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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / d703f65984793c35b1c0dc6d4d2115d237889132 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]114 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
117 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
118 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]119 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
120 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
121 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 </ol>
123 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]124 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]125 <ol>
126 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
127 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
129 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
130 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]131 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
132 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
133 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]135 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
136 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]137 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]138 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#otherops">Other Operations</a>
140 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]141 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
142 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]144 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]146 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]147 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]148 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]149 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]150 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]151 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]152 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]153 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]154 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
155 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]156 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
158 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]159 </ol>
160 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]161 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
162 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]163 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
165 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]166 </ol>
167 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]168 <li><a href="#int_codegen">Code Generator Intrinsics</a>
169 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]170 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
172 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
173 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
174 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
175 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
176 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]177 </ol>
178 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]179 <li><a href="#int_libc">Standard C Library Intrinsics</a>
180 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]181 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
185 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]186 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
188 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]189 </ol>
190 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]191 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]192 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]193 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]194 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
196 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]197 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
198 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]199 </ol>
200 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]201 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]202 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]203 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]206 </ol>
207 </li>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]208 <li><a href="#int_atomics">Atomic intrinsics</a>
209 <ol>
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]210 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
211 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
212 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
213 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]214 </ol>
215 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]216 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]217 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]218 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]219 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]220 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]221 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]222 <li><a href="#int_trap">
223 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]224 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]225 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]226 </ol>
227 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]228</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
230<div class="doc_author">
231 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
232 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]233</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]234
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]235<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]236<div class="doc_section"> <a name="abstract">Abstract </a></div>
237<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]239<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<p>This document is a reference manual for the LLVM assembly language.
241LLVM is an SSA based representation that provides type safety,
242low-level operations, flexibility, and the capability of representing
243'all' high-level languages cleanly. It is the common code
244representation used throughout all phases of the LLVM compilation
245strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]246</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]248<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]249<div class="doc_section"> <a name="introduction">Introduction</a> </div>
250<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]251
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]252<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]254<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]255different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256representation (suitable for fast loading by a Just-In-Time compiler),
257and as a human readable assembly language representation. This allows
258LLVM to provide a powerful intermediate representation for efficient
259compiler transformations and analysis, while providing a natural means
260to debug and visualize the transformations. The three different forms
261of LLVM are all equivalent. This document describes the human readable
262representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]263
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]264<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]265while being expressive, typed, and extensible at the same time. It
266aims to be a "universal IR" of sorts, by being at a low enough level
267that high-level ideas may be cleanly mapped to it (similar to how
268microprocessors are "universal IR's", allowing many source languages to
269be mapped to them). By providing type information, LLVM can be used as
270the target of optimizations: for example, through pointer analysis, it
271can be proven that a C automatic variable is never accessed outside of
272the current function... allowing it to be promoted to a simple SSA
273value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]275</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]277<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]278<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]279
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]280<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]282<p>It is important to note that this document describes 'well formed'
283LLVM assembly language. There is a difference between what the parser
284accepts and what is considered 'well formed'. For example, the
285following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]286
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]287<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]288<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]289%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]290</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]293<p>...because the definition of <tt>%x</tt> does not dominate all of
294its uses. The LLVM infrastructure provides a verification pass that may
295be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]296automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]297the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]298by the verifier pass indicate bugs in transformation passes or input to
299the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]300</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]301
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]302<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]303
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]304<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]305<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]306<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]307
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]308<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]309
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]310 <p>LLVM identifiers come in two basic types: global and local. Global
311 identifiers (functions, global variables) begin with the @ character. Local
312 identifiers (register names, types) begin with the % character. Additionally,
313 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]314
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]316 <li>Named values are represented as a string of characters with their prefix.
317 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
318 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]319 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]320 with quotes. In this way, anything except a <tt>&quot;</tt> character can
321 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]322
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]323 <li>Unnamed values are represented as an unsigned numeric value with their
324 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]326 <li>Constants, which are described in a <a href="#constants">section about
327 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]328</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]330<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331don't need to worry about name clashes with reserved words, and the set of
332reserved words may be expanded in the future without penalty. Additionally,
333unnamed identifiers allow a compiler to quickly come up with a temporary
334variable without having to avoid symbol table conflicts.</p>
335
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]336<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]337languages. There are keywords for different opcodes
338('<tt><a href="#i_add">add</a></tt>',
339 '<tt><a href="#i_bitcast">bitcast</a></tt>',
340 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]341href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]343none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344
345<p>Here is an example of LLVM code to multiply the integer variable
346'<tt>%X</tt>' by 8:</p>
347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]348<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]349
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]350<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]351<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]352%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]353</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]354</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]355
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]356<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]357
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]359<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]360%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]361</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]363
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]364<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]365
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]366<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]367<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]368<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
369<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
370%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]371</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]372</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]373
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]374<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
375important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]378
379 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
380 line.</li>
381
382 <li>Unnamed temporaries are created when the result of a computation is not
383 assigned to a named value.</li>
384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]385 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]387</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]388
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]389<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]390demonstrating instructions, we will follow an instruction with a comment that
391defines the type and name of value produced. Comments are shown in italic
392text.</p>
393
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]394</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]395
396<!-- *********************************************************************** -->
397<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
398<!-- *********************************************************************** -->
399
400<!-- ======================================================================= -->
401<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
402</div>
403
404<div class="doc_text">
405
406<p>LLVM programs are composed of "Module"s, each of which is a
407translation unit of the input programs. Each module consists of
408functions, global variables, and symbol table entries. Modules may be
409combined together with the LLVM linker, which merges function (and
410global variable) definitions, resolves forward declarations, and merges
411symbol table entries. Here is an example of the "hello world" module:</p>
412
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]413<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]414<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]415<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
416 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417
418<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]419<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420
421<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]422define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]423 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]424 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]425 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]426
427 <i>; Call puts function to write out the string to stdout...</i>
428 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]429 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]431 href="#i_ret">ret</a> i32 0<br>}<br>
432</pre>
433</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]434
435<p>This example is made up of a <a href="#globalvars">global variable</a>
436named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
437function, and a <a href="#functionstructure">function definition</a>
438for "<tt>main</tt>".</p>
439
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440<p>In general, a module is made up of a list of global values,
441where both functions and global variables are global values. Global values are
442represented by a pointer to a memory location (in this case, a pointer to an
443array of char, and a pointer to a function), and have one of the following <a
444href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]445
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]446</div>
447
448<!-- ======================================================================= -->
449<div class="doc_subsection">
450 <a name="linkage">Linkage Types</a>
451</div>
452
453<div class="doc_text">
454
455<p>
456All Global Variables and Functions have one of the following types of linkage:
457</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]458
459<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]461 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462
463 <dd>Global values with internal linkage are only directly accessible by
464 objects in the current module. In particular, linking code into a module with
465 an internal global value may cause the internal to be renamed as necessary to
466 avoid collisions. Because the symbol is internal to the module, all
467 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]468 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]473 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
474 the same name when linkage occurs. This is typically used to implement
475 inline functions, templates, or other code which must be generated in each
476 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
477 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]478 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]479
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]481
482 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
483 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]484 used for globals that may be emitted in multiple translation units, but that
485 are not guaranteed to be emitted into every translation unit that uses them.
486 One example of this are common globals in C, such as "<tt>int X;</tt>" at
487 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]489
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]491
492 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
493 pointer to array type. When two global variables with appending linkage are
494 linked together, the two global arrays are appended together. This is the
495 LLVM, typesafe, equivalent of having the system linker append together
496 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]498
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]499 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
500 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
501 until linked, if not linked, the symbol becomes null instead of being an
502 undefined reference.
503 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]504
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]506
507 <dd>If none of the above identifiers are used, the global is externally
508 visible, meaning that it participates in linkage and can be used to resolve
509 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]511</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]512
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]513 <p>
514 The next two types of linkage are targeted for Microsoft Windows platform
515 only. They are designed to support importing (exporting) symbols from (to)
516 DLLs.
517 </p>
518
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]519 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
521
522 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
523 or variable via a global pointer to a pointer that is set up by the DLL
524 exporting the symbol. On Microsoft Windows targets, the pointer name is
525 formed by combining <code>_imp__</code> and the function or variable name.
526 </dd>
527
528 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
531 pointer to a pointer in a DLL, so that it can be referenced with the
532 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
533 name is formed by combining <code>_imp__</code> and the function or variable
534 name.
535 </dd>
536
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]537</dl>
538
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]539<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]540variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
541variable and was linked with this one, one of the two would be renamed,
542preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
543external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]544outside of the current module.</p>
545<p>It is illegal for a function <i>declaration</i>
546to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]547or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]548<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
549linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]550</div>
551
552<!-- ======================================================================= -->
553<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]554 <a name="callingconv">Calling Conventions</a>
555</div>
556
557<div class="doc_text">
558
559<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
560and <a href="#i_invoke">invokes</a> can all have an optional calling convention
561specified for the call. The calling convention of any pair of dynamic
562caller/callee must match, or the behavior of the program is undefined. The
563following calling conventions are supported by LLVM, and more may be added in
564the future:</p>
565
566<dl>
567 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
568
569 <dd>This calling convention (the default if no other calling convention is
570 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]571 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]572 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]573 </dd>
574
575 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
576
577 <dd>This calling convention attempts to make calls as fast as possible
578 (e.g. by passing things in registers). This calling convention allows the
579 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]580 without having to conform to an externally specified ABI. Implementations of
581 this convention should allow arbitrary tail call optimization to be supported.
582 This calling convention does not support varargs and requires the prototype of
583 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]584 </dd>
585
586 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
587
588 <dd>This calling convention attempts to make code in the caller as efficient
589 as possible under the assumption that the call is not commonly executed. As
590 such, these calls often preserve all registers so that the call does not break
591 any live ranges in the caller side. This calling convention does not support
592 varargs and requires the prototype of all callees to exactly match the
593 prototype of the function definition.
594 </dd>
595
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]596 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]597
598 <dd>Any calling convention may be specified by number, allowing
599 target-specific calling conventions to be used. Target specific calling
600 conventions start at 64.
601 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]602</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]603
604<p>More calling conventions can be added/defined on an as-needed basis, to
605support pascal conventions or any other well-known target-independent
606convention.</p>
607
608</div>
609
610<!-- ======================================================================= -->
611<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]612 <a name="visibility">Visibility Styles</a>
613</div>
614
615<div class="doc_text">
616
617<p>
618All Global Variables and Functions have one of the following visibility styles:
619</p>
620
621<dl>
622 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
623
624 <dd>On ELF, default visibility means that the declaration is visible to other
625 modules and, in shared libraries, means that the declared entity may be
626 overridden. On Darwin, default visibility means that the declaration is
627 visible to other modules. Default visibility corresponds to "external
628 linkage" in the language.
629 </dd>
630
631 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
632
633 <dd>Two declarations of an object with hidden visibility refer to the same
634 object if they are in the same shared object. Usually, hidden visibility
635 indicates that the symbol will not be placed into the dynamic symbol table,
636 so no other module (executable or shared library) can reference it
637 directly.
638 </dd>
639
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]640 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
641
642 <dd>On ELF, protected visibility indicates that the symbol will be placed in
643 the dynamic symbol table, but that references within the defining module will
644 bind to the local symbol. That is, the symbol cannot be overridden by another
645 module.
646 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]647</dl>
648
649</div>
650
651<!-- ======================================================================= -->
652<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]653 <a name="globalvars">Global Variables</a>
654</div>
655
656<div class="doc_text">
657
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]658<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]659instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]660an explicit section to be placed in, and may have an optional explicit alignment
661specified. A variable may be defined as "thread_local", which means that it
662will not be shared by threads (each thread will have a separated copy of the
663variable). A variable may be defined as a global "constant," which indicates
664that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]665optimization, allowing the global data to be placed in the read-only section of
666an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]667cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]668
669<p>
670LLVM explicitly allows <em>declarations</em> of global variables to be marked
671constant, even if the final definition of the global is not. This capability
672can be used to enable slightly better optimization of the program, but requires
673the language definition to guarantee that optimizations based on the
674'constantness' are valid for the translation units that do not include the
675definition.
676</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677
678<p>As SSA values, global variables define pointer values that are in
679scope (i.e. they dominate) all basic blocks in the program. Global
680variables always define a pointer to their "content" type because they
681describe a region of memory, and all memory objects in LLVM are
682accessed through pointers.</p>
683
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]684<p>A global variable may be declared to reside in a target-specifc numbered
685address space. For targets that support them, address spaces may affect how
686optimizations are performed and/or what target instructions are used to access
Christopher Lambd49e18d2007-12-12 08:44:39 +0000[diff] [blame]687the variable. The default address space is zero. The address space qualifier
688must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]689
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]690<p>LLVM allows an explicit section to be specified for globals. If the target
691supports it, it will emit globals to the section specified.</p>
692
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]693<p>An explicit alignment may be specified for a global. If not present, or if
694the alignment is set to zero, the alignment of the global is set by the target
695to whatever it feels convenient. If an explicit alignment is specified, the
696global is forced to have at least that much alignment. All alignments must be
697a power of 2.</p>
698
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]699<p>For example, the following defines a global in a numbered address space with
700an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]701
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]702<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]703<pre>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]704@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]705</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]706</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]707
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]708</div>
709
710
711<!-- ======================================================================= -->
712<div class="doc_subsection">
713 <a name="functionstructure">Functions</a>
714</div>
715
716<div class="doc_text">
717
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]718<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
719an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]720<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]721<a href="#callingconv">calling convention</a>, a return type, an optional
722<a href="#paramattrs">parameter attribute</a> for the return type, a function
723name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]724<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]725optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]726opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]727
728LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
729optional <a href="#linkage">linkage type</a>, an optional
730<a href="#visibility">visibility style</a>, an optional
731<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]732<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]733name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]734<a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]735
736<p>A function definition contains a list of basic blocks, forming the CFG for
737the function. Each basic block may optionally start with a label (giving the
738basic block a symbol table entry), contains a list of instructions, and ends
739with a <a href="#terminators">terminator</a> instruction (such as a branch or
740function return).</p>
741
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]742<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]743executed on entrance to the function, and it is not allowed to have predecessor
744basic blocks (i.e. there can not be any branches to the entry block of a
745function). Because the block can have no predecessors, it also cannot have any
746<a href="#i_phi">PHI nodes</a>.</p>
747
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]748<p>LLVM allows an explicit section to be specified for functions. If the target
749supports it, it will emit functions to the section specified.</p>
750
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]751<p>An explicit alignment may be specified for a function. If not present, or if
752the alignment is set to zero, the alignment of the function is set by the target
753to whatever it feels convenient. If an explicit alignment is specified, the
754function is forced to have at least that much alignment. All alignments must be
755a power of 2.</p>
756
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]757</div>
758
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]759
760<!-- ======================================================================= -->
761<div class="doc_subsection">
762 <a name="aliasstructure">Aliases</a>
763</div>
764<div class="doc_text">
765 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]766 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]767 optional <a href="#linkage">linkage type</a>, and an
768 optional <a href="#visibility">visibility style</a>.</p>
769
770 <h5>Syntax:</h5>
771
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]772<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]773<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]774@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]775</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]776</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]777
778</div>
779
780
781
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]782<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]783<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
784<div class="doc_text">
785 <p>The return type and each parameter of a function type may have a set of
786 <i>parameter attributes</i> associated with them. Parameter attributes are
787 used to communicate additional information about the result or parameters of
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]788 a function. Parameter attributes are considered to be part of the function,
789 not of the function type, so functions with different parameter attributes
790 can have the same function type.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]791
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]792 <p>Parameter attributes are simple keywords that follow the type specified. If
793 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]794 example:</p>
795
796<div class="doc_code">
797<pre>
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]798declare i32 @printf(i8* noalias , ...) nounwind
799declare i32 @atoi(i8*) nounwind readonly
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]800</pre>
801</div>
802
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]803 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
804 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]805
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]806 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]807 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]808 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]809 <dd>This indicates that the parameter should be zero extended just before
810 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]811
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]812 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]813 <dd>This indicates that the parameter should be sign extended just before
814 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]815
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]816 <dt><tt>inreg</tt></dt>
817 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]818 possible) during assembling function call. Support for this attribute is
819 target-specific</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]820
821 <dt><tt>byval</tt></dt>
Chris Lattner0747baa2008-01-15 04:34:22 +0000[diff] [blame]822 <dd>This indicates that the pointer parameter should really be passed by
823 value to the function. The attribute implies that a hidden copy of the
824 pointee is made between the caller and the callee, so the callee is unable
825 to modify the value in the callee. This attribute is only valid on llvm
826 pointer arguments. It is generally used to pass structs and arrays by
827 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]828
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]829 <dt><tt>sret</tt></dt>
Duncan Sandse26dec62008-02-18 04:19:38 +0000[diff] [blame]830 <dd>This indicates that the pointer parameter specifies the address of a
831 structure that is the return value of the function in the source program.
