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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / f4cde4ec8197819bf872e551455c8a2e4c4864ab / . / 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 Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1227<h5>Overview:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1228
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1229<p>The function type can be thought of as a function signature. It
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1230consists of a return type and a list of formal parameter types. The
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1231return type of a function type is a scalar type, a void type, or a struct type.
Devang Patel7a3ad1a2008-03-24 20:52:42 +0000[diff] [blame]1232If the return type is a struct type then all struct elements must be of first
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1233class types, and the struct must have at least one element.</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>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1236
1237<pre>
1238 &lt;returntype list&gt; (&lt;parameter list&gt;)
1239</pre>
1240
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1241<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]1242specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1243which indicates that the function takes a variable number of arguments.
1244Variable argument functions can access their arguments with the <a
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1245 href="#int_varargs">variable argument handling intrinsic</a> functions.
1246'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1247<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1248
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1249<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1250<table class="layout">
1251 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1252 <td class="left"><tt>i32 (i32)</tt></td>
1253 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1254 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1255 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1256 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1257 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1258 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1259 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1260 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1261 <tt>float</tt>.
1262 </td>
1263 </tr><tr class="layout">
1264 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1265 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1266 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1267 which returns an integer. This is the signature for <tt>printf</tt> in
1268 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1269 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1270 </tr><tr class="layout">
1271 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel3a5bff82008-03-24 18:10:52 +0000[diff] [blame]1272 <td class="left">A function taking an <tt>i32></tt>, returning two
1273 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]1274 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1275 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1276</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1277
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1278</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1279<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1280<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1281<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1282<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1283<p>The structure type is used to represent a collection of data members
1284together in memory. The packing of the field types is defined to match
1285the ABI of the underlying processor. The elements of a structure may
1286be any type that has a size.</p>
1287<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1288and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1289field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1290instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1291<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1292<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1293<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1294<table class="layout">
1295 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1296 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1297 <td class="left">A triple of three <tt>i32</tt> values</td>
1298 </tr><tr class="layout">
1299 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1300 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1301 second element is a <a href="#t_pointer">pointer</a> to a
1302 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1303 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1304 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1305</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1306</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1307
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1308<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1309<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1310</div>
1311<div class="doc_text">
1312<h5>Overview:</h5>
1313<p>The packed structure type is used to represent a collection of data members
1314together in memory. There is no padding between fields. Further, the alignment
1315of a packed structure is 1 byte. The elements of a packed structure may
1316be any type that has a size.</p>
1317<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1318and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1319field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1320instruction.</p>
1321<h5>Syntax:</h5>
1322<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1323<h5>Examples:</h5>
1324<table class="layout">
1325 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1326 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1327 <td class="left">A triple of three <tt>i32</tt> values</td>
1328 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1329 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1330 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1331 second element is a <a href="#t_pointer">pointer</a> to a
1332 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1333 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1334 </tr>
1335</table>
1336</div>
1337
1338<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1339<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1340<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1341<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1343reference to another object, which must live in memory. Pointer types may have
1344an optional address space attribute defining the target-specific numbered
1345address space where the pointed-to object resides. The default address space is
1346zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1347<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1348<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1349<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1350<table class="layout">
1351 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1352 <td class="left"><tt>[4x i32]*</tt></td>
1353 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1354 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1355 </tr>
1356 <tr class="layout">
1357 <td class="left"><tt>i32 (i32 *) *</tt></td>
1358 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1359 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1360 <tt>i32</tt>.</td>
1361 </tr>
1362 <tr class="layout">
1363 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1364 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1365 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1366 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1367</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1368</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1369
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1370<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1371<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1372<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1373
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1374<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1375
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1376<p>A vector type is a simple derived type that represents a vector
1377of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1378are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1379A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1380elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1381of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1382considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1383
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1384<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1385
1386<pre>
1387 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1388</pre>
1389
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1390<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1391be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1392
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1393<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1394
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1395<table class="layout">
1396 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1397 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1398 <td class="left">Vector of 4 32-bit integer values.</td>
1399 </tr>
1400 <tr class="layout">
1401 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1402 <td class="left">Vector of 8 32-bit floating-point values.</td>
1403 </tr>
1404 <tr class="layout">
1405 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1406 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1407 </tr>
1408</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1409</div>
1410
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
1412<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1413<div class="doc_text">
1414
1415<h5>Overview:</h5>
1416
1417<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1418corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1419In LLVM, opaque types can eventually be resolved to any type (not just a
1420structure type).</p>
1421
1422<h5>Syntax:</h5>
1423
1424<pre>
1425 opaque
1426</pre>
1427
1428<h5>Examples:</h5>
1429
1430<table class="layout">
1431 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1432 <td class="left"><tt>opaque</tt></td>
1433 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1434 </tr>
1435</table>
1436</div>
1437
1438
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1439<!-- *********************************************************************** -->
1440<div class="doc_section"> <a name="constants">Constants</a> </div>
1441<!-- *********************************************************************** -->
1442
1443<div class="doc_text">
1444
1445<p>LLVM has several different basic types of constants. This section describes
1446them all and their syntax.</p>
1447
1448</div>
1449
1450<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1451<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452
1453<div class="doc_text">
1454
1455<dl>
1456 <dt><b>Boolean constants</b></dt>
1457
1458 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1459 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1460 </dd>
1461
1462 <dt><b>Integer constants</b></dt>
1463
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1464 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1465 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1466 integer types.
1467 </dd>
1468
1469 <dt><b>Floating point constants</b></dt>
1470
1471 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1472 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]1473 notation (see below). The assembler requires the exact decimal value of
1474 a floating-point constant. For example, the assembler accepts 1.25 but
1475 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1476 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1477
1478 <dt><b>Null pointer constants</b></dt>
1479
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1480 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1481 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1482
1483</dl>
1484
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1485<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1486of floating point constants. For example, the form '<tt>double
14870x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14884.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1489(and the only time that they are generated by the disassembler) is when a
1490floating point constant must be emitted but it cannot be represented as a
1491decimal floating point number. For example, NaN's, infinities, and other
1492special values are represented in their IEEE hexadecimal format so that
1493assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1494
1495</div>
1496
1497<!-- ======================================================================= -->
1498<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1499</div>
1500
1501<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1502<p>Aggregate constants arise from aggregation of simple constants
1503and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1504
1505<dl>
1506 <dt><b>Structure constants</b></dt>
1507
1508 <dd>Structure constants are represented with notation similar to structure
1509 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1510 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1511 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]1512 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1513 types of elements must match those specified by the type.
1514 </dd>
1515
1516 <dt><b>Array constants</b></dt>
1517
1518 <dd>Array constants are represented with notation similar to array type
1519 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1520 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1521 constants must have <a href="#t_array">array type</a>, and the number and
1522 types of elements must match those specified by the type.
1523 </dd>
1524
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1525 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1526
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1527 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1528 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1529 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]1530 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1531 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1532 match those specified by the type.
1533 </dd>
1534
1535 <dt><b>Zero initialization</b></dt>
1536
1537 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1538 value to zero of <em>any</em> type, including scalar and aggregate types.
1539 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]1540 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1541 initializers.
1542 </dd>
1543</dl>
1544
1545</div>
1546
1547<!-- ======================================================================= -->
1548<div class="doc_subsection">
1549 <a name="globalconstants">Global Variable and Function Addresses</a>
1550</div>
1551
1552<div class="doc_text">
1553
1554<p>The addresses of <a href="#globalvars">global variables</a> and <a
1555href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1556constants. These constants are explicitly referenced when the <a
1557href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1558href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1559file:</p>
1560
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1561<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1562<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1563@X = global i32 17
1564@Y = global i32 42
1565@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1566</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1567</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1568
1569</div>
1570
1571<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1572<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1573<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1574 <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]1575 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1576 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1577
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1578 <p>Undefined values indicate to the compiler that the program is well defined
1579 no matter what value is used, giving the compiler more freedom to optimize.
1580 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1581</div>
1582
1583<!-- ======================================================================= -->
1584<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1585</div>
1586
1587<div class="doc_text">
1588
1589<p>Constant expressions are used to allow expressions involving other constants
1590to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1591href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1592that does not have side effects (e.g. load and call are not supported). The
1593following is the syntax for constant expressions:</p>
1594
1595<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1596 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1597 <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]1598 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1599
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1600 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1601 <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]1602 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]1603
1604 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1605 <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]1606 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]1607
1608 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1609 <dd>Truncate a floating point constant to another floating point type. The
1610 size of CST must be larger than the size of TYPE. Both types must be
1611 floating point.</dd>
1612
1613 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1614 <dd>Floating point extend a constant to another type. The size of CST must be
1615 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1616
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1617 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1618 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1619 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1620 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1621 of the same number of elements. If the value won't fit in the integer type,
1622 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1623
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1624 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1625 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1626 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1627 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1628 of the same number of elements. If the value won't fit in the integer type,
1629 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1630
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1631 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1632 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1633 constant. TYPE must be a scalar or vector floating point type. CST must be of
1634 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1635 of the same number of elements. If the value won't fit in the floating point
1636 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1637
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1638 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1639 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1640 constant. TYPE must be a scalar or vector floating point type. CST must be of
1641 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1642 of the same number of elements. If the value won't fit in the floating point
1643 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1644
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1645 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1646 <dd>Convert a pointer typed constant to the corresponding integer constant
1647 TYPE must be an integer type. CST must be of pointer type. The CST value is
1648 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1649
1650 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1651 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1652 pointer type. CST must be of integer type. The CST value is zero extended,
1653 truncated, or unchanged to make it fit in a pointer size. This one is
1654 <i>really</i> dangerous!</dd>
1655
1656 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1657 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1658 identical (same number of bits). The conversion is done as if the CST value
1659 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]1660 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1661 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]1662 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1663 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1664
1665 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1666
1667 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1668 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1669 instruction, the index list may have zero or more indexes, which are required
1670 to make sense for the type of "CSTPTR".</dd>
1671
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1672 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1673
1674 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1675 constants.</dd>
1676
1677 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1678 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1679
1680 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1681 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1682
1683 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1684
1685 <dd>Perform the <a href="#i_extractelement">extractelement
1686 operation</a> on constants.
1687
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1688 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1689
1690 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1691 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1692
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1693
1694 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1695
1696 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1697 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1698
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1699 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1700
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1701 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1702 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1703 binary</a> operations. The constraints on operands are the same as those for
1704 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1705 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1706</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1707</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1708
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1709<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1710<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1711<!-- *********************************************************************** -->
1712
1713<!-- ======================================================================= -->
1714<div class="doc_subsection">
1715<a name="inlineasm">Inline Assembler Expressions</a>
1716</div>
1717
1718<div class="doc_text">
1719
1720<p>
1721LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1722Module-Level Inline Assembly</a>) through the use of a special value. This
1723value represents the inline assembler as a string (containing the instructions
1724to emit), a list of operand constraints (stored as a string), and a flag that
1725indicates whether or not the inline asm expression has side effects. An example
1726inline assembler expression is:
1727</p>
1728
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1729<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1730<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1731i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1732</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1733</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1734
1735<p>
1736Inline assembler expressions may <b>only</b> be used as the callee operand of
1737a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1738</p>
1739
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1740<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1741<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1742%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]1743</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1744</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1745
1746<p>
1747Inline asms with side effects not visible in the constraint list must be marked
1748as having side effects. This is done through the use of the
1749'<tt>sideeffect</tt>' keyword, like so:
1750</p>
1751
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1752<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1753<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1754call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1755</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1756</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1757
1758<p>TODO: The format of the asm and constraints string still need to be
1759documented here. Constraints on what can be done (e.g. duplication, moving, etc
1760need to be documented).
