow.f64(double %Val, double %Power)
4918 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4919 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4920 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4921</pre>
4922
4923<h5>Overview:</h5>
4924
4925<p>
4926The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4927specified (positive or negative) power.
4928</p>
4929
4930<h5>Arguments:</h5>
4931
4932<p>
4933The second argument is a floating point power, and the first is a value to
4934raise to that power.
4935</p>
4936
4937<h5>Semantics:</h5>
4938
4939<p>
4940This function returns the first value raised to the second power,
4941returning the
4942same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4943conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4944</div>
4945
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4946
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4947<!-- ======================================================================= -->
4948<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4949 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4950</div>
4951
4952<div class="doc_text">
4953<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4954LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4955These allow efficient code generation for some algorithms.
4956</p>
4957
4958</div>
4959
4960<!-- _______________________________________________________________________ -->
4961<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4962 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4963</div>
4964
4965<div class="doc_text">
4966
4967<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4968<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4969type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4970<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4971 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4972 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4973 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4974</pre>
4975
4976<h5>Overview:</h5>
4977
4978<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4979The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4980values with an even number of bytes (positive multiple of 16 bits). These are
4981useful for performing operations on data that is not in the target's native
4982byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4983</p>
4984
4985<h5>Semantics:</h5>
4986
4987<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4988The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4989and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4990intrinsic returns an i32 value that has the four bytes of the input i32
4991swapped, 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]4992i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4993<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4994additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4995</p>
4996
4997</div>
4998
4999<!-- _______________________________________________________________________ -->
5000<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5001 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5002</div>
5003
5004<div class="doc_text">
5005
5006<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5007<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5008width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5009<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5010 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5011 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5012 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5013 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5014 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5015</pre>
5016
5017<h5>Overview:</h5>
5018
5019<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]5020The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5021value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5022</p>
5023
5024<h5>Arguments:</h5>
5025
5026<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5027The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5028integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5029</p>
5030
5031<h5>Semantics:</h5>
5032
5033<p>
5034The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5035</p>
5036</div>
5037
5038<!-- _______________________________________________________________________ -->
5039<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5040 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5041</div>
5042
5043<div class="doc_text">
5044
5045<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5046<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5047integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5048<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5049 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5050 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5051 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5052 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5053 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5054</pre>
5055
5056<h5>Overview:</h5>
5057
5058<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5059The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5060leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5061</p>
5062
5063<h5>Arguments:</h5>
5064
5065<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5066The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5067integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5068</p>
5069
5070<h5>Semantics:</h5>
5071
5072<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5073The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5074in 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]5075of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5076</p>
5077</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5078
5079
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5080
5081<!-- _______________________________________________________________________ -->
5082<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5083 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5084</div>
5085
5086<div class="doc_text">
5087
5088<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5089<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5090integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5091<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5092 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5093 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5094 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5095 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5096 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5097</pre>
5098
5099<h5>Overview:</h5>
5100
5101<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5102The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5103trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5104</p>
5105
5106<h5>Arguments:</h5>
5107
5108<p>
5109The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5110integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5111</p>
5112
5113<h5>Semantics:</h5>
5114
5115<p>
5116The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5117in a variable. If the src == 0 then the result is the size in bits of the type
5118of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5119</p>
5120</div>
5121
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5122<!-- _______________________________________________________________________ -->
5123<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5124 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5125</div>
5126
5127<div class="doc_text">
5128
5129<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5130<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5131on any integer bit width.
5132<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5133 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5134 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5135</pre>
5136
5137<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5138<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5139range of bits from an integer value and returns them in the same bit width as
5140the original value.</p>
5141
5142<h5>Arguments:</h5>
5143<p>The first argument, <tt>%val</tt> and the result may be integer types of
5144any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5145arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5146
5147<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5148<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5149of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5150<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5151operates in forward mode.</p>
5152<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5153right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5154only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5155<ol>
5156 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5157 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5158 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5159 to determine the number of bits to retain.</li>
5160 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5161 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5162</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5163<p>In reverse mode, a similar computation is made except that the bits are
5164returned in the reverse order. So, for example, if <tt>X</tt> has the value
5165<tt>i16 0x0ACF (101011001111)</tt> and we apply
5166<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5167<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5168</div>
5169
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5170<div class="doc_subsubsection">
5171 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5172</div>
5173
5174<div class="doc_text">
5175
5176<h5>Syntax:</h5>
5177<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5178on any integer bit width.
