Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / 08783a88a21cf0397c4891ad861b9e61ef9689f2 / . / llvm / docs / LangRef.html
blob: 5bc81cc98d63f051dc781be30e28023e863d093b [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
Dale Johannesen4188aad2008-05-23 23:13:41 +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
Dale Johannesen4188aad2008-05-23 23:13:41 +0000[diff] [blame]488 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
489
490 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
491 linkage, except that unreferenced <tt>common</tt> globals may not be
492 discarded. This is used for globals that may be emitted in multiple
493 translation units, but that are not guaranteed to be emitted into every
494 translation unit that uses them. One example of this is tentative
495 definitions in C, such as "<tt>int X;</tt>" at global scope.
496 </dd>
497
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]499
Dale Johannesen4188aad2008-05-23 23:13:41 +0000[diff] [blame]500 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
501 that some targets may choose to emit different assembly sequences for them
502 for target-dependent reasons. This is used for globals that are declared
503 "weak" in C source code.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]504 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]505
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]506 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]507
508 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
509 pointer to array type. When two global variables with appending linkage are
510 linked together, the two global arrays are appended together. This is the
511 LLVM, typesafe, equivalent of having the system linker append together
512 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]513 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]514
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]515 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
516 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
517 until linked, if not linked, the symbol becomes null instead of being an
518 undefined reference.
519 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]520
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]522
523 <dd>If none of the above identifiers are used, the global is externally
524 visible, meaning that it participates in linkage and can be used to resolve
525 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]526 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]527</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]528
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]529 <p>
530 The next two types of linkage are targeted for Microsoft Windows platform
531 only. They are designed to support importing (exporting) symbols from (to)
532 DLLs.
533 </p>
534
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]535 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]536 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
537
538 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
539 or variable via a global pointer to a pointer that is set up by the DLL
540 exporting the symbol. On Microsoft Windows targets, the pointer name is
541 formed by combining <code>_imp__</code> and the function or variable name.
542 </dd>
543
544 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
545
546 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
547 pointer to a pointer in a DLL, so that it can be referenced with the
548 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
549 name is formed by combining <code>_imp__</code> and the function or variable
550 name.
551 </dd>
552
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]553</dl>
554
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]555<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]556variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
557variable and was linked with this one, one of the two would be renamed,
558preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
559external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]560outside of the current module.</p>
561<p>It is illegal for a function <i>declaration</i>
562to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]563or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]564<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
565linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]566</div>
567
568<!-- ======================================================================= -->
569<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]570 <a name="callingconv">Calling Conventions</a>
571</div>
572
573<div class="doc_text">
574
575<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
576and <a href="#i_invoke">invokes</a> can all have an optional calling convention
577specified for the call. The calling convention of any pair of dynamic
578caller/callee must match, or the behavior of the program is undefined. The
579following calling conventions are supported by LLVM, and more may be added in
580the future:</p>
581
582<dl>
583 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
584
585 <dd>This calling convention (the default if no other calling convention is
586 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]587 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]588 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]589 </dd>
590
591 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
592
593 <dd>This calling convention attempts to make calls as fast as possible
594 (e.g. by passing things in registers). This calling convention allows the
595 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]596 without having to conform to an externally specified ABI. Implementations of
Arnold Schwaighofer2c6b8882008-05-14 09:17:12 +0000[diff] [blame]597 this convention should allow arbitrary
598 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
599 supported. This calling convention does not support varargs and requires the
600 prototype of all callees to exactly match the prototype of the function
601 definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]602 </dd>
603
604 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
605
606 <dd>This calling convention attempts to make code in the caller as efficient
607 as possible under the assumption that the call is not commonly executed. As
608 such, these calls often preserve all registers so that the call does not break
609 any live ranges in the caller side. This calling convention does not support
610 varargs and requires the prototype of all callees to exactly match the
611 prototype of the function definition.
612 </dd>
613
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]614 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]615
616 <dd>Any calling convention may be specified by number, allowing
617 target-specific calling conventions to be used. Target specific calling
618 conventions start at 64.