1761</p>
1762
1763</div>
1764
1765<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1767<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1769<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1770
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1771<p>The LLVM instruction set consists of several different
1772classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1773instructions</a>, <a href="#binaryops">binary instructions</a>,
1774<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1775 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1776instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1777
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1778</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1779
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1780<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1781<div class="doc_subsection"> <a name="terminators">Terminator
1782Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1783
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1784<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1785
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1786<p>As mentioned <a href="#functionstructure">previously</a>, every
1787basic block in a program ends with a "Terminator" instruction, which
1788indicates which block should be executed after the current block is
1789finished. These terminator instructions typically yield a '<tt>void</tt>'
1790value: they produce control flow, not values (the one exception being
1791the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1792<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1793 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1794instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1795the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1796 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1797 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1799</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1803Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1804<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1806<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]1807 ret void <i>; Return from void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1808 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]1809</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Overview:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1812
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1813<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1814value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1815<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1816returns value(s) and then causes control flow, and one that just causes
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1817control flow to occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<h5>Arguments:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1820
1821<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1822The type of each return value must be a '<a href="#t_firstclass">first
1823class</a>' type. Note that a function is not <a href="#wellformed">well
1824formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1825function that returns values that do not match the return type of the
1826function.</p>
1827
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Semantics:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1829
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1830<p>When the '<tt>ret</tt>' instruction is executed, control flow
1831returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1832 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1833the instruction after the call. If the caller was an "<a
1834 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1835at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1836returns a value, that value shall set the call or invoke instruction's
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1837return value. If the instruction returns multiple values then these
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1838values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1839</a>' instruction.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame^]1842
1843<pre>
1844 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1845 ret void <i>; Return from a void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1846 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1847</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1848</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1849<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1850<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1851<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1852<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1853<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]1854</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<p>The '<tt>br</tt>' instruction is used to cause control flow to
1857transfer to a different basic block in the current function. There are
1858two forms of this instruction, corresponding to a conditional branch
1859and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1860<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1862single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1863unconditional form of the '<tt>br</tt>' instruction takes a single
1864'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1866<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1867argument is evaluated. If the value is <tt>true</tt>, control flows
1868to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1869control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1870<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1871<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]1872 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]1873</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1874<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1875<div class="doc_subsubsection">
1876 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1877</div>
1878
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1879<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1881
1882<pre>
1883 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1884</pre>
1885
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1887
1888<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1889several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1890instruction, allowing a branch to occur to one of many possible
1891destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1892
1893
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1894<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1895
1896<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1897comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1898an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1899table is not allowed to contain duplicate constant entries.</p>
1900
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1901<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1902
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1903<p>The <tt>switch</tt> instruction specifies a table of values and
1904destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1905table is searched for the given value. If the value is found, control flow is
1906transfered to the corresponding destination; otherwise, control flow is
1907transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1908
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1909<h5>Implementation:</h5>
1910
1911<p>Depending on properties of the target machine and the particular
1912<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1913ways. For example, it could be generated as a series of chained conditional
1914branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1915
1916<h5>Example:</h5>
1917
1918<pre>
1919 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1920 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1921 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1922
1923 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1924 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1925
1926 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1927 switch i32 %val, label %otherwise [ i32 0, label %onzero
1928 i32 1, label %onone
1929 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1931</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1932
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1933<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1934<div class="doc_subsubsection">
1935 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1936</div>
1937
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1939
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1941
1942<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]1943 &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]1944 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1945</pre>
1946
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1947<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1948
1949<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1950function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1951'<tt>normal</tt>' label or the
1952'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1953"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1954"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1955href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1956continued at the dynamically nearest "exception" label. If the callee function
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1957returns multiple values then individual return values are only accessible through
1958a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1959
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1960<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1961
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1962<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1964<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1965 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1966 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1967 convention</a> the call should use. If none is specified, the call defaults
1968 to using C calling conventions.
1969 </li>
1970 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1971 function value being invoked. In most cases, this is a direct function
1972 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1973 an arbitrary pointer to function value.
1974 </li>
1975
1976 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1977 function to be invoked. </li>
1978
1979 <li>'<tt>function args</tt>': argument list whose types match the function
1980 signature argument types. If the function signature indicates the function
1981 accepts a variable number of arguments, the extra arguments can be
1982 specified. </li>
1983
1984 <li>'<tt>normal label</tt>': the label reached when the called function
1985 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1986
1987 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1988 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1991
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1993
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1994<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1995href="#i_call">call</a></tt>' instruction in most regards. The primary
1996difference is that it establishes an association with a label, which is used by
1997the runtime library to unwind the stack.</p>
1998
1999<p>This instruction is used in languages with destructors to ensure that proper
2000cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2001exception. Additionally, this is important for implementation of
2002'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2003
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2004<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2005<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2006 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2007 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]2008 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2009 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2010</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2011</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2012
2013
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2014<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2015
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2017Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2018
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2019<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2020
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2021<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2022<pre>
2023 unwind
2024</pre>
2025
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2026<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2027
2028<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2029at the first callee in the dynamic call stack which used an <a
2030href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2031primarily used to implement exception handling.</p>
2032
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2033<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2034
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2035<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2036immediately halt. The dynamic call stack is then searched for the first <a
2037href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2038execution continues at the "exceptional" destination block specified by the
2039<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2040dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2042
2043<!-- _______________________________________________________________________ -->
2044
2045<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2046Instruction</a> </div>
2047
2048<div class="doc_text">
2049
2050<h5>Syntax:</h5>
2051<pre>
2052 unreachable
2053</pre>
2054
2055<h5>Overview:</h5>
2056
2057<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2058instruction is used to inform the optimizer that a particular portion of the
2059code is not reachable. This can be used to indicate that the code after a
2060no-return function cannot be reached, and other facts.</p>
2061
2062<h5>Semantics:</h5>
2063
2064<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2065</div>
2066
2067
2068
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2069<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2070<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2071<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2072<p>Binary operators are used to do most of the computation in a
Chris Lattner5a158142008-04-01 18:47:32 +0000[diff] [blame]2073program. They require two operands of the same type, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2074produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2075multiple 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]2076The result value has the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2077<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2078</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2079<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2080<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2081Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2082<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2083<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2084<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]2085</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2087<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2088<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2089<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2090 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2091 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]2092Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2093<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2094<p>The value produced is the integer or floating point sum of the two
2095operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2096<p>If an integer sum has unsigned overflow, the result returned is the
2097mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2098the result.</p>
2099<p>Because LLVM integers use a two's complement representation, this
2100instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2102<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]2103</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2104</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2105<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2106<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2107Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2108<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2109<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2110<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]2111</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2112<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2113<p>The '<tt>sub</tt>' instruction returns the difference of its two
2114operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2115<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2116instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2117<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2118<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2119 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2120values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2121This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2122Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2123<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2124<p>The value produced is the integer or floating point difference of
2125the two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2126<p>If an integer difference has unsigned overflow, the result returned is the
2127mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2128the result.</p>
2129<p>Because LLVM integers use a two's complement representation, this
2130instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2131<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2132<pre>
2133 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2134 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2135</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2136</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2138<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2139Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2140<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2141<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2142<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]2143</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2144<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2145<p>The '<tt>mul</tt>' instruction returns the product of its two
2146operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2147<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2148<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2149 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2150values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2151This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2152Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2153<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2154<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2155two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2156<p>If the result of an integer multiplication has unsigned overflow,
2157the result returned is the mathematical result modulo
21582<sup>n</sup>, where n is the bit width of the result.</p>
2159<p>Because LLVM integers use a two's complement representation, and the
2160result is the same width as the operands, this instruction returns the
2161correct result for both signed and unsigned integers. If a full product
2162(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2163should be sign-extended or zero-extended as appropriate to the
2164width of the full product.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2165<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2166<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]2167</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2168</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2169<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2170<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2171</a></div>
2172<div class="doc_text">
2173<h5>Syntax:</h5>
2174<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2175</pre>
2176<h5>Overview:</h5>
2177<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2178operands.</p>
2179<h5>Arguments:</h5>
2180<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2181<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2182types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2183of the values in which case the elements must be integers.</p>
2184<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2185<p>The value produced is the unsigned integer quotient of the two operands.</p>
2186<p>Note that unsigned integer division and signed integer division are distinct
2187operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2188<p>Division by zero leads to undefined behavior.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2189<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2190<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]2191</pre>
2192</div>
2193<!-- _______________________________________________________________________ -->
2194<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2195</a> </div>
2196<div class="doc_text">
2197<h5>Syntax:</h5>
2198<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2199</pre>
2200<h5>Overview:</h5>
2201<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2202operands.</p>
2203<h5>Arguments:</h5>
2204<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2205<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2206types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2207of the values in which case the elements must be integers.</p>
2208<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2209<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]2210<p>Note that signed integer division and unsigned integer division are distinct
2211operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2212<p>Division by zero leads to undefined behavior. Overflow also leads to
2213undefined behavior; this is a rare case, but can occur, for example,
2214by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2215<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2216<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]2217</pre>
2218</div>
2219<!-- _______________________________________________________________________ -->
2220<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2221Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2222<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2223<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2224<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]2225</pre>
2226<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2227<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2228operands.</p>
2229<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2230<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2231<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2232identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2233versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2234<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2235<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2236<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2237<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]2238</pre>
2239</div>
2240<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2241<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2242</div>
2243<div class="doc_text">
2244<h5>Syntax:</h5>
2245<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2246</pre>
2247<h5>Overview:</h5>
2248<p>The '<tt>urem</tt>' instruction returns the remainder from the
2249unsigned division of its two arguments.</p>
2250<h5>Arguments:</h5>
2251<p>The two arguments to the '<tt>urem</tt>' instruction must be
2252<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2253types. This instruction can also take <a href="#t_vector">vector</a> versions
2254of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2255<h5>Semantics:</h5>
2256<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2257This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2258<p>Note that unsigned integer remainder and signed integer remainder are
2259distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2260<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2261<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2262<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]2263</pre>
2264
2265</div>
2266<!-- _______________________________________________________________________ -->
2267<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2268Instruction</a> </div>
2269<div class="doc_text">
2270<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2271<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]2272</pre>
2273<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2274<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2275signed division of its two operands. This instruction can also take
2276<a href="#t_vector">vector</a> versions of the values in which case
2277the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2278
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2279<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2280<p>The two arguments to the '<tt>srem</tt>' instruction must be
2281<a href="#t_integer">integer</a> values. Both arguments must have identical
2282types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2283<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2284<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2285has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2286operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2287a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2288 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2289Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2290please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2291Wikipedia: modulo operation</a>.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2292<p>Note that signed integer remainder and unsigned integer remainder are
2293distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2294<p>Taking the remainder of a division by zero leads to undefined behavior.
2295Overflow also leads to undefined behavior; this is a rare case, but can occur,
2296for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2297(The remainder doesn't actually overflow, but this rule lets srem be
2298implemented using instructions that return both the result of the division
2299and the remainder.)</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2300<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2301<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]2302</pre>
2303
2304</div>
2305<!-- _______________________________________________________________________ -->
2306<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2307Instruction</a> </div>
2308<div class="doc_text">
2309<h5>Syntax:</h5>
2310<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2311</pre>
2312<h5>Overview:</h5>
2313<p>The '<tt>frem</tt>' instruction returns the remainder from the
2314division of its two operands.</p>
2315<h5>Arguments:</h5>
2316<p>The two arguments to the '<tt>frem</tt>' instruction must be
2317<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2318identical types. This instruction can also take <a href="#t_vector">vector</a>
2319versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2320<h5>Semantics:</h5>
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2321<p>This instruction returns the <i>remainder</i> of a division.