5179<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5180 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5181 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]5182</pre>
5183
5184<h5>Overview:</h5>
5185<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5186of bits in an integer value with another integer value. It returns the integer
5187with the replaced bits.</p>
5188
5189<h5>Arguments:</h5>
5190<p>The first argument, <tt>%val</tt> and the result may be integer types of
5191any bit width but they must have the same bit width. <tt>%val</tt> is the value
5192whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5193integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5194type since they specify only a bit index.</p>
5195
5196<h5>Semantics:</h5>
5197<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5198of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5199<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5200operates in forward mode.</p>
5201<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5202truncating it down to the size of the replacement area or zero extending it
5203up to that size.</p>
5204<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5205are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5206in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5207to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5208<p>In reverse mode, a similar computation is made except that the bits are
5209reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5210<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]5211<h5>Examples:</h5>
5212<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5213 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5214 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5215 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5216 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5217 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5218</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5219</div>
5220
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5221<!-- ======================================================================= -->
5222<div class="doc_subsection">
5223 <a name="int_debugger">Debugger Intrinsics</a>
5224</div>
5225
5226<div class="doc_text">
5227<p>
5228The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5229are described in the <a
5230href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5231Debugging</a> document.
5232</p>
5233</div>
5234
5235
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5236<!-- ======================================================================= -->
5237<div class="doc_subsection">
5238 <a name="int_eh">Exception Handling Intrinsics</a>
5239</div>
5240
5241<div class="doc_text">
5242<p> The LLVM exception handling intrinsics (which all start with
5243<tt>llvm.eh.</tt> prefix), are described in the <a
5244href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5245Handling</a> document. </p>
5246</div>
5247
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5248<!-- ======================================================================= -->
5249<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5250 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5251</div>
5252
5253<div class="doc_text">
5254<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5255 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5256 the <tt>nest</tt> attribute, from a function. The result is a callable
5257 function pointer lacking the nest parameter - the caller does not need
5258 to provide a value for it. Instead, the value to use is stored in
5259 advance in a "trampoline", a block of memory usually allocated
5260 on the stack, which also contains code to splice the nest value into the
5261 argument list. This is used to implement the GCC nested function address
5262 extension.
5263</p>
5264<p>
5265 For example, if the function is
5266 <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]5267 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]5268<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5269 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5270 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5271 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5272 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5273</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5274 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5275 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5276</div>
5277
5278<!-- _______________________________________________________________________ -->
5279<div class="doc_subsubsection">
5280 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5281</div>
5282<div class="doc_text">
5283<h5>Syntax:</h5>
5284<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5285declare 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]5286</pre>
5287<h5>Overview:</h5>
5288<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5289 This fills the memory pointed to by <tt>tramp</tt> with code
5290 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5291</p>
5292<h5>Arguments:</h5>
5293<p>
5294 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5295 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5296 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5297 intrinsic. Note that the size and the alignment are target-specific - LLVM
5298 currently provides no portable way of determining them, so a front-end that
5299 generates this intrinsic needs to have some target-specific knowledge.
5300 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]5301</p>
5302<h5>Semantics:</h5>
5303<p>
5304 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5305 dependent code, turning it into a function. A pointer to this function is
5306 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5307 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5308 before being called. The new function's signature is the same as that of
5309 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5310 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5311 of pointer type. Calling the new function is equivalent to calling
5312 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5313 missing <tt>nest</tt> argument. If, after calling
5314 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5315 modified, then the effect of any later call to the returned function pointer is
5316 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5317</p>
5318</div>
5319
5320<!-- ======================================================================= -->
5321<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5322 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5323</div>
5324
5325<div class="doc_text">
5326<p>
5327 These intrinsic functions expand the "universal IR" of LLVM to represent
5328 hardware constructs for atomic operations and memory synchronization. This
5329 provides an interface to the hardware, not an interface to the programmer. It
5330 is aimed at a low enough level to allow any programming models or APIs which
5331 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5332 hardware behavior. Just as hardware provides a "universal IR" for source
5333 languages, it also provides a starting point for developing a "universal"
5334 atomic operation and synchronization IR.
5335</p>
5336<p>
5337 These do <em>not</em> form an API such as high-level threading libraries,
5338 software transaction memory systems, atomic primitives, and intrinsic
5339 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5340 application libraries. The hardware interface provided by LLVM should allow
5341 a clean implementation of all of these APIs and parallel programming models.
5342 No one model or paradigm should be selected above others unless the hardware
5343 itself ubiquitously does so.
5344
5345</p>
5346</div>
5347
5348<!-- _______________________________________________________________________ -->
5349<div class="doc_subsubsection">
5350 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5351</div>
5352<div class="doc_text">
5353<h5>Syntax:</h5>
5354<pre>
5355declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5356i1 &lt;device&gt; )
5357
5358</pre>
5359<h5>Overview:</h5>
5360<p>
5361 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5362 specific pairs of memory access types.