832 May only be applied to the first parameter.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]833
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]834 <dt><tt>noalias</tt></dt>
Owen Anderson117bbd32008-02-18 04:09:01 +0000[diff] [blame]835 <dd>This indicates that the parameter does not alias any global or any other
836 parameter. The caller is responsible for ensuring that this is the case,
837 usually by placing the value in a stack allocation.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]838
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]839 <dt><tt>noreturn</tt></dt>
840 <dd>This function attribute indicates that the function never returns. This
841 indicates to LLVM that every call to this function should be treated as if
842 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]843
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]844 <dt><tt>nounwind</tt></dt>
845 <dd>This function attribute indicates that the function type does not use
846 the unwind instruction and does not allow stack unwinding to propagate
847 through it.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]848
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]849 <dt><tt>nest</tt></dt>
850 <dd>This indicates that the parameter can be excised using the
851 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]852 <dt><tt>readonly</tt></dt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]853 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]854 except for producing a return value or throwing an exception. The value
855 returned must only depend on the function arguments and/or global variables.
856 It may use values obtained by dereferencing pointers.</dd>
857 <dt><tt>readnone</tt></dt>
858 <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]859 function, but in addition it is not allowed to dereference any pointer arguments
860 or global variables.
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]861 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]862
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]863</div>
864
865<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]866<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]867 <a name="gc">Garbage Collector Names</a>
868</div>
869
870<div class="doc_text">
871<p>Each function may specify a garbage collector name, which is simply a
872string.</p>
873
874<div class="doc_code"><pre
875>define void @f() gc "name" { ...</pre></div>
876
877<p>The compiler declares the supported values of <i>name</i>. Specifying a
878collector which will cause the compiler to alter its output in order to support
879the named garbage collection algorithm.</p>
880</div>
881
882<!-- ======================================================================= -->
883<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]884 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]885</div>
886
887<div class="doc_text">
888<p>
889Modules may contain "module-level inline asm" blocks, which corresponds to the
890GCC "file scope inline asm" blocks. These blocks are internally concatenated by
891LLVM and treated as a single unit, but may be separated in the .ll file if
892desired. The syntax is very simple:
893</p>
894
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]895<div class="doc_code">
896<pre>
897module asm "inline asm code goes here"
898module asm "more can go here"
899</pre>
900</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]901
902<p>The strings can contain any character by escaping non-printable characters.
903 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
904 for the number.
905</p>
906
907<p>
908 The inline asm code is simply printed to the machine code .s file when
909 assembly code is generated.
910</p>
911</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]912
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]913<!-- ======================================================================= -->
914<div class="doc_subsection">
915 <a name="datalayout">Data Layout</a>
916</div>
917
918<div class="doc_text">
919<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]920data is to be laid out in memory. The syntax for the data layout is simply:</p>
921<pre> target datalayout = "<i>layout specification</i>"</pre>
922<p>The <i>layout specification</i> consists of a list of specifications
923separated by the minus sign character ('-'). Each specification starts with a
924letter and may include other information after the letter to define some
925aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]926<dl>
927 <dt><tt>E</tt></dt>
928 <dd>Specifies that the target lays out data in big-endian form. That is, the
929 bits with the most significance have the lowest address location.</dd>
930 <dt><tt>e</tt></dt>
931 <dd>Specifies that hte target lays out data in little-endian form. That is,
932 the bits with the least significance have the lowest address location.</dd>
933 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
934 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
935 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
936 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
937 too.</dd>
938 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
939 <dd>This specifies the alignment for an integer type of a given bit
940 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
941 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
942 <dd>This specifies the alignment for a vector type of a given bit
943 <i>size</i>.</dd>
944 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
945 <dd>This specifies the alignment for a floating point type of a given bit
946 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
947 (double).</dd>
948 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
949 <dd>This specifies the alignment for an aggregate type of a given bit
950 <i>size</i>.</dd>
951</dl>
952<p>When constructing the data layout for a given target, LLVM starts with a
953default set of specifications which are then (possibly) overriden by the
954specifications in the <tt>datalayout</tt> keyword. The default specifications
955are given in this list:</p>
956<ul>
957 <li><tt>E</tt> - big endian</li>
958 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
959 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
960 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
961 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
962 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
963 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
964 alignment of 64-bits</li>
965 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
966 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
967 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
968 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
969 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
970</ul>
971<p>When llvm is determining the alignment for a given type, it uses the
972following rules:
973<ol>
974 <li>If the type sought is an exact match for one of the specifications, that
975 specification is used.</li>
976 <li>If no match is found, and the type sought is an integer type, then the
977 smallest integer type that is larger than the bitwidth of the sought type is
978 used. If none of the specifications are larger than the bitwidth then the the
979 largest integer type is used. For example, given the default specifications
980 above, the i7 type will use the alignment of i8 (next largest) while both
981 i65 and i256 will use the alignment of i64 (largest specified).</li>
982 <li>If no match is found, and the type sought is a vector type, then the
983 largest vector type that is smaller than the sought vector type will be used
984 as a fall back. This happens because <128 x double> can be implemented in
985 terms of 64 <2 x double>, for example.</li>
986</ol>
987</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]988
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]989<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]990<div class="doc_section"> <a name="typesystem">Type System</a> </div>
991<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]992
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]993<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]994
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]995<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]996intermediate representation. Being typed enables a number of
997optimizations to be performed on the IR directly, without having to do
998extra analyses on the side before the transformation. A strong type
999system makes it easier to read the generated code and enables novel
1000analyses and transformations that are not feasible to perform on normal
1001three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1002
1003</div>
1004
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1005<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1006<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1007Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1008<div class="doc_text">
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1009<p>The types fall into a few useful
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1010classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1011
1012<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1013 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1014 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1015 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1016 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1017 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018 </tr>
1019 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1020 <td><a href="#t_floating">floating point</a></td>
1021 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1022 </tr>
1023 <tr>
1024 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1025 <td><a href="#t_integer">integer</a>,
1026 <a href="#t_floating">floating point</a>,
1027 <a href="#t_pointer">pointer</a>,
1028 <a href="#t_vector">vector</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1029 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1030 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1031 <tr>
1032 <td><a href="#t_primitive">primitive</a></td>
1033 <td><a href="#t_label">label</a>,
1034 <a href="#t_void">void</a>,
1035 <a href="#t_integer">integer</a>,
1036 <a href="#t_floating">floating point</a>.</td>
1037 </tr>
1038 <tr>
1039 <td><a href="#t_derived">derived</a></td>
1040 <td><a href="#t_integer">integer</a>,
1041 <a href="#t_array">array</a>,
1042 <a href="#t_function">function</a>,
1043 <a href="#t_pointer">pointer</a>,
1044 <a href="#t_struct">structure</a>,
1045 <a href="#t_pstruct">packed structure</a>,
1046 <a href="#t_vector">vector</a>,
1047 <a href="#t_opaque">opaque</a>.
1048 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1049 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1050</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1051
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1052<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1053most important. Values of these types are the only ones which can be
1054produced by instructions, passed as arguments, or used as operands to
1055instructions. This means that all structures and arrays must be
1056manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1057</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1058
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1059<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1060<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1061
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1062<div class="doc_text">
1063<p>The primitive types are the fundamental building blocks of the LLVM
1064system.</p>
1065
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1066</div>
1067
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1068<!-- _______________________________________________________________________ -->
1069<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1070
1071<div class="doc_text">
1072 <table>
1073 <tbody>
1074 <tr><th>Type</th><th>Description</th></tr>
1075 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1076 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1077 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1078 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1079 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1080 </tbody>
1081 </table>
1082</div>
1083
1084<!-- _______________________________________________________________________ -->
1085<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1086
1087<div class="doc_text">
1088<h5>Overview:</h5>
1089<p>The void type does not represent any value and has no size.</p>
1090
1091<h5>Syntax:</h5>
1092
1093<pre>
1094 void
1095</pre>
1096</div>
1097
1098<!-- _______________________________________________________________________ -->
1099<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1100
1101<div class="doc_text">
1102<h5>Overview:</h5>
1103<p>The label type represents code labels.</p>
1104
1105<h5>Syntax:</h5>
1106
1107<pre>
1108 label
1109</pre>
1110</div>
1111
1112
1113<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1114<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1115
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1116<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1117
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1118<p>The real power in LLVM comes from the derived types in the system.
1119This is what allows a programmer to represent arrays, functions,
1120pointers, and other useful types. Note that these derived types may be
1121recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1122
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1123</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1124
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1125<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1126<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1127
1128<div class="doc_text">
1129
1130<h5>Overview:</h5>
1131<p>The integer type is a very simple derived type that simply specifies an
1132arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11332^23-1 (about 8 million) can be specified.</p>
1134
1135<h5>Syntax:</h5>
1136
1137<pre>
1138 iN
1139</pre>
1140
1141<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1142value.</p>
1143
1144<h5>Examples:</h5>
1145<table class="layout">
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1146 <tbody>
1147 <tr>
1148 <td><tt>i1</tt></td>
1149 <td>a single-bit integer.</td>
1150 </tr><tr>
1151 <td><tt>i32</tt></td>
1152 <td>a 32-bit integer.</td>
1153 </tr><tr>
1154 <td><tt>i1942652</tt></td>
1155 <td>a really big integer of over 1 million bits.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1156 </tr>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1157 </tbody>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1158</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1159</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1160
1161<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1162<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1163
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1164<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1165
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1166<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1167
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1168<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1169sequentially in memory. The array type requires a size (number of
1170elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1171
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1172<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1173
1174<pre>
1175 [&lt;# elements&gt; x &lt;elementtype&gt;]
1176</pre>
1177
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1178<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1179be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1180
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1181<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1182<table class="layout">
1183 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1184 <td class="left"><tt>[40 x i32]</tt></td>
1185 <td class="left">Array of 40 32-bit integer values.</td>
1186 </tr>
1187 <tr class="layout">
1188 <td class="left"><tt>[41 x i32]</tt></td>
1189 <td class="left">Array of 41 32-bit integer values.</td>
1190 </tr>
1191 <tr class="layout">
1192 <td class="left"><tt>[4 x i8]</tt></td>
1193 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1194 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1195</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1196<p>Here are some examples of multidimensional arrays:</p>
1197<table class="layout">
1198 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1199 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1200 <td class="left">3x4 array of 32-bit integer values.</td>
1201 </tr>
1202 <tr class="layout">
1203 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1204 <td class="left">12x10 array of single precision floating point values.</td>
1205 </tr>
1206 <tr class="layout">
1207 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1208 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1209 </tr>
1210</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1211
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1212<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1213length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1214LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1215As a special case, however, zero length arrays are recognized to be variable
1216length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1217type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1218
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1219</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1220
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1221<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1222<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1223<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1224<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1225<p>The function type can be thought of as a function signature. It
1226consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1227Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1228(which are structures of pointers to functions), for indirect function
1229calls, and when defining a function.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1230
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1231<h5>Syntax:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1232<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1233<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]1234specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1235which indicates that the function takes a variable number of arguments.
1236Variable argument functions can access their arguments with the <a
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1237 href="#int_varargs">variable argument handling intrinsic</a> functions.
1238'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1239<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1240<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1241<table class="layout">
1242 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1243 <td class="left"><tt>i32 (i32)</tt></td>
1244 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1245 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1246 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1247 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1248 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1249 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1250 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1251 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1252 <tt>float</tt>.
1253 </td>
1254 </tr><tr class="layout">
1255 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1256 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1257 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1258 which returns an integer. This is the signature for <tt>printf</tt> in
1259 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1260 </td>
1261 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1262</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1263
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1264</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1266<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1267<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1268<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1269<p>The structure type is used to represent a collection of data members
1270together in memory. The packing of the field types is defined to match
1271the ABI of the underlying processor. The elements of a structure may
1272be any type that has a size.</p>
1273<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1274and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1275field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1276instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1278<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1279<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1280<table class="layout">
1281 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1282 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1283 <td class="left">A triple of three <tt>i32</tt> values</td>
1284 </tr><tr class="layout">
1285 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1286 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1287 second element is a <a href="#t_pointer">pointer</a> to a
1288 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1289 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1290 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1291</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1292</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1293
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1294<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1295<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1296</div>
1297<div class="doc_text">
1298<h5>Overview:</h5>
1299<p>The packed structure type is used to represent a collection of data members
1300together in memory. There is no padding between fields. Further, the alignment
1301of a packed structure is 1 byte. The elements of a packed structure may
1302be any type that has a size.</p>
1303<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1304and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1305field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1306instruction.</p>
1307<h5>Syntax:</h5>
1308<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1309<h5>Examples:</h5>
1310<table class="layout">
1311 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1312 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1313 <td class="left">A triple of three <tt>i32</tt> values</td>
1314 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1315 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1316 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1317 second element is a <a href="#t_pointer">pointer</a> to a
1318 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1319 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1320 </tr>
1321</table>
1322</div>
1323
1324<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1326<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1327<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1328<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1329reference to another object, which must live in memory. Pointer types may have
1330an optional address space attribute defining the target-specific numbered
1331address space where the pointed-to object resides. The default address space is
1332zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1333<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1334<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1335<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1336<table class="layout">
1337 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1338 <td class="left"><tt>[4x i32]*</tt></td>
1339 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1340 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1341 </tr>
1342 <tr class="layout">
1343 <td class="left"><tt>i32 (i32 *) *</tt></td>
1344 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1345 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1346 <tt>i32</tt>.</td>
1347 </tr>
1348 <tr class="layout">
1349 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1350 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1351 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1352 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1353</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1354</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1355
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1356<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1357<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1358<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1359
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1360<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1361
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1362<p>A vector type is a simple derived type that represents a vector
1363of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1364are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1365A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1366elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1367of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1368considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1369
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1370<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1371
1372<pre>
1373 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1374</pre>
1375
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1376<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1377be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1378
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1379<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1380
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1381<table class="layout">
1382 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1383 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1384 <td class="left">Vector of 4 32-bit integer values.</td>
1385 </tr>
1386 <tr class="layout">
1387 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1388 <td class="left">Vector of 8 32-bit floating-point values.</td>
1389 </tr>
1390 <tr class="layout">
1391 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1392 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1393 </tr>
1394</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1395</div>
1396
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
1398<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1399<div class="doc_text">
1400
1401<h5>Overview:</h5>
1402
1403<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1404corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1405In LLVM, opaque types can eventually be resolved to any type (not just a
1406structure type).</p>
1407
1408<h5>Syntax:</h5>
1409
1410<pre>
1411 opaque
1412</pre>
1413
1414<h5>Examples:</h5>
1415
1416<table class="layout">
1417 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1418 <td class="left"><tt>opaque</tt></td>
1419 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1420 </tr>
1421</table>
1422</div>
1423
1424
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1425<!-- *********************************************************************** -->
1426<div class="doc_section"> <a name="constants">Constants</a> </div>
1427<!-- *********************************************************************** -->
1428
1429<div class="doc_text">
1430
1431<p>LLVM has several different basic types of constants. This section describes
1432them all and their syntax.</p>
1433
1434</div>
1435
1436<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1437<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1438
1439<div class="doc_text">
1440
1441<dl>
1442 <dt><b>Boolean constants</b></dt>
1443
1444 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1445 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1446 </dd>
1447
1448 <dt><b>Integer constants</b></dt>
1449
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1450 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1451 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1452 integer types.