2322The remainder has the same sign as the dividend.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2323<h5>Example:</h5>
2324<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]2325</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2326</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2327
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2328<!-- ======================================================================= -->
2329<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2330Operations</a> </div>
2331<div class="doc_text">
2332<p>Bitwise binary operators are used to do various forms of
2333bit-twiddling in a program. They are generally very efficient
2334instructions and can commonly be strength reduced from other
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2335instructions. They require two operands of the same type, execute an operation on them,
2336and 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]2337</div>
2338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2339<!-- _______________________________________________________________________ -->
2340<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2341Instruction</a> </div>
2342<div class="doc_text">
2343<h5>Syntax:</h5>
2344<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2345</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2346
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2347<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2348
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2349<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2350the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2351
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2352<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2353
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2354<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2355 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2356unsigned value.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2357
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2358<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2359
Chris Lattnera73afe02008-04-01 18:45:27 +0000[diff] [blame]2360<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2361where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2362equal 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]2363
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2364<h5>Example:</h5><pre>
2365 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2366 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2367 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2368 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2369</pre>
2370</div>
2371<!-- _______________________________________________________________________ -->
2372<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2373Instruction</a> </div>
2374<div class="doc_text">
2375<h5>Syntax:</h5>
2376<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2377</pre>
2378
2379<h5>Overview:</h5>
2380<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2381operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2382
2383<h5>Arguments:</h5>
2384<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2385<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2386unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2387
2388<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2389
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2390<p>This instruction always performs a logical shift right operation. The most
2391significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2392shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2393the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2394
2395<h5>Example:</h5>
2396<pre>
2397 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2398 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2399 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2400 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2401 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2402</pre>
2403</div>
2404
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2405<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2406<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2407Instruction</a> </div>
2408<div class="doc_text">
2409
2410<h5>Syntax:</h5>
2411<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2412</pre>
2413
2414<h5>Overview:</h5>
2415<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2416operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2417
2418<h5>Arguments:</h5>
2419<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2420<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
2421unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2422
2423<h5>Semantics:</h5>
2424<p>This instruction always performs an arithmetic shift right operation,
2425The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2426of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2427larger than the number of bits in <tt>var1</tt>, the result is undefined.
2428</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2429
2430<h5>Example:</h5>
2431<pre>
2432 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2433 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2434 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2435 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2436 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2437</pre>
2438</div>
2439
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2440<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2441<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2442Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2443<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2444<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2445<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]2446</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2447<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2448<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2449its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2450<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2451<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2452 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2453identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2454<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2455<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2456<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2457<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2458<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2459 <tbody>
2460 <tr>
2461 <td>In0</td>
2462 <td>In1</td>
2463 <td>Out</td>
2464 </tr>
2465 <tr>
2466 <td>0</td>
2467 <td>0</td>
2468 <td>0</td>
2469 </tr>
2470 <tr>
2471 <td>0</td>
2472 <td>1</td>
2473 <td>0</td>
2474 </tr>
2475 <tr>
2476 <td>1</td>
2477 <td>0</td>
2478 <td>0</td>
2479 </tr>
2480 <tr>
2481 <td>1</td>
2482 <td>1</td>
2483 <td>1</td>
2484 </tr>
2485 </tbody>
2486</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2487</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2488<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2489<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2490 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2491 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2492</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2493</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2494<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2495<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2496<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2497<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2498<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]2499</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2500<h5>Overview:</h5>
2501<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2502or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2503<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2504<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2505 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2506identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2507<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2508<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2509<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2510<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511<table border="1" cellspacing="0" cellpadding="4">
2512 <tbody>
2513 <tr>
2514 <td>In0</td>
2515 <td>In1</td>
2516 <td>Out</td>
2517 </tr>
2518 <tr>
2519 <td>0</td>
2520 <td>0</td>
2521 <td>0</td>
2522 </tr>
2523 <tr>
2524 <td>0</td>
2525 <td>1</td>
2526 <td>1</td>
2527 </tr>
2528 <tr>
2529 <td>1</td>
2530 <td>0</td>
2531 <td>1</td>
2532 </tr>
2533 <tr>
2534 <td>1</td>
2535 <td>1</td>
2536 <td>1</td>
2537 </tr>
2538 </tbody>
2539</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2540</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2541<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2542<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2543 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2544 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2546</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2547<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2548<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2549Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2551<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2552<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]2553</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2555<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2556or of its two operands. The <tt>xor</tt> is used to implement the
2557"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2559<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2560 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2561identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2562<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2563<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2564<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2565<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2566<table border="1" cellspacing="0" cellpadding="4">
2567 <tbody>
2568 <tr>
2569 <td>In0</td>
2570 <td>In1</td>
2571 <td>Out</td>
2572 </tr>
2573 <tr>
2574 <td>0</td>
2575 <td>0</td>
2576 <td>0</td>
2577 </tr>
2578 <tr>
2579 <td>0</td>
2580 <td>1</td>
2581 <td>1</td>
2582 </tr>
2583 <tr>
2584 <td>1</td>
2585 <td>0</td>
2586 <td>1</td>
2587 </tr>
2588 <tr>
2589 <td>1</td>
2590 <td>1</td>
2591 <td>0</td>
2592 </tr>
2593 </tbody>
2594</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2595</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2596<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2597<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2598<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2599 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2600 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2601 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2602</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2603</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2606<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2607 <a name="vectorops">Vector Operations</a>
2608</div>
2609
2610<div class="doc_text">
2611
2612<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2613target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2614vector-specific operations needed to process vectors effectively. While LLVM
2615does directly support these vector operations, many sophisticated algorithms
2616will want to use target-specific intrinsics to take full advantage of a specific
2617target.</p>
2618
2619</div>
2620
2621<!-- _______________________________________________________________________ -->
2622<div class="doc_subsubsection">
2623 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2624</div>
2625
2626<div class="doc_text">
2627
2628<h5>Syntax:</h5>
2629
2630<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2631 &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]2632</pre>
2633
2634<h5>Overview:</h5>
2635
2636<p>
2637The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2638element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2639</p>
2640
2641
2642<h5>Arguments:</h5>
2643
2644<p>
2645The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2646value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2647an index indicating the position from which to extract the element.
2648The index may be a variable.</p>
2649
2650<h5>Semantics:</h5>
2651
2652<p>
2653The result is a scalar of the same type as the element type of
2654<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2655<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2656results are undefined.
2657</p>
2658
2659<h5>Example:</h5>
2660
2661<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2662 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2663</pre>
2664</div>
2665
2666
2667<!-- _______________________________________________________________________ -->
2668<div class="doc_subsubsection">
2669 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2670</div>
2671
2672<div class="doc_text">
2673
2674<h5>Syntax:</h5>
2675
2676<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2677 &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]2678</pre>
2679
2680<h5>Overview:</h5>
2681
2682<p>
2683The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2684element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2685</p>
2686
2687
2688<h5>Arguments:</h5>
2689
2690<p>
2691The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2692value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2693scalar value whose type must equal the element type of the first
2694operand. The third operand is an index indicating the position at
2695which to insert the value. The index may be a variable.</p>
2696
2697<h5>Semantics:</h5>
2698
2699<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2700The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2701element values are those of <tt>val</tt> except at position
2702<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2703exceeds the length of <tt>val</tt>, the results are undefined.
2704</p>
2705
2706<h5>Example:</h5>
2707
2708<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2709 %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]2710</pre>
2711</div>
2712
2713<!-- _______________________________________________________________________ -->
2714<div class="doc_subsubsection">
2715 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2716</div>
2717
2718<div class="doc_text">
2719
2720<h5>Syntax:</h5>
2721
2722<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2723 &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]2724</pre>
2725
2726<h5>Overview:</h5>
2727
2728<p>
2729The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2730from two input vectors, returning a vector of the same type.
2731</p>
2732
2733<h5>Arguments:</h5>
2734
2735<p>
2736The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2737with types that match each other and types that match the result of the
2738instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2739of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2740</p>
2741
2742<p>
2743The shuffle mask operand is required to be a constant vector with either
2744constant integer or undef values.
2745</p>
2746
2747<h5>Semantics:</h5>
2748
2749<p>
2750The elements of the two input vectors are numbered from left to right across
2751both of the vectors. The shuffle mask operand specifies, for each element of
2752the result vector, which element of the two input registers the result element
2753gets. The element selector may be undef (meaning "don't care") and the second
2754operand may be undef if performing a shuffle from only one vector.
2755</p>
2756
2757<h5>Example:</h5>
2758
2759<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2760 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2761 &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]2762 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2763 &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]2764</pre>
2765</div>
2766
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2767
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2768<!-- ======================================================================= -->
2769<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2770 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2771</div>
2772
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2773<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2774
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2775<p>A key design point of an SSA-based representation is how it
2776represents memory. In LLVM, no memory locations are in SSA form, which
2777makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2778allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2779
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2780</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2781
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2782<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2783<div class="doc_subsubsection">
2784 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2785</div>
2786
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2787<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2788
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2789<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2790
2791<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2792 &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]2793</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2795<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2796
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2797<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2798heap and returns a pointer to it. The object is always allocated in the generic
2799address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2801<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2802
2803<p>The '<tt>malloc</tt>' instruction allocates
2804<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2805bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2806appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2807number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2808If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2809be aligned to at least that boundary. If not specified, or if zero, the target can
2810choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2811
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2812<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2815
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2816<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2817a pointer is returned. The result of a zero byte allocattion is undefined. The
2818result is null if there is insufficient memory available.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2819
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2820<h5>Example:</h5>
2821
2822<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2823 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2824
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2825 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2826 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2827 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2828 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2829 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2830</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2831</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2832
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2833<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2834<div class="doc_subsubsection">
2835 <a name="i_free">'<tt>free</tt>' Instruction</a>
2836</div>
2837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2838<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2839
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2840<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2841
2842<pre>
2843 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2844</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2845
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2846<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2847
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2848<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2849memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2850
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2852
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2853<p>'<tt>value</tt>' shall be a pointer value that points to a value
2854that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2855instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2856
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2857<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2858
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2859<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattnere0db56d2008-04-19 22:41:32 +0000[diff] [blame]2860after this instruction executes. If the pointer is null, the operation
2861is a noop.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2862
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2863<h5>Example:</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 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2867 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2868</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2869</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2870
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2872<div class="doc_subsubsection">
2873 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2874</div>
2875
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2876<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2877
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2878<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2879
2880<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2881 &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]2882</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2883
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2884<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2885
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2886<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2887currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2888returns to its caller. The object is always allocated in the generic address
2889space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2890
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2891<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2892
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2893<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2894bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2895appropriate type to the program. If "NumElements" is specified, it is the
2896number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2897If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2898to be aligned to at least that boundary. If not specified, or if zero, the target
2899can choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2900
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2901<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2903<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2904
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]2905<p>Memory is allocated; a pointer is returned. The operation is undefiend if
2906there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2907memory is automatically released when the function returns. The '<tt>alloca</tt>'
2908instruction is commonly used to represent automatic variables that must
2909have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2910 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]2911instructions), the memory is reclaimed. Allocating zero bytes
2912is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2914<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2915
2916<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2917 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2918 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2919 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2920 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2921</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2923
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2924<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2925<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2926Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2927<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2928<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2929<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]2930<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2931<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2932<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2933<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2934address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2935 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2936marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2937the number or order of execution of this <tt>load</tt> with other
2938volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2939instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2940<p>
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2941The optional constant "align" argument specifies the alignment of the operation
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2942(that is, the alignment of the memory address). A value of 0 or an
2943omitted "align" argument means that the operation has the preferential
2944alignment for the target. It is the responsibility of the code emitter
2945to ensure that the alignment information is correct. Overestimating
2946the alignment results in an undefined behavior. Underestimating the
2947alignment may produce less efficient code. An alignment of 1 is always
2948safe.