5363</p>
5364<h5>Arguments:</h5>
5365<p>
5366 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5367 The first four arguments enables a specific barrier as listed below. The fith
5368 argument specifies that the barrier applies to io or device or uncached memory.
5369
5370</p>
5371 <ul>
5372 <li><tt>ll</tt>: load-load barrier</li>
5373 <li><tt>ls</tt>: load-store barrier</li>
5374 <li><tt>sl</tt>: store-load barrier</li>
5375 <li><tt>ss</tt>: store-store barrier</li>
5376 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5377 </ul>
5378<h5>Semantics:</h5>
5379<p>
5380 This intrinsic causes the system to enforce some ordering constraints upon
5381 the loads and stores of the program. This barrier does not indicate
5382 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5383 which they occur. For any of the specified pairs of load and store operations
5384 (f.ex. load-load, or store-load), all of the first operations preceding the
5385 barrier will complete before any of the second operations succeeding the
5386 barrier begin. Specifically the semantics for each pairing is as follows:
5387</p>
5388 <ul>
5389 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5390 after the barrier begins.</li>
5391
5392 <li><tt>ls</tt>: All loads before the barrier must complete before any
5393 store after the barrier begins.</li>
5394 <li><tt>ss</tt>: All stores before the barrier must complete before any
5395 store after the barrier begins.</li>
5396 <li><tt>sl</tt>: All stores before the barrier must complete before any
5397 load after the barrier begins.</li>
5398 </ul>
5399<p>
5400 These semantics are applied with a logical "and" behavior when more than one
5401 is enabled in a single memory barrier intrinsic.
5402</p>
5403<p>
5404 Backends may implement stronger barriers than those requested when they do not
5405 support as fine grained a barrier as requested. Some architectures do not
5406 need all types of barriers and on such architectures, these become noops.
5407</p>
5408<h5>Example:</h5>
5409<pre>
5410%ptr = malloc i32
5411 store i32 4, %ptr
5412
5413%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5414 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5415 <i>; guarantee the above finishes</i>
5416 store i32 8, %ptr <i>; before this begins</i>
5417</pre>
5418</div>
5419
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]5420<!-- _______________________________________________________________________ -->
5421<div class="doc_subsubsection">
5422 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5423</div>
5424<div class="doc_text">
5425<h5>Syntax:</h5>
5426<p>
5427 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5428 integer bit width. Not all targets support all bit widths however.</p>
5429
5430<pre>
5431declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5432declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5433declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5434declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5435
5436</pre>
5437<h5>Overview:</h5>
5438<p>
5439 This loads a value in memory and compares it to a given value. If they are
5440 equal, it stores a new value into the memory.
5441</p>
5442<h5>Arguments:</h5>
5443<p>
5444 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5445 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5446 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5447 this integer type. While any bit width integer may be used, targets may only
5448 lower representations they support in hardware.
5449
5450</p>
5451<h5>Semantics:</h5>
5452<p>
5453 This entire intrinsic must be executed atomically. It first loads the value
5454 in memory pointed to by <tt>ptr</tt> and compares it with the value
5455 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5456 loaded value is yielded in all cases. This provides the equivalent of an
5457 atomic compare-and-swap operation within the SSA framework.
5458</p>
5459<h5>Examples:</h5>
5460
5461<pre>
5462%ptr = malloc i32
5463 store i32 4, %ptr
5464
5465%val1 = add i32 4, 4
5466%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5467 <i>; yields {i32}:result1 = 4</i>
5468%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5469%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5470
5471%val2 = add i32 1, 1
5472%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5473 <i>; yields {i32}:result2 = 8</i>
5474%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5475
5476%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5477</pre>
5478</div>
5479
5480<!-- _______________________________________________________________________ -->
5481<div class="doc_subsubsection">
5482 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5483</div>
5484<div class="doc_text">
5485<h5>Syntax:</h5>
5486
5487<p>
5488 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5489 integer bit width. Not all targets support all bit widths however.</p>
5490<pre>
5491declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5492declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5493declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5494declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5495
5496</pre>
5497<h5>Overview:</h5>
5498<p>
5499 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5500 the value from memory. It then stores the value in <tt>val</tt> in the memory
5501 at <tt>ptr</tt>.
5502</p>
5503<h5>Arguments:</h5>
5504
5505<p>
5506 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5507 <tt>val</tt> argument and the result must be integers of the same bit width.
5508 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5509 integer type. The targets may only lower integer representations they
5510 support.
5511</p>
5512<h5>Semantics:</h5>
5513<p>
5514 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5515 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5516 equivalent of an atomic swap operation within the SSA framework.