1453 </dd>
1454
1455 <dt><b>Floating point constants</b></dt>
1456
1457 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1458 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1459 notation (see below). Floating point constants must have a <a
1460 href="#t_floating">floating point</a> type. </dd>
1461
1462 <dt><b>Null pointer constants</b></dt>
1463
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1464 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1465 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1466
1467</dl>
1468
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1469<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1470of floating point constants. For example, the form '<tt>double
14710x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14724.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1473(and the only time that they are generated by the disassembler) is when a
1474floating point constant must be emitted but it cannot be represented as a
1475decimal floating point number. For example, NaN's, infinities, and other
1476special values are represented in their IEEE hexadecimal format so that
1477assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1478
1479</div>
1480
1481<!-- ======================================================================= -->
1482<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1483</div>
1484
1485<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1486<p>Aggregate constants arise from aggregation of simple constants
1487and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1488
1489<dl>
1490 <dt><b>Structure constants</b></dt>
1491
1492 <dd>Structure constants are represented with notation similar to structure
1493 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1494 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1495 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]1496 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1497 types of elements must match those specified by the type.
1498 </dd>
1499
1500 <dt><b>Array constants</b></dt>
1501
1502 <dd>Array constants are represented with notation similar to array type
1503 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1504 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1505 constants must have <a href="#t_array">array type</a>, and the number and
1506 types of elements must match those specified by the type.
1507 </dd>
1508
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1509 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1510
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1511 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1512 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1513 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]1514 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1515 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1516 match those specified by the type.
1517 </dd>
1518
1519 <dt><b>Zero initialization</b></dt>
1520
1521 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1522 value to zero of <em>any</em> type, including scalar and aggregate types.
1523 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]1524 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1525 initializers.
1526 </dd>
1527</dl>
1528
1529</div>
1530
1531<!-- ======================================================================= -->
1532<div class="doc_subsection">
1533 <a name="globalconstants">Global Variable and Function Addresses</a>
1534</div>
1535
1536<div class="doc_text">
1537
1538<p>The addresses of <a href="#globalvars">global variables</a> and <a
1539href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1540constants. These constants are explicitly referenced when the <a
1541href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1543file:</p>
1544
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1545<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1546<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1547@X = global i32 17
1548@Y = global i32 42
1549@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1550</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1551</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1552
1553</div>
1554
1555<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1556<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1557<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1558 <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]1559 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1560 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1561
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1562 <p>Undefined values indicate to the compiler that the program is well defined
1563 no matter what value is used, giving the compiler more freedom to optimize.
1564 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1565</div>
1566
1567<!-- ======================================================================= -->
1568<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1569</div>
1570
1571<div class="doc_text">
1572
1573<p>Constant expressions are used to allow expressions involving other constants
1574to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1575href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1576that does not have side effects (e.g. load and call are not supported). The
1577following is the syntax for constant expressions:</p>
1578
1579<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1580 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1581 <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]1582 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1583
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1584 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1585 <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]1586 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]1587
1588 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1589 <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]1590 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]1591
1592 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1593 <dd>Truncate a floating point constant to another floating point type. The
1594 size of CST must be larger than the size of TYPE. Both types must be
1595 floating point.</dd>
1596
1597 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1598 <dd>Floating point extend a constant to another type. The size of CST must be
1599 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1600
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1601 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1602 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1603 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1604 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1605 of the same number of elements. If the value won't fit in the integer type,
1606 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1607
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1608 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1609 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1610 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1611 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1612 of the same number of elements. If the value won't fit in the integer type,
1613 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1614
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1615 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1616 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1617 constant. TYPE must be a scalar or vector floating point type. CST must be of
1618 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1619 of the same number of elements. If the value won't fit in the floating point
1620 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1621
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1622 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1623 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1624 constant. TYPE must be a scalar or vector floating point type. CST must be of
1625 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1626 of the same number of elements. If the value won't fit in the floating point
1627 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1628
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1629 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1630 <dd>Convert a pointer typed constant to the corresponding integer constant
1631 TYPE must be an integer type. CST must be of pointer type. The CST value is
1632 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1633
1634 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1635 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1636 pointer type. CST must be of integer type. The CST value is zero extended,
1637 truncated, or unchanged to make it fit in a pointer size. This one is
1638 <i>really</i> dangerous!</dd>
1639
1640 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1641 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1642 identical (same number of bits). The conversion is done as if the CST value
1643 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]1644 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1645 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]1646 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1647 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1648
1649 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1650
1651 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1652 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1653 instruction, the index list may have zero or more indexes, which are required
1654 to make sense for the type of "CSTPTR".</dd>
1655
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1656 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1657
1658 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1659 constants.</dd>
1660
1661 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1662 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1663
1664 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1665 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1666
1667 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1668
1669 <dd>Perform the <a href="#i_extractelement">extractelement
1670 operation</a> on constants.
1671
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1672 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1673
1674 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1675 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1676
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1677
1678 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1679
1680 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1681 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1682
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1683 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1684
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1685 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1686 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1687 binary</a> operations. The constraints on operands are the same as those for
1688 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1689 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1690</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1691</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1692
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1693<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1694<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1695<!-- *********************************************************************** -->
1696
1697<!-- ======================================================================= -->
1698<div class="doc_subsection">
1699<a name="inlineasm">Inline Assembler Expressions</a>
1700</div>
1701
1702<div class="doc_text">
1703
1704<p>
1705LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1706Module-Level Inline Assembly</a>) through the use of a special value. This
1707value represents the inline assembler as a string (containing the instructions
1708to emit), a list of operand constraints (stored as a string), and a flag that
1709indicates whether or not the inline asm expression has side effects. An example
1710inline assembler expression is:
1711</p>
1712
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1713<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1714<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1715i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1716</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1717</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1718
1719<p>
1720Inline assembler expressions may <b>only</b> be used as the callee operand of
1721a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1722</p>
1723
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1724<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1725<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1726%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]1727</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1728</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1729
1730<p>
1731Inline asms with side effects not visible in the constraint list must be marked
1732as having side effects. This is done through the use of the
1733'<tt>sideeffect</tt>' keyword, like so:
1734</p>
1735
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1736<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1737<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1738call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1739</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1740</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1741
1742<p>TODO: The format of the asm and constraints string still need to be
1743documented here. Constraints on what can be done (e.g. duplication, moving, etc
1744need to be documented).
1745</p>
1746
1747</div>
1748
1749<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1750<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1751<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1754
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1755<p>The LLVM instruction set consists of several different
1756classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1757instructions</a>, <a href="#binaryops">binary instructions</a>,
1758<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1759 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1760instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1765<div class="doc_subsection"> <a name="terminators">Terminator
1766Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1768<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1769
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1770<p>As mentioned <a href="#functionstructure">previously</a>, every
1771basic block in a program ends with a "Terminator" instruction, which
1772indicates which block should be executed after the current block is
1773finished. These terminator instructions typically yield a '<tt>void</tt>'
1774value: they produce control flow, not values (the one exception being
1775the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1776<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1777 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1778instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1779the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1780 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1781 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1782
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1783</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1784
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1785<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1786<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1787Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1788<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1790<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]1791 ret void <i>; Return from void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1792 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]1793</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1796value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1797<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1798returns a value and then causes control flow, and one that just causes
1799control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Arguments:</h5>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1801<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1802type of each return value must be a '<a href="#t_firstclass">first class</a>'
1803 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1804if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1805returns values that do not match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1807<p>When the '<tt>ret</tt>' instruction is executed, control flow
1808returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1809 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1810the instruction after the call. If the caller was an "<a
1811 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1812at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1813returns a value, that value shall set the call or invoke instruction's
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1814return value. If the instruction returns multiple values then these
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1815values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1816</a>' instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1817<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1818<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1819 ret void <i>; Return from a void function</i>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1820 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1821</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1822</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1825<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1827<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]1828</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1830<p>The '<tt>br</tt>' instruction is used to cause control flow to
1831transfer to a different basic block in the current function. There are
1832two forms of this instruction, corresponding to a conditional branch
1833and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1835<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1836single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1837unconditional form of the '<tt>br</tt>' instruction takes a single
1838'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1840<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1841argument is evaluated. If the value is <tt>true</tt>, control flows
1842to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1843control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1845<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]1846 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]1847</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1848<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1849<div class="doc_subsubsection">
1850 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1851</div>
1852
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1853<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1854<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1855
1856<pre>
1857 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1858</pre>
1859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1860<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1861
1862<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1863several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864instruction, allowing a branch to occur to one of many possible
1865destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1866
1867
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1868<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1869
1870<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1871comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1872an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1873table is not allowed to contain duplicate constant entries.</p>
1874
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1875<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1876
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1877<p>The <tt>switch</tt> instruction specifies a table of values and
1878destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1879table is searched for the given value. If the value is found, control flow is
1880transfered to the corresponding destination; otherwise, control flow is
1881transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1882
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1883<h5>Implementation:</h5>
1884
1885<p>Depending on properties of the target machine and the particular
1886<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1887ways. For example, it could be generated as a series of chained conditional
1888branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1889
1890<h5>Example:</h5>
1891
1892<pre>
1893 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1894 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1895 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1896
1897 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1898 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1899
1900 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1901 switch i32 %val, label %otherwise [ i32 0, label %onzero
1902 i32 1, label %onone
1903 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1904</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1905</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1907<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1908<div class="doc_subsubsection">
1909 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1910</div>
1911
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1913
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1914<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1915
1916<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame^]1917 &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]1918 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1919</pre>
1920
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1921<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1922
1923<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1924function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1925'<tt>normal</tt>' label or the
1926'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1927"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1928"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1929href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1930continued at the dynamically nearest "exception" label. If the callee function
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]1931returns multiple values then individual return values are only accessible through
1932a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1933
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1935
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1936<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1937
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1938<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1939 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1940 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1941 convention</a> the call should use. If none is specified, the call defaults
1942 to using C calling conventions.
1943 </li>
1944 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1945 function value being invoked. In most cases, this is a direct function
1946 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1947 an arbitrary pointer to function value.