2949</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2950<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2951<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2952<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2953<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2954 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2955 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2956 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2957</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2958</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2959<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2960<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2961Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2962<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2963<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2964<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2965 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]2966</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2967<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2968<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2969<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2970<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2971to 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]2972operand must be a pointer to the <a href="#t_firstclass">first class</a> type
2973of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2974operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2975optimizer is not allowed to modify the number or order of execution of
2976this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2977 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2978<p>
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]2979The optional constant "align" argument specifies the alignment of the operation
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2980(that is, the alignment of the memory address). A value of 0 or an
2981omitted "align" argument means that the operation has the preferential
2982alignment for the target. It is the responsibility of the code emitter
2983to ensure that the alignment information is correct. Overestimating
2984the alignment results in an undefined behavior. Underestimating the
2985alignment may produce less efficient code. An alignment of 1 is always
2986safe.
2987</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2988<h5>Semantics:</h5>
2989<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2990at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2991<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2992<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2993 store i32 3, i32* %ptr <i>; yields {void}</i>
2994 %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]2995</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2996</div>
2997
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2998<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2999<div class="doc_subsubsection">
3000 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3001</div>
3002
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3003<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3004<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3005<pre>
3006 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3007</pre>
3008
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3009<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3010
3011<p>
3012The '<tt>getelementptr</tt>' instruction is used to get the address of a
3013subelement of an aggregate data structure.</p>
3014
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3015<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3016
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3017<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3018elements of the aggregate object to index to. The actual types of the arguments
3019provided depend on the type of the first pointer argument. The
3020'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3021levels 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]3022structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3023into an array or pointer, only integers of 32 or 64 bits are allowed, and will
3024be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3025
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3026<p>For example, let's consider a C code fragment and how it gets
3027compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3028
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3029<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3030<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3031struct RT {
3032 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3033 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3034 char C;
3035};
3036struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3037 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3038 double Y;
3039 struct RT Z;
3040};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3041
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3042int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3043 return &amp;s[1].Z.B[5][13];
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
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3048<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3049
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3050<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3051<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3052%RT = type { i8 , [10 x [20 x i32]], i8 }
3053%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3054
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3055define i32* %foo(%ST* %s) {
3056entry:
3057 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3058 ret i32* %reg
3059}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3060</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3061</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3062
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3063<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3064
3065<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]3066on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3067and <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]3068<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]3069to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3070structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3071
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3072<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]3073type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3074}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3075the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3076i8 }</tt>' type, another structure. The third index indexes into the second
3077element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3078array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3079'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3080to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3081
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3082<p>Note that it is perfectly legal to index partially through a
3083structure, returning a pointer to an inner element. Because of this,
3084the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3085
3086<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3087 define i32* %foo(%ST* %s) {
3088 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3089 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3090 %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]3091 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3092 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3093 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3094 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3095</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3096
3097<p>Note that it is undefined to access an array out of bounds: array and
3098pointer indexes must always be within the defined bounds of the array type.
3099The one exception for this rules is zero length arrays. These arrays are
3100defined to be accessible as variable length arrays, which requires access
3101beyond the zero'th element.</p>
3102
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3103<p>The getelementptr instruction is often confusing. For some more insight
3104into how it works, see <a href="GetElementPtr.html">the getelementptr
3105FAQ</a>.</p>
3106
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3107<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3108
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3109<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3110 <i>; yields [12 x i8]*:aptr</i>
3111 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3112</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3113</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3114
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3115<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3116<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3117</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3118<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3119<p>The instructions in this category are the conversion instructions (casting)
3120which all take a single operand and a type. They perform various bit conversions
3121on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3122</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3123
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3124<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3125<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3126 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3127</div>
3128<div class="doc_text">
3129
3130<h5>Syntax:</h5>
3131<pre>
3132 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3133</pre>
3134
3135<h5>Overview:</h5>
3136<p>
3137The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3138</p>
3139
3140<h5>Arguments:</h5>
3141<p>
3142The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3143be 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]3144and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3145type. The bit size of <tt>value</tt> must be larger than the bit size of
3146<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3147
3148<h5>Semantics:</h5>
3149<p>
3150The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3151and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3152larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3153It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3154
3155<h5>Example:</h5>
3156<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3157 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3158 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3159 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3160</pre>
3161</div>
3162
3163<!-- _______________________________________________________________________ -->
3164<div class="doc_subsubsection">
3165 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3166</div>
3167<div class="doc_text">
3168
3169<h5>Syntax:</h5>
3170<pre>
3171 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3172</pre>
3173
3174<h5>Overview:</h5>
3175<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3176<tt>ty2</tt>.</p>
3177
3178
3179<h5>Arguments:</h5>
3180<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]3181<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3182also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3183<tt>value</tt> must be smaller than the bit size of the destination type,
3184<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3185
3186<h5>Semantics:</h5>
3187<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]3188bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3189
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3190<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]3191
3192<h5>Example:</h5>
3193<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3194 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3195 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3196</pre>
3197</div>
3198
3199<!-- _______________________________________________________________________ -->
3200<div class="doc_subsubsection">
3201 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3202</div>
3203<div class="doc_text">
3204
3205<h5>Syntax:</h5>
3206<pre>
3207 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3208</pre>
3209
3210<h5>Overview:</h5>
3211<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3212
3213<h5>Arguments:</h5>
3214<p>
3215The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3216<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3217also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3218<tt>value</tt> must be smaller than the bit size of the destination type,
3219<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3220
3221<h5>Semantics:</h5>
3222<p>
3223The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3224bit (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]3225the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3226
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3227<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]3228
3229<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3230<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3231 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3232 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3233</pre>
3234</div>
3235
3236<!-- _______________________________________________________________________ -->
3237<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3238 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3239</div>
3240
3241<div class="doc_text">
3242
3243<h5>Syntax:</h5>
3244
3245<pre>
3246 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3247</pre>
3248
3249<h5>Overview:</h5>
3250<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3251<tt>ty2</tt>.</p>
3252
3253
3254<h5>Arguments:</h5>
3255<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3256 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3257cast it to. The size of <tt>value</tt> must be larger than the size of
3258<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3259<i>no-op cast</i>.</p>
3260
3261<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3262<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3263<a href="#t_floating">floating point</a> type to a smaller
3264<a href="#t_floating">floating point</a> type. If the value cannot fit within
3265the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3266
3267<h5>Example:</h5>
3268<pre>
3269 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3270 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3271</pre>
3272</div>
3273
3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3276 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3277</div>
3278<div class="doc_text">
3279
3280<h5>Syntax:</h5>
3281<pre>
3282 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3283</pre>
3284
3285<h5>Overview:</h5>
3286<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3287floating point value.</p>
3288
3289<h5>Arguments:</h5>
3290<p>The '<tt>fpext</tt>' instruction takes a
3291<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3292and a <a href="#t_floating">floating point</a> type to cast it to. The source
3293type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3294
3295<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3296<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3297<a href="#t_floating">floating point</a> type to a larger
3298<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3299used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3300<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]3301
3302<h5>Example:</h5>
3303<pre>
3304 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3305 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3306</pre>
3307</div>
3308
3309<!-- _______________________________________________________________________ -->
3310<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3311 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3312</div>
3313<div class="doc_text">
3314
3315<h5>Syntax:</h5>
3316<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3317 &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]3318</pre>
3319
3320<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3321<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3322unsigned integer equivalent of type <tt>ty2</tt>.
3323</p>
3324
3325<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3326<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]3327scalar or vector <a href="#t_floating">floating point</a> value, and a type
3328to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3329type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3330vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3331
3332<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3333<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3334<a href="#t_floating">floating point</a> operand into the nearest (rounding
3335towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3336the results are undefined.</p>
3337
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3338<h5>Example:</h5>
3339<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3340 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3341 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3342 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3343</pre>
3344</div>
3345
3346<!-- _______________________________________________________________________ -->
3347<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3348 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3349</div>
3350<div class="doc_text">
3351
3352<h5>Syntax:</h5>
3353<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3354 &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]3355</pre>
3356
3357<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3358<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3359<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]3360</p>
3361
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3362<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3363<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]3364scalar or vector <a href="#t_floating">floating point</a> value, and a type
3365to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3366type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3367vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3368
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3369<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3370<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3371<a href="#t_floating">floating point</a> operand into the nearest (rounding
3372towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3373the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3374
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3375<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3376<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3377 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3378 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3379 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3380</pre>
3381</div>
3382
3383<!-- _______________________________________________________________________ -->
3384<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3385 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3386</div>
3387<div class="doc_text">
3388
3389<h5>Syntax:</h5>
3390<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3391 &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]3392</pre>
3393
3394<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3395<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3396integer and converts that value to the <tt>ty2</tt> type.</p>
3397
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3398<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3399<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3400scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3401to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3402type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3403floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3404
3405<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3406<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3407integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3408the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3409
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3410<h5>Example:</h5>
3411<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3412 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3413 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3414</pre>
3415</div>
3416
3417<!-- _______________________________________________________________________ -->
3418<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3419 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3420</div>
3421<div class="doc_text">
3422
3423<h5>Syntax:</h5>
3424<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3425 &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]3426</pre>
3427
3428<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3429<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3430integer and converts that value to the <tt>ty2</tt> type.</p>
3431
3432<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3433<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3434scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3435to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3436type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3437floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3438
3439<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3440<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3441integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3442the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3443
3444<h5>Example:</h5>
3445<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3446 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3447 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3448</pre>
3449</div>
3450
3451<!-- _______________________________________________________________________ -->
3452<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3453 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3454</div>
3455<div class="doc_text">
3456
3457<h5>Syntax:</h5>
3458<pre>
3459 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3460</pre>
3461
3462<h5>Overview:</h5>
3463<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3464the integer type <tt>ty2</tt>.</p>
3465
3466<h5>Arguments:</h5>
3467<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3468must 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]3469<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3470
3471<h5>Semantics:</h5>
3472<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3473<tt>ty2</tt> by interpreting the pointer value as an integer and either
3474truncating or zero extending that value to the size of the integer type. If
3475<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3476<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]3477are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3478change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3479
3480<h5>Example:</h5>
3481<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3482 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3483 %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]3484</pre>
3485</div>
3486
3487<!-- _______________________________________________________________________ -->
3488<div class="doc_subsubsection">
3489 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3490</div>
3491<div class="doc_text">
3492
3493<h5>Syntax:</h5>
3494<pre>
3495 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3496</pre>
3497
3498<h5>Overview:</h5>
3499<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3500a pointer type, <tt>ty2</tt>.</p>
3501
3502<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3503<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3504value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3505<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3506
3507<h5>Semantics:</h5>
3508<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3509<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3510the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3511size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3512the size of a pointer then a zero extension is done. If they are the same size,
3513nothing is done (<i>no-op cast</i>).</p>
3514
3515<h5>Example:</h5>
3516<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3517 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3518 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3519 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3520</pre>
3521</div>
3522
3523<!-- _______________________________________________________________________ -->
3524<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3525 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3526</div>
3527<div class="doc_text">
3528
3529<h5>Syntax:</h5>
3530<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3531 &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]3532</pre>
3533
3534<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3535<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3536<tt>ty2</tt> without changing any bits.</p>
3537
3538<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3539<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3540a first class value, and a type to cast it to, which must also be a <a
3541 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3542and the destination type, <tt>ty2</tt>, must be identical. If the source
3543type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3544
3545<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3546<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3547<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3548this conversion. The conversion is done as if the <tt>value</tt> had been
3549stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3550converted to other pointer types with this instruction. To convert pointers to
3551other types, use the <a href="#i_inttoptr">inttoptr</a> or
3552<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3553
3554<h5>Example:</h5>
3555<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3556 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3557 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3558 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3559</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3560</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3561
