Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / 34d1c0d0f8e6d328ad192e06715266a6706147ad / . / llvm / docs / LangRef.html
blob: 0fcc26313ef04906ce98180e386d192c808eb99a [file] [log] [blame]
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikov546ea7e2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner7824d182008-01-04 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattner98f013c2006-01-25 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 Lattner2f7c9632001-06-06 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 Lattner48b383b02003-11-25 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 Brukman76307852003-11-08 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner48b383b02003-11-25 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 Spencer7e80b0b2006-10-26 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 Spencer7eb55b32006-11-02 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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer2ab01932007-02-02 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 Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattnerce83bff2006-04-08 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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]114 <li><a href="#aggregateops">Aggregate Operations</a>
115 <ol>
116 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
117 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
118 </ol>
119 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]120 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]121 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
123 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
124 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]125 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
126 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
127 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]130 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]131 <ol>
132 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
133 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]137 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
139 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
140 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]141 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
142 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]143 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]144 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#otherops">Other Operations</a>
146 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]147 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
148 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]149 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
150 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]152 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]154 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]155 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]156 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]157 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]159 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]160 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]161 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]162 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
163 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
165 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]167 </ol>
168 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]169 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
170 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]171 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
172 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]174 </ol>
175 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]176 <li><a href="#int_codegen">Code Generator Intrinsics</a>
177 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]178 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
179 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
181 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
182 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
183 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
184 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]185 </ol>
186 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]187 <li><a href="#int_libc">Standard C Library Intrinsics</a>
188 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]189 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
190 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]194 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]197 </ol>
198 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]199 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]200 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]201 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]202 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
203 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]205 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]207 </ol>
208 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]209 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]210 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]211 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]214 </ol>
215 </li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]216 <li><a href="#int_atomics">Atomic intrinsics</a>
217 <ol>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]218 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
219 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
220 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
221 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]222 </ol>
223 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]224 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]225 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]226 <li><a href="#int_var_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]227 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]228 <li><a href="#int_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]229 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]230 <li><a href="#int_trap">
231 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]232 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]233 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]236</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]237
238<div class="doc_author">
239 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
240 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]241</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]243<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]244<div class="doc_section"> <a name="abstract">Abstract </a></div>
245<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]246
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]247<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]248<p>This document is a reference manual for the LLVM assembly language.
249LLVM is an SSA based representation that provides type safety,
250low-level operations, flexibility, and the capability of representing
251'all' high-level languages cleanly. It is the common code
252representation used throughout all phases of the LLVM compilation
253strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]254</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]255
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]256<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]257<div class="doc_section"> <a name="introduction">Introduction</a> </div>
258<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]259
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]260<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]261
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]262<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]263different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]264representation (suitable for fast loading by a Just-In-Time compiler),
265and as a human readable assembly language representation. This allows
266LLVM to provide a powerful intermediate representation for efficient
267compiler transformations and analysis, while providing a natural means
268to debug and visualize the transformations. The three different forms
269of LLVM are all equivalent. This document describes the human readable
270representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]271
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]272<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]273while being expressive, typed, and extensible at the same time. It
274aims to be a "universal IR" of sorts, by being at a low enough level
275that high-level ideas may be cleanly mapped to it (similar to how
276microprocessors are "universal IR's", allowing many source languages to
277be mapped to them). By providing type information, LLVM can be used as
278the target of optimizations: for example, through pointer analysis, it
279can be proven that a C automatic variable is never accessed outside of
280the current function... allowing it to be promoted to a simple SSA
281value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]282
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]283</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]284
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]285<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]286<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]287
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]288<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]289
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]290<p>It is important to note that this document describes 'well formed'
291LLVM assembly language. There is a difference between what the parser
292accepts and what is considered 'well formed'. For example, the
293following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]294
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]295<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]296<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]297%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]298</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]299</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]300
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]301<p>...because the definition of <tt>%x</tt> does not dominate all of
302its uses. The LLVM infrastructure provides a verification pass that may
303be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]304automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]305the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]306by the verifier pass indicate bugs in transformation passes or input to
307the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]308</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]309
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]310<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]312<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]313<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]314<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]316<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]317
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]318 <p>LLVM identifiers come in two basic types: global and local. Global
319 identifiers (functions, global variables) begin with the @ character. Local
320 identifiers (register names, types) begin with the % character. Additionally,
321 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]323<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]324 <li>Named values are represented as a string of characters with their prefix.
325 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
326 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]327 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]328 with quotes. In this way, anything except a <tt>&quot;</tt> character can
329 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]330
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]331 <li>Unnamed values are represented as an unsigned numeric value with their
332 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]333
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]334 <li>Constants, which are described in a <a href="#constants">section about
335 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]336</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]337
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]338<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]339don't need to worry about name clashes with reserved words, and the set of
340reserved words may be expanded in the future without penalty. Additionally,
341unnamed identifiers allow a compiler to quickly come up with a temporary
342variable without having to avoid symbol table conflicts.</p>
343
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]344<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]345languages. There are keywords for different opcodes
346('<tt><a href="#i_add">add</a></tt>',
347 '<tt><a href="#i_bitcast">bitcast</a></tt>',
348 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]349href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]350and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]351none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]352
353<p>Here is an example of LLVM code to multiply the integer variable
354'<tt>%X</tt>' by 8:</p>
355
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]356<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]357
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]359<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]360%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]361</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]364<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]365
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]366<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]367<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]368%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]369</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]370</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]371
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]372<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]373
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]375<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]376<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
377<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
378%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]379</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]380</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]381
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]382<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
383important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]384
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]385<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
387 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
388 line.</li>
389
390 <li>Unnamed temporaries are created when the result of a computation is not
391 assigned to a named value.</li>
392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]394
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]395</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]396
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]397<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]398demonstrating instructions, we will follow an instruction with a comment that
399defines the type and name of value produced. Comments are shown in italic
400text.</p>
401
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]402</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]403
404<!-- *********************************************************************** -->
405<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
406<!-- *********************************************************************** -->
407
408<!-- ======================================================================= -->
409<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
410</div>
411
412<div class="doc_text">
413
414<p>LLVM programs are composed of "Module"s, each of which is a
415translation unit of the input programs. Each module consists of
416functions, global variables, and symbol table entries. Modules may be
417combined together with the LLVM linker, which merges function (and
418global variable) definitions, resolves forward declarations, and merges
419symbol table entries. Here is an example of the "hello world" module:</p>
420
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]421<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]422<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]423<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
424 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]425
426<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]427<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]428
429<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]430define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]431 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]432 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]433 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]434
435 <i>; Call puts function to write out the string to stdout...</i>
436 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]437 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]438 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439 href="#i_ret">ret</a> i32 0<br>}<br>
440</pre>
441</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]442
443<p>This example is made up of a <a href="#globalvars">global variable</a>
444named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
445function, and a <a href="#functionstructure">function definition</a>
446for "<tt>main</tt>".</p>
447
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448<p>In general, a module is made up of a list of global values,
449where both functions and global variables are global values. Global values are
450represented by a pointer to a memory location (in this case, a pointer to an
451array of char, and a pointer to a function), and have one of the following <a
452href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]453
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</div>
455
456<!-- ======================================================================= -->
457<div class="doc_subsection">
458 <a name="linkage">Linkage Types</a>
459</div>
460
461<div class="doc_text">
462
463<p>
464All Global Variables and Functions have one of the following types of linkage:
465</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]466
467<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]469 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
471 <dd>Global values with internal linkage are only directly accessible by
472 objects in the current module. In particular, linking code into a module with
473 an internal global value may cause the internal to be renamed as necessary to
474 avoid collisions. Because the symbol is internal to the module, all
475 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]476 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]478
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]479 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]481 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
482 the same name when linkage occurs. This is typically used to implement
483 inline functions, templates, or other code which must be generated in each
484 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
485 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]487
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]488 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]489
490 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
491 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]492 used for globals that may be emitted in multiple translation units, but that
493 are not guaranteed to be emitted into every translation unit that uses them.
494 One example of this are common globals in C, such as "<tt>int X;</tt>" at
495 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]497
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]499
500 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
501 pointer to array type. When two global variables with appending linkage are
502 linked together, the two global arrays are appended together. This is the
503 LLVM, typesafe, equivalent of having the system linker append together
504 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]506
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]507 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
508 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
509 until linked, if not linked, the symbol becomes null instead of being an
510 undefined reference.
511 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]512
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]513 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]514
515 <dd>If none of the above identifiers are used, the global is externally
516 visible, meaning that it participates in linkage and can be used to resolve
517 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]518 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]519</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]520
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]521 <p>
522 The next two types of linkage are targeted for Microsoft Windows platform
523 only. They are designed to support importing (exporting) symbols from (to)
524 DLLs.
525 </p>
526
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]527 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]528 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
531 or variable via a global pointer to a pointer that is set up by the DLL
532 exporting the symbol. On Microsoft Windows targets, the pointer name is
533 formed by combining <code>_imp__</code> and the function or variable name.
534 </dd>
535
536 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
537
538 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
539 pointer to a pointer in a DLL, so that it can be referenced with the
540 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
541 name is formed by combining <code>_imp__</code> and the function or variable
542 name.
543 </dd>
544
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]545</dl>
546
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]547<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]548variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
549variable and was linked with this one, one of the two would be renamed,
550preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
551external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]552outside of the current module.</p>
553<p>It is illegal for a function <i>declaration</i>
554to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]555or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]556<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
557linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]558</div>
559
560<!-- ======================================================================= -->
561<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]562 <a name="callingconv">Calling Conventions</a>
563</div>
564
565<div class="doc_text">
566
567<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
568and <a href="#i_invoke">invokes</a> can all have an optional calling convention
569specified for the call. The calling convention of any pair of dynamic
570caller/callee must match, or the behavior of the program is undefined. The
571following calling conventions are supported by LLVM, and more may be added in
572the future:</p>
573
574<dl>
575 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
576
577 <dd>This calling convention (the default if no other calling convention is
578 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]579 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]580 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]581 </dd>
582
583 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
584
585 <dd>This calling convention attempts to make calls as fast as possible
586 (e.g. by passing things in registers). This calling convention allows the
587 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]588 without having to conform to an externally specified ABI. Implementations of
Arnold Schwaighofer2c6b8882008-05-14 09:17:12 +0000[diff] [blame]589 this convention should allow arbitrary
590 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
591 supported. This calling convention does not support varargs and requires the
592 prototype of all callees to exactly match the prototype of the function
593 definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]594 </dd>
595
596 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
597
598 <dd>This calling convention attempts to make code in the caller as efficient
599 as possible under the assumption that the call is not commonly executed. As
600 such, these calls often preserve all registers so that the call does not break
601 any live ranges in the caller side. This calling convention does not support
602 varargs and requires the prototype of all callees to exactly match the
603 prototype of the function definition.
604 </dd>
605
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]606 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]607
608 <dd>Any calling convention may be specified by number, allowing
609 target-specific calling conventions to be used. Target specific calling
610 conventions start at 64.
611 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]612</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]613
614<p>More calling conventions can be added/defined on an as-needed basis, to
615support pascal conventions or any other well-known target-independent
616convention.</p>
617
618</div>
619
620<!-- ======================================================================= -->
621<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]622 <a name="visibility">Visibility Styles</a>
623</div>
624
625<div class="doc_text">
626
627<p>
628All Global Variables and Functions have one of the following visibility styles:
629</p>
630
631<dl>
632 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
633
634 <dd>On ELF, default visibility means that the declaration is visible to other
635 modules and, in shared libraries, means that the declared entity may be
636 overridden. On Darwin, default visibility means that the declaration is
637 visible to other modules. Default visibility corresponds to "external
638 linkage" in the language.
639 </dd>
640
641 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
642
643 <dd>Two declarations of an object with hidden visibility refer to the same
644 object if they are in the same shared object. Usually, hidden visibility
645 indicates that the symbol will not be placed into the dynamic symbol table,
646 so no other module (executable or shared library) can reference it
647 directly.
648 </dd>
649
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]650 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
651
652 <dd>On ELF, protected visibility indicates that the symbol will be placed in
653 the dynamic symbol table, but that references within the defining module will
654 bind to the local symbol. That is, the symbol cannot be overridden by another
655 module.
656 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]657</dl>
658
659</div>
660
661<!-- ======================================================================= -->
662<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]663 <a name="globalvars">Global Variables</a>
664</div>
665
666<div class="doc_text">
667
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]668<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]669instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]670an explicit section to be placed in, and may have an optional explicit alignment
671specified. A variable may be defined as "thread_local", which means that it
672will not be shared by threads (each thread will have a separated copy of the
673variable). A variable may be defined as a global "constant," which indicates
674that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]675optimization, allowing the global data to be placed in the read-only section of
676an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]677cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]678
679<p>
680LLVM explicitly allows <em>declarations</em> of global variables to be marked
681constant, even if the final definition of the global is not. This capability
682can be used to enable slightly better optimization of the program, but requires
683the language definition to guarantee that optimizations based on the
684'constantness' are valid for the translation units that do not include the
685definition.
686</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]687
688<p>As SSA values, global variables define pointer values that are in
689scope (i.e. they dominate) all basic blocks in the program. Global
690variables always define a pointer to their "content" type because they
691describe a region of memory, and all memory objects in LLVM are
692accessed through pointers.</p>
693
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]694<p>A global variable may be declared to reside in a target-specifc numbered
695address space. For targets that support them, address spaces may affect how
696optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]697the variable. The default address space is zero. The address space qualifier
698must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]699
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]700<p>LLVM allows an explicit section to be specified for globals. If the target
701supports it, it will emit globals to the section specified.</p>
702
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]703<p>An explicit alignment may be specified for a global. If not present, or if
704the alignment is set to zero, the alignment of the global is set by the target
705to whatever it feels convenient. If an explicit alignment is specified, the
706global is forced to have at least that much alignment. All alignments must be
707a power of 2.</p>
708
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]709<p>For example, the following defines a global in a numbered address space with
710an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]711
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]712<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]713<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]714@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]715</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]716</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]717
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]718</div>
719
720
721<!-- ======================================================================= -->
722<div class="doc_subsection">
723 <a name="functionstructure">Functions</a>
724</div>
725
726<div class="doc_text">
727
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]728<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
729an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]730<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]731<a href="#callingconv">calling convention</a>, a return type, an optional
732<a href="#paramattrs">parameter attribute</a> for the return type, a function
733name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]734<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]735optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]736opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]737
738LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
739optional <a href="#linkage">linkage type</a>, an optional
740<a href="#visibility">visibility style</a>, an optional
741<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]742<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]743name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]744<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]745
746<p>A function definition contains a list of basic blocks, forming the CFG for
747the function. Each basic block may optionally start with a label (giving the
748basic block a symbol table entry), contains a list of instructions, and ends
749with a <a href="#terminators">terminator</a> instruction (such as a branch or
750function return).</p>
751
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]752<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]753executed on entrance to the function, and it is not allowed to have predecessor
754basic blocks (i.e. there can not be any branches to the entry block of a
755function). Because the block can have no predecessors, it also cannot have any
756<a href="#i_phi">PHI nodes</a>.</p>
757
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]758<p>LLVM allows an explicit section to be specified for functions. If the target
759supports it, it will emit functions to the section specified.</p>
760
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]761<p>An explicit alignment may be specified for a function. If not present, or if
762the alignment is set to zero, the alignment of the function is set by the target
763to whatever it feels convenient. If an explicit alignment is specified, the
764function is forced to have at least that much alignment. All alignments must be
765a power of 2.</p>
766
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]767</div>
768
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]769
770<!-- ======================================================================= -->
771<div class="doc_subsection">
772 <a name="aliasstructure">Aliases</a>
773</div>
774<div class="doc_text">
775 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov25b2e822008-03-22 08:36:14 +0000[diff] [blame]776 function, global variable, another alias or bitcast of global value). Aliases
777 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]778 optional <a href="#visibility">visibility style</a>.</p>
779
780 <h5>Syntax:</h5>
781
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]782<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]783<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]784@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]785</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]786</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]787
788</div>
789
790
791
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]792<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]793<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
794<div class="doc_text">
795 <p>The return type and each parameter of a function type may have a set of
796 <i>parameter attributes</i> associated with them. Parameter attributes are
797 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]798 a function. Parameter attributes are considered to be part of the function,
799 not of the function type, so functions with different parameter attributes
800 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]801
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]802 <p>Parameter attributes are simple keywords that follow the type specified. If
803 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]804 example:</p>
805
806<div class="doc_code">
807<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]808declare i32 @printf(i8* noalias , ...) nounwind
809declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]810</pre>
811</div>
812
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]813 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
814 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]815
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]816 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]817 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]818 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]819 <dd>This indicates that the parameter should be zero extended just before
820 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]821
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]822 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]823 <dd>This indicates that the parameter should be sign extended just before
824 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]825
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]826 <dt><tt>inreg</tt></dt>
827 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]828 possible) during assembling function call. Support for this attribute is
829 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]830
831 <dt><tt>byval</tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000[diff] [blame]832 <dd>This indicates that the pointer parameter should really be passed by
833 value to the function. The attribute implies that a hidden copy of the
834 pointee is made between the caller and the callee, so the callee is unable
835 to modify the value in the callee. This attribute is only valid on llvm
836 pointer arguments. It is generally used to pass structs and arrays by
837 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]838
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]839 <dt><tt>sret</tt></dt>
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]840 <dd>This indicates that the pointer parameter specifies the address of a
841 structure that is the return value of the function in the source program.