1948 </li>
1949
1950 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1951 function to be invoked. </li>
1952
1953 <li>'<tt>function args</tt>': argument list whose types match the function
1954 signature argument types. If the function signature indicates the function
1955 accepts a variable number of arguments, the extra arguments can be
1956 specified. </li>
1957
1958 <li>'<tt>normal label</tt>': the label reached when the called function
1959 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1960
1961 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1962 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1963
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1964</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1965
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1966<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1967
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1968<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1969href="#i_call">call</a></tt>' instruction in most regards. The primary
1970difference is that it establishes an association with a label, which is used by
1971the runtime library to unwind the stack.</p>
1972
1973<p>This instruction is used in languages with destructors to ensure that proper
1974cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1975exception. Additionally, this is important for implementation of
1976'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1979<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame^]1980 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1981 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame^]1982 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1983 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1984</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1985</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1986
1987
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1988<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1989
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1990<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1991Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1992
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1993<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1994
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1995<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1996<pre>
1997 unwind
1998</pre>
1999
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2000<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2001
2002<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2003at the first callee in the dynamic call stack which used an <a
2004href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2005primarily used to implement exception handling.</p>
2006
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]2007<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2008
2009<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
2010immediately halt. The dynamic call stack is then searched for the first <a
2011href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2012execution continues at the "exceptional" destination block specified by the
2013<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2014dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2015</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]2016
2017<!-- _______________________________________________________________________ -->
2018
2019<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2020Instruction</a> </div>
2021
2022<div class="doc_text">
2023
2024<h5>Syntax:</h5>
2025<pre>
2026 unreachable
2027</pre>
2028
2029<h5>Overview:</h5>
2030
2031<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2032instruction is used to inform the optimizer that a particular portion of the
2033code is not reachable. This can be used to indicate that the code after a
2034no-return function cannot be reached, and other facts.</p>
2035
2036<h5>Semantics:</h5>
2037
2038<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2039</div>
2040
2041
2042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2044<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2045<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2046<p>Binary operators are used to do most of the computation in a
2047program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2048produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2049multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2050The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2051necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2052<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2053</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2054<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2055<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2056Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2057<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2058<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2059<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]2060</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2061<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2062<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2063<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2064<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2065 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2066 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]2067Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2069<p>The value produced is the integer or floating point sum of the two
2070operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2071<p>If an integer sum has unsigned overflow, the result returned is the
2072mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2073the result.</p>
2074<p>Because LLVM integers use a two's complement representation, this
2075instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2076<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2077<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]2078</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2079</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2080<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2081<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2082Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2083<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2084<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2085<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]2086</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2087<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2088<p>The '<tt>sub</tt>' instruction returns the difference of its two
2089operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2090<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2091instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2093<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2094 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2095values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2096This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2097Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2098<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2099<p>The value produced is the integer or floating point difference of
2100the two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2101<p>If an integer difference has unsigned overflow, the result returned is the
2102mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2103the result.</p>
2104<p>Because LLVM integers use a two's complement representation, this
2105instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2106<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2107<pre>
2108 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2109 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2110</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2111</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2112<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2113<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2114Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2115<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2116<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2117<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]2118</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2119<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2120<p>The '<tt>mul</tt>' instruction returns the product of its two
2121operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2122<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2123<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2124 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2125values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2126This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2127Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2128<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2129<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2130two operands.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2131<p>If the result of an integer multiplication has unsigned overflow,
2132the result returned is the mathematical result modulo
21332<sup>n</sup>, where n is the bit width of the result.</p>
2134<p>Because LLVM integers use a two's complement representation, and the
2135result is the same width as the operands, this instruction returns the
2136correct result for both signed and unsigned integers. If a full product
2137(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2138should be sign-extended or zero-extended as appropriate to the
2139width of the full product.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2140<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2141<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]2142</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2143</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2144<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2145<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2146</a></div>
2147<div class="doc_text">
2148<h5>Syntax:</h5>
2149<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2150</pre>
2151<h5>Overview:</h5>
2152<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2153operands.</p>
2154<h5>Arguments:</h5>
2155<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2156<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2157types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2158of the values in which case the elements must be integers.</p>
2159<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2160<p>The value produced is the unsigned integer quotient of the two operands.</p>
2161<p>Note that unsigned integer division and signed integer division are distinct
2162operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2163<p>Division by zero leads to undefined behavior.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2164<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2165<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]2166</pre>
2167</div>
2168<!-- _______________________________________________________________________ -->
2169<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2170</a> </div>
2171<div class="doc_text">
2172<h5>Syntax:</h5>
2173<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2174</pre>
2175<h5>Overview:</h5>
2176<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2177operands.</p>
2178<h5>Arguments:</h5>
2179<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2180<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2181types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2182of the values in which case the elements must be integers.</p>
2183<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2184<p>The value produced is the signed integer quotient of the two operands.</p>
2185<p>Note that signed integer division and unsigned integer division are distinct
2186operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2187<p>Division by zero leads to undefined behavior. Overflow also leads to
2188undefined behavior; this is a rare case, but can occur, for example,
2189by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2190<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2191<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]2192</pre>
2193</div>
2194<!-- _______________________________________________________________________ -->
2195<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2196Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2197<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2198<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2199<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]2200</pre>
2201<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2202<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2203operands.</p>
2204<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2205<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2206<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2207identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2208versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2209<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2210<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2211<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2212<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]2213</pre>
2214</div>
2215<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2216<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2217</div>
2218<div class="doc_text">
2219<h5>Syntax:</h5>
2220<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2221</pre>
2222<h5>Overview:</h5>
2223<p>The '<tt>urem</tt>' instruction returns the remainder from the
2224unsigned division of its two arguments.</p>
2225<h5>Arguments:</h5>
2226<p>The two arguments to the '<tt>urem</tt>' instruction must be
2227<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2228types. This instruction can also take <a href="#t_vector">vector</a> versions
2229of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2230<h5>Semantics:</h5>
2231<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2232This instruction always performs an unsigned division to get the remainder,
2233regardless of whether the arguments are unsigned or not.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2234<p>Note that unsigned integer remainder and signed integer remainder are
2235distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2236<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2237<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2238<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]2239</pre>
2240
2241</div>
2242<!-- _______________________________________________________________________ -->
2243<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2244Instruction</a> </div>
2245<div class="doc_text">
2246<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2247<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]2248</pre>
2249<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2250<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2251signed division of its two operands. This instruction can also take
2252<a href="#t_vector">vector</a> versions of the values in which case
2253the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2254
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2255<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2256<p>The two arguments to the '<tt>srem</tt>' instruction must be
2257<a href="#t_integer">integer</a> values. Both arguments must have identical
2258types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2259<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2260<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2261has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2262operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2263a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2264 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2265Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2266please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2267Wikipedia: modulo operation</a>.</p>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]2268<p>Note that signed integer remainder and unsigned integer remainder are
2269distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2270<p>Taking the remainder of a division by zero leads to undefined behavior.
2271Overflow also leads to undefined behavior; this is a rare case, but can occur,
2272for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2273(The remainder doesn't actually overflow, but this rule lets srem be
2274implemented using instructions that return both the result of the division
2275and the remainder.)</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2276<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2277<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]2278</pre>
2279
2280</div>
2281<!-- _______________________________________________________________________ -->
2282<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2283Instruction</a> </div>
2284<div class="doc_text">
2285<h5>Syntax:</h5>
2286<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2287</pre>
2288<h5>Overview:</h5>
2289<p>The '<tt>frem</tt>' instruction returns the remainder from the
2290division of its two operands.</p>
2291<h5>Arguments:</h5>
2292<p>The two arguments to the '<tt>frem</tt>' instruction must be
2293<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2294identical types. This instruction can also take <a href="#t_vector">vector</a>
2295versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2296<h5>Semantics:</h5>
2297<p>This instruction returns the <i>remainder</i> of a division.</p>
2298<h5>Example:</h5>
2299<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]2300</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2301</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2302
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2303<!-- ======================================================================= -->
2304<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2305Operations</a> </div>
2306<div class="doc_text">
2307<p>Bitwise binary operators are used to do various forms of
2308bit-twiddling in a program. They are generally very efficient
2309instructions and can commonly be strength reduced from other
2310instructions. They require two operands, execute an operation on them,
2311and produce a single value. The resulting value of the bitwise binary
2312operators is always the same type as its first operand.</p>
2313</div>
2314
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2315<!-- _______________________________________________________________________ -->
2316<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2317Instruction</a> </div>
2318<div class="doc_text">
2319<h5>Syntax:</h5>
2320<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2321</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2322
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2323<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2324
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2325<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2326the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2327
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2328<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2329
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2330<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2331 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2332
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2333<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2334
2335<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2336<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2337of bits in <tt>var1</tt>, the result is undefined.</p>
2338
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2339<h5>Example:</h5><pre>
2340 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2341 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2342 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2343 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2344</pre>
2345</div>
2346<!-- _______________________________________________________________________ -->
2347<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2348Instruction</a> </div>
2349<div class="doc_text">
2350<h5>Syntax:</h5>
2351<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2352</pre>
2353
2354<h5>Overview:</h5>
2355<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2356operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2357
2358<h5>Arguments:</h5>
2359<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2360<a href="#t_integer">integer</a> type.</p>
2361
2362<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2363
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2364<p>This instruction always performs a logical shift right operation. The most
2365significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2366shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2367the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2368
2369<h5>Example:</h5>
2370<pre>
2371 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2372 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2373 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2374 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2375 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2376</pre>
2377</div>
2378
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2379<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2380<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2381Instruction</a> </div>
2382<div class="doc_text">
2383
2384<h5>Syntax:</h5>
2385<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2386</pre>
2387
2388<h5>Overview:</h5>
2389<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2390operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2391
2392<h5>Arguments:</h5>
2393<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2394<a href="#t_integer">integer</a> type.</p>
2395
2396<h5>Semantics:</h5>
2397<p>This instruction always performs an arithmetic shift right operation,
2398The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2399of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2400larger than the number of bits in <tt>var1</tt>, the result is undefined.
2401</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2402
2403<h5>Example:</h5>
2404<pre>
2405 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2406 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2407 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2408 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2409 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2410</pre>
2411</div>
2412
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2413<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2414<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2415Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2416<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2417<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2418<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]2419</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2420<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2421<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2422its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2423<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2424<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2425 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2426identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2427<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2429<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2430<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2431<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2432 <tbody>
2433 <tr>
2434 <td>In0</td>
2435 <td>In1</td>
2436 <td>Out</td>
2437 </tr>
2438 <tr>
2439 <td>0</td>
2440 <td>0</td>
2441 <td>0</td>
2442 </tr>
2443 <tr>
2444 <td>0</td>
2445 <td>1</td>
2446 <td>0</td>
2447 </tr>
2448 <tr>
2449 <td>1</td>
2450 <td>0</td>
2451 <td>0</td>
2452 </tr>
2453 <tr>
2454 <td>1</td>
2455 <td>1</td>
2456 <td>1</td>
2457 </tr>
2458 </tbody>
2459</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2460</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2461<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2462<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2463 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2464 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2465</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2466</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2467<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2468<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2469<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2470<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2471<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]2472</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2473<h5>Overview:</h5>
2474<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2475or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2476<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2477<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2478 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2479identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2480<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2481<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2482<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2483<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2484<table border="1" cellspacing="0" cellpadding="4">
2485 <tbody>
2486 <tr>
2487 <td>In0</td>
2488 <td>In1</td>
2489 <td>Out</td>
2490 </tr>
2491 <tr>
2492 <td>0</td>
2493 <td>0</td>
2494 <td>0</td>
2495 </tr>
2496 <tr>
2497 <td>0</td>
2498 <td>1</td>
2499 <td>1</td>
2500 </tr>
2501 <tr>
2502 <td>1</td>
2503 <td>0</td>
2504 <td>1</td>
2505 </tr>
2506 <tr>
2507 <td>1</td>
2508 <td>1</td>
2509 <td>1</td>
2510 </tr>
2511 </tbody>
2512</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2513</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2514<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2515<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2516 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2517 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2518</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2519</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2520<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2521<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2522Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2523<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2525<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]2526</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2528<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2529or of its two operands. The <tt>xor</tt> is used to implement the
2530"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2531<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2532<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2533 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2534identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2536<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2537<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2538<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2539<table border="1" cellspacing="0" cellpadding="4">
2540 <tbody>
2541 <tr>
2542 <td>In0</td>
2543 <td>In1</td>
2544 <td>Out</td>
2545 </tr>
2546 <tr>
2547 <td>0</td>
2548 <td>0</td>
2549 <td>0</td>
2550 </tr>
2551 <tr>
2552 <td>0</td>
2553 <td>1</td>
2554 <td>1</td>
2555 </tr>
2556 <tr>
2557 <td>1</td>
2558 <td>0</td>
2559 <td>1</td>
2560 </tr>
2561 <tr>
2562 <td>1</td>
2563 <td>1</td>
2564 <td>0</td>
2565 </tr>
2566 </tbody>
2567</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2568</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2569<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2570<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2571<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2572 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2573 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2574 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2575</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2576</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2578<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2579<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2580 <a name="vectorops">Vector Operations</a>
2581</div>
2582
2583<div class="doc_text">
2584
2585<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2586target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2587vector-specific operations needed to process vectors effectively. While LLVM
2588does directly support these vector operations, many sophisticated algorithms
2589will want to use target-specific intrinsics to take full advantage of a specific
2590target.</p>
2591
2592</div>
2593
2594<!-- _______________________________________________________________________ -->
2595<div class="doc_subsubsection">
2596 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2597</div>
2598
2599<div class="doc_text">
2600
2601<h5>Syntax:</h5>
2602
2603<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2604 &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]2605</pre>
2606
2607<h5>Overview:</h5>
2608
2609<p>
2610The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2611element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2612</p>
2613
2614
2615<h5>Arguments:</h5>
2616
2617<p>
2618The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2619value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2620an index indicating the position from which to extract the element.
2621The index may be a variable.</p>
2622
2623<h5>Semantics:</h5>
2624
2625<p>
2626The result is a scalar of the same type as the element type of
2627<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2628<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2629results are undefined.
2630</p>
2631
2632<h5>Example:</h5>
2633
2634<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2635 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2636</pre>
2637</div>
2638
2639
2640<!-- _______________________________________________________________________ -->
2641<div class="doc_subsubsection">
2642 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2643</div>
2644
2645<div class="doc_text">
2646
2647<h5>Syntax:</h5>
2648
2649<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2650 &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]2651</pre>
2652
2653<h5>Overview:</h5>
2654
2655<p>
2656The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2657element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2658</p>
2659
2660
2661<h5>Arguments:</h5>
2662
2663<p>
2664The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2665value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2666scalar value whose type must equal the element type of the first
2667operand. The third operand is an index indicating the position at
2668which to insert the value. The index may be a variable.</p>
2669
2670<h5>Semantics:</h5>
2671
2672<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2673The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2674element values are those of <tt>val</tt> except at position
2675<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2676exceeds the length of <tt>val</tt>, the results are undefined.
2677</p>
2678
2679<h5>Example:</h5>
2680
2681<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2682 %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]2683</pre>
2684</div>
2685
2686<!-- _______________________________________________________________________ -->
2687<div class="doc_subsubsection">
2688 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2689</div>
2690
2691<div class="doc_text">
2692
2693<h5>Syntax:</h5>
2694
2695<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2696 &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]2697</pre>
2698
2699<h5>Overview:</h5>
2700
2701<p>
2702The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2703from two input vectors, returning a vector of the same type.
2704</p>
2705
2706<h5>Arguments:</h5>
2707
2708<p>
2709The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2710with types that match each other and types that match the result of the
2711instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2712of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2713</p>
2714
2715<p>
2716The shuffle mask operand is required to be a constant vector with either
2717constant integer or undef values.
2718</p>
2719
2720<h5>Semantics:</h5>
2721
2722<p>
2723The elements of the two input vectors are numbered from left to right across
2724both of the vectors. The shuffle mask operand specifies, for each element of
2725the result vector, which element of the two input registers the result element
2726gets. The element selector may be undef (meaning "don't care") and the second
2727operand may be undef if performing a shuffle from only one vector.
2728</p>
2729
2730<h5>Example:</h5>
2731
2732<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2733 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2734 &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]2735 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2736 &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]2737</pre>
2738</div>
2739
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2740
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2741<!-- ======================================================================= -->
2742<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2743 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2744</div>
2745
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2747
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2748<p>A key design point of an SSA-based representation is how it
2749represents memory. In LLVM, no memory locations are in SSA form, which
2750makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2751allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2752
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2753</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2754
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2755<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2756<div class="doc_subsubsection">
2757 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2758</div>
2759
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2760<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2761
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2762<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2763
2764<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2765 &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]2766</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2768<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2769
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2770<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2771heap and returns a pointer to it. The object is always allocated in the generic
2772address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2774<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2775
2776<p>The '<tt>malloc</tt>' instruction allocates
2777<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2778bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2779appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2780number of elements allocated, otherwise "NumElements" is defaulted to be one.
2781If an alignment is specified, the value result of the allocation is guaranteed to
2782be aligned to at least that boundary. If not specified, or if zero, the target can
2783choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2785<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2786
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2787<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2788
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2789<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2790a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2791
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2792<h5>Example:</h5>
2793
2794<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2795 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2796
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2797 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2798 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2799 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2800 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2801 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2802</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2803</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2804
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2805<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2806<div class="doc_subsubsection">
2807 <a name="i_free">'<tt>free</tt>' Instruction</a>
2808</div>
2809
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2810<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2812<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2813
2814<pre>
2815 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2816</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2817
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2818<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2819
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2820<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2821memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2822
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2823<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2825<p>'<tt>value</tt>' shall be a pointer value that points to a value
2826that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2827instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2828
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2829<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2830
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2831<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2832after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2833
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2835
2836<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2837 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2838 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2840</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2841
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2843<div class="doc_subsubsection">
2844 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2845</div>
2846
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2847<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2849<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2850
2851<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2852 &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]2853</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2854
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2855<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2856
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2857<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2858currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2859returns to its caller. The object is always allocated in the generic address
2860space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2861
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2863
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2864<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2865bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif1acd2ee2008-02-09 22:24:34 +0000[diff] [blame]2866appropriate type to the program. If "NumElements" is specified, it is the
2867number of elements allocated, otherwise "NumElements" is defaulted to be one.