619 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]620</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]621
622<p>More calling conventions can be added/defined on an as-needed basis, to
623support pascal conventions or any other well-known target-independent
624convention.</p>
625
626</div>
627
628<!-- ======================================================================= -->
629<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]630 <a name="visibility">Visibility Styles</a>
631</div>
632
633<div class="doc_text">
634
635<p>
636All Global Variables and Functions have one of the following visibility styles:
637</p>
638
639<dl>
640 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
641
642 <dd>On ELF, default visibility means that the declaration is visible to other
643 modules and, in shared libraries, means that the declared entity may be
644 overridden. On Darwin, default visibility means that the declaration is
645 visible to other modules. Default visibility corresponds to "external
646 linkage" in the language.
647 </dd>
648
649 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
650
651 <dd>Two declarations of an object with hidden visibility refer to the same
652 object if they are in the same shared object. Usually, hidden visibility
653 indicates that the symbol will not be placed into the dynamic symbol table,
654 so no other module (executable or shared library) can reference it
655 directly.
656 </dd>
657
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]658 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
659
660 <dd>On ELF, protected visibility indicates that the symbol will be placed in
661 the dynamic symbol table, but that references within the defining module will
662 bind to the local symbol. That is, the symbol cannot be overridden by another
663 module.
664 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]665</dl>
666
667</div>
668
669<!-- ======================================================================= -->
670<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]671 <a name="globalvars">Global Variables</a>
672</div>
673
674<div class="doc_text">
675
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]676<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]677instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]678an explicit section to be placed in, and may have an optional explicit alignment
679specified. A variable may be defined as "thread_local", which means that it
680will not be shared by threads (each thread will have a separated copy of the
681variable). A variable may be defined as a global "constant," which indicates
682that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]683optimization, allowing the global data to be placed in the read-only section of
684an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]685cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]686
687<p>
688LLVM explicitly allows <em>declarations</em> of global variables to be marked
689constant, even if the final definition of the global is not. This capability
690can be used to enable slightly better optimization of the program, but requires
691the language definition to guarantee that optimizations based on the
692'constantness' are valid for the translation units that do not include the
693definition.
694</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]695
696<p>As SSA values, global variables define pointer values that are in
697scope (i.e. they dominate) all basic blocks in the program. Global
698variables always define a pointer to their "content" type because they
699describe a region of memory, and all memory objects in LLVM are
700accessed through pointers.</p>
701
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]702<p>A global variable may be declared to reside in a target-specifc numbered
703address space. For targets that support them, address spaces may affect how
704optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]705the variable. The default address space is zero. The address space qualifier
706must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]707
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]708<p>LLVM allows an explicit section to be specified for globals. If the target
709supports it, it will emit globals to the section specified.</p>
710
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]711<p>An explicit alignment may be specified for a global. If not present, or if
712the alignment is set to zero, the alignment of the global is set by the target
713to whatever it feels convenient. If an explicit alignment is specified, the
714global is forced to have at least that much alignment. All alignments must be
715a power of 2.</p>
716
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]717<p>For example, the following defines a global in a numbered address space with
718an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]719
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]720<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]721<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]722@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]723</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]724</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]725
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]726</div>
727
728
729<!-- ======================================================================= -->
730<div class="doc_subsection">
731 <a name="functionstructure">Functions</a>
732</div>
733
734<div class="doc_text">
735
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]736<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
737an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]738<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]739<a href="#callingconv">calling convention</a>, a return type, an optional
740<a href="#paramattrs">parameter attribute</a> for the return type, a function
741name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]742<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]743optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]744opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]745
746LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
747optional <a href="#linkage">linkage type</a>, an optional
748<a href="#visibility">visibility style</a>, an optional
749<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]750<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]751name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]752<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]753
754<p>A function definition contains a list of basic blocks, forming the CFG for
755the function. Each basic block may optionally start with a label (giving the
756basic block a symbol table entry), contains a list of instructions, and ends
757with a <a href="#terminators">terminator</a> instruction (such as a branch or