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]842 Loads and stores to the structure are assumed not to trap.
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]843 May only be applied to the first parameter.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]844
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]845 <dt><tt>noalias</tt></dt>
Owen Anderson61101282008-02-18 04:09:01 +0000[diff] [blame]846 <dd>This indicates that the parameter does not alias any global or any other
847 parameter. The caller is responsible for ensuring that this is the case,
848 usually by placing the value in a stack allocation.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]849
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]850 <dt><tt>noreturn</tt></dt>
851 <dd>This function attribute indicates that the function never returns. This
852 indicates to LLVM that every call to this function should be treated as if
853 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]854
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]855 <dt><tt>nounwind</tt></dt>
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]856 <dd>This function attribute indicates that no exceptions unwind out of the
857 function. Usually this is because the function makes no use of exceptions,
858 but it may also be that the function catches any exceptions thrown when
859 executing it.</dd>
860
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]861 <dt><tt>nest</tt></dt>
862 <dd>This indicates that the parameter can be excised using the
863 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]864 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]865 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]866 except for producing a return value or throwing an exception. The value
867 returned must only depend on the function arguments and/or global variables.
868 It may use values obtained by dereferencing pointers.</dd>
869 <dt><tt>readnone</tt></dt>
870 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]871 function, but in addition it is not allowed to dereference any pointer arguments
872 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]873 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]874
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]875</div>
876
877<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]878<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]879 <a name="gc">Garbage Collector Names</a>
880</div>
881
882<div class="doc_text">
883<p>Each function may specify a garbage collector name, which is simply a
884string.</p>
885
886<div class="doc_code"><pre
887>define void @f() gc "name" { ...</pre></div>
888
889<p>The compiler declares the supported values of <i>name</i>. Specifying a
890collector which will cause the compiler to alter its output in order to support
891the named garbage collection algorithm.</p>
892</div>
893
894<!-- ======================================================================= -->
895<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]896 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]897</div>
898
899<div class="doc_text">
900<p>
901Modules may contain "module-level inline asm" blocks, which corresponds to the
902GCC "file scope inline asm" blocks. These blocks are internally concatenated by
903LLVM and treated as a single unit, but may be separated in the .ll file if
904desired. The syntax is very simple:
905</p>
906
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]907<div class="doc_code">
908<pre>
909module asm "inline asm code goes here"
910module asm "more can go here"
911</pre>
912</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]913
914<p>The strings can contain any character by escaping non-printable characters.
915 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
916 for the number.
917</p>
918
919<p>
920 The inline asm code is simply printed to the machine code .s file when
921 assembly code is generated.
922</p>
923</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="datalayout">Data Layout</a>
928</div>
929
930<div class="doc_text">
931<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]932data is to be laid out in memory. The syntax for the data layout is simply:</p>
933<pre> target datalayout = "<i>layout specification</i>"</pre>
934<p>The <i>layout specification</i> consists of a list of specifications
935separated by the minus sign character ('-'). Each specification starts with a
936letter and may include other information after the letter to define some
937aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]938<dl>
939 <dt><tt>E</tt></dt>
940 <dd>Specifies that the target lays out data in big-endian form. That is, the
941 bits with the most significance have the lowest address location.</dd>
942 <dt><tt>e</tt></dt>
943 <dd>Specifies that hte target lays out data in little-endian form. That is,
944 the bits with the least significance have the lowest address location.</dd>
945 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
946 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
947 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
948 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
949 too.</dd>
950 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an integer type of a given bit
952 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
953 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
954 <dd>This specifies the alignment for a vector type of a given bit
955 <i>size</i>.</dd>
956 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
957 <dd>This specifies the alignment for a floating point type of a given bit
958 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
959 (double).</dd>
960 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
961 <dd>This specifies the alignment for an aggregate type of a given bit
962 <i>size</i>.</dd>
963</dl>
964<p>When constructing the data layout for a given target, LLVM starts with a
965default set of specifications which are then (possibly) overriden by the
966specifications in the <tt>datalayout</tt> keyword. The default specifications
967are given in this list:</p>
968<ul>
969 <li><tt>E</tt> - big endian</li>
970 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
971 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
972 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
973 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
974 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
975 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
976 alignment of 64-bits</li>
977 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
978 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
979 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
980 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
981 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
982</ul>
983<p>When llvm is determining the alignment for a given type, it uses the
984following rules:
985<ol>
986 <li>If the type sought is an exact match for one of the specifications, that
987 specification is used.</li>
988 <li>If no match is found, and the type sought is an integer type, then the
989 smallest integer type that is larger than the bitwidth of the sought type is
990 used. If none of the specifications are larger than the bitwidth then the the
991 largest integer type is used. For example, given the default specifications
992 above, the i7 type will use the alignment of i8 (next largest) while both
993 i65 and i256 will use the alignment of i64 (largest specified).</li>
994 <li>If no match is found, and the type sought is a vector type, then the
995 largest vector type that is smaller than the sought vector type will be used
996 as a fall back. This happens because <128 x double> can be implemented in
997 terms of 64 <2 x double>, for example.</li>
998</ol>
999</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1000
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1001<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1002<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1003<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1004
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1005<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1006
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1007<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1008intermediate representation. Being typed enables a number of
1009optimizations to be performed on the IR directly, without having to do
1010extra analyses on the side before the transformation. A strong type
1011system makes it easier to read the generated code and enables novel
1012analyses and transformations that are not feasible to perform on normal
1013three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1014
1015</div>
1016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1017<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1018<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1019Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1020<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1021<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1022classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1023
1024<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1025 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1026 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1027 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1028 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1029 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1030 </tr>
1031 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1032 <td><a href="#t_floating">floating point</a></td>
1033 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1034 </tr>
1035 <tr>
1036 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1037 <td><a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>,
1039 <a href="#t_pointer">pointer</a>,
1040 <a href="#t_vector">vector</a>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1041 <a href="#t_struct">structure</a>,
1042 <a href="#t_array">array</a>,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1043 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1044 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1045 <tr>
1046 <td><a href="#t_primitive">primitive</a></td>
1047 <td><a href="#t_label">label</a>,
1048 <a href="#t_void">void</a>,
1049 <a href="#t_integer">integer</a>,
1050 <a href="#t_floating">floating point</a>.</td>
1051 </tr>
1052 <tr>
1053 <td><a href="#t_derived">derived</a></td>
1054 <td><a href="#t_integer">integer</a>,
1055 <a href="#t_array">array</a>,
1056 <a href="#t_function">function</a>,
1057 <a href="#t_pointer">pointer</a>,
1058 <a href="#t_struct">structure</a>,
1059 <a href="#t_pstruct">packed structure</a>,
1060 <a href="#t_vector">vector</a>,
1061 <a href="#t_opaque">opaque</a>.
1062 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1063 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1064</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1065
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1066<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1067most important. Values of these types are the only ones which can be
1068produced by instructions, passed as arguments, or used as operands to
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame^]1069instructions.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1070</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1072<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1073<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1074
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1075<div class="doc_text">
1076<p>The primitive types are the fundamental building blocks of the LLVM
1077system.</p>
1078
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1079</div>
1080
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1081<!-- _______________________________________________________________________ -->
1082<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1083
1084<div class="doc_text">
1085 <table>
1086 <tbody>
1087 <tr><th>Type</th><th>Description</th></tr>
1088 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1089 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1090 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1091 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1092 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1093 </tbody>
1094 </table>
1095</div>
1096
1097<!-- _______________________________________________________________________ -->
1098<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1099
1100<div class="doc_text">
1101<h5>Overview:</h5>
1102<p>The void type does not represent any value and has no size.</p>
1103
1104<h5>Syntax:</h5>
1105
1106<pre>
1107 void
1108</pre>
1109</div>
1110
1111<!-- _______________________________________________________________________ -->
1112<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1113
1114<div class="doc_text">
1115<h5>Overview:</h5>
1116<p>The label type represents code labels.</p>
1117
1118<h5>Syntax:</h5>
1119
1120<pre>
1121 label
1122</pre>
1123</div>
1124
1125
1126<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1127<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1128
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1129<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1130
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1131<p>The real power in LLVM comes from the derived types in the system.
1132This is what allows a programmer to represent arrays, functions,
1133pointers, and other useful types. Note that these derived types may be
1134recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1135
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1136</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1137
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1138<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1139<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1140
1141<div class="doc_text">
1142
1143<h5>Overview:</h5>
1144<p>The integer type is a very simple derived type that simply specifies an
1145arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11462^23-1 (about 8 million) can be specified.</p>
1147
1148<h5>Syntax:</h5>
1149
1150<pre>
1151 iN
1152</pre>
1153
1154<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1155value.</p>
1156
1157<h5>Examples:</h5>
1158<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1159 <tbody>
1160 <tr>
1161 <td><tt>i1</tt></td>
1162 <td>a single-bit integer.</td>
1163 </tr><tr>
1164 <td><tt>i32</tt></td>
1165 <td>a 32-bit integer.</td>
1166 </tr><tr>
1167 <td><tt>i1942652</tt></td>
1168 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1169 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1170 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1171</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1172</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1173
1174<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1175<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1176
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1177<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1179<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1180
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1181<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1182sequentially in memory. The array type requires a size (number of
1183elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1184
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1185<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1186
1187<pre>
1188 [&lt;# elements&gt; x &lt;elementtype&gt;]
1189</pre>
1190
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1191<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1192be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1193
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1194<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1195<table class="layout">
1196 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1197 <td class="left"><tt>[40 x i32]</tt></td>
1198 <td class="left">Array of 40 32-bit integer values.</td>
1199 </tr>
1200 <tr class="layout">
1201 <td class="left"><tt>[41 x i32]</tt></td>
1202 <td class="left">Array of 41 32-bit integer values.</td>
1203 </tr>
1204 <tr class="layout">
1205 <td class="left"><tt>[4 x i8]</tt></td>
1206 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1207 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1208</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1209<p>Here are some examples of multidimensional arrays:</p>
1210<table class="layout">
1211 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1212 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1213 <td class="left">3x4 array of 32-bit integer values.</td>
1214 </tr>
1215 <tr class="layout">
1216 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1217 <td class="left">12x10 array of single precision floating point values.</td>
1218 </tr>
1219 <tr class="layout">
1220 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1221 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1222 </tr>
1223</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1224
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1225<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1226length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1227LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1228As a special case, however, zero length arrays are recognized to be variable
1229length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1230type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1231
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1232</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1234<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1235<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1236<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1237
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1238<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1239
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1240<p>The function type can be thought of as a function signature. It
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1241consists of a return type and a list of formal parameter types. The
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1242return type of a function type is a scalar type, a void type, or a struct type.
Devang Patel9c1f8b12008-03-24 20:52:42 +0000[diff] [blame]1243If the return type is a struct type then all struct elements must be of first
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1244class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1245
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1246<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1247
1248<pre>
1249 &lt;returntype list&gt; (&lt;parameter list&gt;)
1250</pre>
1251
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1252<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]1253specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1254which indicates that the function takes a variable number of arguments.
1255Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1256 href="#int_varargs">variable argument handling intrinsic</a> functions.
1257'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1258<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1259
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1260<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1261<table class="layout">
1262 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1263 <td class="left"><tt>i32 (i32)</tt></td>
1264 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1265 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1266 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1267 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1268 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1269 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1270 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1271 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1272 <tt>float</tt>.
1273 </td>
1274 </tr><tr class="layout">
1275 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1276 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1277 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1278 which returns an integer. This is the signature for <tt>printf</tt> in
1279 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1280 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1281 </tr><tr class="layout">
1282 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel8dec6c22008-03-24 18:10:52 +0000[diff] [blame]1283 <td class="left">A function taking an <tt>i32></tt>, returning two
1284 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1285 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1286 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1287</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1288
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1289</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1290<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1291<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1292<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1293<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1294<p>The structure type is used to represent a collection of data members
1295together in memory. The packing of the field types is defined to match
1296the ABI of the underlying processor. The elements of a structure may
1297be any type that has a size.</p>
1298<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1299and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1300field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1301instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1302<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1303<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1304<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1305<table class="layout">
1306 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1307 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1308 <td class="left">A triple of three <tt>i32</tt> values</td>
1309 </tr><tr class="layout">
1310 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1311 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1312 second element is a <a href="#t_pointer">pointer</a> to a
1313 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1314 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1315 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1316</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1317</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1318
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1319<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1320<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1321</div>
1322<div class="doc_text">
1323<h5>Overview:</h5>
1324<p>The packed structure type is used to represent a collection of data members
1325together in memory. There is no padding between fields. Further, the alignment
1326of a packed structure is 1 byte. The elements of a packed structure may
1327be any type that has a size.</p>
1328<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1329and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1330field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1331instruction.</p>
1332<h5>Syntax:</h5>
1333<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1334<h5>Examples:</h5>
1335<table class="layout">
1336 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1337 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1338 <td class="left">A triple of three <tt>i32</tt> values</td>
1339 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1340 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1341 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1342 second element is a <a href="#t_pointer">pointer</a> to a
1343 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1344 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1345 </tr>
1346</table>
1347</div>
1348
1349<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1350<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1351<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1352<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1353<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1354reference to another object, which must live in memory. Pointer types may have
1355an optional address space attribute defining the target-specific numbered
1356address space where the pointed-to object resides. The default address space is
1357zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1358<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1359<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1360<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1361<table class="layout">
1362 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1363 <td class="left"><tt>[4x i32]*</tt></td>
1364 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1365 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1366 </tr>
1367 <tr class="layout">
1368 <td class="left"><tt>i32 (i32 *) *</tt></td>
1369 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1370 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1371 <tt>i32</tt>.</td>
1372 </tr>
1373 <tr class="layout">
1374 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1375 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1376 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1377 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1378</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1380
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1381<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1382<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1383<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1384
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1385<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1386
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1387<p>A vector type is a simple derived type that represents a vector
1388of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1389are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1390A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1391elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1392of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1393considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1394
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1395<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1396
1397<pre>
1398 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1399</pre>
1400
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1401<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1402be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1403
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1404<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1405
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1406<table class="layout">
1407 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1408 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1409 <td class="left">Vector of 4 32-bit integer values.</td>
1410 </tr>
1411 <tr class="layout">
1412 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1413 <td class="left">Vector of 8 32-bit floating-point values.</td>
1414 </tr>
1415 <tr class="layout">
1416 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1417 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1418 </tr>
1419</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1420</div>
1421
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1422<!-- _______________________________________________________________________ -->
1423<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1424<div class="doc_text">
1425
1426<h5>Overview:</h5>
1427
1428<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1429corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1430In LLVM, opaque types can eventually be resolved to any type (not just a
1431structure type).</p>
1432
1433<h5>Syntax:</h5>
1434
1435<pre>
1436 opaque
1437</pre>
1438
1439<h5>Examples:</h5>
1440
1441<table class="layout">
1442 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1443 <td class="left"><tt>opaque</tt></td>
1444 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1445 </tr>
1446</table>
1447</div>
1448
1449
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1450<!-- *********************************************************************** -->
1451<div class="doc_section"> <a name="constants">Constants</a> </div>
1452<!-- *********************************************************************** -->
1453
1454<div class="doc_text">
1455
1456<p>LLVM has several different basic types of constants. This section describes
1457them all and their syntax.</p>
1458
1459</div>
1460
1461<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1462<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1463
1464<div class="doc_text">
1465
1466<dl>
1467 <dt><b>Boolean constants</b></dt>
1468
1469 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1470 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1471 </dd>
1472
1473 <dt><b>Integer constants</b></dt>
1474
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1475 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1476 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1477 integer types.