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3562<!-- ======================================================================= -->
3563<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3564<div class="doc_text">
3565<p>The instructions in this category are the "miscellaneous"
3566instructions, which defy better classification.</p>
3567</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3568
3569<!-- _______________________________________________________________________ -->
3570<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3571</div>
3572<div class="doc_text">
3573<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3574<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]3575</pre>
3576<h5>Overview:</h5>
3577<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner4316dec2008-04-02 00:38:26 +0000[diff] [blame]3578of its two integer or pointer operands.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3579<h5>Arguments:</h5>
3580<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3581the condition code indicating the kind of comparison to perform. It is not
3582a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3583<ol>
3584 <li><tt>eq</tt>: equal</li>
3585 <li><tt>ne</tt>: not equal </li>
3586 <li><tt>ugt</tt>: unsigned greater than</li>
3587 <li><tt>uge</tt>: unsigned greater or equal</li>
3588 <li><tt>ult</tt>: unsigned less than</li>
3589 <li><tt>ule</tt>: unsigned less or equal</li>
3590 <li><tt>sgt</tt>: signed greater than</li>
3591 <li><tt>sge</tt>: signed greater or equal</li>
3592 <li><tt>slt</tt>: signed less than</li>
3593 <li><tt>sle</tt>: signed less or equal</li>
3594</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3595<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3596<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3597<h5>Semantics:</h5>
3598<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3599the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3600yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3601<ol>
3602 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3603 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3604 </li>
3605 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3606 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3607 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3608 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3609 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3610 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3611 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3612 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3613 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3614 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3615 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3616 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3617 <li><tt>sge</tt>: interprets the operands as signed values and yields
3618 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3619 <li><tt>slt</tt>: interprets the operands as signed values and yields
3620 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3621 <li><tt>sle</tt>: interprets the operands as signed values and yields
3622 <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]3623</ol>
3624<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3625values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3626
3627<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3628<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3629 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3630 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3631 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3632 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3633 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3634</pre>
3635</div>
3636
3637<!-- _______________________________________________________________________ -->
3638<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3639</div>
3640<div class="doc_text">
3641<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3642<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]3643</pre>
3644<h5>Overview:</h5>
3645<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3646of its floating point operands.</p>
3647<h5>Arguments:</h5>
3648<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3649the condition code indicating the kind of comparison to perform. It is not
3650a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3651<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3652 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3653 <li><tt>oeq</tt>: ordered and equal</li>
3654 <li><tt>ogt</tt>: ordered and greater than </li>
3655 <li><tt>oge</tt>: ordered and greater than or equal</li>
3656 <li><tt>olt</tt>: ordered and less than </li>
3657 <li><tt>ole</tt>: ordered and less than or equal</li>
3658 <li><tt>one</tt>: ordered and not equal</li>
3659 <li><tt>ord</tt>: ordered (no nans)</li>
3660 <li><tt>ueq</tt>: unordered or equal</li>
3661 <li><tt>ugt</tt>: unordered or greater than </li>
3662 <li><tt>uge</tt>: unordered or greater than or equal</li>
3663 <li><tt>ult</tt>: unordered or less than </li>
3664 <li><tt>ule</tt>: unordered or less than or equal</li>
3665 <li><tt>une</tt>: unordered or not equal</li>
3666 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3667 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3668</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3669<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3670<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3671<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3672<a href="#t_floating">floating point</a> typed. They must have identical
3673types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3674<h5>Semantics:</h5>
3675<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3676the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3677yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3678<ol>
3679 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3680 <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]3681 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3682 <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]3683 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3684 <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]3685 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3686 <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]3687 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3688 <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]3689 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3690 <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]3691 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3692 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3693 <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]3694 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3695 <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]3696 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3697 <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]3698 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3699 <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]3700 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3701 <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]3702 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3703 <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]3704 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3705 <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]3706 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3707</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3708
3709<h5>Example:</h5>
3710<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3711 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3712 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3713 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3714</pre>
3715</div>
3716
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3717<!-- _______________________________________________________________________ -->
3718<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3719Instruction</a> </div>
3720<div class="doc_text">
3721<h5>Syntax:</h5>
3722<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3723<h5>Overview:</h5>
3724<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3725the SSA graph representing the function.</p>
3726<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3727<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3728field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3729as arguments, with one pair for each predecessor basic block of the
3730current block. Only values of <a href="#t_firstclass">first class</a>
3731type may be used as the value arguments to the PHI node. Only labels
3732may be used as the label arguments.</p>
3733<p>There must be no non-phi instructions between the start of a basic
3734block and the PHI instructions: i.e. PHI instructions must be first in
3735a basic block.</p>
3736<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3737<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3738specified by the pair corresponding to the predecessor basic block that executed
3739just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3740<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3741<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]3742</div>
3743
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3744<!-- _______________________________________________________________________ -->
3745<div class="doc_subsubsection">
3746 <a name="i_select">'<tt>select</tt>' Instruction</a>
3747</div>
3748
3749<div class="doc_text">
3750
3751<h5>Syntax:</h5>
3752
3753<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3754 &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]3755</pre>
3756
3757<h5>Overview:</h5>
3758
3759<p>
3760The '<tt>select</tt>' instruction is used to choose one value based on a
3761condition, without branching.
3762</p>
3763
3764
3765<h5>Arguments:</h5>
3766
3767<p>
3768The '<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.
3769</p>
3770
3771<h5>Semantics:</h5>
3772
3773<p>
3774If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3775value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3776</p>
3777
3778<h5>Example:</h5>
3779
3780<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3781 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3782</pre>
3783</div>
3784
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3785
3786<!-- _______________________________________________________________________ -->
3787<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3788 <a name="i_call">'<tt>call</tt>' Instruction</a>
3789</div>
3790
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3791<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3793<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3794<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3795 &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]3796</pre>
3797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3799
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3800<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3801
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3802<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3803
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3804<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3805
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3806<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3807 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3808 <p>The optional "tail" marker indicates whether the callee function accesses
3809 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3810 function call is eligible for tail call optimization. Note that calls may
3811 be marked "tail" even if they do not occur before a <a
3812 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3813 </li>
3814 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3815 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3816 convention</a> the call should use. If none is specified, the call defaults
3817 to using C calling conventions.
3818 </li>
3819 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3820 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3821 the type of the return value. Functions that return no value are marked
3822 <tt><a href="#t_void">void</a></tt>.</p>
3823 </li>
3824 <li>
3825 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3826 value being invoked. The argument types must match the types implied by
3827 this signature. This type can be omitted if the function is not varargs
3828 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3829 </li>
3830 <li>
3831 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3832 be invoked. In most cases, this is a direct function invocation, but
3833 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3834 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3835 </li>
3836 <li>
3837 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3838 function signature argument types. All arguments must be of
3839 <a href="#t_firstclass">first class</a> type. If the function signature
3840 indicates the function accepts a variable number of arguments, the extra
3841 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3842 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3843</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3845<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3846
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3847<p>The '<tt>call</tt>' instruction is used to cause control flow to
3848transfer to a specified function, with its incoming arguments bound to
3849the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3850instruction in the called function, control flow continues with the
3851instruction after the function call, and the return value of the
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3852function is bound to the result argument. If the callee returns multiple
3853values then the return values of the function are only accessible through
3854the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3856<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3857
3858<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3859 %retval = call i32 @test(i32 %argc)
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3860 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
3861 %X = tail call i32 @foo() <i>; yields i32</i>
3862 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
3863 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3864
3865 %struct.A = type { i32, i8 }
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]3866 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
3867 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
3868 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3869</pre>
3870
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3871</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3872
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3873<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3874<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3875 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3876</div>
3877
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3878<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3879
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3880<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3881
3882<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3883 &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]3884</pre>
3885
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3886<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3887
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3888<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3889the "variable argument" area of a function call. It is used to implement the
3890<tt>va_arg</tt> macro in C.</p>
3891
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3892<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3893
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3894<p>This instruction takes a <tt>va_list*</tt> value and the type of
3895the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3896increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3897actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3898
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3899<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3900
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3901<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3902type from the specified <tt>va_list</tt> and causes the
3903<tt>va_list</tt> to point to the next argument. For more information,
3904see the variable argument handling <a href="#int_varargs">Intrinsic
3905Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3906
3907<p>It is legal for this instruction to be called in a function which does not
3908take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3909function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3910
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3911<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3912href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3913argument.</p>
3914
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3915<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3916
3917<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3919</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3920
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3921<!-- _______________________________________________________________________ -->
3922<div class="doc_subsubsection">
3923 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3924</div>
3925
3926<div class="doc_text">
3927
3928<h5>Syntax:</h5>
3929<pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3930 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3931</pre>
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3932
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3933<h5>Overview:</h5>
3934
3935<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3936from a '<tt><a href="#i_call">call</a></tt>'
3937or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
3938results.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3939
3940<h5>Arguments:</h5>
3941
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3942<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattner1c406d72008-04-23 04:06:52 +0000[diff] [blame]3943first argument, or an undef value. The value must have <a
3944href="#t_struct">structure type</a>. The second argument is a constant
3945unsigned index value which must be in range for the number of values returned
3946by the call.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3947
3948<h5>Semantics:</h5>
3949
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3950<p>The '<tt>getresult</tt>' instruction extracts the element identified by
3951'<tt>index</tt>' from the aggregate value.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3952
3953<h5>Example:</h5>
3954
3955<pre>
3956 %struct.A = type { i32, i8 }
3957
3958 %r = call %struct.A @foo()
Chris Lattner45c5e8b2008-03-21 17:20:51 +0000[diff] [blame]3959 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
3960 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3961 add i32 %gr, 42
3962 add i8 %gr1, 41
3963</pre>
3964
3965</div>
3966
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3967<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3968<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3969<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3971<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3972
3973<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3974well known names and semantics and are required to follow certain restrictions.
3975Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3976language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3977adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3978
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3979<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3980prefix is reserved in LLVM for intrinsic names; thus, function names may not
3981begin with this prefix. Intrinsic functions must always be external functions:
3982you cannot define the body of intrinsic functions. Intrinsic functions may
3983only be used in call or invoke instructions: it is illegal to take the address
3984of an intrinsic function. Additionally, because intrinsic functions are part
3985of the LLVM language, it is required if any are added that they be documented
3986here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3987
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3988<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3989a family of functions that perform the same operation but on different data
3990types. Because LLVM can represent over 8 million different integer types,
3991overloading is used commonly to allow an intrinsic function to operate on any
3992integer type. One or more of the argument types or the result type can be
3993overloaded to accept any integer type. Argument types may also be defined as
3994exactly matching a previous argument's type or the result type. This allows an
3995intrinsic function which accepts multiple arguments, but needs all of them to
3996be of the same type, to only be overloaded with respect to a single argument or
3997the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3998
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3999<p>Overloaded intrinsics will have the names of its overloaded argument types
4000encoded into its function name, each preceded by a period. Only those types
4001which are overloaded result in a name suffix. Arguments whose type is matched
4002against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4003take an integer of any width and returns an integer of exactly the same integer
4004width. This leads to a family of functions such as
4005<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4006Only one type, the return type, is overloaded, and only one type suffix is
4007required. Because the argument's type is matched against the return type, it
4008does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4009
4010<p>To learn how to add an intrinsic function, please see the
4011<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4012</p>
4013
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4014</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4015
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4016<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4017<div class="doc_subsection">
4018 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4019</div>
4020
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4021<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4022
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4023<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]4024 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4025intrinsic functions. These functions are related to the similarly
4026named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4027
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4028<p>All of these functions operate on arguments that use a
4029target-specific value type "<tt>va_list</tt>". The LLVM assembly
4030language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4031transformations should be prepared to handle these functions regardless of
4032the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4033
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]4034<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]4035instruction and the variable argument handling intrinsic functions are
4036used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4037
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4038<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4039<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4040define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4041 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4042 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4043 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4044 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4045
4046 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4047 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4048
4049 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4050 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4051 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4052 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4053 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4054
4055 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4056 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4057 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4058}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4059
4060declare void @llvm.va_start(i8*)
4061declare void @llvm.va_copy(i8*, i8*)
4062declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4063</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4064</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4065
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4066</div>
4067
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4068<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4069<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4070 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4071</div>
4072
4073
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4074<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4075<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4076<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4077<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4078<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4079<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4080href="#i_va_arg">va_arg</a></tt>.</p>
4081
4082<h5>Arguments:</h5>
4083
4084<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4085
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4086<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4087
4088<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4089macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4090<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]4091<tt>va_arg</tt> will produce the first variable argument passed to the function.