758function return).</p>
759
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]760<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]761executed on entrance to the function, and it is not allowed to have predecessor
762basic blocks (i.e. there can not be any branches to the entry block of a
763function). Because the block can have no predecessors, it also cannot have any
764<a href="#i_phi">PHI nodes</a>.</p>
765
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]766<p>LLVM allows an explicit section to be specified for functions. If the target
767supports it, it will emit functions to the section specified.</p>
768
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]769<p>An explicit alignment may be specified for a function. If not present, or if
770the alignment is set to zero, the alignment of the function is set by the target
771to whatever it feels convenient. If an explicit alignment is specified, the
772function is forced to have at least that much alignment. All alignments must be
773a power of 2.</p>
774
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]775</div>
776
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]777
778<!-- ======================================================================= -->
779<div class="doc_subsection">
780 <a name="aliasstructure">Aliases</a>
781</div>
782<div class="doc_text">
783 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov25b2e822008-03-22 08:36:14 +0000[diff] [blame]784 function, global variable, another alias or bitcast of global value). Aliases
785 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]786 optional <a href="#visibility">visibility style</a>.</p>
787
788 <h5>Syntax:</h5>
789
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]790<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]791<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]792@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]793</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]794</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]795
796</div>
797
798
799
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]800<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]801<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
802<div class="doc_text">
803 <p>The return type and each parameter of a function type may have a set of
804 <i>parameter attributes</i> associated with them. Parameter attributes are
805 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]806 a function. Parameter attributes are considered to be part of the function,
807 not of the function type, so functions with different parameter attributes
808 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]809
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]810 <p>Parameter attributes are simple keywords that follow the type specified. If
811 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]812 example:</p>
813
814<div class="doc_code">
815<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]816declare i32 @printf(i8* noalias , ...) nounwind
817declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]818</pre>
819</div>
820
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]821 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
822 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]823
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]824 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]825 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]826 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]827 <dd>This indicates that the parameter should be zero extended just before
828 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]829
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]830 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]831 <dd>This indicates that the parameter should be sign extended just before
832 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]833
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]834 <dt><tt>inreg</tt></dt>
835 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]836 possible) during assembling function call. Support for this attribute is
837 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]838
839 <dt><tt>byval</tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000[diff] [blame]840 <dd>This indicates that the pointer parameter should really be passed by
841 value to the function. The attribute implies that a hidden copy of the
842 pointee is made between the caller and the callee, so the callee is unable
843 to modify the value in the callee. This attribute is only valid on llvm
844 pointer arguments. It is generally used to pass structs and arrays by
845 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]846
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]847 <dt><tt>sret</tt></dt>
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]848 <dd>This indicates that the pointer parameter specifies the address of a
849 structure that is the return value of the function in the source program.
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]850 Loads and stores to the structure are assumed not to trap.
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]851 May only be applied to the first parameter.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]852
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]853 <dt><tt>noalias</tt></dt>
Owen Anderson61101282008-02-18 04:09:01 +0000[diff] [blame]854 <dd>This indicates that the parameter does not alias any global or any other
855 parameter. The caller is responsible for ensuring that this is the case,
856 usually by placing the value in a stack allocation.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]857
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]858 <dt><tt>noreturn</tt></dt>
859 <dd>This function attribute indicates that the function never returns. This
860 indicates to LLVM that every call to this function should be treated as if
861 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]862
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]863 <dt><tt>nounwind</tt></dt>
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]864 <dd>This function attribute indicates that no exceptions unwind out of the
865 function. Usually this is because the function makes no use of exceptions,
866 but it may also be that the function catches any exceptions thrown when
867 executing it.</dd>
868
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]869 <dt><tt>nest</tt></dt>
870 <dd>This indicates that the parameter can be excised using the
871 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]872 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]873 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]874 except for producing a return value or throwing an exception. The value
875 returned must only depend on the function arguments and/or global variables.