1478 </dd>
1479
1480 <dt><b>Floating point constants</b></dt>
1481
1482 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1483 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]1484 notation (see below). The assembler requires the exact decimal value of
1485 a floating-point constant. For example, the assembler accepts 1.25 but
1486 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1487 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1488
1489 <dt><b>Null pointer constants</b></dt>
1490
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1491 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1492 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1493
1494</dl>
1495
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1496<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1497of floating point constants. For example, the form '<tt>double
14980x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14994.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1500(and the only time that they are generated by the disassembler) is when a
1501floating point constant must be emitted but it cannot be represented as a
1502decimal floating point number. For example, NaN's, infinities, and other
1503special values are represented in their IEEE hexadecimal format so that
1504assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1505
1506</div>
1507
1508<!-- ======================================================================= -->
1509<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1510</div>
1511
1512<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1513<p>Aggregate constants arise from aggregation of simple constants
1514and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1515
1516<dl>
1517 <dt><b>Structure constants</b></dt>
1518
1519 <dd>Structure constants are represented with notation similar to structure
1520 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1521 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1522 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1523 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1524 types of elements must match those specified by the type.
1525 </dd>
1526
1527 <dt><b>Array constants</b></dt>
1528
1529 <dd>Array constants are represented with notation similar to array type
1530 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1531 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1532 constants must have <a href="#t_array">array type</a>, and the number and
1533 types of elements must match those specified by the type.
1534 </dd>
1535
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1536 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1537
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1538 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1539 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1540 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1541 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1542 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1543 match those specified by the type.
1544 </dd>
1545
1546 <dt><b>Zero initialization</b></dt>
1547
1548 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1549 value to zero of <em>any</em> type, including scalar and aggregate types.
1550 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1551 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1552 initializers.
1553 </dd>
1554</dl>
1555
1556</div>
1557
1558<!-- ======================================================================= -->
1559<div class="doc_subsection">
1560 <a name="globalconstants">Global Variable and Function Addresses</a>
1561</div>
1562
1563<div class="doc_text">
1564
1565<p>The addresses of <a href="#globalvars">global variables</a> and <a
1566href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1567constants. These constants are explicitly referenced when the <a
1568href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1569href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1570file:</p>
1571
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1572<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1573<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1574@X = global i32 17
1575@Y = global i32 42
1576@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1577</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1578</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1579
1580</div>
1581
1582<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1583<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1584<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1585 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1586 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1587 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1588
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1589 <p>Undefined values indicate to the compiler that the program is well defined
1590 no matter what value is used, giving the compiler more freedom to optimize.
1591 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1592</div>
1593
1594<!-- ======================================================================= -->
1595<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1596</div>
1597
1598<div class="doc_text">
1599
1600<p>Constant expressions are used to allow expressions involving other constants
1601to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1602href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1603that does not have side effects (e.g. load and call are not supported). The
1604following is the syntax for constant expressions:</p>
1605
1606<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1607 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1608 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1609 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1610
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1611 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1612 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1613 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1614
1615 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1616 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1617 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1618
1619 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1620 <dd>Truncate a floating point constant to another floating point type. The
1621 size of CST must be larger than the size of TYPE. Both types must be
1622 floating point.</dd>
1623
1624 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1625 <dd>Floating point extend a constant to another type. The size of CST must be
1626 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1627
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1628 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1629 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1630 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1631 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1632 of the same number of elements. If the value won't fit in the integer type,
1633 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1634
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1635 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1636 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1637 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1638 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1639 of the same number of elements. If the value won't fit in the integer type,
1640 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1641
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1642 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1643 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1644 constant. TYPE must be a scalar or vector floating point type. CST must be of
1645 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1646 of the same number of elements. If the value won't fit in the floating point
1647 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1648
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1649 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1650 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1651 constant. TYPE must be a scalar or vector floating point type. CST must be of
1652 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1653 of the same number of elements. If the value won't fit in the floating point
1654 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1655
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1656 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1657 <dd>Convert a pointer typed constant to the corresponding integer constant
1658 TYPE must be an integer type. CST must be of pointer type. The CST value is
1659 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1660
1661 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1662 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1663 pointer type. CST must be of integer type. The CST value is zero extended,
1664 truncated, or unchanged to make it fit in a pointer size. This one is
1665 <i>really</i> dangerous!</dd>
1666
1667 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1668 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1669 identical (same number of bits). The conversion is done as if the CST value
1670 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1671 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1672 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1673 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1674 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1675
1676 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1677
1678 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1679 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1680 instruction, the index list may have zero or more indexes, which are required
1681 to make sense for the type of "CSTPTR".</dd>
1682
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1683 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1684
1685 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1686 constants.</dd>
1687
1688 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1689 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1690
1691 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1692 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1693
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]1694 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1695 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1696
1697 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1698 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1699
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1700 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1701
1702 <dd>Perform the <a href="#i_extractelement">extractelement
1703 operation</a> on constants.
1704
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1705 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1706
1707 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1708 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1709
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1710
1711 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1712
1713 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1714 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1715
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1716 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1717
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1718 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1719 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1720 binary</a> operations. The constraints on operands are the same as those for
1721 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1722 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1723</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1724</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1725
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1726<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1727<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1728<!-- *********************************************************************** -->
1729
1730<!-- ======================================================================= -->
1731<div class="doc_subsection">
1732<a name="inlineasm">Inline Assembler Expressions</a>
1733</div>
1734
1735<div class="doc_text">
1736
1737<p>
1738LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1739Module-Level Inline Assembly</a>) through the use of a special value. This
1740value represents the inline assembler as a string (containing the instructions
1741to emit), a list of operand constraints (stored as a string), and a flag that
1742indicates whether or not the inline asm expression has side effects. An example
1743inline assembler expression is:
1744</p>
1745
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1746<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1747<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1748i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1749</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1750</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1751
1752<p>
1753Inline assembler expressions may <b>only</b> be used as the callee operand of
1754a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1755</p>
1756
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1757<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1758<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1759%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1760</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1761</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1762
1763<p>
1764Inline asms with side effects not visible in the constraint list must be marked
1765as having side effects. This is done through the use of the
1766'<tt>sideeffect</tt>' keyword, like so:
1767</p>
1768
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1769<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1770<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1771call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1772</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1773</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1774
1775<p>TODO: The format of the asm and constraints string still need to be
1776documented here. Constraints on what can be done (e.g. duplication, moving, etc
1777need to be documented).
1778</p>
1779
1780</div>
1781
1782<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1783<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1784<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1785
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1786<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1787
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1788<p>The LLVM instruction set consists of several different
1789classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1790instructions</a>, <a href="#binaryops">binary instructions</a>,
1791<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1792 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1793instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1795</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1796
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1798<div class="doc_subsection"> <a name="terminators">Terminator
1799Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1800
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1801<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1802
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1803<p>As mentioned <a href="#functionstructure">previously</a>, every
1804basic block in a program ends with a "Terminator" instruction, which
1805indicates which block should be executed after the current block is
1806finished. These terminator instructions typically yield a '<tt>void</tt>'
1807value: they produce control flow, not values (the one exception being
1808the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1809<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1810 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1811instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1812the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1813 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1814 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1815
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1816</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1817
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1818<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1819<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1820Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1821<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1822<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1823<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1824 ret void <i>; Return from void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1825 ret &lt;type&gt; &lt;value&gt;, &lt;type&gt; &lt;value&gt; <i>; Return two values from a non-void function </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1826</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1827
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1829
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1830<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1831value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1832<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1833returns value(s) and then causes control flow, and one that just causes
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1834control flow to occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1835
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1836<h5>Arguments:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1837
1838<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1839The type of each return value must be a '<a href="#t_firstclass">first
1840class</a>' type. Note that a function is not <a href="#wellformed">well
1841formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1842function that returns values that do not match the return type of the
1843function.</p>
1844
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Semantics:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1846
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1847<p>When the '<tt>ret</tt>' instruction is executed, control flow
1848returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1849 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1850the instruction after the call. If the caller was an "<a
1851 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1852at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1853returns a value, that value shall set the call or invoke instruction's
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1854return value. If the instruction returns multiple values then these
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1855values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1856</a>' instruction.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1857
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1858<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1859
1860<pre>
1861 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1862 ret void <i>; Return from a void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1863 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1864</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1865</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1866<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1867<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1868<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1869<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1870<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 Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1871</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1872<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1873<p>The '<tt>br</tt>' instruction is used to cause control flow to
1874transfer to a different basic block in the current function. There are
1875two forms of this instruction, corresponding to a conditional branch
1876and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1878<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1879single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1880unconditional form of the '<tt>br</tt>' instruction takes a single
1881'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1882<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1883<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1884argument is evaluated. If the value is <tt>true</tt>, control flows
1885to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1886control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1887<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1888<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 Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1889 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1890</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1891<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1892<div class="doc_subsubsection">
1893 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1894</div>
1895
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1896<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1897<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1898
1899<pre>
1900 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1901</pre>
1902
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1903<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1904
1905<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1906several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1907instruction, allowing a branch to occur to one of many possible
1908destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1909
1910
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1911<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1912
1913<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1914comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1915an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1916table is not allowed to contain duplicate constant entries.</p>
1917
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1918<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1919
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1920<p>The <tt>switch</tt> instruction specifies a table of values and
1921destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1922table is searched for the given value. If the value is found, control flow is
1923transfered to the corresponding destination; otherwise, control flow is
1924transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1925
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1926<h5>Implementation:</h5>
1927
1928<p>Depending on properties of the target machine and the particular
1929<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1930ways. For example, it could be generated as a series of chained conditional
1931branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1932
1933<h5>Example:</h5>
1934
1935<pre>
1936 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1937 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1938 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1939
1940 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1941 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1942
1943 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1944 switch i32 %val, label %otherwise [ i32 0, label %onzero
1945 i32 1, label %onone
1946 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1947</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1948</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1949
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1950<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1951<div class="doc_subsubsection">
1952 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1953</div>
1954
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1955<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1956
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1958
1959<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1960 &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 Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]1961 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1962</pre>
1963
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1964<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1965
1966<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1967function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1968'<tt>normal</tt>' label or the
1969'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1970"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1971"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1972href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1973continued at the dynamically nearest "exception" label. If the callee function
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1974returns multiple values then individual return values are only accessible through
1975a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1976
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1978
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1979<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1980
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1981<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1982 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1983 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1984 convention</a> the call should use. If none is specified, the call defaults
1985 to using C calling conventions.
1986 </li>
1987 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1988 function value being invoked. In most cases, this is a direct function
1989 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1990 an arbitrary pointer to function value.
1991 </li>
1992
1993 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1994 function to be invoked. </li>
1995
1996 <li>'<tt>function args</tt>': argument list whose types match the function
1997 signature argument types. If the function signature indicates the function
1998 accepts a variable number of arguments, the extra arguments can be
1999 specified. </li>
2000
2001 <li>'<tt>normal label</tt>': the label reached when the called function
2002 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2003
2004 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2005 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2007</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2009<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2010
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2011<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2012href="#i_call">call</a></tt>' instruction in most regards. The primary
2013difference is that it establishes an association with a label, which is used by
2014the runtime library to unwind the stack.</p>
2015
2016<p>This instruction is used in languages with destructors to ensure that proper
2017cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2018exception. Additionally, this is important for implementation of
2019'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2020
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2021<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2022<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2023 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2024 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2025 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2026 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2027</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2028</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2029
2030
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2031<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2032
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2033<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2034Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2035
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2036<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2037
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2038<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2039<pre>
2040 unwind
2041</pre>
2042
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2043<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2044
2045<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2046at the first callee in the dynamic call stack which used an <a
2047href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2048primarily used to implement exception handling.</p>
2049
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2050<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2051
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2052<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2053immediately halt. The dynamic call stack is then searched for the first <a
2054href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2055execution continues at the "exceptional" destination block specified by the
2056<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2057dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2058</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2059
2060<!-- _______________________________________________________________________ -->
2061
2062<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2063Instruction</a> </div>
2064
2065<div class="doc_text">
2066
2067<h5>Syntax:</h5>
2068<pre>
2069 unreachable
2070</pre>
2071
2072<h5>Overview:</h5>
2073
2074<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2075instruction is used to inform the optimizer that a particular portion of the
2076code is not reachable. This can be used to indicate that the code after a
2077no-return function cannot be reached, and other facts.</p>
2078
2079<h5>Semantics:</h5>
2080
2081<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2082</div>
2083
2084
2085
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2086<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2087<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2088<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2089<p>Binary operators are used to do most of the computation in a
Chris Lattner81f92972008-04-01 18:47:32 +0000[diff] [blame]2090program. They require two operands of the same type, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2091produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2092multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner81f92972008-04-01 18:47:32 +0000[diff] [blame]2093The result value has the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2094<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2095</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2097<div class="doc_subsubsection">
2098 <a name="i_add">'<tt>add</tt>' Instruction</a>
2099</div>
2100
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2101<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2102
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2103<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2104
2105<pre>
2106 &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2107</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2108
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2109<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2110
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2111<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2112
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2113<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2114
2115<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2116 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2117 <a href="#t_vector">vector</a> values. Both arguments must have identical
2118 types.</p>
2119
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2120<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2121
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2122<p>The value produced is the integer or floating point sum of the two
2123operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2124
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2125<p>If an integer sum has unsigned overflow, the result returned is the
2126mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2127the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2128
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2129<p>Because LLVM integers use a two's complement representation, this
2130instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2131
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2132<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2133
2134<pre>
2135 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2136</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2137</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2138<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2139<div class="doc_subsubsection">
2140 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2141</div>
2142
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2143<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2144
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2145<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2146
2147<pre>
2148 &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2149</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2150
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2151<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2152
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2153<p>The '<tt>sub</tt>' instruction returns the difference of its two
2154operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2155
2156<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2157'<tt>neg</tt>' instruction present in most other intermediate
2158representations.</p>
2159
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2160<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2161
2162<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2163 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2164 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2165 types.</p>
2166
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2167<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2168
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2169<p>The value produced is the integer or floating point difference of
2170the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2171
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2172<p>If an integer difference has unsigned overflow, the result returned is the
2173mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2174the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2175
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2176<p>Because LLVM integers use a two's complement representation, this
2177instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2179<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2180<pre>
2181 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2182 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2183</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2184</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2185
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2186<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2187<div class="doc_subsubsection">
2188 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2189</div>
2190
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2191<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2192
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2193<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2194<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2195</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2196<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2197<p>The '<tt>mul</tt>' instruction returns the product of its two
2198operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2201
2202<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2203href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2204or <a href="#t_vector">vector</a> values. Both arguments must have identical
2205types.</p>
2206
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2207<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2208
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2209<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2210two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2211
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2212<p>If the result of an integer multiplication has unsigned overflow,
2213the result returned is the mathematical result modulo
22142<sup>n</sup>, where n is the bit width of the result.</p>
2215<p>Because LLVM integers use a two's complement representation, and the
2216result is the same width as the operands, this instruction returns the
2217correct result for both signed and unsigned integers. If a full product
2218(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2219should be sign-extended or zero-extended as appropriate to the
2220width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2221<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2222<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2223</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2224</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2226<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2227<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2228</a></div>
2229<div class="doc_text">
2230<h5>Syntax:</h5>
2231<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2232</pre>
2233<h5>Overview:</h5>
2234<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2235operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2236
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2237<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2238
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2239<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2240<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2241values. Both arguments must have identical types.</p>
2242
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2243<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2244
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2245<p>The value produced is the unsigned integer quotient of the two operands.</p>
2246<p>Note that unsigned integer division and signed integer division are distinct
2247operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2248<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2249<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2250<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2251</pre>
2252</div>
2253<!-- _______________________________________________________________________ -->
2254<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2255</a> </div>
2256<div class="doc_text">
2257<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2258<pre>
2259 &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2260</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2261
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2262<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2263
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2264<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2265operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2266
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2267<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2268
2269<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2270<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2271values. Both arguments must have identical types.</p>
2272
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2273<h5>Semantics:</h5>
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2274<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2275<p>Note that signed integer division and unsigned integer division are distinct
2276operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2277<p>Division by zero leads to undefined behavior. Overflow also leads to
2278undefined behavior; this is a rare case, but can occur, for example,
2279by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2280<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2281<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2282</pre>
2283</div>
2284<!-- _______________________________________________________________________ -->
2285<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2286Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2287<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2288<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2289<pre>
2290 &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2291</pre>
2292<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2293
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2294<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2295operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2296
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2297<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2298
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2299<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2300<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2301of floating point values. Both arguments must have identical types.</p>
2302
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2303<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2304
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2305<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2306
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2307<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2308
2309<pre>
2310 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2311</pre>
2312</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2313
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2314<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2315<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2316</div>
2317<div class="doc_text">
2318<h5>Syntax:</h5>
2319<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2320</pre>
2321<h5>Overview:</h5>
2322<p>The '<tt>urem</tt>' instruction returns the remainder from the
2323unsigned division of its two arguments.</p>
2324<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2325<p>The two arguments to the '<tt>urem</tt>' instruction must be
2326<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2327values. Both arguments must have identical types.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2328<h5>Semantics:</h5>
2329<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2330This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2331<p>Note that unsigned integer remainder and signed integer remainder are
2332distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2333<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2334<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2335<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2336</pre>
2337
2338</div>
2339<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2340<div class="doc_subsubsection">
2341 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2342</div>
2343
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2344<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2345
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2346<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2347
2348<pre>
2349 &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2350</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2351
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2352<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2353
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2354<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2355signed division of its two operands. This instruction can also take
2356<a href="#t_vector">vector</a> versions of the values in which case
2357the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2358
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2359<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2360
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2361<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2362<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2363values. Both arguments must have identical types.</p>
2364
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2365<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2366
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2367<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2368has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2369operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2370a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2371 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2372Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2373please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2374Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2375<p>Note that signed integer remainder and unsigned integer remainder are
2376distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2377<p>Taking the remainder of a division by zero leads to undefined behavior.