2868If an alignment is specified, the value result of the allocation is guaranteed
2869to be aligned to at least that boundary. If not specified, or if zero, the target
2870can choose to align the allocation on any convenient boundary.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2871
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2872<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2873
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2874<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2875
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2876<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2877memory is automatically released when the function returns. The '<tt>alloca</tt>'
2878instruction is commonly used to represent automatic variables that must
2879have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2880 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2881instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2882
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2884
2885<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2886 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2887 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2888 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2889 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2890</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2891</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2892
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2893<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2894<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2895Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2896<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2897<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2898<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]2899<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2900<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2901<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2902<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2903address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2904 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2905marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2906the number or order of execution of this <tt>load</tt> with other
2907volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2908instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2909<p>
2910The optional "align" argument specifies the alignment of the operation
2911(that is, the alignment of the memory address). A value of 0 or an
2912omitted "align" argument means that the operation has the preferential
2913alignment for the target. It is the responsibility of the code emitter
2914to ensure that the alignment information is correct. Overestimating
2915the alignment results in an undefined behavior. Underestimating the
2916alignment may produce less efficient code. An alignment of 1 is always
2917safe.
2918</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2919<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2920<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2921<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2922<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2923 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2924 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2925 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2926</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2927</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2928<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2929<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2930Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2931<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2932<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2933<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2934 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]2935</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2936<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2937<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2938<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2939<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2940to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2941operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2942operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2943optimizer is not allowed to modify the number or order of execution of
2944this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2945 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2946<p>
2947The optional "align" argument specifies the alignment of the operation
2948(that is, the alignment of the memory address). A value of 0 or an
2949omitted "align" argument means that the operation has the preferential
2950alignment for the target. It is the responsibility of the code emitter
2951to ensure that the alignment information is correct. Overestimating
2952the alignment results in an undefined behavior. Underestimating the
2953alignment may produce less efficient code. An alignment of 1 is always
2954safe.
2955</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2956<h5>Semantics:</h5>
2957<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2958at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2959<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2960<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2961 store i32 3, i32* %ptr <i>; yields {void}</i>
2962 %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]2963</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2964</div>
2965
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2966<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2967<div class="doc_subsubsection">
2968 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2969</div>
2970
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2971<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2972<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2973<pre>
2974 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2975</pre>
2976
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2977<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2978
2979<p>
2980The '<tt>getelementptr</tt>' instruction is used to get the address of a
2981subelement of an aggregate data structure.</p>
2982
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2983<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2984
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2985<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2986elements of the aggregate object to index to. The actual types of the arguments
2987provided depend on the type of the first pointer argument. The
2988'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2989levels 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]2990structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2991into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2992be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2993
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2994<p>For example, let's consider a C code fragment and how it gets
2995compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2996
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2997<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2998<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2999struct RT {
3000 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3001 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3002 char C;
3003};
3004struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3005 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3006 double Y;
3007 struct RT Z;
3008};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3009
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]3010int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3011 return &amp;s[1].Z.B[5][13];
3012}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3013</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3014</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3015
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3016<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3017
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3018<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3019<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3020%RT = type { i8 , [10 x [20 x i32]], i8 }
3021%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3022
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3023define i32* %foo(%ST* %s) {
3024entry:
3025 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3026 ret i32* %reg
3027}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3028</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3029</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3030
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3031<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3032
3033<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]3034on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]3035and <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]3036<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3037to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]3038<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3039
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3040<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]3041type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3042}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3043the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3044i8 }</tt>' type, another structure. The third index indexes into the second
3045element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3046array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3047'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3048to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3049
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3050<p>Note that it is perfectly legal to index partially through a
3051structure, returning a pointer to an inner element. Because of this,
3052the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3053
3054<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3055 define i32* %foo(%ST* %s) {
3056 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3057 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3058 %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]3059 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3060 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3061 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3062 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3063</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3064
3065<p>Note that it is undefined to access an array out of bounds: array and
3066pointer indexes must always be within the defined bounds of the array type.
3067The one exception for this rules is zero length arrays. These arrays are
3068defined to be accessible as variable length arrays, which requires access
3069beyond the zero'th element.</p>
3070
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3071<p>The getelementptr instruction is often confusing. For some more insight
3072into how it works, see <a href="GetElementPtr.html">the getelementptr
3073FAQ</a>.</p>
3074
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3075<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3076
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3077<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3078 <i>; yields [12 x i8]*:aptr</i>
3079 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3080</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3081</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3082
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3083<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3084<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3085</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3086<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3087<p>The instructions in this category are the conversion instructions (casting)
3088which all take a single operand and a type. They perform various bit conversions
3089on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3090</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3091
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3092<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3093<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3094 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3095</div>
3096<div class="doc_text">
3097
3098<h5>Syntax:</h5>
3099<pre>
3100 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3101</pre>
3102
3103<h5>Overview:</h5>
3104<p>
3105The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3106</p>
3107
3108<h5>Arguments:</h5>
3109<p>
3110The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3111be 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]3112and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3113type. The bit size of <tt>value</tt> must be larger than the bit size of
3114<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3115
3116<h5>Semantics:</h5>
3117<p>
3118The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3119and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3120larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3121It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3122
3123<h5>Example:</h5>
3124<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3125 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3126 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3127 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3128</pre>
3129</div>
3130
3131<!-- _______________________________________________________________________ -->
3132<div class="doc_subsubsection">
3133 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3134</div>
3135<div class="doc_text">
3136
3137<h5>Syntax:</h5>
3138<pre>
3139 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3140</pre>
3141
3142<h5>Overview:</h5>
3143<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3144<tt>ty2</tt>.</p>
3145
3146
3147<h5>Arguments:</h5>
3148<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]3149<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3150also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3151<tt>value</tt> must be smaller than the bit size of the destination type,
3152<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3153
3154<h5>Semantics:</h5>
3155<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]3156bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3157
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3158<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]3159
3160<h5>Example:</h5>
3161<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3162 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3163 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3164</pre>
3165</div>
3166
3167<!-- _______________________________________________________________________ -->
3168<div class="doc_subsubsection">
3169 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3170</div>
3171<div class="doc_text">
3172
3173<h5>Syntax:</h5>
3174<pre>
3175 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3176</pre>
3177
3178<h5>Overview:</h5>
3179<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3180
3181<h5>Arguments:</h5>
3182<p>
3183The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3184<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3185also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3186<tt>value</tt> must be smaller than the bit size of the destination type,
3187<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3188
3189<h5>Semantics:</h5>
3190<p>
3191The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3192bit (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]3193the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3194
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3195<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]3196
3197<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3198<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3199 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3200 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3201</pre>
3202</div>
3203
3204<!-- _______________________________________________________________________ -->
3205<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3206 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3207</div>
3208
3209<div class="doc_text">
3210
3211<h5>Syntax:</h5>
3212
3213<pre>
3214 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3215</pre>
3216
3217<h5>Overview:</h5>
3218<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3219<tt>ty2</tt>.</p>
3220
3221
3222<h5>Arguments:</h5>
3223<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3224 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3225cast it to. The size of <tt>value</tt> must be larger than the size of
3226<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3227<i>no-op cast</i>.</p>
3228
3229<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3230<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3231<a href="#t_floating">floating point</a> type to a smaller
3232<a href="#t_floating">floating point</a> type. If the value cannot fit within
3233the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3234
3235<h5>Example:</h5>
3236<pre>
3237 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3238 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3239</pre>
3240</div>
3241
3242<!-- _______________________________________________________________________ -->
3243<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3244 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3245</div>
3246<div class="doc_text">
3247
3248<h5>Syntax:</h5>
3249<pre>
3250 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3251</pre>
3252
3253<h5>Overview:</h5>
3254<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3255floating point value.</p>
3256
3257<h5>Arguments:</h5>
3258<p>The '<tt>fpext</tt>' instruction takes a
3259<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3260and a <a href="#t_floating">floating point</a> type to cast it to. The source
3261type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3262
3263<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3264<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3265<a href="#t_floating">floating point</a> type to a larger
3266<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3267used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3268<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]3269
3270<h5>Example:</h5>
3271<pre>
3272 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3273 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3274</pre>
3275</div>
3276
3277<!-- _______________________________________________________________________ -->
3278<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3279 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3280</div>
3281<div class="doc_text">
3282
3283<h5>Syntax:</h5>
3284<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3285 &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]3286</pre>
3287
3288<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3289<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3290unsigned integer equivalent of type <tt>ty2</tt>.
3291</p>
3292
3293<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3294<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]3295scalar or vector <a href="#t_floating">floating point</a> value, and a type
3296to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3297type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3298vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3299
3300<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3301<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3302<a href="#t_floating">floating point</a> operand into the nearest (rounding
3303towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3304the results are undefined.</p>
3305
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3306<h5>Example:</h5>
3307<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3308 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3309 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3310 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3311</pre>
3312</div>
3313
3314<!-- _______________________________________________________________________ -->
3315<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3316 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3317</div>
3318<div class="doc_text">
3319
3320<h5>Syntax:</h5>
3321<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3322 &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]3323</pre>
3324
3325<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3326<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3327<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]3328</p>
3329
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3330<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3331<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]3332scalar or vector <a href="#t_floating">floating point</a> value, and a type
3333to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3334type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3335vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3336
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3337<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3338<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3339<a href="#t_floating">floating point</a> operand into the nearest (rounding
3340towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3341the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3342
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3343<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3344<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3345 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3346 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3347 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3348</pre>
3349</div>
3350
3351<!-- _______________________________________________________________________ -->
3352<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3353 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3354</div>
3355<div class="doc_text">
3356
3357<h5>Syntax:</h5>
3358<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3359 &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]3360</pre>
3361
3362<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3363<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3364integer and converts that value to the <tt>ty2</tt> type.</p>
3365
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3366<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3367<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3368scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3369to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3370type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3371floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3372
3373<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3374<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3375integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3376the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3377
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3378<h5>Example:</h5>
3379<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3380 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3381 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3382</pre>
3383</div>
3384
3385<!-- _______________________________________________________________________ -->
3386<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3387 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3388</div>
3389<div class="doc_text">
3390
3391<h5>Syntax:</h5>
3392<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3393 &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]3394</pre>
3395
3396<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3397<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3398integer and converts that value to the <tt>ty2</tt> type.</p>
3399
3400<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3401<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3402scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3403to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3404type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3405floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3406
3407<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3408<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3409integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3410the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3411
3412<h5>Example:</h5>
3413<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3414 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3415 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3416</pre>
3417</div>
3418
3419<!-- _______________________________________________________________________ -->
3420<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3421 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3422</div>
3423<div class="doc_text">
3424
3425<h5>Syntax:</h5>
3426<pre>
3427 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3428</pre>
3429
3430<h5>Overview:</h5>
3431<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3432the integer type <tt>ty2</tt>.</p>
3433
3434<h5>Arguments:</h5>
3435<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3436must 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]3437<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3438
3439<h5>Semantics:</h5>
3440<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3441<tt>ty2</tt> by interpreting the pointer value as an integer and either
3442truncating or zero extending that value to the size of the integer type. If
3443<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3444<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]3445are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3446change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3447
3448<h5>Example:</h5>
3449<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3450 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3451 %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]3452</pre>
3453</div>
3454
3455<!-- _______________________________________________________________________ -->
3456<div class="doc_subsubsection">
3457 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3458</div>
3459<div class="doc_text">
3460
3461<h5>Syntax:</h5>
3462<pre>
3463 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3464</pre>
3465
3466<h5>Overview:</h5>
3467<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3468a pointer type, <tt>ty2</tt>.</p>
3469
3470<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3471<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3472value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3473<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3474
3475<h5>Semantics:</h5>
3476<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3477<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3478the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3479size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3480the size of a pointer then a zero extension is done. If they are the same size,
3481nothing is done (<i>no-op cast</i>).</p>
3482
3483<h5>Example:</h5>
3484<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3485 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3486 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3487 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3488</pre>
3489</div>
3490
3491<!-- _______________________________________________________________________ -->
3492<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3493 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3494</div>
3495<div class="doc_text">
3496
3497<h5>Syntax:</h5>
3498<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3499 &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]3500</pre>
3501
3502<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3503<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3504<tt>ty2</tt> without changing any bits.</p>
3505
3506<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3507<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3508a first class value, and a type to cast it to, which must also be a <a
3509 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3510and the destination type, <tt>ty2</tt>, must be identical. If the source
3511type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3512
3513<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3514<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3515<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3516this conversion. The conversion is done as if the <tt>value</tt> had been
3517stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3518converted to other pointer types with this instruction. To convert pointers to
3519other types, use the <a href="#i_inttoptr">inttoptr</a> or
3520<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3521
3522<h5>Example:</h5>
3523<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3524 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3525 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3526 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3527</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3528</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3529
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3530<!-- ======================================================================= -->
3531<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3532<div class="doc_text">
3533<p>The instructions in this category are the "miscellaneous"
3534instructions, which defy better classification.</p>
3535</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3536
3537<!-- _______________________________________________________________________ -->
3538<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3539</div>
3540<div class="doc_text">
3541<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3542<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]3543</pre>
3544<h5>Overview:</h5>
3545<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3546of its two integer operands.</p>
3547<h5>Arguments:</h5>
3548<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3549the condition code indicating the kind of comparison to perform. It is not
3550a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3551<ol>
3552 <li><tt>eq</tt>: equal</li>
3553 <li><tt>ne</tt>: not equal </li>
3554 <li><tt>ugt</tt>: unsigned greater than</li>
3555 <li><tt>uge</tt>: unsigned greater or equal</li>
3556 <li><tt>ult</tt>: unsigned less than</li>
3557 <li><tt>ule</tt>: unsigned less or equal</li>
3558 <li><tt>sgt</tt>: signed greater than</li>
3559 <li><tt>sge</tt>: signed greater or equal</li>
3560 <li><tt>slt</tt>: signed less than</li>
3561 <li><tt>sle</tt>: signed less or equal</li>
3562</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3563<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3564<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3565<h5>Semantics:</h5>
3566<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3567the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3568yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3569<ol>
3570 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3571 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3572 </li>
3573 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3574 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3575 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3576 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3577 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3578 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3579 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3580 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3581 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3582 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3583 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3584 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3585 <li><tt>sge</tt>: interprets the operands as signed values and yields
3586 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3587 <li><tt>slt</tt>: interprets the operands as signed values and yields
3588 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3589 <li><tt>sle</tt>: interprets the operands as signed values and yields
3590 <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]3591</ol>
3592<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3593values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3594
3595<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3596<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3597 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3598 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3599 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3600 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3601 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3602</pre>
3603</div>
3604
3605<!-- _______________________________________________________________________ -->
3606<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3607</div>
3608<div class="doc_text">
3609<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3610<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]3611</pre>
3612<h5>Overview:</h5>
3613<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3614of its floating point operands.</p>
3615<h5>Arguments:</h5>
3616<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3617the condition code indicating the kind of comparison to perform. It is not
3618a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3619<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3620 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3621 <li><tt>oeq</tt>: ordered and equal</li>
3622 <li><tt>ogt</tt>: ordered and greater than </li>
3623 <li><tt>oge</tt>: ordered and greater than or equal</li>
3624 <li><tt>olt</tt>: ordered and less than </li>
3625 <li><tt>ole</tt>: ordered and less than or equal</li>
3626 <li><tt>one</tt>: ordered and not equal</li>
3627 <li><tt>ord</tt>: ordered (no nans)</li>
3628 <li><tt>ueq</tt>: unordered or equal</li>
3629 <li><tt>ugt</tt>: unordered or greater than </li>
3630 <li><tt>uge</tt>: unordered or greater than or equal</li>
3631 <li><tt>ult</tt>: unordered or less than </li>
3632 <li><tt>ule</tt>: unordered or less than or equal</li>
3633 <li><tt>une</tt>: unordered or not equal</li>
3634 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3635 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3636</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3637<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3638<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3639<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3640<a href="#t_floating">floating point</a> typed. They must have identical
3641types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3642<h5>Semantics:</h5>
3643<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3644the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3645yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3646<ol>
3647 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3648 <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]3649 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3650 <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]3651 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3652 <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]3653 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3654 <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]3655 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3656 <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]3657 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3658 <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]3659 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3660 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3661 <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]3662 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3663 <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]3664 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3665 <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]3666 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3667 <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]3668 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3669 <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]3670 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3671 <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]3672 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3673 <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]3674 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3675</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3676
3677<h5>Example:</h5>
3678<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3679 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3680 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3681 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3682</pre>
3683</div>
3684
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3685<!-- _______________________________________________________________________ -->
3686<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3687Instruction</a> </div>
3688<div class="doc_text">
3689<h5>Syntax:</h5>
3690<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3691<h5>Overview:</h5>
3692<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3693the SSA graph representing the function.</p>
3694<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3695<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3696field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3697as arguments, with one pair for each predecessor basic block of the
3698current block. Only values of <a href="#t_firstclass">first class</a>
3699type may be used as the value arguments to the PHI node. Only labels
3700may be used as the label arguments.</p>
3701<p>There must be no non-phi instructions between the start of a basic
3702block and the PHI instructions: i.e. PHI instructions must be first in
3703a basic block.</p>
3704<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3705<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3706specified by the pair corresponding to the predecessor basic block that executed
3707just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3708<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3709<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]3710</div>
3711
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection">
3714 <a name="i_select">'<tt>select</tt>' Instruction</a>
3715</div>
3716
3717<div class="doc_text">
3718
3719<h5>Syntax:</h5>
3720
3721<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3722 &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]3723</pre>
3724
3725<h5>Overview:</h5>
3726
3727<p>
3728The '<tt>select</tt>' instruction is used to choose one value based on a
3729condition, without branching.