5517
5518</p>
5519<h5>Examples:</h5>
5520<pre>
5521%ptr = malloc i32
5522 store i32 4, %ptr
5523
5524%val1 = add i32 4, 4
5525%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5526 <i>; yields {i32}:result1 = 4</i>
5527%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5528%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5529
5530%val2 = add i32 1, 1
5531%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5532 <i>; yields {i32}:result2 = 8</i>
5533
5534%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5535%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5536</pre>
5537</div>
5538
5539<!-- _______________________________________________________________________ -->
5540<div class="doc_subsubsection">
5541 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5542
5543</div>
5544<div class="doc_text">
5545<h5>Syntax:</h5>
5546<p>
5547 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5548 integer bit width. Not all targets support all bit widths however.</p>
5549<pre>
5550declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5551declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5552declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5553declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5554
5555</pre>
5556<h5>Overview:</h5>
5557<p>
5558 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5559 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5560</p>
5561<h5>Arguments:</h5>
5562<p>
5563
5564 The intrinsic takes two arguments, the first a pointer to an integer value
5565 and the second an integer value. The result is also an integer value. These
5566 integer types can have any bit width, but they must all have the same bit
5567 width. The targets may only lower integer representations they support.
5568</p>
5569<h5>Semantics:</h5>
5570<p>
5571 This intrinsic does a series of operations atomically. It first loads the
5572 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5573 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5574</p>
5575
5576<h5>Examples:</h5>
5577<pre>
5578%ptr = malloc i32
5579 store i32 4, %ptr
5580%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5581 <i>; yields {i32}:result1 = 4</i>
5582%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5583 <i>; yields {i32}:result2 = 8</i>
5584%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5585 <i>; yields {i32}:result3 = 10</i>
5586%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5587</pre>
5588</div>
5589
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5590
5591<!-- ======================================================================= -->
5592<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5593 <a name="int_general">General Intrinsics</a>
5594</div>
5595
5596<div class="doc_text">
5597<p> This class of intrinsics is designed to be generic and has
5598no specific purpose. </p>
5599</div>
5600
5601<!-- _______________________________________________________________________ -->
5602<div class="doc_subsubsection">
5603 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5604</div>
5605
5606<div class="doc_text">
5607
5608<h5>Syntax:</h5>
5609<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5610 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]5611</pre>
5612
5613<h5>Overview:</h5>
5614
5615<p>
5616The '<tt>llvm.var.annotation</tt>' intrinsic
5617</p>
5618
5619<h5>Arguments:</h5>
5620
5621<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5622The first argument is a pointer to a value, the second is a pointer to a
5623global string, the third is a pointer to a global string which is the source
5624file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5625</p>
5626
5627<h5>Semantics:</h5>
5628
5629<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5630This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5631This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5632annotations. These have no other defined use, they are ignored by code
5633generation and optimization.
5634</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5635</div>
5636
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5637<!-- _______________________________________________________________________ -->
5638<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5639 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5640</div>
5641
5642<div class="doc_text">
5643
5644<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5645<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5646any integer bit width.
5647</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5648<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5649 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5650 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5651 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5652 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5653 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]5654</pre>
5655
5656<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5657
5658<p>
5659The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5660</p>
5661
5662<h5>Arguments:</h5>
5663
5664<p>
5665The first argument is an integer value (result of some expression),
5666the second is a pointer to a global string, the third is a pointer to a global
5667string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5668It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5669</p>
5670
5671<h5>Semantics:</h5>
5672
5673<p>
5674This intrinsic allows annotations to be put on arbitrary expressions
5675with arbitrary strings. This can be useful for special purpose optimizations
5676that want to look for these annotations. These have no other defined use, they
5677are ignored by code generation and optimization.
5678</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5679
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5680<!-- _______________________________________________________________________ -->
5681<div class="doc_subsubsection">
5682 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5683</div>
5684
5685<div class="doc_text">
5686
5687<h5>Syntax:</h5>
5688<pre>
5689 declare void @llvm.trap()
5690</pre>
5691
5692<h5>Overview:</h5>
5693
5694<p>
5695The '<tt>llvm.trap</tt>' intrinsic
5696</p>
5697
5698<h5>Arguments:</h5>
5699
5700<p>
5701None
5702</p>
5703
5704<h5>Semantics:</h5>
5705
5706<p>
5707This intrinsics is lowered to the target dependent trap instruction. If the
5708target does not have a trap instruction, this intrinsic will be lowered to the
5709call of the abort() function.
5710</p>
5711</div>
5712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5713<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5714<hr>
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5720
5721 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5722 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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5724</address>
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