2378Overflow also leads to undefined behavior; this is a rare case, but can occur,
2379for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2380(The remainder doesn't actually overflow, but this rule lets srem be
2381implemented using instructions that return both the result of the division
2382and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2383<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2384<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2385</pre>
2386
2387</div>
2388<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2389<div class="doc_subsubsection">
2390 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2391
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2392<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2393
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2394<h5>Syntax:</h5>
2395<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2396</pre>
2397<h5>Overview:</h5>
2398<p>The '<tt>frem</tt>' instruction returns the remainder from the
2399division of its two operands.</p>
2400<h5>Arguments:</h5>
2401<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2402<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2403of floating point values. Both arguments must have identical types.</p>
2404
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2405<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2406
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2407<p>This instruction returns the <i>remainder</i> of a division.
2408The remainder has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2409
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2410<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2411
2412<pre>
2413 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2414</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2415</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2416
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2417<!-- ======================================================================= -->
2418<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2419Operations</a> </div>
2420<div class="doc_text">
2421<p>Bitwise binary operators are used to do various forms of
2422bit-twiddling in a program. They are generally very efficient
2423instructions and can commonly be strength reduced from other
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2424instructions. They require two operands of the same type, execute an operation on them,
2425and produce a single value. The resulting value is the same type as its operands.</p>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2426</div>
2427
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2428<!-- _______________________________________________________________________ -->
2429<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2430Instruction</a> </div>
2431<div class="doc_text">
2432<h5>Syntax:</h5>
2433<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2434</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2435
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2436<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2437
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2438<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2439the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2440
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2441<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2442
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2443<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2444 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2445unsigned value. This instruction does not support
2446<a href="#t_vector">vector</a> operands.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2447
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2448<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2449
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2450<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2451where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2452equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2453
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2454<h5>Example:</h5><pre>
2455 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2456 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2457 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2458 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2459</pre>
2460</div>
2461<!-- _______________________________________________________________________ -->
2462<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2463Instruction</a> </div>
2464<div class="doc_text">
2465<h5>Syntax:</h5>
2466<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2467</pre>
2468
2469<h5>Overview:</h5>
2470<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2471operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2472
2473<h5>Arguments:</h5>
2474<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2475<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2476unsigned value. This instruction does not support
2477<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2478
2479<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2480
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2481<p>This instruction always performs a logical shift right operation. The most
2482significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2483shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2484the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2485
2486<h5>Example:</h5>
2487<pre>
2488 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2489 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2490 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2491 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2492 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2493</pre>
2494</div>
2495
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2496<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2497<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2498Instruction</a> </div>
2499<div class="doc_text">
2500
2501<h5>Syntax:</h5>
2502<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2503</pre>
2504
2505<h5>Overview:</h5>
2506<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2507operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2508
2509<h5>Arguments:</h5>
2510<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2511<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2512unsigned value. This instruction does not support
2513<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2514
2515<h5>Semantics:</h5>
2516<p>This instruction always performs an arithmetic shift right operation,
2517The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2518of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2519larger than the number of bits in <tt>var1</tt>, the result is undefined.
2520</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2521
2522<h5>Example:</h5>
2523<pre>
2524 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2525 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2526 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2527 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2528 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2529</pre>
2530</div>
2531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2532<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2533<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2534Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2535
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2536<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2537
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2538<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2539
2540<pre>
2541 &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2542</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2543
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2544<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2545
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2546<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2547its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2548
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2549<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2550
2551<p>The two arguments to the '<tt>and</tt>' instruction must be
2552<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2553values. Both arguments must have identical types.</p>
2554
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2555<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2556<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2557<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2558<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2559<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2560 <tbody>
2561 <tr>
2562 <td>In0</td>
2563 <td>In1</td>
2564 <td>Out</td>
2565 </tr>
2566 <tr>
2567 <td>0</td>
2568 <td>0</td>
2569 <td>0</td>
2570 </tr>
2571 <tr>
2572 <td>0</td>
2573 <td>1</td>
2574 <td>0</td>
2575 </tr>
2576 <tr>
2577 <td>1</td>
2578 <td>0</td>
2579 <td>0</td>
2580 </tr>
2581 <tr>
2582 <td>1</td>
2583 <td>1</td>
2584 <td>1</td>
2585 </tr>
2586 </tbody>
2587</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2588</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2590<pre>
2591 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2592 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2593 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2594</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2595</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2596<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2597<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2598<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2599<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2600<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2601</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2602<h5>Overview:</h5>
2603<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2604or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2605<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2606
2607<p>The two arguments to the '<tt>or</tt>' instruction must be
2608<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2609values. Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2610<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2611<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2612<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2613<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2614<table border="1" cellspacing="0" cellpadding="4">
2615 <tbody>
2616 <tr>
2617 <td>In0</td>
2618 <td>In1</td>
2619 <td>Out</td>
2620 </tr>
2621 <tr>
2622 <td>0</td>
2623 <td>0</td>
2624 <td>0</td>
2625 </tr>
2626 <tr>
2627 <td>0</td>
2628 <td>1</td>
2629 <td>1</td>
2630 </tr>
2631 <tr>
2632 <td>1</td>
2633 <td>0</td>
2634 <td>1</td>
2635 </tr>
2636 <tr>
2637 <td>1</td>
2638 <td>1</td>
2639 <td>1</td>
2640 </tr>
2641 </tbody>
2642</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2643</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2644<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2645<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2646 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2647 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2648</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2649</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2650<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2651<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2652Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2653<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2654<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2655<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2656</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2657<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2658<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2659or of its two operands. The <tt>xor</tt> is used to implement the
2660"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2661<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2662<p>The two arguments to the '<tt>xor</tt>' instruction must be
2663<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2664values. Both arguments must have identical types.</p>
2665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2666<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2668<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2669<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2670<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2671<table border="1" cellspacing="0" cellpadding="4">
2672 <tbody>
2673 <tr>
2674 <td>In0</td>
2675 <td>In1</td>
2676 <td>Out</td>
2677 </tr>
2678 <tr>
2679 <td>0</td>
2680 <td>0</td>
2681 <td>0</td>
2682 </tr>
2683 <tr>
2684 <td>0</td>
2685 <td>1</td>
2686 <td>1</td>
2687 </tr>
2688 <tr>
2689 <td>1</td>
2690 <td>0</td>
2691 <td>1</td>
2692 </tr>
2693 <tr>
2694 <td>1</td>
2695 <td>1</td>
2696 <td>0</td>
2697 </tr>
2698 </tbody>
2699</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2700</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2701<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2702<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2703<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2704 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2705 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2706 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2707</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2708</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2710<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2711<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2712 <a name="vectorops">Vector Operations</a>
2713</div>
2714
2715<div class="doc_text">
2716
2717<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2718target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2719vector-specific operations needed to process vectors effectively. While LLVM
2720does directly support these vector operations, many sophisticated algorithms
2721will want to use target-specific intrinsics to take full advantage of a specific
2722target.</p>
2723
2724</div>
2725
2726<!-- _______________________________________________________________________ -->
2727<div class="doc_subsubsection">
2728 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2729</div>
2730
2731<div class="doc_text">
2732
2733<h5>Syntax:</h5>
2734
2735<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2736 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2737</pre>
2738
2739<h5>Overview:</h5>
2740
2741<p>
2742The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2743element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2744</p>
2745
2746
2747<h5>Arguments:</h5>
2748
2749<p>
2750The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2751value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2752an index indicating the position from which to extract the element.
2753The index may be a variable.</p>
2754
2755<h5>Semantics:</h5>
2756
2757<p>
2758The result is a scalar of the same type as the element type of
2759<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2760<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2761results are undefined.
2762</p>
2763
2764<h5>Example:</h5>
2765
2766<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2767 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2768</pre>
2769</div>
2770
2771
2772<!-- _______________________________________________________________________ -->
2773<div class="doc_subsubsection">
2774 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2775</div>
2776
2777<div class="doc_text">
2778
2779<h5>Syntax:</h5>
2780
2781<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]2782 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2783</pre>
2784
2785<h5>Overview:</h5>
2786
2787<p>
2788The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2789element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2790</p>
2791
2792
2793<h5>Arguments:</h5>
2794
2795<p>
2796The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2797value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2798scalar value whose type must equal the element type of the first
2799operand. The third operand is an index indicating the position at
2800which to insert the value. The index may be a variable.</p>
2801
2802<h5>Semantics:</h5>
2803
2804<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2805The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2806element values are those of <tt>val</tt> except at position
2807<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2808exceeds the length of <tt>val</tt>, the results are undefined.
2809</p>
2810
2811<h5>Example:</h5>
2812
2813<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2814 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2815</pre>
2816</div>
2817
2818<!-- _______________________________________________________________________ -->
2819<div class="doc_subsubsection">
2820 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2821</div>
2822
2823<div class="doc_text">
2824
2825<h5>Syntax:</h5>
2826
2827<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2828 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2829</pre>
2830
2831<h5>Overview:</h5>
2832
2833<p>
2834The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2835from two input vectors, returning a vector of the same type.
2836</p>
2837
2838<h5>Arguments:</h5>
2839
2840<p>
2841The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2842with types that match each other and types that match the result of the
2843instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2844of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2845</p>
2846
2847<p>
2848The shuffle mask operand is required to be a constant vector with either
2849constant integer or undef values.
2850</p>
2851
2852<h5>Semantics:</h5>
2853
2854<p>
2855The elements of the two input vectors are numbered from left to right across
2856both of the vectors. The shuffle mask operand specifies, for each element of
2857the result vector, which element of the two input registers the result element
2858gets. The element selector may be undef (meaning "don't care") and the second
2859operand may be undef if performing a shuffle from only one vector.
2860</p>
2861
2862<h5>Example:</h5>
2863
2864<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2865 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2866 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2867 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2868 &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 Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2869</pre>
2870</div>
2871
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2872
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2873<!-- ======================================================================= -->
2874<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2875 <a name="aggregateops">Aggregate Operations</a>
2876</div>
2877
2878<div class="doc_text">
2879
2880<p>LLVM supports several instructions for working with aggregate values.
2881</p>
2882
2883</div>
2884
2885<!-- _______________________________________________________________________ -->
2886<div class="doc_subsubsection">
2887 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2888</div>
2889
2890<div class="doc_text">
2891
2892<h5>Syntax:</h5>
2893
2894<pre>
2895 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2896</pre>
2897
2898<h5>Overview:</h5>
2899
2900<p>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2901The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2902or array element from an aggregate value.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2903</p>
2904
2905
2906<h5>Arguments:</h5>
2907
2908<p>
2909The first operand of an '<tt>extractvalue</tt>' instruction is a
2910value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2911type. The operands are constant indices to specify which value to extract
2912in the same manner as indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2913'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2914</p>
2915
2916<h5>Semantics:</h5>
2917
2918<p>
2919The result is the value at the position in the aggregate specified by
2920the index operands.
2921</p>
2922
2923<h5>Example:</h5>
2924
2925<pre>
2926 %result = extractvalue {i32, float} %agg, i32 0 <i>; yields i32</i>
2927</pre>
2928</div>
2929
2930
2931<!-- _______________________________________________________________________ -->
2932<div class="doc_subsubsection">
2933 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2934</div>
2935
2936<div class="doc_text">
2937
2938<h5>Syntax:</h5>
2939
2940<pre>
2941 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2942</pre>
2943
2944<h5>Overview:</h5>
2945
2946<p>
2947The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2948into a struct field or array element in an aggregate.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2949</p>
2950
2951
2952<h5>Arguments:</h5>
2953
2954<p>
2955The first operand of an '<tt>insertvalue</tt>' instruction is a
2956value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2957The second operand is a first-class value to insert.
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame^]2958The following operands are constant indices
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2959indicating the position at which to insert the value in the same manner as
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2960indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2961'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2962The value to insert must have the same type as the value identified
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2963by the indices.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2964
2965<h5>Semantics:</h5>
2966
2967<p>
2968The result is an aggregate of the same type as <tt>val</tt>. Its
2969value is that of <tt>val</tt> except that the value at the position
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2970specified by the indices is that of <tt>elt</tt>.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2971</p>
2972
2973<h5>Example:</h5>
2974
2975<pre>
2976 %result = insertvalue {i32, float} %agg, i32 1, i32 0 <i>; yields {i32, float}</i>
2977</pre>
2978</div>
2979
2980
2981<!-- ======================================================================= -->
2982<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2983 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2984</div>
2985
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2986<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2987
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2988<p>A key design point of an SSA-based representation is how it
2989represents memory. In LLVM, no memory locations are in SSA form, which
2990makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2991allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2992
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2993</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2995<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2996<div class="doc_subsubsection">
2997 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2998</div>
2999
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3000<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3001
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3002<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3003
3004<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3005 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3006</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3007
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3008<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3009
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3010<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3011heap and returns a pointer to it. The object is always allocated in the generic
3012address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3013
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3014<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3015
3016<p>The '<tt>malloc</tt>' instruction allocates
3017<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]3018bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3019appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3020number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3021If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3022be aligned to at least that boundary. If not specified, or if zero, the target can
3023choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3024
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3025<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3026
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3027<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3028
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3029<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3030a pointer is returned. The result of a zero byte allocattion is undefined. The
3031result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3032
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3033<h5>Example:</h5>
3034
3035<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3036 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3037
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3038 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3039 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3040 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3041 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3042 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3043</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3044</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3045
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3046<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3047<div class="doc_subsubsection">
3048 <a name="i_free">'<tt>free</tt>' Instruction</a>
3049</div>
3050
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3051<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3052
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3053<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3054
3055<pre>
3056 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3057</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3058
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3059<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3060
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3061<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3062memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3063
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3064<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3065
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3066<p>'<tt>value</tt>' shall be a pointer value that points to a value
3067that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3068instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3069
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3070<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3071
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3072<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner0f103e12008-04-19 22:41:32 +0000[diff] [blame]3073after this instruction executes. If the pointer is null, the operation
3074is a noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3076<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3077
3078<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3079 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3080 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3081</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3082</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3083
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3084<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3085<div class="doc_subsubsection">
3086 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3087</div>
3088
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3089<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3090
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3091<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3092
3093<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3094 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3095</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3096
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3097<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3098
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3099<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3100currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3101returns to its caller. The object is always allocated in the generic address
3102space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3103
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3104<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3105
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3106<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3107bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3108appropriate type to the program. If "NumElements" is specified, it is the
3109number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3110If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3111to be aligned to at least that boundary. If not specified, or if zero, the target
3112can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3113
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3114<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3115
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3116<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3117
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3118<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3119there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3120memory is automatically released when the function returns. The '<tt>alloca</tt>'
3121instruction is commonly used to represent automatic variables that must
3122have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]3123 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3124instructions), the memory is reclaimed. Allocating zero bytes
3125is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3127<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3128
3129<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3130 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3131 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3132 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3133 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3134</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3135</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3136
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3137<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3138<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3139Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3140<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3141<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3142<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 Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3143<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3144<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3145<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3146<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3147address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]3148 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3149marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3150the number or order of execution of this <tt>load</tt> with other
3151volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3152instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3153<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3154The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3155(that is, the alignment of the memory address). A value of 0 or an
3156omitted "align" argument means that the operation has the preferential
3157alignment for the target. It is the responsibility of the code emitter
3158to ensure that the alignment information is correct. Overestimating
3159the alignment results in an undefined behavior. Underestimating the
3160alignment may produce less efficient code. An alignment of 1 is always
3161safe.