3730</p>
3731
3732
3733<h5>Arguments:</h5>
3734
3735<p>
3736The '<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.
3737</p>
3738
3739<h5>Semantics:</h5>
3740
3741<p>
3742If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3743value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3744</p>
3745
3746<h5>Example:</h5>
3747
3748<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3749 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3750</pre>
3751</div>
3752
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3753
3754<!-- _______________________________________________________________________ -->
3755<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3756 <a name="i_call">'<tt>call</tt>' Instruction</a>
3757</div>
3758
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3759<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3760
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3762<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3763 &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]3764</pre>
3765
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3766<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3767
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3768<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3769
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3770<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3771
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3772<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3773
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3774<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3775 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3776 <p>The optional "tail" marker indicates whether the callee function accesses
3777 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3778 function call is eligible for tail call optimization. Note that calls may
3779 be marked "tail" even if they do not occur before a <a
3780 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3781 </li>
3782 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3783 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3784 convention</a> the call should use. If none is specified, the call defaults
3785 to using C calling conventions.
3786 </li>
3787 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3788 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3789 the type of the return value. Functions that return no value are marked
3790 <tt><a href="#t_void">void</a></tt>.</p>
3791 </li>
3792 <li>
3793 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3794 value being invoked. The argument types must match the types implied by
3795 this signature. This type can be omitted if the function is not varargs
3796 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3797 </li>
3798 <li>
3799 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3800 be invoked. In most cases, this is a direct function invocation, but
3801 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3802 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3803 </li>
3804 <li>
3805 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3806 function signature argument types. All arguments must be of
3807 <a href="#t_firstclass">first class</a> type. If the function signature
3808 indicates the function accepts a variable number of arguments, the extra
3809 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3810 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3811</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3812
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3813<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3814
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3815<p>The '<tt>call</tt>' instruction is used to cause control flow to
3816transfer to a specified function, with its incoming arguments bound to
3817the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3818instruction in the called function, control flow continues with the
3819instruction after the function call, and the return value of the
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3820function is bound to the result argument. If the '<tt><a href="#i_ret">ret</a>
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]3821</tt>' instruction returns multiple values then the return values of the
3822function are only accessible through a '<tt><a href="#i_getresult">getresult</a>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3823</tt>' instruction. This is a simpler case of
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3824the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3826<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3827
3828<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3829 %retval = call i32 @test(i32 %argc)
3830 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3831 %X = tail call i32 @foo()
3832 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3833 %Z = call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3834
3835 %struct.A = type { i32, i8 }
3836 %r = call %struct.A @foo()
3837 %gr = getresult %struct.A %r, 0
3838 %gr1 = getresult %struct.A %r, 1
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3839</pre>
3840
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3841</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3842
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3843<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3844<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3845 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3846</div>
3847
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3848<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3849
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3850<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3851
3852<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3853 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3854</pre>
3855
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3856<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3857
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3858<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3859the "variable argument" area of a function call. It is used to implement the
3860<tt>va_arg</tt> macro in C.</p>
3861
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3862<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3863
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3864<p>This instruction takes a <tt>va_list*</tt> value and the type of
3865the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3866increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3867actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3868
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3869<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3870
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3871<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3872type from the specified <tt>va_list</tt> and causes the
3873<tt>va_list</tt> to point to the next argument. For more information,
3874see the variable argument handling <a href="#int_varargs">Intrinsic
3875Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3876
3877<p>It is legal for this instruction to be called in a function which does not
3878take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3879function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3880
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3881<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3882href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3883argument.</p>
3884
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3885<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3886
3887<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3888
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3889</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3890
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3891<!-- _______________________________________________________________________ -->
3892<div class="doc_subsubsection">
3893 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3894</div>
3895
3896<div class="doc_text">
3897
3898<h5>Syntax:</h5>
3899<pre>
3900 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
3901</pre>
3902<h5>Overview:</h5>
3903
3904<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]3905from multiple values returned by a '<tt><a href="#i_call">call</a></tt>'
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3906or '<tt><a href="#i_invoke">invoke</a></tt>' instruction.
3907
3908<h5>Arguments:</h5>
3909
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]3910The '<tt>getresult</tt>' instruction takes a return value as first argument.
3911The value must have <a href="#t_struct">structure type</a>. The second argument
3912is an unsigned index value.
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3913
3914<h5>Semantics:</h5>
3915
Devang Patel0dbb4a12008-03-11 05:51:59 +0000[diff] [blame]3916The '<tt>getresult</tt>' instruction extracts the element identified by
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]3917'<tt>index</tt>' from the aggregate value.
3918
3919<h5>Example:</h5>
3920
3921<pre>
3922 %struct.A = type { i32, i8 }
3923
3924 %r = call %struct.A @foo()
3925 %gr = getresult %struct.A %r, 0
3926 %gr1 = getresult %struct.A %r, 1
3927 add i32 %gr, 42
3928 add i8 %gr1, 41
3929</pre>
3930
3931</div>
3932
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3933<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3934<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3935<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3936
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3937<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3938
3939<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3940well known names and semantics and are required to follow certain restrictions.
3941Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3942language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3943adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3944
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3945<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3946prefix is reserved in LLVM for intrinsic names; thus, function names may not
3947begin with this prefix. Intrinsic functions must always be external functions:
3948you cannot define the body of intrinsic functions. Intrinsic functions may
3949only be used in call or invoke instructions: it is illegal to take the address
3950of an intrinsic function. Additionally, because intrinsic functions are part
3951of the LLVM language, it is required if any are added that they be documented
3952here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3953
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3954<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3955a family of functions that perform the same operation but on different data
3956types. Because LLVM can represent over 8 million different integer types,
3957overloading is used commonly to allow an intrinsic function to operate on any
3958integer type. One or more of the argument types or the result type can be
3959overloaded to accept any integer type. Argument types may also be defined as
3960exactly matching a previous argument's type or the result type. This allows an
3961intrinsic function which accepts multiple arguments, but needs all of them to
3962be of the same type, to only be overloaded with respect to a single argument or
3963the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3964
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3965<p>Overloaded intrinsics will have the names of its overloaded argument types
3966encoded into its function name, each preceded by a period. Only those types
3967which are overloaded result in a name suffix. Arguments whose type is matched
3968against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3969take an integer of any width and returns an integer of exactly the same integer
3970width. This leads to a family of functions such as
3971<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3972Only one type, the return type, is overloaded, and only one type suffix is
3973required. Because the argument's type is matched against the return type, it
3974does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3975
3976<p>To learn how to add an intrinsic function, please see the
3977<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3978</p>
3979
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3980</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3981
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3982<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3983<div class="doc_subsection">
3984 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3985</div>
3986
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3987<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3988
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3989<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3990 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3991intrinsic functions. These functions are related to the similarly
3992named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3993
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3994<p>All of these functions operate on arguments that use a
3995target-specific value type "<tt>va_list</tt>". The LLVM assembly
3996language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3997transformations should be prepared to handle these functions regardless of
3998the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3999
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]4000<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]4001instruction and the variable argument handling intrinsic functions are
4002used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4003
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4004<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4005<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4006define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4007 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4008 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4009 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4010 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4011
4012 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4013 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4014
4015 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4016 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4017 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4018 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4019 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4020
4021 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4022 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4023 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4024}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]4025
4026declare void @llvm.va_start(i8*)
4027declare void @llvm.va_copy(i8*, i8*)
4028declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4029</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4030</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4031
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]4032</div>
4033
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4034<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4035<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4036 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4037</div>
4038
4039
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4040<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4041<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4042<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4043<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4044<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4045<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4046href="#i_va_arg">va_arg</a></tt>.</p>
4047
4048<h5>Arguments:</h5>
4049
4050<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4051
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4052<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4053
4054<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4055macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4056<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]4057<tt>va_arg</tt> will produce the first variable argument passed to the function.
4058Unlike 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]4059last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4060
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4061</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4062
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4063<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4064<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4065 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4066</div>
4067
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4068<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4069<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4070<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4071<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4072
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4073<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4074which 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]4075or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4076
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4077<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4078
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4079<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]4080
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4081<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4082
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4083<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]4084macro available in C. In a target-dependent way, it destroys the
4085<tt>va_list</tt> element to which the argument points. Calls to <a
4086href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4087<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4088<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]4089
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4090</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4091
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4092<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4093<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4094 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4095</div>
4096
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4097<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4098
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4099<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4100
4101<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4102 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4103</pre>
4104
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4105<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4106
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4107<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4108from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4109
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4110<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4111
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4112<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]4113The 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]4114
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4115
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4116<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4117
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4118<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4119macro available in C. In a target-dependent way, it copies the source
4120<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4121intrinsic is necessary because the <tt><a href="#int_va_start">
4122llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4123example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4124
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4125</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4126
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4127<!-- ======================================================================= -->
4128<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4129 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4130</div>
4131
4132<div class="doc_text">
4133
4134<p>
4135LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4136Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4137These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4138stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4139href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4140Front-ends for type-safe garbage collected languages should generate these
4141intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4142href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4143</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4144
4145<p>The garbage collection intrinsics only operate on objects in the generic
4146 address space (address space zero).</p>
4147
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4148</div>
4149
4150<!-- _______________________________________________________________________ -->
4151<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4152 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4153</div>
4154
4155<div class="doc_text">
4156
4157<h5>Syntax:</h5>
4158
4159<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4160 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4161</pre>
4162
4163<h5>Overview:</h5>
4164
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4165<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]4166the code generator, and allows some metadata to be associated with it.</p>
4167
4168<h5>Arguments:</h5>
4169
4170<p>The first argument specifies the address of a stack object that contains the
4171root pointer. The second pointer (which must be either a constant or a global
4172value address) contains the meta-data to be associated with the root.</p>
4173
4174<h5>Semantics:</h5>
4175
4176<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4177location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4178the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4179intrinsic may only be used in a function which <a href="#gc">specifies a GC
4180algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4181
4182</div>
4183
4184
4185<!-- _______________________________________________________________________ -->
4186<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4187 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4188</div>
4189
4190<div class="doc_text">
4191
4192<h5>Syntax:</h5>
4193
4194<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4195 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4196</pre>
4197
4198<h5>Overview:</h5>
4199
4200<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4201locations, allowing garbage collector implementations that require read
4202barriers.</p>
4203
4204<h5>Arguments:</h5>
4205
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4206<p>The second argument is the address to read from, which should be an address
4207allocated from the garbage collector. The first object is a pointer to the
4208start of the referenced object, if needed by the language runtime (otherwise
4209null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4210
4211<h5>Semantics:</h5>
4212
4213<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4214instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4215garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4216may only be used in a function which <a href="#gc">specifies a GC
4217algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4218
4219</div>
4220
4221
4222<!-- _______________________________________________________________________ -->
4223<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4224 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4225</div>
4226
4227<div class="doc_text">
4228
4229<h5>Syntax:</h5>
4230
4231<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4232 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4233</pre>
4234
4235<h5>Overview:</h5>
4236
4237<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4238locations, allowing garbage collector implementations that require write
4239barriers (such as generational or reference counting collectors).</p>
4240
4241<h5>Arguments:</h5>
4242
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4243<p>The first argument is the reference to store, the second is the start of the
4244object to store it to, and the third is the address of the field of Obj to
4245store to. If the runtime does not require a pointer to the object, Obj may be
4246null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4247
4248<h5>Semantics:</h5>
4249
4250<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4251instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4252garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4253may only be used in a function which <a href="#gc">specifies a GC
4254algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4255
4256</div>
4257
4258
4259
4260<!-- ======================================================================= -->
4261<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4262 <a name="int_codegen">Code Generator Intrinsics</a>
4263</div>
4264
4265<div class="doc_text">
4266<p>
4267These intrinsics are provided by LLVM to expose special features that may only
4268be implemented with code generator support.
4269</p>
4270
4271</div>
4272
4273<!-- _______________________________________________________________________ -->
4274<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4275 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4276</div>
4277
4278<div class="doc_text">
4279
4280<h5>Syntax:</h5>
4281<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4282 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4283</pre>
4284
4285<h5>Overview:</h5>
4286
4287<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4288The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4289target-specific value indicating the return address of the current function
4290or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4291</p>
4292
4293<h5>Arguments:</h5>
4294
4295<p>
4296The argument to this intrinsic indicates which function to return the address
4297for. Zero indicates the calling function, one indicates its caller, etc. The
4298argument is <b>required</b> to be a constant integer value.
4299</p>
4300
4301<h5>Semantics:</h5>
4302
4303<p>
4304The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4305the return address of the specified call frame, or zero if it cannot be
4306identified. The value returned by this intrinsic is likely to be incorrect or 0
4307for arguments other than zero, so it should only be used for debugging purposes.
4308</p>
4309
4310<p>
4311Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4312aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4313source-language caller.