876 It may use values obtained by dereferencing pointers.</dd>
877 <dt><tt>readnone</tt></dt>
878 <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]879 function, but in addition it is not allowed to dereference any pointer arguments
880 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]881 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]882
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]883</div>
884
885<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]886<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]887 <a name="gc">Garbage Collector Names</a>
888</div>
889
890<div class="doc_text">
891<p>Each function may specify a garbage collector name, which is simply a
892string.</p>
893
894<div class="doc_code"><pre
895>define void @f() gc "name" { ...</pre></div>
896
897<p>The compiler declares the supported values of <i>name</i>. Specifying a
898collector which will cause the compiler to alter its output in order to support
899the named garbage collection algorithm.</p>
900</div>
901
902<!-- ======================================================================= -->
903<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]904 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]905</div>
906
907<div class="doc_text">
908<p>
909Modules may contain "module-level inline asm" blocks, which corresponds to the
910GCC "file scope inline asm" blocks. These blocks are internally concatenated by
911LLVM and treated as a single unit, but may be separated in the .ll file if
912desired. The syntax is very simple:
913</p>
914
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]915<div class="doc_code">
916<pre>
917module asm "inline asm code goes here"
918module asm "more can go here"
919</pre>
920</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]921
922<p>The strings can contain any character by escaping non-printable characters.
923 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
924 for the number.
925</p>
926
927<p>
928 The inline asm code is simply printed to the machine code .s file when
929 assembly code is generated.
930</p>
931</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]932
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]933<!-- ======================================================================= -->
934<div class="doc_subsection">
935 <a name="datalayout">Data Layout</a>
936</div>
937
938<div class="doc_text">
939<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]940data is to be laid out in memory. The syntax for the data layout is simply:</p>
941<pre> target datalayout = "<i>layout specification</i>"</pre>
942<p>The <i>layout specification</i> consists of a list of specifications
943separated by the minus sign character ('-'). Each specification starts with a
944letter and may include other information after the letter to define some
945aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]946<dl>
947 <dt><tt>E</tt></dt>
948 <dd>Specifies that the target lays out data in big-endian form. That is, the
949 bits with the most significance have the lowest address location.</dd>
950 <dt><tt>e</tt></dt>
951 <dd>Specifies that hte target lays out data in little-endian form. That is,
952 the bits with the least significance have the lowest address location.</dd>
953 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
954 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
955 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
956 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
957 too.</dd>
958 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
959 <dd>This specifies the alignment for an integer type of a given bit
960 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
961 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
962 <dd>This specifies the alignment for a vector type of a given bit
963 <i>size</i>.</dd>
964 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
965 <dd>This specifies the alignment for a floating point type of a given bit
966 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
967 (double).</dd>
968 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
969 <dd>This specifies the alignment for an aggregate type of a given bit
970 <i>size</i>.</dd>
971</dl>
972<p>When constructing the data layout for a given target, LLVM starts with a
973default set of specifications which are then (possibly) overriden by the
974specifications in the <tt>datalayout</tt> keyword. The default specifications
975are given in this list:</p>
976<ul>
977 <li><tt>E</tt> - big endian</li>
978 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
979 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
980 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
981 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
982 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
983 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
984 alignment of 64-bits</li>
985 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
986 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
987 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
988 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
989 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
990</ul>
991<p>When llvm is determining the alignment for a given type, it uses the
992following rules:
993<ol>
994 <li>If the type sought is an exact match for one of the specifications, that
995 specification is used.</li>
996 <li>If no match is found, and the type sought is an integer type, then the
997 smallest integer type that is larger than the bitwidth of the sought type is
998 used. If none of the specifications are larger than the bitwidth then the the
999 largest integer type is used. For example, given the default specifications
1000 above, the i7 type will use the alignment of i8 (next largest) while both
1001 i65 and i256 will use the alignment of i64 (largest specified).</li>
1002 <li>If no match is found, and the type sought is a vector type, then the
1003 largest vector type that is smaller than the sought vector type will be used
1004 as a fall back. This happens because <128 x double> can be implemented in
1005 terms of 64 <2 x double>, for example.</li>
1006</ol>
1007</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1009<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1010<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1011<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1012
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1013<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1015<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1016intermediate representation. Being typed enables a number of
1017optimizations to be performed on the IR directly, without having to do
1018extra analyses on the side before the transformation. A strong type
1019system makes it easier to read the generated code and enables novel
1020analyses and transformations that are not feasible to perform on normal
1021three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1022
1023</div>
1024
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1025<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1026<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1027Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1028<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1029<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1030classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1031
1032<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1033 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1034 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1035 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1036 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1037 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1038 </tr>
1039 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1040 <td><a href="#t_floating">floating point</a></td>
1041 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1042 </tr>
1043 <tr>
1044 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1045 <td><a href="#t_integer">integer</a>,
1046 <a href="#t_floating">floating point</a>,
1047 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame^]1048 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1049 <a href="#t_struct">structure</a>,
1050 <a href="#t_array">array</a>,
Dan Gohmanda52d212008-05-23 22:50:26 +0000[diff] [blame]1051 <a href="#t_label">label</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1052 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1053 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1054 <tr>
1055 <td><a href="#t_primitive">primitive</a></td>
1056 <td><a href="#t_label">label</a>,
1057 <a href="#t_void">void</a>,
1058 <a href="#t_integer">integer</a>,
1059 <a href="#t_floating">floating point</a>.</td>
1060 </tr>
1061 <tr>
1062 <td><a href="#t_derived">derived</a></td>
1063 <td><a href="#t_integer">integer</a>,
1064 <a href="#t_array">array</a>,
1065 <a href="#t_function">function</a>,
1066 <a href="#t_pointer">pointer</a>,
1067 <a href="#t_struct">structure</a>,
1068 <a href="#t_pstruct">packed structure</a>,
1069 <a href="#t_vector">vector</a>,
1070 <a href="#t_opaque">opaque</a>.