3162</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3163<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3164<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3165<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3166<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3167 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3168 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3169 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3170</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3171</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3172<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3173<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3174Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]3175<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3176<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3177<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3178 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3179</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3180<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3181<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3182<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3183<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3184to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3185operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3186of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3187operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3188optimizer is not allowed to modify the number or order of execution of
3189this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3190 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3191<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3192The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3193(that is, the alignment of the memory address). A value of 0 or an
3194omitted "align" argument means that the operation has the preferential
3195alignment for the target. It is the responsibility of the code emitter
3196to ensure that the alignment information is correct. Overestimating
3197the alignment results in an undefined behavior. Underestimating the
3198alignment may produce less efficient code. An alignment of 1 is always
3199safe.
3200</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3201<h5>Semantics:</h5>
3202<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3203at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3204<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3205<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]3206 store i32 3, i32* %ptr <i>; yields {void}</i>
3207 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3208</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3209</div>
3210
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3211<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3212<div class="doc_subsubsection">
3213 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3214</div>
3215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3216<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3217<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3218<pre>
3219 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3220</pre>
3221
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3222<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3223
3224<p>
3225The '<tt>getelementptr</tt>' instruction is used to get the address of a
3226subelement of an aggregate data structure.</p>
3227
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3228<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3229
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3230<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3231elements of the aggregate object to index to. The actual types of the arguments
3232provided depend on the type of the first pointer argument. The
3233'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3234levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3235structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3236into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3237values will be sign extended to 64-bits if required.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3238
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3239<p>For example, let's consider a C code fragment and how it gets
3240compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3241
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3242<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3243<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3244struct RT {
3245 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3246 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3247 char C;
3248};
3249struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3250 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3251 double Y;
3252 struct RT Z;
3253};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3254
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3255int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3256 return &amp;s[1].Z.B[5][13];
3257}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3258</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3259</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3260
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3261<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3262
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3263<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3264<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3265%RT = type { i8 , [10 x [20 x i32]], i8 }
3266%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3267
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3268define i32* %foo(%ST* %s) {
3269entry:
3270 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3271 ret i32* %reg
3272}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3273</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3274</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3275
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3276<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3277
3278<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3279on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3280and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]3281<a href="#t_integer">integer</a> type but the value will always be sign extended
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3282to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3283structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3284
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3285<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3286type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3287}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3288the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3289i8 }</tt>' type, another structure. The third index indexes into the second
3290element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3291array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3292'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3293to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3294
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3295<p>Note that it is perfectly legal to index partially through a
3296structure, returning a pointer to an inner element. Because of this,
3297the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3298
3299<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3300 define i32* %foo(%ST* %s) {
3301 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3302 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3303 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3304 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3305 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3306 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3307 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3308</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3309
3310<p>Note that it is undefined to access an array out of bounds: array and
3311pointer indexes must always be within the defined bounds of the array type.
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3312The one exception for this rule is zero length arrays. These arrays are
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3313defined to be accessible as variable length arrays, which requires access
3314beyond the zero'th element.</p>
3315
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3316<p>The getelementptr instruction is often confusing. For some more insight
3317into how it works, see <a href="GetElementPtr.html">the getelementptr
3318FAQ</a>.</p>
3319
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3320<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3321
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3322<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3323 <i>; yields [12 x i8]*:aptr</i>
3324 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3325</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3326</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3328<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3329<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3330</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3331<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3332<p>The instructions in this category are the conversion instructions (casting)
3333which all take a single operand and a type. They perform various bit conversions
3334on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3335</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3336
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3337<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3338<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3339 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3340</div>
3341<div class="doc_text">
3342
3343<h5>Syntax:</h5>
3344<pre>
3345 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3346</pre>
3347
3348<h5>Overview:</h5>
3349<p>
3350The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3351</p>
3352
3353<h5>Arguments:</h5>
3354<p>
3355The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3356be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3357and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3358type. The bit size of <tt>value</tt> must be larger than the bit size of
3359<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3360
3361<h5>Semantics:</h5>
3362<p>
3363The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3364and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3365larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3366It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3367
3368<h5>Example:</h5>
3369<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3370 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3371 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3372 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3373</pre>
3374</div>
3375
3376<!-- _______________________________________________________________________ -->
3377<div class="doc_subsubsection">
3378 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3379</div>
3380<div class="doc_text">
3381
3382<h5>Syntax:</h5>
3383<pre>
3384 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3385</pre>
3386
3387<h5>Overview:</h5>
3388<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3389<tt>ty2</tt>.</p>
3390
3391
3392<h5>Arguments:</h5>
3393<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3394<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3395also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3396<tt>value</tt> must be smaller than the bit size of the destination type,
3397<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3398
3399<h5>Semantics:</h5>
3400<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3401bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3402
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3403<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3404
3405<h5>Example:</h5>
3406<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3407 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3408 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3409</pre>
3410</div>
3411
3412<!-- _______________________________________________________________________ -->
3413<div class="doc_subsubsection">
3414 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3415</div>
3416<div class="doc_text">
3417
3418<h5>Syntax:</h5>
3419<pre>
3420 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3421</pre>
3422
3423<h5>Overview:</h5>
3424<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3425
3426<h5>Arguments:</h5>
3427<p>
3428The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3429<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3430also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3431<tt>value</tt> must be smaller than the bit size of the destination type,
3432<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3433
3434<h5>Semantics:</h5>
3435<p>
3436The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3437bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3438the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3439
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3440<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3441
3442<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3443<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3444 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3445 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3446</pre>
3447</div>
3448
3449<!-- _______________________________________________________________________ -->
3450<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3451 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3452</div>
3453
3454<div class="doc_text">
3455
3456<h5>Syntax:</h5>
3457
3458<pre>
3459 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3460</pre>
3461
3462<h5>Overview:</h5>
3463<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3464<tt>ty2</tt>.</p>
3465
3466
3467<h5>Arguments:</h5>
3468<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3469 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3470cast it to. The size of <tt>value</tt> must be larger than the size of
3471<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3472<i>no-op cast</i>.</p>
3473
3474<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3475<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3476<a href="#t_floating">floating point</a> type to a smaller
3477<a href="#t_floating">floating point</a> type. If the value cannot fit within
3478the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3479
3480<h5>Example:</h5>
3481<pre>
3482 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3483 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3484</pre>
3485</div>
3486
3487<!-- _______________________________________________________________________ -->
3488<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3489 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3490</div>
3491<div class="doc_text">
3492
3493<h5>Syntax:</h5>
3494<pre>
3495 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3496</pre>
3497
3498<h5>Overview:</h5>
3499<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3500floating point value.</p>
3501
3502<h5>Arguments:</h5>
3503<p>The '<tt>fpext</tt>' instruction takes a
3504<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3505and a <a href="#t_floating">floating point</a> type to cast it to. The source
3506type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3507
3508<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3509<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3510<a href="#t_floating">floating point</a> type to a larger
3511<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3512used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3513<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3514
3515<h5>Example:</h5>
3516<pre>
3517 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3518 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3519</pre>
3520</div>
3521
3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3524 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3525</div>
3526<div class="doc_text">
3527
3528<h5>Syntax:</h5>
3529<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3530 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3531</pre>
3532
3533<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3534<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3535unsigned integer equivalent of type <tt>ty2</tt>.
3536</p>
3537
3538<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3539<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3540scalar or vector <a href="#t_floating">floating point</a> value, and a type
3541to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3542type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3543vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3544
3545<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3546<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3547<a href="#t_floating">floating point</a> operand into the nearest (rounding
3548towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3549the results are undefined.</p>
3550
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3551<h5>Example:</h5>
3552<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3553 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3554 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3555 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3556</pre>
3557</div>
3558
3559<!-- _______________________________________________________________________ -->
3560<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3561 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3562</div>
3563<div class="doc_text">
3564
3565<h5>Syntax:</h5>
3566<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3567 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3568</pre>
3569
3570<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3571<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3572<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3573</p>
3574
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3575<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3576<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3577scalar or vector <a href="#t_floating">floating point</a> value, and a type
3578to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3579type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3580vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3581
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3582<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3583<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3584<a href="#t_floating">floating point</a> operand into the nearest (rounding
3585towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3586the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3587
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3588<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3589<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3590 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3591 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3592 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3593</pre>
3594</div>
3595
3596<!-- _______________________________________________________________________ -->
3597<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3598 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3599</div>
3600<div class="doc_text">
3601
3602<h5>Syntax:</h5>
3603<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3604 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3605</pre>
3606
3607<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3608<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3609integer and converts that value to the <tt>ty2</tt> type.</p>
3610
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3611<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3612<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3613scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3614to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3615type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3616floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3617
3618<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3619<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3620integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3621the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3622
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3623<h5>Example:</h5>
3624<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3625 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3626 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3627</pre>
3628</div>
3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3632 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3633</div>
3634<div class="doc_text">
3635
3636<h5>Syntax:</h5>
3637<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3638 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3639</pre>
3640
3641<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3642<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3643integer and converts that value to the <tt>ty2</tt> type.</p>
3644
3645<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3646<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3647scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3648to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3649type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3650floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3651
3652<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3653<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3654integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3655the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3656
3657<h5>Example:</h5>
3658<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3659 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3660 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3661</pre>
3662</div>
3663
3664<!-- _______________________________________________________________________ -->
3665<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3666 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3667</div>
3668<div class="doc_text">
3669
3670<h5>Syntax:</h5>
3671<pre>
3672 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3673</pre>
3674
3675<h5>Overview:</h5>
3676<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3677the integer type <tt>ty2</tt>.</p>
3678
3679<h5>Arguments:</h5>
3680<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3681must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3682<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3683
3684<h5>Semantics:</h5>
3685<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3686<tt>ty2</tt> by interpreting the pointer value as an integer and either
3687truncating or zero extending that value to the size of the integer type. If
3688<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3689<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3690are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3691change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3692
3693<h5>Example:</h5>
3694<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3695 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3696 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3697</pre>
3698</div>
3699
3700<!-- _______________________________________________________________________ -->
3701<div class="doc_subsubsection">
3702 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3703</div>
3704<div class="doc_text">
3705
3706<h5>Syntax:</h5>
3707<pre>
3708 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3709</pre>
3710
3711<h5>Overview:</h5>
3712<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3713a pointer type, <tt>ty2</tt>.</p>
3714
3715<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3716<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3717value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3718<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3719
3720<h5>Semantics:</h5>
3721<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3722<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3723the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3724size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3725the size of a pointer then a zero extension is done. If they are the same size,
3726nothing is done (<i>no-op cast</i>).</p>
3727
3728<h5>Example:</h5>
3729<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3730 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3731 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3732 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3733</pre>
3734</div>
3735
3736<!-- _______________________________________________________________________ -->
3737<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3738 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3739</div>
3740<div class="doc_text">
3741
3742<h5>Syntax:</h5>
3743<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3744 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3745</pre>
3746
3747<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3748
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3749<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3750<tt>ty2</tt> without changing any bits.</p>
3751
3752<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3753
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3754<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3755a first class value, and a type to cast it to, which must also be a <a
3756 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3757and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3758type is a pointer, the destination type must also be a pointer. This
3759instruction supports bitwise conversion of vectors to integers and to vectors
3760of other types (as long as they have the same size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3761
3762<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3763<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3764<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3765this conversion. The conversion is done as if the <tt>value</tt> had been
3766stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3767converted to other pointer types with this instruction. To convert pointers to
3768other types, use the <a href="#i_inttoptr">inttoptr</a> or
3769<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3770
3771<h5>Example:</h5>
3772<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3773 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3774 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3775 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3776</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3777</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3778
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3779<!-- ======================================================================= -->
3780<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3781<div class="doc_text">
3782<p>The instructions in this category are the "miscellaneous"
3783instructions, which defy better classification.</p>
3784</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3785
3786<!-- _______________________________________________________________________ -->
3787<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3788</div>
3789<div class="doc_text">
3790<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3791<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3792</pre>
3793<h5>Overview:</h5>
3794<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3795of its two integer or pointer operands.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3796<h5>Arguments:</h5>
3797<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3798the condition code indicating the kind of comparison to perform. It is not
3799a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3800<ol>
3801 <li><tt>eq</tt>: equal</li>
3802 <li><tt>ne</tt>: not equal </li>
3803 <li><tt>ugt</tt>: unsigned greater than</li>
3804 <li><tt>uge</tt>: unsigned greater or equal</li>
3805 <li><tt>ult</tt>: unsigned less than</li>
3806 <li><tt>ule</tt>: unsigned less or equal</li>
3807 <li><tt>sgt</tt>: signed greater than</li>
3808 <li><tt>sge</tt>: signed greater or equal</li>
3809 <li><tt>slt</tt>: signed less than</li>
3810 <li><tt>sle</tt>: signed less or equal</li>
3811</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3812<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3813<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3814<h5>Semantics:</h5>
3815<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3816the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3817yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3818<ol>
3819 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3820 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3821 </li>
3822 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3823 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3824 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3825 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3826 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3827 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3828 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3829 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3830 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3831 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3832 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3833 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3834 <li><tt>sge</tt>: interprets the operands as signed values and yields
3835 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3836 <li><tt>slt</tt>: interprets the operands as signed values and yields
3837 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3838 <li><tt>sle</tt>: interprets the operands as signed values and yields
3839 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3840</ol>
3841<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3842values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3843
3844<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3845<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3846 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3847 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3848 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3849 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3850 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3851</pre>
3852</div>
3853
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3856</div>
3857<div class="doc_text">
3858<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3859<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3860</pre>
3861<h5>Overview:</h5>
3862<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3863of its floating point operands.</p>
3864<h5>Arguments:</h5>
3865<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3866the condition code indicating the kind of comparison to perform. It is not
3867a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3868<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3869 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3870 <li><tt>oeq</tt>: ordered and equal</li>
3871 <li><tt>ogt</tt>: ordered and greater than </li>
3872 <li><tt>oge</tt>: ordered and greater than or equal</li>
3873 <li><tt>olt</tt>: ordered and less than </li>
3874 <li><tt>ole</tt>: ordered and less than or equal</li>
3875 <li><tt>one</tt>: ordered and not equal</li>
3876 <li><tt>ord</tt>: ordered (no nans)</li>
3877 <li><tt>ueq</tt>: unordered or equal</li>
3878 <li><tt>ugt</tt>: unordered or greater than </li>
3879 <li><tt>uge</tt>: unordered or greater than or equal</li>
3880 <li><tt>ult</tt>: unordered or less than </li>
3881 <li><tt>ule</tt>: unordered or less than or equal</li>
3882 <li><tt>une</tt>: unordered or not equal</li>
3883 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3884 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3885</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3886<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3887<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3888<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3889<a href="#t_floating">floating point</a> typed. They must have identical
3890types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3891<h5>Semantics:</h5>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3892<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3893according to the condition code given as <tt>cond</tt>. The comparison performed
3894always yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3895<ol>
3896 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3897 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3898 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3899 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3900 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3901 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3902 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3903 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3904 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3905 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3906 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3907 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3908 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3909 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3910 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3911 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3912 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3913 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3914 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3915 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3916 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3917 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3918 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3919 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3920 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3921 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3922 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3923 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3924</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3925
3926<h5>Example:</h5>
3927<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3928 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3929 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3930 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3931</pre>
3932</div>
3933
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3934<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3935<div class="doc_subsubsection">
3936 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3937</div>
3938<div class="doc_text">
3939<h5>Syntax:</h5>
3940<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3941</pre>
3942<h5>Overview:</h5>
3943<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3944element-wise comparison of its two integer vector operands.</p>
3945<h5>Arguments:</h5>
3946<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3947the condition code indicating the kind of comparison to perform. It is not
3948a value, just a keyword. The possible condition code are:
3949<ol>
3950 <li><tt>eq</tt>: equal</li>
3951 <li><tt>ne</tt>: not equal </li>
3952 <li><tt>ugt</tt>: unsigned greater than</li>
3953 <li><tt>uge</tt>: unsigned greater or equal</li>
3954 <li><tt>ult</tt>: unsigned less than</li>
3955 <li><tt>ule</tt>: unsigned less or equal</li>
3956 <li><tt>sgt</tt>: signed greater than</li>
3957 <li><tt>sge</tt>: signed greater or equal</li>
3958 <li><tt>slt</tt>: signed less than</li>
3959 <li><tt>sle</tt>: signed less or equal</li>
3960</ol>
3961<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3962<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3963<h5>Semantics:</h5>
3964<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3965according to the condition code given as <tt>cond</tt>. The comparison yields a
3966<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3967identical type as the values being compared. The most significant bit in each
3968element is 1 if the element-wise comparison evaluates to true, and is 0
3969otherwise. All other bits of the result are undefined. The condition codes
3970are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3971instruction</a>.