4314</p>
4315</div>
4316
4317
4318<!-- _______________________________________________________________________ -->
4319<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4320 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4321</div>
4322
4323<div class="doc_text">
4324
4325<h5>Syntax:</h5>
4326<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4327 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4328</pre>
4329
4330<h5>Overview:</h5>
4331
4332<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4333The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4334target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4335</p>
4336
4337<h5>Arguments:</h5>
4338
4339<p>
4340The argument to this intrinsic indicates which function to return the frame
4341pointer for. Zero indicates the calling function, one indicates its caller,
4342etc. The argument is <b>required</b> to be a constant integer value.
4343</p>
4344
4345<h5>Semantics:</h5>
4346
4347<p>
4348The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4349the frame address of the specified call frame, or zero if it cannot be
4350identified. The value returned by this intrinsic is likely to be incorrect or 0
4351for arguments other than zero, so it should only be used for debugging purposes.
4352</p>
4353
4354<p>
4355Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4356aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4357source-language caller.
4358</p>
4359</div>
4360
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4361<!-- _______________________________________________________________________ -->
4362<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4363 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4364</div>
4365
4366<div class="doc_text">
4367
4368<h5>Syntax:</h5>
4369<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4370 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4371</pre>
4372
4373<h5>Overview:</h5>
4374
4375<p>
4376The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4377the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4378<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4379features like scoped automatic variable sized arrays in C99.
4380</p>
4381
4382<h5>Semantics:</h5>
4383
4384<p>
4385This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4386href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4387<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4388<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4389state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4390practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4391that were allocated after the <tt>llvm.stacksave</tt> was executed.
4392</p>
4393
4394</div>
4395
4396<!-- _______________________________________________________________________ -->
4397<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4398 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4399</div>
4400
4401<div class="doc_text">
4402
4403<h5>Syntax:</h5>
4404<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4405 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4406</pre>
4407
4408<h5>Overview:</h5>
4409
4410<p>
4411The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4412the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4413href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4414useful for implementing language features like scoped automatic variable sized
4415arrays in C99.
4416</p>
4417
4418<h5>Semantics:</h5>
4419
4420<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4421See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4422</p>
4423
4424</div>
4425
4426
4427<!-- _______________________________________________________________________ -->
4428<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4429 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4430</div>
4431
4432<div class="doc_text">
4433
4434<h5>Syntax:</h5>
4435<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4436 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]4437</pre>
4438
4439<h5>Overview:</h5>
4440
4441
4442<p>
4443The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4444a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4445no
4446effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4447characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4448</p>
4449
4450<h5>Arguments:</h5>
4451
4452<p>
4453<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4454determining if the fetch should be for a read (0) or write (1), and
4455<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4456locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4457<tt>locality</tt> arguments must be constant integers.
4458</p>
4459
4460<h5>Semantics:</h5>
4461
4462<p>
4463This intrinsic does not modify the behavior of the program. In particular,
4464prefetches cannot trap and do not produce a value. On targets that support this
4465intrinsic, the prefetch can provide hints to the processor cache for better
4466performance.
4467</p>
4468
4469</div>
4470
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4471<!-- _______________________________________________________________________ -->
4472<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4473 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4474</div>
4475
4476<div class="doc_text">
4477
4478<h5>Syntax:</h5>
4479<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4480 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4481</pre>
4482
4483<h5>Overview:</h5>
4484
4485
4486<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4487The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4488(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4489code to simulators and other tools. The method is target specific, but it is
4490expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4491The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4492after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4493optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4494correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4495</p>
4496
4497<h5>Arguments:</h5>
4498
4499<p>
4500<tt>id</tt> is a numerical id identifying the marker.
4501</p>
4502
4503<h5>Semantics:</h5>
4504
4505<p>
4506This intrinsic does not modify the behavior of the program. Backends that do not
4507support this intrinisic may ignore it.
4508</p>
4509
4510</div>
4511
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4512<!-- _______________________________________________________________________ -->
4513<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4514 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4515</div>
4516
4517<div class="doc_text">
4518
4519<h5>Syntax:</h5>
4520<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4521 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4522</pre>
4523
4524<h5>Overview:</h5>
4525
4526
4527<p>
4528The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4529counter register (or similar low latency, high accuracy clocks) on those targets
4530that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4531As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4532should only be used for small timings.
4533</p>
4534
4535<h5>Semantics:</h5>
4536
4537<p>
4538When directly supported, reading the cycle counter should not modify any memory.
4539Implementations are allowed to either return a application specific value or a
4540system wide value. On backends without support, this is lowered to a constant 0.
4541</p>
4542
4543</div>
4544
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4545<!-- ======================================================================= -->
4546<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4547 <a name="int_libc">Standard C Library Intrinsics</a>
4548</div>
4549
4550<div class="doc_text">
4551<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4552LLVM provides intrinsics for a few important standard C library functions.
4553These intrinsics allow source-language front-ends to pass information about the
4554alignment of the pointer arguments to the code generator, providing opportunity
4555for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4556</p>
4557
4558</div>
4559
4560<!-- _______________________________________________________________________ -->
4561<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4562 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4563</div>
4564
4565<div class="doc_text">
4566
4567<h5>Syntax:</h5>
4568<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4569 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4570 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4571 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4572 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4573</pre>
4574
4575<h5>Overview:</h5>
4576
4577<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4578The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4579location to the destination location.
4580</p>
4581
4582<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4583Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4584intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4585</p>
4586
4587<h5>Arguments:</h5>
4588
4589<p>
4590The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4591the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4592specifying the number of bytes to copy, and the fourth argument is the alignment
4593of the source and destination locations.
4594</p>
4595
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4596<p>
4597If 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]4598the caller guarantees that both the source and destination pointers are aligned
4599to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4600</p>
4601
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4602<h5>Semantics:</h5>
4603
4604<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4605The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4606location to the destination location, which are not allowed to overlap. It
4607copies "len" bytes of memory over. If the argument is known to be aligned to
4608some boundary, this can be specified as the fourth argument, otherwise it should
4609be set to 0 or 1.
4610</p>
4611</div>
4612
4613
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4614<!-- _______________________________________________________________________ -->
4615<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4616 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4617</div>
4618
4619<div class="doc_text">
4620
4621<h5>Syntax:</h5>
4622<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4623 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4624 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4625 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4626 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4627</pre>
4628
4629<h5>Overview:</h5>
4630
4631<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4632The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4633location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4634'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4635</p>
4636
4637<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4638Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4639intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4640</p>
4641
4642<h5>Arguments:</h5>
4643
4644<p>
4645The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4646the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4647specifying the number of bytes to copy, and the fourth argument is the alignment
4648of the source and destination locations.
4649</p>
4650
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4651<p>
4652If 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]4653the caller guarantees that the source and destination pointers are aligned to
4654that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4655</p>
4656
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4657<h5>Semantics:</h5>
4658
4659<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4660The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4661location to the destination location, which may overlap. It
4662copies "len" bytes of memory over. If the argument is known to be aligned to
4663some boundary, this can be specified as the fourth argument, otherwise it should
4664be set to 0 or 1.
4665</p>
4666</div>
4667
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4668
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4669<!-- _______________________________________________________________________ -->
4670<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4671 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4672</div>
4673
4674<div class="doc_text">
4675
4676<h5>Syntax:</h5>
4677<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4678 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4679 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4680 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4681 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4682</pre>
4683
4684<h5>Overview:</h5>
4685
4686<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4687The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4688byte value.
4689</p>
4690
4691<p>
4692Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4693does not return a value, and takes an extra alignment argument.
4694</p>
4695
4696<h5>Arguments:</h5>
4697
4698<p>
4699The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4700byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4701argument specifying the number of bytes to fill, and the fourth argument is the
4702known alignment of destination location.
4703</p>
4704
4705<p>
4706If 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]4707the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4708</p>
4709
4710<h5>Semantics:</h5>
4711
4712<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4713The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4714the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4715destination location. If the argument is known to be aligned to some boundary,
4716this can be specified as the fourth argument, otherwise it should be set to 0 or
47171.
4718</p>
4719</div>
4720
4721
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4722<!-- _______________________________________________________________________ -->
4723<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4724 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4725</div>
4726
4727<div class="doc_text">
4728
4729<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4730<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]4731floating point or vector of floating point type. Not all targets support all
4732types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4733<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4734 declare float @llvm.sqrt.f32(float %Val)
4735 declare double @llvm.sqrt.f64(double %Val)
4736 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4737 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4738 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4739</pre>
4740
4741<h5>Overview:</h5>
4742
4743<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4744The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4745returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4746<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner103e2d72008-01-29 07:00:44 +0000[diff] [blame]4747negative numbers other than -0.0 (which allows for better optimization, because
4748there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4749defined to return -0.0 like IEEE sqrt.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4750</p>
4751
4752<h5>Arguments:</h5>
4753
4754<p>
4755The argument and return value are floating point numbers of the same type.
4756</p>
4757
4758<h5>Semantics:</h5>
4759
4760<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4761This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4762floating point number.
4763</p>
4764</div>
4765
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4766<!-- _______________________________________________________________________ -->
4767<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4768 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4769</div>
4770
4771<div class="doc_text">
4772
4773<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4774<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]4775floating point or vector of floating point type. Not all targets support all
4776types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4777<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4778 declare float @llvm.powi.f32(float %Val, i32 %power)
4779 declare double @llvm.powi.f64(double %Val, i32 %power)
4780 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4781 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4782 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4783</pre>
4784
4785<h5>Overview:</h5>
4786
4787<p>
4788The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4789specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4790multiplications is not defined. When a vector of floating point type is
4791used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4792</p>
4793
4794<h5>Arguments:</h5>
4795
4796<p>
4797The second argument is an integer power, and the first is a value to raise to
4798that power.
4799</p>
4800
4801<h5>Semantics:</h5>
4802
4803<p>
4804This function returns the first value raised to the second power with an
4805unspecified sequence of rounding operations.</p>
4806</div>
4807
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4808<!-- _______________________________________________________________________ -->
4809<div class="doc_subsubsection">
4810 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4811</div>
4812
4813<div class="doc_text">
4814
4815<h5>Syntax:</h5>
4816<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4817floating point or vector of floating point type. Not all targets support all
4818types however.
4819<pre>
4820 declare float @llvm.sin.f32(float %Val)
4821 declare double @llvm.sin.f64(double %Val)
4822 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4823 declare fp128 @llvm.sin.f128(fp128 %Val)
4824 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4825</pre>
4826
4827<h5>Overview:</h5>
4828
4829<p>
4830The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4831</p>
4832
4833<h5>Arguments:</h5>
4834
4835<p>
4836The argument and return value are floating point numbers of the same type.
4837</p>
4838
4839<h5>Semantics:</h5>
4840
4841<p>
4842This function returns the sine of the specified operand, returning the
4843same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4844conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4845</div>
4846
4847<!-- _______________________________________________________________________ -->
4848<div class="doc_subsubsection">
4849 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4850</div>
4851
4852<div class="doc_text">
4853
4854<h5>Syntax:</h5>
4855<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4856floating point or vector of floating point type. Not all targets support all
4857types however.
4858<pre>
4859 declare float @llvm.cos.f32(float %Val)
4860 declare double @llvm.cos.f64(double %Val)
4861 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4862 declare fp128 @llvm.cos.f128(fp128 %Val)
4863 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4864</pre>
4865
4866<h5>Overview:</h5>
4867
4868<p>
4869The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4870</p>
4871
4872<h5>Arguments:</h5>
4873
4874<p>
4875The argument and return value are floating point numbers of the same type.
4876</p>
4877
4878<h5>Semantics:</h5>
4879
4880<p>
4881This function returns the cosine of the specified operand, returning the
4882same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4883conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4884</div>
4885
4886<!-- _______________________________________________________________________ -->
4887<div class="doc_subsubsection">
4888 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4889</div>
4890
4891<div class="doc_text">
4892
4893<h5>Syntax:</h5>
4894<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4895floating point or vector of floating point type. Not all targets support all
4896types however.
4897<pre>
4898 declare float @llvm.pow.f32(float %Val, float %Power)
4899 declare double @llvm.pow.f64(double %Val, double %Power)
4900 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4901 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4902 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4903</pre>
4904
4905<h5>Overview:</h5>
4906
4907<p>
4908The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4909specified (positive or negative) power.
4910</p>
4911
4912<h5>Arguments:</h5>
4913
4914<p>
4915The second argument is a floating point power, and the first is a value to
4916raise to that power.
4917</p>
4918
4919<h5>Semantics:</h5>
4920
4921<p>
4922This function returns the first value raised to the second power,
4923returning the
4924same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4925conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4926</div>
4927
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4928
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4929<!-- ======================================================================= -->
4930<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4931 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4932</div>
4933
4934<div class="doc_text">
4935<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4936LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4937These allow efficient code generation for some algorithms.
4938</p>
4939
4940</div>
4941
4942<!-- _______________________________________________________________________ -->
4943<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4944 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4945</div>
4946
4947<div class="doc_text">
4948
4949<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4950<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4951type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4952<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4953 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4954 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4955 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4956</pre>
4957
4958<h5>Overview:</h5>
4959
4960<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4961The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4962values with an even number of bytes (positive multiple of 16 bits). These are
4963useful for performing operations on data that is not in the target's native
4964byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4965</p>
4966
4967<h5>Semantics:</h5>
4968
4969<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4970The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4971and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4972intrinsic returns an i32 value that has the four bytes of the input i32
4973swapped, 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]4974i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4975<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4976additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4977</p>
4978
4979</div>
4980
4981<!-- _______________________________________________________________________ -->
4982<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4983 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4984</div>
4985
4986<div class="doc_text">
4987
4988<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4989<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4990width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4991<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4992 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4993 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4994 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4995 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4996 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4997</pre>
4998
4999<h5>Overview:</h5>
5000
5001<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]5002The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5003value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5004</p>
5005
5006<h5>Arguments:</h5>
5007
5008<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5009The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5010integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5011</p>
5012
5013<h5>Semantics:</h5>
5014
5015<p>
5016The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5017</p>
5018</div>
5019
5020<!-- _______________________________________________________________________ -->
5021<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5022 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5023</div>
5024
5025<div class="doc_text">
5026
5027<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5028<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5029integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5030<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5031 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5032 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5033 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5034 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5035 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5036</pre>
5037
5038<h5>Overview:</h5>
5039
5040<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5041The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5042leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5043</p>
5044
5045<h5>Arguments:</h5>
5046
5047<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]5048The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5049integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5050</p>
5051
5052<h5>Semantics:</h5>
5053
5054<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5055The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5056in 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]5057of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]5058</p>
5059</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]5060
5061
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5062
5063<!-- _______________________________________________________________________ -->
5064<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]5065 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5066</div>
5067
5068<div class="doc_text">
5069
5070<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]5071<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5072integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5073<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5074 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5075 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]5076 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5077 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5078 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5079</pre>
5080
5081<h5>Overview:</h5>
5082
5083<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]5084The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5085trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5086</p>
5087
5088<h5>Arguments:</h5>
5089
5090<p>
5091The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]5092integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]5093</p>
5094
5095<h5>Semantics:</h5>
5096
5097<p>
5098The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5099in a variable. If the src == 0 then the result is the size in bits of the type
5100of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5101</p>
5102</div>
5103
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5104<!-- _______________________________________________________________________ -->
5105<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5106 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5107</div>
5108
5109<div class="doc_text">
5110
5111<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5112<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5113on any integer bit width.