4092Unlike 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]4093last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4094
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4095</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4096
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4097<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4098<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4099 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4100</div>
4101
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4102<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4103<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4104<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4105<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4106
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4107<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4108which 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]4109or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4110
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4111<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4112
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4113<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]4114
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4115<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4116
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4117<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]4118macro available in C. In a target-dependent way, it destroys the
4119<tt>va_list</tt> element to which the argument points. Calls to <a
4120href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4121<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4122<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4123
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4124</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4125
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4126<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4127<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4128 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4129</div>
4130
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4131<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4132
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4133<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4134
4135<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4136 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4137</pre>
4138
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4139<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4140
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4141<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4142from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4143
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4144<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4145
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4146<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]4147The 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]4148
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4149
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4150<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4151
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4152<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4153macro available in C. In a target-dependent way, it copies the source
4154<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4155intrinsic is necessary because the <tt><a href="#int_va_start">
4156llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4157example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4158
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4159</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4160
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4161<!-- ======================================================================= -->
4162<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4163 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4164</div>
4165
4166<div class="doc_text">
4167
4168<p>
4169LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4170Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4171These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4172stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4173href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4174Front-ends for type-safe garbage collected languages should generate these
4175intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4176href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4177</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4178
4179<p>The garbage collection intrinsics only operate on objects in the generic
4180 address space (address space zero).</p>
4181
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4182</div>
4183
4184<!-- _______________________________________________________________________ -->
4185<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4186 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4187</div>
4188
4189<div class="doc_text">
4190
4191<h5>Syntax:</h5>
4192
4193<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4194 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4195</pre>
4196
4197<h5>Overview:</h5>
4198
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4199<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]4200the code generator, and allows some metadata to be associated with it.</p>
4201
4202<h5>Arguments:</h5>
4203
4204<p>The first argument specifies the address of a stack object that contains the
4205root pointer. The second pointer (which must be either a constant or a global
4206value address) contains the meta-data to be associated with the root.</p>
4207
4208<h5>Semantics:</h5>
4209
4210<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4211location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4212the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4213intrinsic may only be used in a function which <a href="#gc">specifies a GC
4214algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4215
4216</div>
4217
4218
4219<!-- _______________________________________________________________________ -->
4220<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4221 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4222</div>
4223
4224<div class="doc_text">
4225
4226<h5>Syntax:</h5>
4227
4228<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4229 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4230</pre>
4231
4232<h5>Overview:</h5>
4233
4234<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4235locations, allowing garbage collector implementations that require read
4236barriers.</p>
4237
4238<h5>Arguments:</h5>
4239
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4240<p>The second argument is the address to read from, which should be an address
4241allocated from the garbage collector. The first object is a pointer to the
4242start of the referenced object, if needed by the language runtime (otherwise
4243null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4244
4245<h5>Semantics:</h5>
4246
4247<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4248instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4249garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4250may only be used in a function which <a href="#gc">specifies a GC
4251algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4252
4253</div>
4254
4255
4256<!-- _______________________________________________________________________ -->
4257<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4258 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4259</div>
4260
4261<div class="doc_text">
4262
4263<h5>Syntax:</h5>
4264
4265<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4266 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4267</pre>
4268
4269<h5>Overview:</h5>
4270
4271<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4272locations, allowing garbage collector implementations that require write
4273barriers (such as generational or reference counting collectors).</p>
4274
4275<h5>Arguments:</h5>
4276
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4277<p>The first argument is the reference to store, the second is the start of the
4278object to store it to, and the third is the address of the field of Obj to
4279store to. If the runtime does not require a pointer to the object, Obj may be
4280null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4281
4282<h5>Semantics:</h5>
4283
4284<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4285instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4286garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4287may only be used in a function which <a href="#gc">specifies a GC
4288algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4289
4290</div>
4291
4292
4293
4294<!-- ======================================================================= -->
4295<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4296 <a name="int_codegen">Code Generator Intrinsics</a>
4297</div>
4298
4299<div class="doc_text">
4300<p>
4301These intrinsics are provided by LLVM to expose special features that may only
4302be implemented with code generator support.
4303</p>
4304
4305</div>
4306
4307<!-- _______________________________________________________________________ -->
4308<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4309 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4310</div>
4311
4312<div class="doc_text">
4313
4314<h5>Syntax:</h5>
4315<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4316 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4317</pre>
4318
4319<h5>Overview:</h5>
4320
4321<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4322The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4323target-specific value indicating the return address of the current function
4324or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4325</p>
4326
4327<h5>Arguments:</h5>
4328
4329<p>
4330The argument to this intrinsic indicates which function to return the address
4331for. Zero indicates the calling function, one indicates its caller, etc. The
4332argument is <b>required</b> to be a constant integer value.
4333</p>
4334
4335<h5>Semantics:</h5>
4336
4337<p>
4338The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4339the return address of the specified call frame, or zero if it cannot be
4340identified. The value returned by this intrinsic is likely to be incorrect or 0
4341for arguments other than zero, so it should only be used for debugging purposes.
4342</p>
4343
4344<p>
4345Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4346aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4347source-language caller.
4348</p>
4349</div>
4350
4351
4352<!-- _______________________________________________________________________ -->
4353<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4354 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4355</div>
4356
4357<div class="doc_text">
4358
4359<h5>Syntax:</h5>
4360<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4361 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4362</pre>
4363
4364<h5>Overview:</h5>
4365
4366<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4367The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4368target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4369</p>
4370
4371<h5>Arguments:</h5>
4372
4373<p>
4374The argument to this intrinsic indicates which function to return the frame
4375pointer for. Zero indicates the calling function, one indicates its caller,
4376etc. The argument is <b>required</b> to be a constant integer value.
4377</p>
4378
4379<h5>Semantics:</h5>
4380
4381<p>
4382The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4383the frame address of the specified call frame, or zero if it cannot be
4384identified. The value returned by this intrinsic is likely to be incorrect or 0
4385for arguments other than zero, so it should only be used for debugging purposes.
4386</p>
4387
4388<p>
4389Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4390aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4391source-language caller.
4392</p>
4393</div>
4394
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4395<!-- _______________________________________________________________________ -->
4396<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4397 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4398</div>
4399
4400<div class="doc_text">
4401
4402<h5>Syntax:</h5>
4403<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4404 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4405</pre>
4406
4407<h5>Overview:</h5>
4408
4409<p>
4410The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4411the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4412<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4413features like scoped automatic variable sized arrays in C99.
4414</p>
4415
4416<h5>Semantics:</h5>
4417
4418<p>
4419This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4420href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4421<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4422<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4423state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4424practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4425that were allocated after the <tt>llvm.stacksave</tt> was executed.
4426</p>
4427
4428</div>
4429
4430<!-- _______________________________________________________________________ -->
4431<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4432 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4433</div>
4434
4435<div class="doc_text">
4436
4437<h5>Syntax:</h5>
4438<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4439 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4440</pre>
4441
4442<h5>Overview:</h5>
4443
4444<p>
4445The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4446the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4447href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4448useful for implementing language features like scoped automatic variable sized
4449arrays in C99.
4450</p>
4451
4452<h5>Semantics:</h5>
4453
4454<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4455See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4456</p>
4457
4458</div>
4459
4460
4461<!-- _______________________________________________________________________ -->
4462<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4463 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4464</div>
4465
4466<div class="doc_text">
4467
4468<h5>Syntax:</h5>
4469<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4470 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]4471</pre>
4472
4473<h5>Overview:</h5>
4474
4475
4476<p>
4477The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4478a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4479no
4480effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4481characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4482</p>
4483
4484<h5>Arguments:</h5>
4485
4486<p>
4487<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4488determining if the fetch should be for a read (0) or write (1), and
4489<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4490locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4491<tt>locality</tt> arguments must be constant integers.
4492</p>
4493
4494<h5>Semantics:</h5>
4495
4496<p>
4497This intrinsic does not modify the behavior of the program. In particular,
4498prefetches cannot trap and do not produce a value. On targets that support this
4499intrinsic, the prefetch can provide hints to the processor cache for better
4500performance.
4501</p>
4502
4503</div>
4504
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4505<!-- _______________________________________________________________________ -->
4506<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4507 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4508</div>
4509
4510<div class="doc_text">
4511
4512<h5>Syntax:</h5>
4513<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4514 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4515</pre>
4516
4517<h5>Overview:</h5>
4518
4519
4520<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4521The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4522(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4523code to simulators and other tools. The method is target specific, but it is
4524expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4525The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4526after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4527optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4528correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4529</p>
4530
4531<h5>Arguments:</h5>
4532
4533<p>
4534<tt>id</tt> is a numerical id identifying the marker.
4535</p>
4536
4537<h5>Semantics:</h5>
4538
4539<p>
4540This intrinsic does not modify the behavior of the program. Backends that do not
4541support this intrinisic may ignore it.
4542</p>
4543
4544</div>
4545
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4546<!-- _______________________________________________________________________ -->
4547<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4548 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4549</div>
4550
4551<div class="doc_text">
4552
4553<h5>Syntax:</h5>
4554<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4555 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4556</pre>
4557
4558<h5>Overview:</h5>
4559
4560
4561<p>
4562The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4563counter register (or similar low latency, high accuracy clocks) on those targets
4564that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4565As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4566should only be used for small timings.
4567</p>
4568
4569<h5>Semantics:</h5>
4570
4571<p>
4572When directly supported, reading the cycle counter should not modify any memory.
4573Implementations are allowed to either return a application specific value or a
4574system wide value. On backends without support, this is lowered to a constant 0.
4575</p>
4576
4577</div>
4578
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4579<!-- ======================================================================= -->
4580<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4581 <a name="int_libc">Standard C Library Intrinsics</a>
4582</div>
4583
4584<div class="doc_text">
4585<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4586LLVM provides intrinsics for a few important standard C library functions.
4587These intrinsics allow source-language front-ends to pass information about the
4588alignment of the pointer arguments to the code generator, providing opportunity
4589for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4590</p>
4591
4592</div>
4593
4594<!-- _______________________________________________________________________ -->
4595<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4596 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4597</div>
4598
4599<div class="doc_text">
4600
4601<h5>Syntax:</h5>
4602<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4603 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4604 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4605 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4606 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4607</pre>
4608
4609<h5>Overview:</h5>
4610
4611<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4612The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4613location to the destination location.
4614</p>
4615
4616<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4617Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4618intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4619</p>
4620
4621<h5>Arguments:</h5>
4622
4623<p>
4624The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4625the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4626specifying the number of bytes to copy, and the fourth argument is the alignment
4627of the source and destination locations.
4628</p>
4629
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4630<p>
4631If 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]4632the caller guarantees that both the source and destination pointers are aligned
4633to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4634</p>
4635
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4636<h5>Semantics:</h5>
4637
4638<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4639The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4640location to the destination location, which are not allowed to overlap. It
4641copies "len" bytes of memory over. If the argument is known to be aligned to
4642some boundary, this can be specified as the fourth argument, otherwise it should
4643be set to 0 or 1.
4644</p>
4645</div>
4646
4647
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4648<!-- _______________________________________________________________________ -->
4649<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4650 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4651</div>
4652
4653<div class="doc_text">
4654
4655<h5>Syntax:</h5>
4656<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4657 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4658 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4659 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4660 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4661</pre>
4662
4663<h5>Overview:</h5>
4664
4665<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4666The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4667location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4668'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4669</p>
4670
4671<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4672Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4673intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4674</p>
4675
4676<h5>Arguments:</h5>
4677
4678<p>
4679The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4680the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4681specifying the number of bytes to copy, and the fourth argument is the alignment
4682of the source and destination locations.