1071 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1072 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1073</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1074
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1075<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1076most important. Values of these types are the only ones which can be
1077produced by instructions, passed as arguments, or used as operands to
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame]1078instructions.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1079</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1080
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1081<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1082<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1083
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1084<div class="doc_text">
1085<p>The primitive types are the fundamental building blocks of the LLVM
1086system.</p>
1087
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1088</div>
1089
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1090<!-- _______________________________________________________________________ -->
1091<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1092
1093<div class="doc_text">
1094 <table>
1095 <tbody>
1096 <tr><th>Type</th><th>Description</th></tr>
1097 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1098 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1099 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1100 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1101 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1102 </tbody>
1103 </table>
1104</div>
1105
1106<!-- _______________________________________________________________________ -->
1107<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1108
1109<div class="doc_text">
1110<h5>Overview:</h5>
1111<p>The void type does not represent any value and has no size.</p>
1112
1113<h5>Syntax:</h5>
1114
1115<pre>
1116 void
1117</pre>
1118</div>
1119
1120<!-- _______________________________________________________________________ -->
1121<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1122
1123<div class="doc_text">
1124<h5>Overview:</h5>
1125<p>The label type represents code labels.</p>
1126
1127<h5>Syntax:</h5>
1128
1129<pre>
1130 label
1131</pre>
1132</div>
1133
1134
1135<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1136<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1137
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1138<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1139
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1140<p>The real power in LLVM comes from the derived types in the system.
1141This is what allows a programmer to represent arrays, functions,
1142pointers, and other useful types. Note that these derived types may be
1143recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1144
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1145</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1146
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1147<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1148<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1149
1150<div class="doc_text">
1151
1152<h5>Overview:</h5>
1153<p>The integer type is a very simple derived type that simply specifies an
1154arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11552^23-1 (about 8 million) can be specified.</p>
1156
1157<h5>Syntax:</h5>
1158
1159<pre>
1160 iN
1161</pre>
1162
1163<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1164value.</p>
1165
1166<h5>Examples:</h5>
1167<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1168 <tbody>
1169 <tr>
1170 <td><tt>i1</tt></td>
1171 <td>a single-bit integer.</td>
1172 </tr><tr>
1173 <td><tt>i32</tt></td>
1174 <td>a 32-bit integer.</td>
1175 </tr><tr>
1176 <td><tt>i1942652</tt></td>
1177 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1178 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1179 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1180</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1181</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1182
1183<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1184<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1185
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1186<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1188<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1189
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1190<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1191sequentially in memory. The array type requires a size (number of
1192elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1193
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1194<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1195
1196<pre>
1197 [&lt;# elements&gt; x &lt;elementtype&gt;]
1198</pre>
1199
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1200<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1201be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1202
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1203<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1204<table class="layout">
1205 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1206 <td class="left"><tt>[40 x i32]</tt></td>
1207 <td class="left">Array of 40 32-bit integer values.</td>
1208 </tr>
1209 <tr class="layout">
1210 <td class="left"><tt>[41 x i32]</tt></td>
1211 <td class="left">Array of 41 32-bit integer values.</td>
1212 </tr>
1213 <tr class="layout">
1214 <td class="left"><tt>[4 x i8]</tt></td>
1215 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1216 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1217</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1218<p>Here are some examples of multidimensional arrays:</p>
1219<table class="layout">
1220 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1221 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1222 <td class="left">3x4 array of 32-bit integer values.</td>
1223 </tr>
1224 <tr class="layout">
1225 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1226 <td class="left">12x10 array of single precision floating point values.</td>
1227 </tr>
1228 <tr class="layout">
1229 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1230 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1231 </tr>
1232</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1233
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1234<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1235length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1236LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1237As a special case, however, zero length arrays are recognized to be variable
1238length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1239type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1240
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1241</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1242
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1243<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1244<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1245<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1247<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1248
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1249<p>The function type can be thought of as a function signature. It
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1250consists of a return type and a list of formal parameter types. The
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1251return 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]1252If 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]1253class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1254
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1255<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1256
1257<pre>
1258 &lt;returntype list&gt; (&lt;parameter list&gt;)
1259</pre>
1260
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1261<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]1262specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1263which indicates that the function takes a variable number of arguments.