5114<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5115 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5116 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5117</pre>
5118
5119<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5120<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5121range of bits from an integer value and returns them in the same bit width as
5122the original value.</p>
5123
5124<h5>Arguments:</h5>
5125<p>The first argument, <tt>%val</tt> and the result may be integer types of
5126any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5127arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5128
5129<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5130<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5131of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5132<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5133operates in forward mode.</p>
5134<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5135right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5136only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5137<ol>
5138 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5139 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5140 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5141 to determine the number of bits to retain.</li>
5142 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5143 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5144</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5145<p>In reverse mode, a similar computation is made except that the bits are
5146returned in the reverse order. So, for example, if <tt>X</tt> has the value
5147<tt>i16 0x0ACF (101011001111)</tt> and we apply
5148<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5149<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5150</div>
5151
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5152<div class="doc_subsubsection">
5153 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5154</div>
5155
5156<div class="doc_text">
5157
5158<h5>Syntax:</h5>
5159<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5160on any integer bit width.
5161<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5162 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5163 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]5164</pre>
5165
5166<h5>Overview:</h5>
5167<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5168of bits in an integer value with another integer value. It returns the integer
5169with the replaced bits.</p>
5170
5171<h5>Arguments:</h5>
5172<p>The first argument, <tt>%val</tt> and the result may be integer types of
5173any bit width but they must have the same bit width. <tt>%val</tt> is the value
5174whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5175integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5176type since they specify only a bit index.</p>
5177
5178<h5>Semantics:</h5>
5179<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5180of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5181<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5182operates in forward mode.</p>
5183<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5184truncating it down to the size of the replacement area or zero extending it
5185up to that size.</p>
5186<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5187are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5188in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5189to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5190<p>In reverse mode, a similar computation is made except that the bits are
5191reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5192<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]5193<h5>Examples:</h5>
5194<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5195 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5196 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5197 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5198 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5199 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5200</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5201</div>
5202
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5203<!-- ======================================================================= -->
5204<div class="doc_subsection">
5205 <a name="int_debugger">Debugger Intrinsics</a>
5206</div>
5207
5208<div class="doc_text">
5209<p>
5210The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5211are described in the <a
5212href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5213Debugging</a> document.
5214</p>
5215</div>
5216
5217
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5218<!-- ======================================================================= -->
5219<div class="doc_subsection">
5220 <a name="int_eh">Exception Handling Intrinsics</a>
5221</div>
5222
5223<div class="doc_text">
5224<p> The LLVM exception handling intrinsics (which all start with
5225<tt>llvm.eh.</tt> prefix), are described in the <a
5226href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5227Handling</a> document. </p>
5228</div>
5229
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5230<!-- ======================================================================= -->
5231<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5232 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5233</div>
5234
5235<div class="doc_text">
5236<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5237 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5238 the <tt>nest</tt> attribute, from a function. The result is a callable
5239 function pointer lacking the nest parameter - the caller does not need
5240 to provide a value for it. Instead, the value to use is stored in
5241 advance in a "trampoline", a block of memory usually allocated
5242 on the stack, which also contains code to splice the nest value into the
5243 argument list. This is used to implement the GCC nested function address
5244 extension.
5245</p>
5246<p>
5247 For example, if the function is
5248 <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]5249 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]5250<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5251 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5252 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5253 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5254 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5255</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5256 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5257 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5258</div>
5259
5260<!-- _______________________________________________________________________ -->
5261<div class="doc_subsubsection">
5262 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5263</div>
5264<div class="doc_text">
5265<h5>Syntax:</h5>
5266<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5267declare 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]5268</pre>
5269<h5>Overview:</h5>
5270<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5271 This fills the memory pointed to by <tt>tramp</tt> with code
5272 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5273</p>
5274<h5>Arguments:</h5>
5275<p>
5276 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5277 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5278 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5279 intrinsic. Note that the size and the alignment are target-specific - LLVM
5280 currently provides no portable way of determining them, so a front-end that
5281 generates this intrinsic needs to have some target-specific knowledge.
5282 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]5283</p>
5284<h5>Semantics:</h5>
5285<p>
5286 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5287 dependent code, turning it into a function. A pointer to this function is
5288 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5289 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5290 before being called. The new function's signature is the same as that of
5291 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5292 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5293 of pointer type. Calling the new function is equivalent to calling
5294 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5295 missing <tt>nest</tt> argument. If, after calling
5296 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5297 modified, then the effect of any later call to the returned function pointer is
5298 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5299</p>
5300</div>
5301
5302<!-- ======================================================================= -->
5303<div class="doc_subsection">
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5304 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5305</div>
5306
5307<div class="doc_text">
5308<p>
5309 These intrinsic functions expand the "universal IR" of LLVM to represent
5310 hardware constructs for atomic operations and memory synchronization. This
5311 provides an interface to the hardware, not an interface to the programmer. It
5312 is aimed at a low enough level to allow any programming models or APIs which
5313 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5314 hardware behavior. Just as hardware provides a "universal IR" for source
5315 languages, it also provides a starting point for developing a "universal"
5316 atomic operation and synchronization IR.
5317</p>
5318<p>
5319 These do <em>not</em> form an API such as high-level threading libraries,
5320 software transaction memory systems, atomic primitives, and intrinsic
5321 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5322 application libraries. The hardware interface provided by LLVM should allow
5323 a clean implementation of all of these APIs and parallel programming models.
5324 No one model or paradigm should be selected above others unless the hardware
5325 itself ubiquitously does so.
5326
5327</p>
5328</div>
5329
5330<!-- _______________________________________________________________________ -->
5331<div class="doc_subsubsection">
5332 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5333</div>
5334<div class="doc_text">
5335<h5>Syntax:</h5>
5336<pre>
5337declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5338i1 &lt;device&gt; )
5339
5340</pre>
5341<h5>Overview:</h5>
5342<p>
5343 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5344 specific pairs of memory access types.
5345</p>
5346<h5>Arguments:</h5>
5347<p>
5348 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5349 The first four arguments enables a specific barrier as listed below. The fith
5350 argument specifies that the barrier applies to io or device or uncached memory.
5351
5352</p>
5353 <ul>
5354 <li><tt>ll</tt>: load-load barrier</li>
5355 <li><tt>ls</tt>: load-store barrier</li>
5356 <li><tt>sl</tt>: store-load barrier</li>
5357 <li><tt>ss</tt>: store-store barrier</li>
5358 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5359 </ul>
5360<h5>Semantics:</h5>
5361<p>
5362 This intrinsic causes the system to enforce some ordering constraints upon
5363 the loads and stores of the program. This barrier does not indicate
5364 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5365 which they occur. For any of the specified pairs of load and store operations
5366 (f.ex. load-load, or store-load), all of the first operations preceding the
5367 barrier will complete before any of the second operations succeeding the
5368 barrier begin. Specifically the semantics for each pairing is as follows:
5369</p>
5370 <ul>
5371 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5372 after the barrier begins.</li>
5373
5374 <li><tt>ls</tt>: All loads before the barrier must complete before any
5375 store after the barrier begins.</li>
5376 <li><tt>ss</tt>: All stores before the barrier must complete before any
5377 store after the barrier begins.</li>
5378 <li><tt>sl</tt>: All stores before the barrier must complete before any
5379 load after the barrier begins.</li>
5380 </ul>
5381<p>
5382 These semantics are applied with a logical "and" behavior when more than one
5383 is enabled in a single memory barrier intrinsic.
5384</p>
5385<p>
5386 Backends may implement stronger barriers than those requested when they do not
5387 support as fine grained a barrier as requested. Some architectures do not
5388 need all types of barriers and on such architectures, these become noops.
5389</p>
5390<h5>Example:</h5>
5391<pre>
5392%ptr = malloc i32
5393 store i32 4, %ptr
5394
5395%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5396 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5397 <i>; guarantee the above finishes</i>
5398 store i32 8, %ptr <i>; before this begins</i>
5399</pre>
5400</div>
5401
Andrew Lenharthab0b9492008-02-21 06:45:13 +0000[diff] [blame]5402<!-- _______________________________________________________________________ -->
5403<div class="doc_subsubsection">
5404 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5405</div>
5406<div class="doc_text">
5407<h5>Syntax:</h5>
5408<p>
5409 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5410 integer bit width. Not all targets support all bit widths however.</p>
5411
5412<pre>
5413declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5414declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5415declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5416declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5417
5418</pre>
5419<h5>Overview:</h5>
5420<p>
5421 This loads a value in memory and compares it to a given value. If they are
5422 equal, it stores a new value into the memory.
5423</p>
5424<h5>Arguments:</h5>
5425<p>
5426 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5427 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5428 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5429 this integer type. While any bit width integer may be used, targets may only
5430 lower representations they support in hardware.
5431
5432</p>
5433<h5>Semantics:</h5>
5434<p>
5435 This entire intrinsic must be executed atomically. It first loads the value
5436 in memory pointed to by <tt>ptr</tt> and compares it with the value
5437 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5438 loaded value is yielded in all cases. This provides the equivalent of an
5439 atomic compare-and-swap operation within the SSA framework.
5440</p>
5441<h5>Examples:</h5>
5442
5443<pre>
5444%ptr = malloc i32
5445 store i32 4, %ptr
5446
5447%val1 = add i32 4, 4
5448%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5449 <i>; yields {i32}:result1 = 4</i>
5450%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5451%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5452
5453%val2 = add i32 1, 1
5454%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5455 <i>; yields {i32}:result2 = 8</i>
5456%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5457
5458%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5459</pre>
5460</div>
5461
5462<!-- _______________________________________________________________________ -->
5463<div class="doc_subsubsection">
5464 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5465</div>
5466<div class="doc_text">
5467<h5>Syntax:</h5>
5468
5469<p>
5470 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5471 integer bit width. Not all targets support all bit widths however.</p>
5472<pre>
5473declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5474declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5475declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5476declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5477
5478</pre>
5479<h5>Overview:</h5>
5480<p>
5481 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5482 the value from memory. It then stores the value in <tt>val</tt> in the memory
5483 at <tt>ptr</tt>.
5484</p>
5485<h5>Arguments:</h5>
5486
5487<p>
5488 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5489 <tt>val</tt> argument and the result must be integers of the same bit width.
5490 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5491 integer type. The targets may only lower integer representations they
5492 support.
5493</p>
5494<h5>Semantics:</h5>
5495<p>
5496 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5497 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5498 equivalent of an atomic swap operation within the SSA framework.
5499
5500</p>
5501<h5>Examples:</h5>
5502<pre>
5503%ptr = malloc i32
5504 store i32 4, %ptr
5505
5506%val1 = add i32 4, 4
5507%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5508 <i>; yields {i32}:result1 = 4</i>
5509%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5510%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5511
5512%val2 = add i32 1, 1
5513%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5514 <i>; yields {i32}:result2 = 8</i>
5515
5516%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5517%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5518</pre>
5519</div>
5520
5521<!-- _______________________________________________________________________ -->
5522<div class="doc_subsubsection">
5523 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5524
5525</div>
5526<div class="doc_text">
5527<h5>Syntax:</h5>
5528<p>
5529 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5530 integer bit width. Not all targets support all bit widths however.</p>
5531<pre>
5532declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5533declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5534declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5535declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5536
5537</pre>
5538<h5>Overview:</h5>
5539<p>
5540 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5541 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5542</p>
5543<h5>Arguments:</h5>
5544<p>
5545
5546 The intrinsic takes two arguments, the first a pointer to an integer value
5547 and the second an integer value. The result is also an integer value. These
5548 integer types can have any bit width, but they must all have the same bit
5549 width. The targets may only lower integer representations they support.
5550</p>
5551<h5>Semantics:</h5>
5552<p>
5553 This intrinsic does a series of operations atomically. It first loads the
5554 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5555 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5556</p>
5557
5558<h5>Examples:</h5>
5559<pre>
5560%ptr = malloc i32
5561 store i32 4, %ptr
5562%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5563 <i>; yields {i32}:result1 = 4</i>
5564%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5565 <i>; yields {i32}:result2 = 8</i>
5566%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5567 <i>; yields {i32}:result3 = 10</i>
5568%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5569</pre>
5570</div>
5571
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]5572
5573<!-- ======================================================================= -->
5574<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5575 <a name="int_general">General Intrinsics</a>
5576</div>
5577
5578<div class="doc_text">
5579<p> This class of intrinsics is designed to be generic and has
5580no specific purpose. </p>
5581</div>
5582
5583<!-- _______________________________________________________________________ -->
5584<div class="doc_subsubsection">
5585 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5586</div>
5587
5588<div class="doc_text">
5589
5590<h5>Syntax:</h5>
5591<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5592 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]5593</pre>
5594
5595<h5>Overview:</h5>
5596
5597<p>
5598The '<tt>llvm.var.annotation</tt>' intrinsic
5599</p>
5600
5601<h5>Arguments:</h5>
5602
5603<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5604The first argument is a pointer to a value, the second is a pointer to a
5605global string, the third is a pointer to a global string which is the source
5606file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5607</p>
5608
5609<h5>Semantics:</h5>
5610
5611<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5612This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5613This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5614annotations. These have no other defined use, they are ignored by code
5615generation and optimization.
5616</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5617</div>
5618
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5619<!-- _______________________________________________________________________ -->
5620<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5621 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5622</div>
5623
5624<div class="doc_text">
5625
5626<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5627<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5628any integer bit width.
5629</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5630<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5631 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5632 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5633 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5634 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5635 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]5636</pre>
5637
5638<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5639
5640<p>
5641The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5642</p>
5643
5644<h5>Arguments:</h5>
5645
5646<p>
5647The first argument is an integer value (result of some expression),
5648the second is a pointer to a global string, the third is a pointer to a global
5649string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5650It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5651</p>
5652
5653<h5>Semantics:</h5>
5654
5655<p>
5656This intrinsic allows annotations to be put on arbitrary expressions
5657with arbitrary strings. This can be useful for special purpose optimizations
5658that want to look for these annotations. These have no other defined use, they
5659are ignored by code generation and optimization.
5660</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5661
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]5662<!-- _______________________________________________________________________ -->
5663<div class="doc_subsubsection">
5664 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5665</div>
5666
5667<div class="doc_text">
5668
5669<h5>Syntax:</h5>
5670<pre>
5671 declare void @llvm.trap()
5672</pre>
5673
5674<h5>Overview:</h5>
5675
5676<p>
5677The '<tt>llvm.trap</tt>' intrinsic
5678</p>
5679
5680<h5>Arguments:</h5>
5681
5682<p>
5683None
5684</p>
5685
5686<h5>Semantics:</h5>
5687
5688<p>
5689This intrinsics is lowered to the target dependent trap instruction. If the
5690target does not have a trap instruction, this intrinsic will be lowered to the
5691call of the abort() function.
5692</p>
5693</div>
5694
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5695<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5696<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5697<address>
5698 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5699 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5700 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5701 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5702
5703 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5704 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5705 Last modified: $Date$
5706</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5707
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