4683</p>
4684
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4685<p>
4686If 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]4687the caller guarantees that the source and destination pointers are aligned to
4688that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4689</p>
4690
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4691<h5>Semantics:</h5>
4692
4693<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4694The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4695location to the destination location, which may overlap. It
4696copies "len" bytes of memory over. If the argument is known to be aligned to
4697some boundary, this can be specified as the fourth argument, otherwise it should
4698be set to 0 or 1.
4699</p>
4700</div>
4701
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4702
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4703<!-- _______________________________________________________________________ -->
4704<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4705 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4706</div>
4707
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
4711<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4712 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4713 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4714 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4715 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4716</pre>
4717
4718<h5>Overview:</h5>
4719
4720<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4721The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4722byte value.
4723</p>
4724
4725<p>
4726Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4727does not return a value, and takes an extra alignment argument.
4728</p>
4729
4730<h5>Arguments:</h5>
4731
4732<p>
4733The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4734byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4735argument specifying the number of bytes to fill, and the fourth argument is the
4736known alignment of destination location.
4737</p>
4738
4739<p>
4740If 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]4741the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4742</p>
4743
4744<h5>Semantics:</h5>
4745
4746<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4747The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4748the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4749destination location. If the argument is known to be aligned to some boundary,
4750this can be specified as the fourth argument, otherwise it should be set to 0 or
47511.
4752</p>
4753</div>
4754
4755
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4756<!-- _______________________________________________________________________ -->
4757<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4758 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4759</div>
4760
4761<div class="doc_text">
4762
4763<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4764<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]4765floating point or vector of floating point type. Not all targets support all
4766types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4767<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4768 declare float @llvm.sqrt.f32(float %Val)
4769 declare double @llvm.sqrt.f64(double %Val)
4770 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4771 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4772 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4773</pre>
4774
4775<h5>Overview:</h5>
4776
4777<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4778The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4779returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4780<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner103e2d72008-01-29 07:00:44 +0000[diff] [blame]4781negative numbers other than -0.0 (which allows for better optimization, because
4782there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4783defined to return -0.0 like IEEE sqrt.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4784</p>
4785
4786<h5>Arguments:</h5>
4787
4788<p>
4789The argument and return value are floating point numbers of the same type.
4790</p>
4791
4792<h5>Semantics:</h5>
4793
4794<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4795This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4796floating point number.
4797</p>
4798</div>
4799
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4800<!-- _______________________________________________________________________ -->
4801<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4802 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4803</div>
4804
4805<div class="doc_text">
4806
4807<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4808<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]4809floating point or vector of floating point type. Not all targets support all
4810types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4811<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4812 declare float @llvm.powi.f32(float %Val, i32 %power)
4813 declare double @llvm.powi.f64(double %Val, i32 %power)
4814 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4815 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4816 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4817</pre>
4818
4819<h5>Overview:</h5>
4820
4821<p>
4822The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4823specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4824multiplications is not defined. When a vector of floating point type is
4825used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4826</p>
4827
4828<h5>Arguments:</h5>
4829
4830<p>
4831The second argument is an integer power, and the first is a value to raise to
4832that power.
4833</p>
4834
4835<h5>Semantics:</h5>
4836
4837<p>
4838This function returns the first value raised to the second power with an
4839unspecified sequence of rounding operations.</p>
4840</div>
4841
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4842<!-- _______________________________________________________________________ -->
4843<div class="doc_subsubsection">
4844 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4845</div>
4846
4847<div class="doc_text">
4848
4849<h5>Syntax:</h5>
4850<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4851floating point or vector of floating point type. Not all targets support all
4852types however.
4853<pre>
4854 declare float @llvm.sin.f32(float %Val)
4855 declare double @llvm.sin.f64(double %Val)
4856 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4857 declare fp128 @llvm.sin.f128(fp128 %Val)
4858 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4859</pre>
4860
4861<h5>Overview:</h5>
4862
4863<p>
4864The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4865</p>
4866
4867<h5>Arguments:</h5>
4868
4869<p>
4870The argument and return value are floating point numbers of the same type.
4871</p>
4872
4873<h5>Semantics:</h5>
4874
4875<p>
4876This function returns the sine of the specified operand, returning the
4877same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4878conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
4883 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4884</div>
4885
4886<div class="doc_text">
4887
4888<h5>Syntax:</h5>
4889<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4890floating point or vector of floating point type. Not all targets support all
4891types however.
4892<pre>
4893 declare float @llvm.cos.f32(float %Val)
4894 declare double @llvm.cos.f64(double %Val)
4895 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4896 declare fp128 @llvm.cos.f128(fp128 %Val)
4897 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4898</pre>
4899
4900<h5>Overview:</h5>
4901
4902<p>
4903The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4904</p>
4905
4906<h5>Arguments:</h5>
4907
4908<p>
4909The argument and return value are floating point numbers of the same type.
4910</p>
4911
4912<h5>Semantics:</h5>
4913
4914<p>
4915This function returns the cosine of the specified operand, returning the
4916same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4917conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4923</div>
4924
4925<div class="doc_text">
4926
4927<h5>Syntax:</h5>
4928<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4929floating point or vector of floating point type. Not all targets support all
4930types however.
4931<pre>
4932 declare float @llvm.pow.f32(float %Val, float %Power)
4933 declare double @llvm.pow.f64(double %Val, double %Power)
4934 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4935 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4936 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4937</pre>
4938
4939<h5>Overview:</h5>
4940
4941<p>
4942The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4943specified (positive or negative) power.
4944</p>
4945
4946<h5>Arguments:</h5>
4947
4948<p>
4949The second argument is a floating point power, and the first is a value to
4950raise to that power.
4951</p>
4952
4953<h5>Semantics:</h5>
4954
4955<p>
4956This function returns the first value raised to the second power,
4957returning the
4958same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4959conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4960</div>
4961
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4962
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4963<!-- ======================================================================= -->
4964<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4965 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4966</div>
4967
4968<div class="doc_text">
4969<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4970LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4971These allow efficient code generation for some algorithms.
4972</p>
4973
4974</div>
4975
4976<!-- _______________________________________________________________________ -->
4977<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4978 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4979</div>
4980
4981<div class="doc_text">
4982
4983<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4984<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4985type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4986<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4987 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4988 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4989 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4990</pre>
4991
4992<h5>Overview:</h5>
4993
4994<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4995The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4996values with an even number of bytes (positive multiple of 16 bits). These are
4997useful for performing operations on data that is not in the target's native
4998byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4999</p>
5000
5001<h5>Semantics:</h5>
5002
5003<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5004The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5005and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5006intrinsic returns an i32 value that has the four bytes of the input i32
5007swapped, 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]5008i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5009<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5010additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]5011</p>
5012
5013</div>
5014
5015<!-- _______________________________________________________________________ -->
5016<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5017 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5018</div>
5019
5020<div class="doc_text">
5021
5022<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5023<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5024width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5025<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5026 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5027 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5028 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5029 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5030 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5031</pre>
5032
5033<h5>Overview:</h5>
5034
5035<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]5036The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5037value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5038</p>
5039
5040<h5>Arguments:</h5>
5041
5042<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5043The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5044integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5045</p>
5046
5047<h5>Semantics:</h5>
5048
5049<p>
5050The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5051</p>
5052</div>
5053
5054<!-- _______________________________________________________________________ -->
5055<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5056 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5057</div>
5058
5059<div class="doc_text">
5060
5061<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5062<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5063integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5064<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5065 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5066 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5067 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5068 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5069 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5070</pre>
5071
5072<h5>Overview:</h5>
5073
5074<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5075The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5076leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5077</p>
5078
5079<h5>Arguments:</h5>
5080
5081<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5082The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5083integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5084</p>
5085
5086<h5>Semantics:</h5>
5087
5088<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5089The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5090in 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]5091of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5092</p>
5093</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5094
5095
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5096
5097<!-- _______________________________________________________________________ -->
5098<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5099 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5100</div>
5101
5102<div class="doc_text">
5103
5104<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5105<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5106integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5107<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5108 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5109 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5110 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5111 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5112 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5113</pre>
5114
5115<h5>Overview:</h5>
5116
5117<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5118The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5119trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5120</p>
5121
5122<h5>Arguments:</h5>
5123
5124<p>
5125The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5126integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5127</p>
5128
5129<h5>Semantics:</h5>
5130
5131<p>
5132The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5133in a variable. If the src == 0 then the result is the size in bits of the type
5134of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5135</p>
5136</div>
5137
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5138<!-- _______________________________________________________________________ -->
5139<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5140 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5141</div>
5142
5143<div class="doc_text">
5144
5145<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5146<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5147on any integer bit width.
5148<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5149 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5150 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5151</pre>
5152
5153<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5154<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5155range of bits from an integer value and returns them in the same bit width as
5156the original value.</p>
5157
5158<h5>Arguments:</h5>
5159<p>The first argument, <tt>%val</tt> and the result may be integer types of
5160any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5161arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5162
5163<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5164<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5165of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5166<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5167operates in forward mode.</p>
5168<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5169right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5170only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5171<ol>
5172 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5173 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5174 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5175 to determine the number of bits to retain.</li>
5176 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5177 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5178</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5179<p>In reverse mode, a similar computation is made except that the bits are
5180returned in the reverse order. So, for example, if <tt>X</tt> has the value
5181<tt>i16 0x0ACF (101011001111)</tt> and we apply
5182<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5183<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5184</div>
5185
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5186<div class="doc_subsubsection">
5187 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5188</div>
5189
5190<div class="doc_text">
5191
5192<h5>Syntax:</h5>
5193<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5194on any integer bit width.
5195<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5196 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5197 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]5198</pre>
5199
5200<h5>Overview:</h5>
5201<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5202of bits in an integer value with another integer value. It returns the integer
5203with the replaced bits.</p>
5204
5205<h5>Arguments:</h5>
5206<p>The first argument, <tt>%val</tt> and the result may be integer types of
5207any bit width but they must have the same bit width. <tt>%val</tt> is the value
5208whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5209integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5210type since they specify only a bit index.</p>
5211
5212<h5>Semantics:</h5>
5213<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5214of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5215<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5216operates in forward mode.</p>
5217<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5218truncating it down to the size of the replacement area or zero extending it
5219up to that size.</p>
5220<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5221are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5222in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5223to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5224<p>In reverse mode, a similar computation is made except that the bits are
5225reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5226<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]5227<h5>Examples:</h5>
5228<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5229 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5230 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5231 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5232 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5233 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5234</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5235</div>
5236
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5237<!-- ======================================================================= -->
5238<div class="doc_subsection">
5239 <a name="int_debugger">Debugger Intrinsics</a>
5240</div>
5241
5242<div class="doc_text">
5243<p>
5244The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5245are described in the <a
5246href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5247Debugging</a> document.
5248</p>
5249</div>
5250
5251
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5252<!-- ======================================================================= -->
5253<div class="doc_subsection">
5254 <a name="int_eh">Exception Handling Intrinsics</a>
5255</div>
5256
5257<div class="doc_text">
5258<p> The LLVM exception handling intrinsics (which all start with
5259<tt>llvm.eh.</tt> prefix), are described in the <a
5260href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5261Handling</a> document. </p>
5262</div>
5263
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5264<!-- ======================================================================= -->
5265<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5266 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5267</div>
5268
5269<div class="doc_text">
5270<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5271 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5272 the <tt>nest</tt> attribute, from a function. The result is a callable
5273 function pointer lacking the nest parameter - the caller does not need
5274 to provide a value for it. Instead, the value to use is stored in
5275 advance in a "trampoline", a block of memory usually allocated
5276 on the stack, which also contains code to splice the nest value into the
5277 argument list. This is used to implement the GCC nested function address
5278 extension.