3972
3973<h5>Example:</h5>
3974<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3975 &lt;result&gt; = vicmp eq &lt;2 x i32&gt; &lt; i32 4, i32 0&gt;, &lt; i32 5, i32 0&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
3976 &lt;result&gt; = vicmp ult &lt;2 x i8 &gt; &lt; i8 1, i8 2&gt;, &lt; i8 2, i8 2 &gt; <i>; yields: result=&lt;2 x i8&gt; &lt; i8 -1, i8 0 &gt;</i>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3977</pre>
3978</div>
3979
3980<!-- _______________________________________________________________________ -->
3981<div class="doc_subsubsection">
3982 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
3983</div>
3984<div class="doc_text">
3985<h5>Syntax:</h5>
3986<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
3987<h5>Overview:</h5>
3988<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
3989element-wise comparison of its two floating point vector operands. The output
3990elements have the same width as the input elements.</p>
3991<h5>Arguments:</h5>
3992<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
3993the condition code indicating the kind of comparison to perform. It is not
3994a value, just a keyword. The possible condition code are:
3995<ol>
3996 <li><tt>false</tt>: no comparison, always returns false</li>
3997 <li><tt>oeq</tt>: ordered and equal</li>
3998 <li><tt>ogt</tt>: ordered and greater than </li>
3999 <li><tt>oge</tt>: ordered and greater than or equal</li>
4000 <li><tt>olt</tt>: ordered and less than </li>
4001 <li><tt>ole</tt>: ordered and less than or equal</li>
4002 <li><tt>one</tt>: ordered and not equal</li>
4003 <li><tt>ord</tt>: ordered (no nans)</li>
4004 <li><tt>ueq</tt>: unordered or equal</li>
4005 <li><tt>ugt</tt>: unordered or greater than </li>
4006 <li><tt>uge</tt>: unordered or greater than or equal</li>
4007 <li><tt>ult</tt>: unordered or less than </li>
4008 <li><tt>ule</tt>: unordered or less than or equal</li>
4009 <li><tt>une</tt>: unordered or not equal</li>
4010 <li><tt>uno</tt>: unordered (either nans)</li>
4011 <li><tt>true</tt>: no comparison, always returns true</li>
4012</ol>
4013<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4014<a href="#t_floating">floating point</a> typed. They must also be identical
4015types.</p>
4016<h5>Semantics:</h5>
4017<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4018according to the condition code given as <tt>cond</tt>. The comparison yields a
4019<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4020an identical number of elements as the values being compared, and each element
4021having identical with to the width of the floating point elements. The most
4022significant bit in each element is 1 if the element-wise comparison evaluates to
4023true, and is 0 otherwise. All other bits of the result are undefined. The
4024condition codes are evaluated identically to the
4025<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4026
4027<h5>Example:</h5>
4028<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4029 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4030 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt; <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]4031</pre>
4032</div>
4033
4034<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4035<div class="doc_subsubsection">
4036 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4037</div>
4038
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4039<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4040
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4041<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4042
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4043<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4044<h5>Overview:</h5>
4045<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4046the SSA graph representing the function.</p>
4047<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4048
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4049<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4050field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4051as arguments, with one pair for each predecessor basic block of the
4052current block. Only values of <a href="#t_firstclass">first class</a>
4053type may be used as the value arguments to the PHI node. Only labels
4054may be used as the label arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4055
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4056<p>There must be no non-phi instructions between the start of a basic
4057block and the PHI instructions: i.e. PHI instructions must be first in
4058a basic block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4059
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4060<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4061
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4062<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4063specified by the pair corresponding to the predecessor basic block that executed
4064just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4065
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4066<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4067<pre>
4068Loop: ; Infinite loop that counts from 0 on up...
4069 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4070 %nextindvar = add i32 %indvar, 1
4071 br label %Loop
4072</pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4073</div>
4074
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4075<!-- _______________________________________________________________________ -->
4076<div class="doc_subsubsection">
4077 <a name="i_select">'<tt>select</tt>' Instruction</a>
4078</div>
4079
4080<div class="doc_text">
4081
4082<h5>Syntax:</h5>
4083
4084<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4085 &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 Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4086</pre>
4087
4088<h5>Overview:</h5>
4089
4090<p>
4091The '<tt>select</tt>' instruction is used to choose one value based on a
4092condition, without branching.
4093</p>
4094
4095
4096<h5>Arguments:</h5>
4097
4098<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4099The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4100condition, and two values of the same <a href="#t_firstclass">first class</a>
4101type. If the val1/val2 are vectors, the entire vectors are selected, not
4102individual elements.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4103</p>
4104
4105<h5>Semantics:</h5>
4106
4107<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4108If the i1 condition evaluates is 1, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4109value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4110</p>
4111
4112<h5>Example:</h5>
4113
4114<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4115 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4116</pre>
4117</div>
4118
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4119
4120<!-- _______________________________________________________________________ -->
4121<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4122 <a name="i_call">'<tt>call</tt>' Instruction</a>
4123</div>
4124
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4125<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4127<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4128<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4129 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4130</pre>
4131
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4132<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4133
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4134<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4135
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4136<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4137
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4138<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4139
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4140<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4141 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4142 <p>The optional "tail" marker indicates whether the callee function accesses
4143 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4144 function call is eligible for tail call optimization. Note that calls may
4145 be marked "tail" even if they do not occur before a <a
4146 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4147 </li>
4148 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4149 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4150 convention</a> the call should use. If none is specified, the call defaults
4151 to using C calling conventions.
4152 </li>
4153 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4154 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4155 the type of the return value. Functions that return no value are marked
4156 <tt><a href="#t_void">void</a></tt>.</p>
4157 </li>
4158 <li>
4159 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4160 value being invoked. The argument types must match the types implied by
4161 this signature. This type can be omitted if the function is not varargs
4162 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4163 </li>
4164 <li>
4165 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4166 be invoked. In most cases, this is a direct function invocation, but
4167 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4168 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4169 </li>
4170 <li>
4171 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]4172 function signature argument types. All arguments must be of
4173 <a href="#t_firstclass">first class</a> type. If the function signature
4174 indicates the function accepts a variable number of arguments, the extra
4175 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4176 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4177</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4179<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4180
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4181<p>The '<tt>call</tt>' instruction is used to cause control flow to
4182transfer to a specified function, with its incoming arguments bound to
4183the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4184instruction in the called function, control flow continues with the
4185instruction after the function call, and the return value of the
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4186function is bound to the result argument. If the callee returns multiple
4187values then the return values of the function are only accessible through
4188the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4189
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4190<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4191
4192<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4193 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4194 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4195 %X = tail call i32 @foo() <i>; yields i32</i>
4196 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4197 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4198
4199 %struct.A = type { i32, i8 }
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4200 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4201 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4202 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4203</pre>
4204
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4205</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4206
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4207<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4208<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4209 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4210</div>
4211
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4212<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4213
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4214<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4215
4216<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4217 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4218</pre>
4219
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4220<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4221
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4222<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4223the "variable argument" area of a function call. It is used to implement the
4224<tt>va_arg</tt> macro in C.</p>
4225
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4226<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4227
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4228<p>This instruction takes a <tt>va_list*</tt> value and the type of
4229the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4230increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4231actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4232
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4233<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4234
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4235<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4236type from the specified <tt>va_list</tt> and causes the
4237<tt>va_list</tt> to point to the next argument. For more information,
4238see the variable argument handling <a href="#int_varargs">Intrinsic
4239Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4240
4241<p>It is legal for this instruction to be called in a function which does not
4242take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4243function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4244
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4245<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4246href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4247argument.</p>
4248
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4249<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4250
4251<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4252
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4253</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4254
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4255<!-- _______________________________________________________________________ -->
4256<div class="doc_subsubsection">
4257 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4258</div>
4259
4260<div class="doc_text">
4261
4262<h5>Syntax:</h5>
4263<pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4264 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4265</pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4266
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4267<h5>Overview:</h5>
4268
4269<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4270from a '<tt><a href="#i_call">call</a></tt>'
4271or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4272results.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4273
4274<h5>Arguments:</h5>
4275
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4276<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattner1a640a62008-04-23 04:06:52 +0000[diff] [blame]4277first argument, or an undef value. The value must have <a
4278href="#t_struct">structure type</a>. The second argument is a constant
4279unsigned index value which must be in range for the number of values returned
4280by the call.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4281
4282<h5>Semantics:</h5>
4283
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4284<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4285'<tt>index</tt>' from the aggregate value.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4286
4287<h5>Example:</h5>
4288
4289<pre>
4290 %struct.A = type { i32, i8 }
4291
4292 %r = call %struct.A @foo()
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4293 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4294 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4295 add i32 %gr, 42
4296 add i8 %gr1, 41
4297</pre>
4298
4299</div>
4300
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4301<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4302<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4303<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4304
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4305<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4306
4307<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4308well known names and semantics and are required to follow certain restrictions.
4309Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4310language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]4311adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4312
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4313<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4314prefix is reserved in LLVM for intrinsic names; thus, function names may not
4315begin with this prefix. Intrinsic functions must always be external functions:
4316you cannot define the body of intrinsic functions. Intrinsic functions may
4317only be used in call or invoke instructions: it is illegal to take the address
4318of an intrinsic function. Additionally, because intrinsic functions are part
4319of the LLVM language, it is required if any are added that they be documented
4320here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4321
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4322<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4323a family of functions that perform the same operation but on different data
4324types. Because LLVM can represent over 8 million different integer types,
4325overloading is used commonly to allow an intrinsic function to operate on any
4326integer type. One or more of the argument types or the result type can be
4327overloaded to accept any integer type. Argument types may also be defined as
4328exactly matching a previous argument's type or the result type. This allows an
4329intrinsic function which accepts multiple arguments, but needs all of them to
4330be of the same type, to only be overloaded with respect to a single argument or
4331the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4332
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4333<p>Overloaded intrinsics will have the names of its overloaded argument types
4334encoded into its function name, each preceded by a period. Only those types
4335which are overloaded result in a name suffix. Arguments whose type is matched
4336against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4337take an integer of any width and returns an integer of exactly the same integer
4338width. This leads to a family of functions such as
4339<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4340Only one type, the return type, is overloaded, and only one type suffix is
4341required. Because the argument's type is matched against the return type, it
4342does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4343
4344<p>To learn how to add an intrinsic function, please see the
4345<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4346</p>
4347
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4348</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4349
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4350<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4351<div class="doc_subsection">
4352 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4353</div>
4354
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4355<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4357<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4358 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4359intrinsic functions. These functions are related to the similarly
4360named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4361
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4362<p>All of these functions operate on arguments that use a
4363target-specific value type "<tt>va_list</tt>". The LLVM assembly
4364language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4365transformations should be prepared to handle these functions regardless of
4366the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4367
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]4368<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4369instruction and the variable argument handling intrinsic functions are
4370used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4371
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4372<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4373<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4374define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4375 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4376 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4377 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4378 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4379
4380 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4381 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4382
4383 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4384 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4385 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4386 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4387 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4388
4389 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4390 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4391 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4392}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4393
4394declare void @llvm.va_start(i8*)
4395declare void @llvm.va_copy(i8*, i8*)
4396declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4397</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4398</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4399
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4400</div>
4401
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4402<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4403<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4404 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4405</div>
4406
4407
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4408<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4409<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4410<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4411<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4412<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4413<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4414href="#i_va_arg">va_arg</a></tt>.</p>
4415
4416<h5>Arguments:</h5>
4417
4418<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4419
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4420<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4421
4422<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4423macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4424<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4425<tt>va_arg</tt> will produce the first variable argument passed to the function.
4426Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4427last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4429</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4430
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4431<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4432<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4433 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4434</div>
4435
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4436<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4437<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4438<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4439<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4440
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4441<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4442which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4443or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4444
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4445<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4446
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4447<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4448
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4449<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4450
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4451<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4452macro available in C. In a target-dependent way, it destroys the
4453<tt>va_list</tt> element to which the argument points. Calls to <a
4454href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4455<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4456<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4457
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4458</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4459
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4460<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4461<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4462 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4463</div>
4464
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4465<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4466
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4467<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4468
4469<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4470 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4471</pre>
4472
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4473<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4474
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4475<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4476from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4477
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4478<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4479
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4480<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]4481The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4482
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4483
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4484<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4485
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4486<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4487macro available in C. In a target-dependent way, it copies the source
4488<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4489intrinsic is necessary because the <tt><a href="#int_va_start">
4490llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4491example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4492
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4493</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4494
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4495<!-- ======================================================================= -->
4496<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4497 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4498</div>
4499
4500<div class="doc_text">
4501
4502<p>
4503LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4504Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4505These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4506stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4507href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4508Front-ends for type-safe garbage collected languages should generate these
4509intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4510href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4511</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4512
4513<p>The garbage collection intrinsics only operate on objects in the generic
4514 address space (address space zero).</p>
4515
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4516</div>
4517
4518<!-- _______________________________________________________________________ -->
4519<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4520 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4521</div>
4522
4523<div class="doc_text">
4524
4525<h5>Syntax:</h5>
4526
4527<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4528 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4529</pre>
4530
4531<h5>Overview:</h5>
4532
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4533<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4534the code generator, and allows some metadata to be associated with it.</p>
4535
4536<h5>Arguments:</h5>
4537
4538<p>The first argument specifies the address of a stack object that contains the
4539root pointer. The second pointer (which must be either a constant or a global
4540value address) contains the meta-data to be associated with the root.</p>
4541
4542<h5>Semantics:</h5>
4543
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]4544<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4545location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4546the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4547intrinsic may only be used in a function which <a href="#gc">specifies a GC
4548algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4549
4550</div>
4551
4552
4553<!-- _______________________________________________________________________ -->
4554<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4555 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4556</div>
4557
4558<div class="doc_text">
4559
4560<h5>Syntax:</h5>
4561
4562<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4563 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4564</pre>
4565
4566<h5>Overview:</h5>
4567
4568<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4569locations, allowing garbage collector implementations that require read
4570barriers.</p>
4571
4572<h5>Arguments:</h5>
4573
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4574<p>The second argument is the address to read from, which should be an address
4575allocated from the garbage collector. The first object is a pointer to the
4576start of the referenced object, if needed by the language runtime (otherwise
4577null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4578
4579<h5>Semantics:</h5>
4580
4581<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4582instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4583garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4584may only be used in a function which <a href="#gc">specifies a GC
4585algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4586
4587</div>
4588
4589
4590<!-- _______________________________________________________________________ -->
4591<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4592 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4593</div>
4594
4595<div class="doc_text">
4596
4597<h5>Syntax:</h5>
4598
4599<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4600 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4601</pre>
4602
4603<h5>Overview:</h5>
4604
4605<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4606locations, allowing garbage collector implementations that require write
4607barriers (such as generational or reference counting collectors).</p>
4608
4609<h5>Arguments:</h5>
4610
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4611<p>The first argument is the reference to store, the second is the start of the
4612object to store it to, and the third is the address of the field of Obj to
4613store to. If the runtime does not require a pointer to the object, Obj may be
4614null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4615
4616<h5>Semantics:</h5>
4617
4618<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4619instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4620garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4621may only be used in a function which <a href="#gc">specifies a GC
4622algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4623
4624</div>
4625
4626
4627
4628<!-- ======================================================================= -->
4629<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4630 <a name="int_codegen">Code Generator Intrinsics</a>
4631</div>
4632
4633<div class="doc_text">
4634<p>
4635These intrinsics are provided by LLVM to expose special features that may only
4636be implemented with code generator support.