1264Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1265 href="#int_varargs">variable argument handling intrinsic</a> functions.
1266'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1267<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1268
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1269<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1270<table class="layout">
1271 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1272 <td class="left"><tt>i32 (i32)</tt></td>
1273 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1274 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1275 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1276 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1277 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1278 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1279 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1280 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1281 <tt>float</tt>.
1282 </td>
1283 </tr><tr class="layout">
1284 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1285 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1286 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1287 which returns an integer. This is the signature for <tt>printf</tt> in
1288 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1289 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1290 </tr><tr class="layout">
1291 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel8dec6c22008-03-24 18:10:52 +0000[diff] [blame]1292 <td class="left">A function taking an <tt>i32></tt>, returning two
1293 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1294 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1295 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1296</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1297
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1298</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1299<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1300<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1301<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1302<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1303<p>The structure type is used to represent a collection of data members
1304together in memory. The packing of the field types is defined to match
1305the ABI of the underlying processor. The elements of a structure may
1306be any type that has a size.</p>
1307<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1308and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1309field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1310instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1311<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1312<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1313<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1314<table class="layout">
1315 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1316 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1317 <td class="left">A triple of three <tt>i32</tt> values</td>
1318 </tr><tr class="layout">
1319 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1320 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1321 second element is a <a href="#t_pointer">pointer</a> to a
1322 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1323 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1324 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1325</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1326</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1328<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1329<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1330</div>
1331<div class="doc_text">
1332<h5>Overview:</h5>
1333<p>The packed structure type is used to represent a collection of data members
1334together in memory. There is no padding between fields. Further, the alignment
1335of a packed structure is 1 byte. The elements of a packed structure may
1336be any type that has a size.</p>
1337<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1338and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1339field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1340instruction.</p>
1341<h5>Syntax:</h5>
1342<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1343<h5>Examples:</h5>
1344<table class="layout">
1345 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1346 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1347 <td class="left">A triple of three <tt>i32</tt> values</td>
1348 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1349 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1350 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1351 second element is a <a href="#t_pointer">pointer</a> to a
1352 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1353 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1354 </tr>
1355</table>
1356</div>
1357
1358<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1359<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1360<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1361<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1362<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1363reference to another object, which must live in memory. Pointer types may have
1364an optional address space attribute defining the target-specific numbered
1365address space where the pointed-to object resides. The default address space is
1366zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1367<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1368<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1369<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1370<table class="layout">
1371 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1372 <td class="left"><tt>[4x i32]*</tt></td>
1373 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1374 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1375 </tr>
1376 <tr class="layout">
1377 <td class="left"><tt>i32 (i32 *) *</tt></td>
1378 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1379 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1380 <tt>i32</tt>.</td>
1381 </tr>
1382 <tr class="layout">
1383 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1384 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1385 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1386 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1387</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1388</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1389
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1390<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1391<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1392<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1393
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1394<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1395
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1396<p>A vector type is a simple derived type that represents a vector
1397of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1398are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1399A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1400elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1401of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1402considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1403
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1404<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1405
1406<pre>