5279</p>
5280<p>
5281 For example, if the function is
5282 <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]5283 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]5284<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5285 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5286 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5287 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5288 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5289</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5290 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5291 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5292</div>
5293
5294<!-- _______________________________________________________________________ -->
5295<div class="doc_subsubsection">
5296 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5297</div>
5298<div class="doc_text">
5299<h5>Syntax:</h5>
5300<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5301declare 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]5302</pre>
5303<h5>Overview:</h5>
5304<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5305 This fills the memory pointed to by <tt>tramp</tt> with code
5306 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5307</p>
5308<h5>Arguments:</h5>
5309<p>
5310 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5311 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5312 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5313 intrinsic. Note that the size and the alignment are target-specific - LLVM
5314 currently provides no portable way of determining them, so a front-end that
5315 generates this intrinsic needs to have some target-specific knowledge.
5316 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]5317</p>
5318<h5>Semantics:</h5>
5319<p>
5320 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5321 dependent code, turning it into a function. A pointer to this function is
5322 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5323 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5324 before being called. The new function's signature is the same as that of
5325 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5326 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5327 of pointer type. Calling the new function is equivalent to calling
5328 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5329 missing <tt>nest</tt> argument. If, after calling
5330 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5331 modified, then the effect of any later call to the returned function pointer is
5332 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5333</p>
5334</div>
5335
5336<!-- ======================================================================= -->
5337<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5338 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5339</div>
5340
5341<div class="doc_text">
5342<p>
5343 These intrinsic functions expand the "universal IR" of LLVM to represent
5344 hardware constructs for atomic operations and memory synchronization. This
5345 provides an interface to the hardware, not an interface to the programmer. It
5346 is aimed at a low enough level to allow any programming models or APIs which
5347 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5348 hardware behavior. Just as hardware provides a "universal IR" for source
5349 languages, it also provides a starting point for developing a "universal"
5350 atomic operation and synchronization IR.
5351</p>
5352<p>
5353 These do <em>not</em> form an API such as high-level threading libraries,
5354 software transaction memory systems, atomic primitives, and intrinsic
5355 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5356 application libraries. The hardware interface provided by LLVM should allow
5357 a clean implementation of all of these APIs and parallel programming models.
5358 No one model or paradigm should be selected above others unless the hardware
5359 itself ubiquitously does so.
5360
5361</p>
5362</div>
5363
5364<!-- _______________________________________________________________________ -->
5365<div class="doc_subsubsection">
5366 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5367</div>
5368<div class="doc_text">
5369<h5>Syntax:</h5>
5370<pre>
5371declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5372i1 &lt;device&gt; )
5373
5374</pre>
5375<h5>Overview:</h5>
5376<p>
5377 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5378 specific pairs of memory access types.
5379</p>
5380<h5>Arguments:</h5>
5381<p>
5382 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5383 The first four arguments enables a specific barrier as listed below. The fith
5384 argument specifies that the barrier applies to io or device or uncached memory.
5385
5386</p>
5387 <ul>
5388 <li><tt>ll</tt>: load-load barrier</li>
5389 <li><tt>ls</tt>: load-store barrier</li>
5390 <li><tt>sl</tt>: store-load barrier</li>
5391 <li><tt>ss</tt>: store-store barrier</li>
5392 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5393 </ul>
5394<h5>Semantics:</h5>
5395<p>
5396 This intrinsic causes the system to enforce some ordering constraints upon
5397 the loads and stores of the program. This barrier does not indicate
5398 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5399 which they occur. For any of the specified pairs of load and store operations
5400 (f.ex. load-load, or store-load), all of the first operations preceding the
5401 barrier will complete before any of the second operations succeeding the
5402 barrier begin. Specifically the semantics for each pairing is as follows:
5403</p>
5404 <ul>
5405 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5406 after the barrier begins.</li>
5407
5408 <li><tt>ls</tt>: All loads before the barrier must complete before any
5409 store after the barrier begins.</li>
5410 <li><tt>ss</tt>: All stores before the barrier must complete before any
5411 store after the barrier begins.</li>
5412 <li><tt>sl</tt>: All stores before the barrier must complete before any
5413 load after the barrier begins.</li>
5414 </ul>
5415<p>
5416 These semantics are applied with a logical "and" behavior when more than one
5417 is enabled in a single memory barrier intrinsic.
5418</p>
5419<p>
5420 Backends may implement stronger barriers than those requested when they do not
5421 support as fine grained a barrier as requested. Some architectures do not
5422 need all types of barriers and on such architectures, these become noops.
5423</p>
5424<h5>Example:</h5>
5425<pre>
5426%ptr = malloc i32
5427 store i32 4, %ptr
5428
5429%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5430 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5431 <i>; guarantee the above finishes</i>
5432 store i32 8, %ptr <i>; before this begins</i>
5433</pre>
5434</div>
5435
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]5436<!-- _______________________________________________________________________ -->
5437<div class="doc_subsubsection">
5438 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5439</div>
5440<div class="doc_text">
5441<h5>Syntax:</h5>
5442<p>
5443 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5444 integer bit width. Not all targets support all bit widths however.</p>
5445
5446<pre>
5447declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5448declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5449declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5450declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5451
5452</pre>
5453<h5>Overview:</h5>
5454<p>
5455 This loads a value in memory and compares it to a given value. If they are
5456 equal, it stores a new value into the memory.
5457</p>
5458<h5>Arguments:</h5>
5459<p>
5460 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5461 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5462 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5463 this integer type. While any bit width integer may be used, targets may only
5464 lower representations they support in hardware.
5465
5466</p>
5467<h5>Semantics:</h5>
5468<p>
5469 This entire intrinsic must be executed atomically. It first loads the value
5470 in memory pointed to by <tt>ptr</tt> and compares it with the value
5471 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5472 loaded value is yielded in all cases. This provides the equivalent of an
5473 atomic compare-and-swap operation within the SSA framework.
5474</p>
5475<h5>Examples:</h5>
5476
5477<pre>
5478%ptr = malloc i32
5479 store i32 4, %ptr
5480
5481%val1 = add i32 4, 4
5482%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5483 <i>; yields {i32}:result1 = 4</i>
5484%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5485%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5486
5487%val2 = add i32 1, 1
5488%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5489 <i>; yields {i32}:result2 = 8</i>
5490%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5491
5492%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5493</pre>
5494</div>
5495
5496<!-- _______________________________________________________________________ -->
5497<div class="doc_subsubsection">
5498 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5499</div>
5500<div class="doc_text">
5501<h5>Syntax:</h5>
5502
5503<p>
5504 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5505 integer bit width. Not all targets support all bit widths however.</p>
5506<pre>
5507declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5508declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5509declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5510declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5511
5512</pre>
5513<h5>Overview:</h5>
5514<p>
5515 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5516 the value from memory. It then stores the value in <tt>val</tt> in the memory
5517 at <tt>ptr</tt>.
5518</p>
5519<h5>Arguments:</h5>
5520
5521<p>
5522 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5523 <tt>val</tt> argument and the result must be integers of the same bit width.
5524 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5525 integer type. The targets may only lower integer representations they
5526 support.
5527</p>
5528<h5>Semantics:</h5>
5529<p>
5530 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5531 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5532 equivalent of an atomic swap operation within the SSA framework.
5533
5534</p>
5535<h5>Examples:</h5>
5536<pre>
5537%ptr = malloc i32
5538 store i32 4, %ptr
5539
5540%val1 = add i32 4, 4
5541%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5542 <i>; yields {i32}:result1 = 4</i>
5543%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5544%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5545
5546%val2 = add i32 1, 1
5547%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5548 <i>; yields {i32}:result2 = 8</i>
5549
5550%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5551%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5552</pre>
5553</div>
5554
5555<!-- _______________________________________________________________________ -->
5556<div class="doc_subsubsection">
5557 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5558
5559</div>
5560<div class="doc_text">
5561<h5>Syntax:</h5>
5562<p>
5563 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5564 integer bit width. Not all targets support all bit widths however.</p>
5565<pre>
5566declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5567declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5568declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5569declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5570
5571</pre>
5572<h5>Overview:</h5>
5573<p>
5574 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5575 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5576</p>
5577<h5>Arguments:</h5>
5578<p>
5579
5580 The intrinsic takes two arguments, the first a pointer to an integer value
5581 and the second an integer value. The result is also an integer value. These
5582 integer types can have any bit width, but they must all have the same bit
5583 width. The targets may only lower integer representations they support.
5584</p>
5585<h5>Semantics:</h5>
5586<p>
5587 This intrinsic does a series of operations atomically. It first loads the
5588 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5589 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5590</p>
5591
5592<h5>Examples:</h5>
5593<pre>
5594%ptr = malloc i32
5595 store i32 4, %ptr
5596%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5597 <i>; yields {i32}:result1 = 4</i>
5598%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5599 <i>; yields {i32}:result2 = 8</i>
5600%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5601 <i>; yields {i32}:result3 = 10</i>
5602%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5603</pre>
5604</div>
5605
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5606
5607<!-- ======================================================================= -->
5608<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5609 <a name="int_general">General Intrinsics</a>
5610</div>
5611
5612<div class="doc_text">
5613<p> This class of intrinsics is designed to be generic and has
5614no specific purpose. </p>
5615</div>
5616
5617<!-- _______________________________________________________________________ -->
5618<div class="doc_subsubsection">
5619 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5620</div>
5621
5622<div class="doc_text">
5623
5624<h5>Syntax:</h5>
5625<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5626 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]5627</pre>
5628
5629<h5>Overview:</h5>
5630
5631<p>
5632The '<tt>llvm.var.annotation</tt>' intrinsic
5633</p>
5634
5635<h5>Arguments:</h5>
5636
5637<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5638The first argument is a pointer to a value, the second is a pointer to a
5639global string, the third is a pointer to a global string which is the source
5640file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5641</p>
5642
5643<h5>Semantics:</h5>
5644
5645<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5646This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5647This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5648annotations. These have no other defined use, they are ignored by code
5649generation and optimization.
5650</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5651</div>
5652
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5655 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5661<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5662any integer bit width.
5663</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5664<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5665 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5666 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5667 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5668 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5669 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]5670</pre>
5671
5672<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5673
5674<p>
5675The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5676</p>
5677
5678<h5>Arguments:</h5>
5679
5680<p>
5681The first argument is an integer value (result of some expression),
5682the second is a pointer to a global string, the third is a pointer to a global
5683string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5684It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5685</p>
5686
5687<h5>Semantics:</h5>
5688
5689<p>
5690This intrinsic allows annotations to be put on arbitrary expressions
5691with arbitrary strings. This can be useful for special purpose optimizations
5692that want to look for these annotations. These have no other defined use, they
5693are ignored by code generation and optimization.
5694</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5695
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5696<!-- _______________________________________________________________________ -->
5697<div class="doc_subsubsection">
5698 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5699</div>
5700
5701<div class="doc_text">
5702
5703<h5>Syntax:</h5>
5704<pre>
5705 declare void @llvm.trap()
5706</pre>
5707
5708<h5>Overview:</h5>
5709
5710<p>
5711The '<tt>llvm.trap</tt>' intrinsic
5712</p>
5713
5714<h5>Arguments:</h5>
5715
5716<p>
5717None
5718</p>
5719
5720<h5>Semantics:</h5>
5721
5722<p>
5723This intrinsics is lowered to the target dependent trap instruction. If the
5724target does not have a trap instruction, this intrinsic will be lowered to the
5725call of the abort() function.
5726</p>
5727</div>
5728
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5729<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5730<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5731<address>
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Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5736
5737 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5738 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5739 Last modified: $Date$
5740</address>
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