4637</p>
4638
4639</div>
4640
4641<!-- _______________________________________________________________________ -->
4642<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4643 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4644</div>
4645
4646<div class="doc_text">
4647
4648<h5>Syntax:</h5>
4649<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4650 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4651</pre>
4652
4653<h5>Overview:</h5>
4654
4655<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4656The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4657target-specific value indicating the return address of the current function
4658or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4659</p>
4660
4661<h5>Arguments:</h5>
4662
4663<p>
4664The argument to this intrinsic indicates which function to return the address
4665for. Zero indicates the calling function, one indicates its caller, etc. The
4666argument is <b>required</b> to be a constant integer value.
4667</p>
4668
4669<h5>Semantics:</h5>
4670
4671<p>
4672The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4673the return address of the specified call frame, or zero if it cannot be
4674identified. The value returned by this intrinsic is likely to be incorrect or 0
4675for arguments other than zero, so it should only be used for debugging purposes.
4676</p>
4677
4678<p>
4679Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4680aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4681source-language caller.
4682</p>
4683</div>
4684
4685
4686<!-- _______________________________________________________________________ -->
4687<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4688 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4689</div>
4690
4691<div class="doc_text">
4692
4693<h5>Syntax:</h5>
4694<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4695 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4696</pre>
4697
4698<h5>Overview:</h5>
4699
4700<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4701The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4702target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4703</p>
4704
4705<h5>Arguments:</h5>
4706
4707<p>
4708The argument to this intrinsic indicates which function to return the frame
4709pointer for. Zero indicates the calling function, one indicates its caller,
4710etc. The argument is <b>required</b> to be a constant integer value.
4711</p>
4712
4713<h5>Semantics:</h5>
4714
4715<p>
4716The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4717the frame address of the specified call frame, or zero if it cannot be
4718identified. The value returned by this intrinsic is likely to be incorrect or 0
4719for arguments other than zero, so it should only be used for debugging purposes.
4720</p>
4721
4722<p>
4723Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4724aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4725source-language caller.
4726</p>
4727</div>
4728
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4729<!-- _______________________________________________________________________ -->
4730<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4731 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4732</div>
4733
4734<div class="doc_text">
4735
4736<h5>Syntax:</h5>
4737<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4738 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4739</pre>
4740
4741<h5>Overview:</h5>
4742
4743<p>
4744The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4745the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4746<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4747features like scoped automatic variable sized arrays in C99.
4748</p>
4749
4750<h5>Semantics:</h5>
4751
4752<p>
4753This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4754href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4755<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4756<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4757state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4758practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4759that were allocated after the <tt>llvm.stacksave</tt> was executed.
4760</p>
4761
4762</div>
4763
4764<!-- _______________________________________________________________________ -->
4765<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4766 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4767</div>
4768
4769<div class="doc_text">
4770
4771<h5>Syntax:</h5>
4772<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4773 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4774</pre>
4775
4776<h5>Overview:</h5>
4777
4778<p>
4779The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4780the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4781href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4782useful for implementing language features like scoped automatic variable sized
4783arrays in C99.
4784</p>
4785
4786<h5>Semantics:</h5>
4787
4788<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4789See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4790</p>
4791
4792</div>
4793
4794
4795<!-- _______________________________________________________________________ -->
4796<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4797 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4798</div>
4799
4800<div class="doc_text">
4801
4802<h5>Syntax:</h5>
4803<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4804 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4805</pre>
4806
4807<h5>Overview:</h5>
4808
4809
4810<p>
4811The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4812a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4813no
4814effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4815characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4816</p>
4817
4818<h5>Arguments:</h5>
4819
4820<p>
4821<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4822determining if the fetch should be for a read (0) or write (1), and
4823<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4824locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4825<tt>locality</tt> arguments must be constant integers.
4826</p>
4827
4828<h5>Semantics:</h5>
4829
4830<p>
4831This intrinsic does not modify the behavior of the program. In particular,
4832prefetches cannot trap and do not produce a value. On targets that support this
4833intrinsic, the prefetch can provide hints to the processor cache for better
4834performance.
4835</p>
4836
4837</div>
4838
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4839<!-- _______________________________________________________________________ -->
4840<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4841 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4842</div>
4843
4844<div class="doc_text">
4845
4846<h5>Syntax:</h5>
4847<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4848 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4849</pre>
4850
4851<h5>Overview:</h5>
4852
4853
4854<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4855The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4856(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4857code to simulators and other tools. The method is target specific, but it is
4858expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4859The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4860after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4861optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4862correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4863</p>
4864
4865<h5>Arguments:</h5>
4866
4867<p>
4868<tt>id</tt> is a numerical id identifying the marker.
4869</p>
4870
4871<h5>Semantics:</h5>
4872
4873<p>
4874This intrinsic does not modify the behavior of the program. Backends that do not
4875support this intrinisic may ignore it.
4876</p>
4877
4878</div>
4879
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4880<!-- _______________________________________________________________________ -->
4881<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4882 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4883</div>
4884
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
4888<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4889 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4890</pre>
4891
4892<h5>Overview:</h5>
4893
4894
4895<p>
4896The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4897counter register (or similar low latency, high accuracy clocks) on those targets
4898that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4899As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4900should only be used for small timings.
4901</p>
4902
4903<h5>Semantics:</h5>
4904
4905<p>
4906When directly supported, reading the cycle counter should not modify any memory.
4907Implementations are allowed to either return a application specific value or a
4908system wide value. On backends without support, this is lowered to a constant 0.
4909</p>
4910
4911</div>
4912
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4913<!-- ======================================================================= -->
4914<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4915 <a name="int_libc">Standard C Library Intrinsics</a>
4916</div>
4917
4918<div class="doc_text">
4919<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4920LLVM provides intrinsics for a few important standard C library functions.
4921These intrinsics allow source-language front-ends to pass information about the
4922alignment of the pointer arguments to the code generator, providing opportunity
4923for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4924</p>
4925
4926</div>
4927
4928<!-- _______________________________________________________________________ -->
4929<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4930 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4931</div>
4932
4933<div class="doc_text">
4934
4935<h5>Syntax:</h5>
4936<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4937 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4938 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4939 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4940 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4941</pre>
4942
4943<h5>Overview:</h5>
4944
4945<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4946The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4947location to the destination location.
4948</p>
4949
4950<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4951Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4952intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4953</p>
4954
4955<h5>Arguments:</h5>
4956
4957<p>
4958The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4959the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4960specifying the number of bytes to copy, and the fourth argument is the alignment
4961of the source and destination locations.
4962</p>
4963
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4964<p>
4965If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4966the caller guarantees that both the source and destination pointers are aligned
4967to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4968</p>
4969
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4970<h5>Semantics:</h5>
4971
4972<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4973The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4974location to the destination location, which are not allowed to overlap. It
4975copies "len" bytes of memory over. If the argument is known to be aligned to
4976some boundary, this can be specified as the fourth argument, otherwise it should
4977be set to 0 or 1.
4978</p>
4979</div>
4980
4981
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4982<!-- _______________________________________________________________________ -->
4983<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4984 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4985</div>
4986
4987<div class="doc_text">
4988
4989<h5>Syntax:</h5>
4990<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4991 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4992 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4993 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4994 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4995</pre>
4996
4997<h5>Overview:</h5>
4998
4999<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5000The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5001location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]5002'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5003</p>
5004
5005<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5006Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5007intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5008</p>
5009
5010<h5>Arguments:</h5>
5011
5012<p>
5013The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5014the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5015specifying the number of bytes to copy, and the fourth argument is the alignment
5016of the source and destination locations.
5017</p>
5018
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5019<p>
5020If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]5021the caller guarantees that the source and destination pointers are aligned to
5022that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5023</p>
5024
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5025<h5>Semantics:</h5>
5026
5027<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5028The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5029location to the destination location, which may overlap. It
5030copies "len" bytes of memory over. If the argument is known to be aligned to
5031some boundary, this can be specified as the fourth argument, otherwise it should
5032be set to 0 or 1.
5033</p>
5034</div>
5035
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5036
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5037<!-- _______________________________________________________________________ -->
5038<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5039 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5040</div>
5041
5042<div class="doc_text">
5043
5044<h5>Syntax:</h5>
5045<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5046 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5047 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5048 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5049 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5050</pre>
5051
5052<h5>Overview:</h5>
5053
5054<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5055The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5056byte value.
5057</p>
5058
5059<p>
5060Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5061does not return a value, and takes an extra alignment argument.
5062</p>
5063
5064<h5>Arguments:</h5>
5065
5066<p>
5067The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5068byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5069argument specifying the number of bytes to fill, and the fourth argument is the
5070known alignment of destination location.
5071</p>
5072
5073<p>
5074If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]5075the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5076</p>
5077
5078<h5>Semantics:</h5>
5079
5080<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5081The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5082the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5083destination location. If the argument is known to be aligned to some boundary,
5084this can be specified as the fourth argument, otherwise it should be set to 0 or
50851.
5086</p>
5087</div>
5088
5089
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5090<!-- _______________________________________________________________________ -->
5091<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5092 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5093</div>
5094
5095<div class="doc_text">
5096
5097<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5098<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5099floating point or vector of floating point type. Not all targets support all
5100types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5101<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5102 declare float @llvm.sqrt.f32(float %Val)
5103 declare double @llvm.sqrt.f64(double %Val)
5104 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5105 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5106 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5107</pre>
5108
5109<h5>Overview:</h5>
5110
5111<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5112The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5113returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5114<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]5115negative numbers other than -0.0 (which allows for better optimization, because
5116there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5117defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5118</p>
5119
5120<h5>Arguments:</h5>
5121
5122<p>
5123The argument and return value are floating point numbers of the same type.
5124</p>
5125
5126<h5>Semantics:</h5>
5127
5128<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]5129This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5130floating point number.
5131</p>
5132</div>
5133
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5134<!-- _______________________________________________________________________ -->
5135<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5136 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5137</div>
5138
5139<div class="doc_text">
5140
5141<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5142<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5143floating point or vector of floating point type. Not all targets support all
5144types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5145<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5146 declare float @llvm.powi.f32(float %Val, i32 %power)
5147 declare double @llvm.powi.f64(double %Val, i32 %power)
5148 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5149 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5150 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5151</pre>
5152
5153<h5>Overview:</h5>
5154
5155<p>
5156The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5157specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5158multiplications is not defined. When a vector of floating point type is
5159used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5160</p>
5161
5162<h5>Arguments:</h5>
5163
5164<p>
5165The second argument is an integer power, and the first is a value to raise to
5166that power.
5167</p>
5168
5169<h5>Semantics:</h5>
5170
5171<p>
5172This function returns the first value raised to the second power with an
5173unspecified sequence of rounding operations.</p>
5174</div>
5175
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5176<!-- _______________________________________________________________________ -->
5177<div class="doc_subsubsection">
5178 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5179</div>
5180
5181<div class="doc_text">
5182
5183<h5>Syntax:</h5>
5184<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5185floating point or vector of floating point type. Not all targets support all
5186types however.
5187<pre>
5188 declare float @llvm.sin.f32(float %Val)
5189 declare double @llvm.sin.f64(double %Val)
5190 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5191 declare fp128 @llvm.sin.f128(fp128 %Val)
5192 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5193</pre>
5194
5195<h5>Overview:</h5>
5196
5197<p>
5198The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5199</p>
5200
5201<h5>Arguments:</h5>
5202
5203<p>
5204The argument and return value are floating point numbers of the same type.
5205</p>
5206
5207<h5>Semantics:</h5>
5208
5209<p>
5210This function returns the sine of the specified operand, returning the
5211same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5212conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5213</div>
5214
5215<!-- _______________________________________________________________________ -->
5216<div class="doc_subsubsection">
5217 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5218</div>
5219
5220<div class="doc_text">
5221
5222<h5>Syntax:</h5>
5223<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5224floating point or vector of floating point type. Not all targets support all
5225types however.
5226<pre>
5227 declare float @llvm.cos.f32(float %Val)
5228 declare double @llvm.cos.f64(double %Val)
5229 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5230 declare fp128 @llvm.cos.f128(fp128 %Val)
5231 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5232</pre>
5233
5234<h5>Overview:</h5>
5235
5236<p>
5237The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5238</p>
5239
5240<h5>Arguments:</h5>
5241
5242<p>
5243The argument and return value are floating point numbers of the same type.
5244</p>
5245
5246<h5>Semantics:</h5>
5247
5248<p>
5249This function returns the cosine of the specified operand, returning the
5250same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5251conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5252</div>
5253
5254<!-- _______________________________________________________________________ -->
5255<div class="doc_subsubsection">
5256 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5257</div>
5258
5259<div class="doc_text">
5260
5261<h5>Syntax:</h5>
5262<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5263floating point or vector of floating point type. Not all targets support all
5264types however.
5265<pre>
5266 declare float @llvm.pow.f32(float %Val, float %Power)
5267 declare double @llvm.pow.f64(double %Val, double %Power)
5268 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5269 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5270 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5271</pre>
5272
5273<h5>Overview:</h5>
5274
5275<p>
5276The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5277specified (positive or negative) power.
5278</p>
5279
5280<h5>Arguments:</h5>
5281
5282<p>
5283The second argument is a floating point power, and the first is a value to
5284raise to that power.
5285</p>
5286
5287<h5>Semantics:</h5>
5288
5289<p>
5290This function returns the first value raised to the second power,
5291returning the
5292same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5293conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5294</div>
5295
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5296
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5297<!-- ======================================================================= -->
5298<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5299 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5300</div>
5301
5302<div class="doc_text">
5303<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5304LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5305These allow efficient code generation for some algorithms.
5306</p>
5307
5308</div>
5309
5310<!-- _______________________________________________________________________ -->
5311<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5312 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5313</div>
5314
5315<div class="doc_text">
5316
5317<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5318<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5319type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5320<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5321 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5322 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5323 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5324</pre>
5325
5326<h5>Overview:</h5>
5327
5328<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]5329The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5330values with an even number of bytes (positive multiple of 16 bits). These are
5331useful for performing operations on data that is not in the target's native
5332byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5333</p>
5334
5335<h5>Semantics:</h5>
5336
5337<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5338The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5339and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5340intrinsic returns an i32 value that has the four bytes of the input i32
5341swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5342i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5343<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5344additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5345</p>
5346
5347</div>
5348
5349<!-- _______________________________________________________________________ -->
5350<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5351 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5352</div>
5353
5354<div class="doc_text">
5355
5356<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5357<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5358width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5359<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5360 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5361 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5362 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5363 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5364 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5365</pre>
5366
5367<h5>Overview:</h5>
5368
5369<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]5370The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5371value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5372</p>
5373
5374<h5>Arguments:</h5>
5375
5376<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5377The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5378integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5379</p>
5380
5381<h5>Semantics:</h5>
5382
5383<p>
5384The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5385</p>
5386</div>
5387
5388<!-- _______________________________________________________________________ -->
5389<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5390 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5391</div>
5392
5393<div class="doc_text">
5394
5395<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5396<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5397integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5398<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5399 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5400 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5401 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5402 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5403 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5404</pre>
5405
5406<h5>Overview:</h5>
5407
5408<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5409The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5410leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5411</p>
5412
5413<h5>Arguments:</h5>
5414
5415<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5416The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5417integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5418</p>
5419
5420<h5>Semantics:</h5>
5421
5422<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5423The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5424in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5425of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5426</p>
5427</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5428
5429
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5430
5431<!-- _______________________________________________________________________ -->
5432<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5433 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5434</div>
5435
5436<div class="doc_text">
5437
5438<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5439<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5440integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5441<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5442 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5443 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5444 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5445 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5446 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5447</pre>
5448
5449<h5>Overview:</h5>
5450
5451<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5452The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5453trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5454</p>
5455
5456<h5>Arguments:</h5>
5457
5458<p>
5459The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5460integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5461</p>
5462
5463<h5>Semantics:</h5>
5464
5465<p>
5466The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5467in a variable. If the src == 0 then the result is the size in bits of the type
5468of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5469</p>
5470</div>
5471
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5472<!-- _______________________________________________________________________ -->
5473<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5474 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5475</div>
5476
5477<div class="doc_text">
5478
5479<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5480<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5481on any integer bit width.
5482<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5483 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5484 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5485</pre>
5486
5487<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5488<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5489range of bits from an integer value and returns them in the same bit width as
5490the original value.</p>
5491
5492<h5>Arguments:</h5>
5493<p>The first argument, <tt>%val</tt> and the result may be integer types of
5494any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5495arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5496
5497<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5498<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5499of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5500<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5501operates in forward mode.</p>
5502<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5503right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5504only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5505<ol>
5506 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5507 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5508 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5509 to determine the number of bits to retain.</li>
5510 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5511 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5512</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5513<p>In reverse mode, a similar computation is made except that the bits are
5514returned in the reverse order. So, for example, if <tt>X</tt> has the value
5515<tt>i16 0x0ACF (101011001111)</tt> and we apply
5516<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5517<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5518</div>
5519
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5520<div class="doc_subsubsection">
5521 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5522</div>
5523
5524<div class="doc_text">
5525
5526<h5>Syntax:</h5>
5527<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5528on any integer bit width.
5529<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5530 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5531 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5532</pre>
5533
5534<h5>Overview:</h5>
5535<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5536of bits in an integer value with another integer value. It returns the integer
5537with the replaced bits.</p>
5538
5539<h5>Arguments:</h5>
5540<p>The first argument, <tt>%val</tt> and the result may be integer types of
5541any bit width but they must have the same bit width. <tt>%val</tt> is the value
5542whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5543integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5544type since they specify only a bit index.</p>
5545
5546<h5>Semantics:</h5>
5547<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5548of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5549<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5550operates in forward mode.</p>
5551<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5552truncating it down to the size of the replacement area or zero extending it
5553up to that size.</p>
5554<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5555are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5556in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5557to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5558<p>In reverse mode, a similar computation is made except that the bits are
5559reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5560<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5561<h5>Examples:</h5>
5562<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5563 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5564 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5565 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5566 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5567 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5568</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5569</div>
5570
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5571<!-- ======================================================================= -->
5572<div class="doc_subsection">
5573 <a name="int_debugger">Debugger Intrinsics</a>
5574</div>
5575
5576<div class="doc_text">
5577<p>
5578The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5579are described in the <a
5580href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5581Debugging</a> document.
5582</p>
5583</div>
5584
5585
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5586<!-- ======================================================================= -->
5587<div class="doc_subsection">
5588 <a name="int_eh">Exception Handling Intrinsics</a>
5589</div>
5590
5591<div class="doc_text">
5592<p> The LLVM exception handling intrinsics (which all start with
5593<tt>llvm.eh.</tt> prefix), are described in the <a
5594href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5595Handling</a> document. </p>
5596</div>
5597
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5598<!-- ======================================================================= -->
5599<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5600 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5601</div>
5602
5603<div class="doc_text">
5604<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5605 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5606 the <tt>nest</tt> attribute, from a function. The result is a callable
5607 function pointer lacking the nest parameter - the caller does not need
5608 to provide a value for it. Instead, the value to use is stored in
5609 advance in a "trampoline", a block of memory usually allocated
5610 on the stack, which also contains code to splice the nest value into the
5611 argument list. This is used to implement the GCC nested function address
5612 extension.
5613</p>
5614<p>
5615 For example, if the function is
5616 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5617 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5618<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5619 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5620 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5621 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5622 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5623</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5624 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5625 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5626</div>
5627
5628<!-- _______________________________________________________________________ -->
5629<div class="doc_subsubsection">
5630 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5631</div>
5632<div class="doc_text">
5633<h5>Syntax:</h5>
5634<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5635declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5636</pre>
5637<h5>Overview:</h5>
5638<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5639 This fills the memory pointed to by <tt>tramp</tt> with code
5640 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5641</p>
5642<h5>Arguments:</h5>
5643<p>
5644 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5645 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5646 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5647 intrinsic. Note that the size and the alignment are target-specific - LLVM
5648 currently provides no portable way of determining them, so a front-end that
5649 generates this intrinsic needs to have some target-specific knowledge.
5650 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5651</p>
5652<h5>Semantics:</h5>
5653<p>
5654 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5655 dependent code, turning it into a function. A pointer to this function is
5656 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5657 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5658 before being called. The new function's signature is the same as that of
5659 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5660 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5661 of pointer type. Calling the new function is equivalent to calling
5662 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5663 missing <tt>nest</tt> argument. If, after calling
5664 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5665 modified, then the effect of any later call to the returned function pointer is
5666 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5667</p>
5668</div>
5669
5670<!-- ======================================================================= -->
5671<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5672 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5673</div>
5674
5675<div class="doc_text">
5676<p>
5677 These intrinsic functions expand the "universal IR" of LLVM to represent
5678 hardware constructs for atomic operations and memory synchronization. This
5679 provides an interface to the hardware, not an interface to the programmer. It
5680 is aimed at a low enough level to allow any programming models or APIs which
5681 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5682 hardware behavior. Just as hardware provides a "universal IR" for source
5683 languages, it also provides a starting point for developing a "universal"
5684 atomic operation and synchronization IR.
5685</p>
5686<p>
5687 These do <em>not</em> form an API such as high-level threading libraries,
5688 software transaction memory systems, atomic primitives, and intrinsic
5689 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5690 application libraries. The hardware interface provided by LLVM should allow
5691 a clean implementation of all of these APIs and parallel programming models.
5692 No one model or paradigm should be selected above others unless the hardware
5693 itself ubiquitously does so.
5694
5695</p>
5696</div>
5697
5698<!-- _______________________________________________________________________ -->
5699<div class="doc_subsubsection">
5700 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5701</div>
5702<div class="doc_text">
5703<h5>Syntax:</h5>
5704<pre>
5705declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5706i1 &lt;device&gt; )
5707
5708</pre>
5709<h5>Overview:</h5>
5710<p>
5711 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5712 specific pairs of memory access types.
5713</p>
5714<h5>Arguments:</h5>
5715<p>
5716 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5717 The first four arguments enables a specific barrier as listed below. The fith
5718 argument specifies that the barrier applies to io or device or uncached memory.
5719
5720</p>
5721 <ul>
5722 <li><tt>ll</tt>: load-load barrier</li>
5723 <li><tt>ls</tt>: load-store barrier</li>
5724 <li><tt>sl</tt>: store-load barrier</li>
5725 <li><tt>ss</tt>: store-store barrier</li>
5726 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5727 </ul>
5728<h5>Semantics:</h5>
5729<p>
5730 This intrinsic causes the system to enforce some ordering constraints upon
5731 the loads and stores of the program. This barrier does not indicate
5732 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5733 which they occur. For any of the specified pairs of load and store operations
5734 (f.ex. load-load, or store-load), all of the first operations preceding the
5735 barrier will complete before any of the second operations succeeding the
5736 barrier begin. Specifically the semantics for each pairing is as follows:
5737</p>
5738 <ul>
5739 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5740 after the barrier begins.</li>
5741
5742 <li><tt>ls</tt>: All loads before the barrier must complete before any
5743 store after the barrier begins.</li>
5744 <li><tt>ss</tt>: All stores before the barrier must complete before any
5745 store after the barrier begins.</li>
5746 <li><tt>sl</tt>: All stores before the barrier must complete before any
5747 load after the barrier begins.</li>
5748 </ul>
5749<p>
5750 These semantics are applied with a logical "and" behavior when more than one
5751 is enabled in a single memory barrier intrinsic.
5752</p>
5753<p>
5754 Backends may implement stronger barriers than those requested when they do not
5755 support as fine grained a barrier as requested. Some architectures do not
5756 need all types of barriers and on such architectures, these become noops.
5757</p>
5758<h5>Example:</h5>
5759<pre>
5760%ptr = malloc i32
5761 store i32 4, %ptr
5762
5763%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5764 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5765 <i>; guarantee the above finishes</i>
5766 store i32 8, %ptr <i>; before this begins</i>
5767</pre>
5768</div>
5769
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]5770<!-- _______________________________________________________________________ -->
5771<div class="doc_subsubsection">
5772 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5773</div>
5774<div class="doc_text">
5775<h5>Syntax:</h5>
5776<p>
5777 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5778 integer bit width. Not all targets support all bit widths however.</p>
5779
5780<pre>
5781declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5782declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5783declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5784declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5785
5786</pre>
5787<h5>Overview:</h5>
5788<p>
5789 This loads a value in memory and compares it to a given value. If they are
5790 equal, it stores a new value into the memory.
5791</p>
5792<h5>Arguments:</h5>
5793<p>
5794 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5795 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5796 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5797 this integer type. While any bit width integer may be used, targets may only
5798 lower representations they support in hardware.
5799
5800</p>
5801<h5>Semantics:</h5>
5802<p>
5803 This entire intrinsic must be executed atomically. It first loads the value
5804 in memory pointed to by <tt>ptr</tt> and compares it with the value
5805 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5806 loaded value is yielded in all cases. This provides the equivalent of an
5807 atomic compare-and-swap operation within the SSA framework.
5808</p>
5809<h5>Examples:</h5>
5810
5811<pre>
5812%ptr = malloc i32
5813 store i32 4, %ptr
5814
5815%val1 = add i32 4, 4
5816%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5817 <i>; yields {i32}:result1 = 4</i>
5818%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5819%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5820
5821%val2 = add i32 1, 1
5822%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5823 <i>; yields {i32}:result2 = 8</i>
5824%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5825
5826%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5827</pre>
5828</div>
5829
5830<!-- _______________________________________________________________________ -->
5831<div class="doc_subsubsection">
5832 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5833</div>
5834<div class="doc_text">
5835<h5>Syntax:</h5>
5836
5837<p>
5838 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5839 integer bit width. Not all targets support all bit widths however.</p>
5840<pre>
5841declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5842declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5843declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5844declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5845
5846</pre>
5847<h5>Overview:</h5>
5848<p>
5849 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5850 the value from memory. It then stores the value in <tt>val</tt> in the memory
5851 at <tt>ptr</tt>.
5852</p>
5853<h5>Arguments:</h5>
5854
5855<p>
5856 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5857 <tt>val</tt> argument and the result must be integers of the same bit width.
5858 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5859 integer type. The targets may only lower integer representations they
5860 support.
5861</p>
5862<h5>Semantics:</h5>
5863<p>
5864 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5865 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5866 equivalent of an atomic swap operation within the SSA framework.
5867
5868</p>
5869<h5>Examples:</h5>
5870<pre>
5871%ptr = malloc i32
5872 store i32 4, %ptr
5873
5874%val1 = add i32 4, 4
5875%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5876 <i>; yields {i32}:result1 = 4</i>
5877%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5878%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5879
5880%val2 = add i32 1, 1
5881%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5882 <i>; yields {i32}:result2 = 8</i>
5883
5884%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5885%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5886</pre>
5887</div>
5888
5889<!-- _______________________________________________________________________ -->
5890<div class="doc_subsubsection">
5891 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5892
5893</div>
5894<div class="doc_text">
5895<h5>Syntax:</h5>
5896<p>
5897 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5898 integer bit width. Not all targets support all bit widths however.</p>
5899<pre>
5900declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5901declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5902declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5903declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5904
5905</pre>
5906<h5>Overview:</h5>
5907<p>
5908 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5909 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5910</p>
5911<h5>Arguments:</h5>
5912<p>
5913
5914 The intrinsic takes two arguments, the first a pointer to an integer value
5915 and the second an integer value. The result is also an integer value. These
5916 integer types can have any bit width, but they must all have the same bit
5917 width. The targets may only lower integer representations they support.
5918</p>
5919<h5>Semantics:</h5>
5920<p>
5921 This intrinsic does a series of operations atomically. It first loads the
5922 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5923 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5924</p>
5925
5926<h5>Examples:</h5>
5927<pre>
5928%ptr = malloc i32
5929 store i32 4, %ptr
5930%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5931 <i>; yields {i32}:result1 = 4</i>
5932%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5933 <i>; yields {i32}:result2 = 8</i>
5934%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5935 <i>; yields {i32}:result3 = 10</i>
5936%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5937</pre>
5938</div>
5939
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5940
5941<!-- ======================================================================= -->
5942<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5943 <a name="int_general">General Intrinsics</a>
5944</div>
5945
5946<div class="doc_text">
5947<p> This class of intrinsics is designed to be generic and has
5948no specific purpose. </p>
5949</div>
5950
5951<!-- _______________________________________________________________________ -->
5952<div class="doc_subsubsection">
5953 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
5959<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5960 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5961</pre>
5962
5963<h5>Overview:</h5>
5964
5965<p>
5966The '<tt>llvm.var.annotation</tt>' intrinsic
5967</p>
5968
5969<h5>Arguments:</h5>
5970
5971<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5972The first argument is a pointer to a value, the second is a pointer to a
5973global string, the third is a pointer to a global string which is the source
5974file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5975</p>
5976
5977<h5>Semantics:</h5>
5978
5979<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5980This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5981This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5982annotations. These have no other defined use, they are ignored by code
5983generation and optimization.
5984</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5985</div>
5986
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5987<!-- _______________________________________________________________________ -->
5988<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5989 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5990</div>
5991
5992<div class="doc_text">
5993
5994<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5995<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5996any integer bit width.
5997</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5998<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]5999 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6000 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6001 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6002 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6003 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6004</pre>
6005
6006<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6007
6008<p>
6009The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6010</p>
6011
6012<h5>Arguments:</h5>
6013
6014<p>
6015The first argument is an integer value (result of some expression),
6016the second is a pointer to a global string, the third is a pointer to a global
6017string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6018It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6019</p>
6020
6021<h5>Semantics:</h5>
6022
6023<p>
6024This intrinsic allows annotations to be put on arbitrary expressions
6025with arbitrary strings. This can be useful for special purpose optimizations
6026that want to look for these annotations. These have no other defined use, they
6027are ignored by code generation and optimization.
6028</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6029
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
6031<div class="doc_subsubsection">
6032 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6033</div>
6034
6035<div class="doc_text">
6036
6037<h5>Syntax:</h5>
6038<pre>
6039 declare void @llvm.trap()
6040</pre>
6041
6042<h5>Overview:</h5>
6043
6044<p>
6045The '<tt>llvm.trap</tt>' intrinsic
6046</p>
6047
6048<h5>Arguments:</h5>
6049
6050<p>
6051None
6052</p>
6053
6054<h5>Semantics:</h5>
6055
6056<p>
6057This intrinsics is lowered to the target dependent trap instruction. If the
6058target does not have a trap instruction, this intrinsic will be lowered to the
6059call of the abort() function.
6060</p>
6061</div>
6062
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6063<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6064<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6065<address>
6066 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6067 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6068 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]6069 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6070
6071 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]6072 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6073 Last modified: $Date$
6074</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]6075
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6076</body>
6077</html>