1407 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1408</pre>
1409
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1410<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1411be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1412
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1413<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1414
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1415<table class="layout">
1416 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1417 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1418 <td class="left">Vector of 4 32-bit integer values.</td>
1419 </tr>
1420 <tr class="layout">
1421 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1422 <td class="left">Vector of 8 32-bit floating-point values.</td>
1423 </tr>
1424 <tr class="layout">
1425 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1426 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1427 </tr>
1428</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1429</div>
1430
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1431<!-- _______________________________________________________________________ -->
1432<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1433<div class="doc_text">
1434
1435<h5>Overview:</h5>
1436
1437<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1438corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1439In LLVM, opaque types can eventually be resolved to any type (not just a
1440structure type).</p>
1441
1442<h5>Syntax:</h5>
1443
1444<pre>
1445 opaque
1446</pre>
1447
1448<h5>Examples:</h5>
1449
1450<table class="layout">
1451 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1452 <td class="left"><tt>opaque</tt></td>
1453 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1454 </tr>
1455</table>
1456</div>
1457
1458
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1459<!-- *********************************************************************** -->
1460<div class="doc_section"> <a name="constants">Constants</a> </div>
1461<!-- *********************************************************************** -->
1462
1463<div class="doc_text">
1464
1465<p>LLVM has several different basic types of constants. This section describes
1466them all and their syntax.</p>
1467
1468</div>
1469
1470<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1471<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472
1473<div class="doc_text">
1474
1475<dl>
1476 <dt><b>Boolean constants</b></dt>
1477
1478 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1479 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1480 </dd>
1481
1482 <dt><b>Integer constants</b></dt>
1483
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1484 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1485 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1486 integer types.
1487 </dd>
1488
1489 <dt><b>Floating point constants</b></dt>
1490
1491 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1492 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]1493 notation (see below). The assembler requires the exact decimal value of
1494 a floating-point constant. For example, the assembler accepts 1.25 but
1495 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1496 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1497
1498 <dt><b>Null pointer constants</b></dt>
1499
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1500 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1501 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1502
1503</dl>
1504
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1505<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1506of floating point constants. For example, the form '<tt>double
15070x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
15084.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1509(and the only time that they are generated by the disassembler) is when a
1510floating point constant must be emitted but it cannot be represented as a
1511decimal floating point number. For example, NaN's, infinities, and other
1512special values are represented in their IEEE hexadecimal format so that
1513assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1514
1515</div>
1516
1517<!-- ======================================================================= -->
1518<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1519</div>
1520
1521<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1522<p>Aggregate constants arise from aggregation of simple constants
1523and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1524
1525<dl>
1526 <dt><b>Structure constants</b></dt>
1527
1528 <dd>Structure constants are represented with notation similar to structure
1529 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1530 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1531 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]1532 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1533 types of elements must match those specified by the type.
1534 </dd>
1535
1536 <dt><b>Array constants</b></dt>
1537
1538 <dd>Array constants are represented with notation similar to array type
1539 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1540 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1541 constants must have <a href="#t_array">array type</a>, and the number and
1542 types of elements must match those specified by the type.
1543 </dd>
1544
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1545 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1546
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1547 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1548 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1549 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]1550 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1551 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1552 match those specified by the type.
1553 </dd>
1554
1555 <dt><b>Zero initialization</b></dt>
1556
1557 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1558 value to zero of <em>any</em> type, including scalar and aggregate types.
1559 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]1560 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1561 initializers.
1562 </dd>
1563</dl>
1564
1565</div>
1566
1567<!-- ======================================================================= -->
1568<div class="doc_subsection">
1569 <a name="globalconstants">Global Variable and Function Addresses</a>
1570</div>
1571
1572<div class="doc_text">
1573
1574<p>The addresses of <a href="#globalvars">global variables</a> and <a
1575href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1576constants. These constants are explicitly referenced when the <a
1577href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1578href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1579file:</p>
1580
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1581<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1582<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1583@X = global i32 17
1584@Y = global i32 42
1585@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1586</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1587</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1588
1589</div>
1590
1591<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1592<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1593<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1594 <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]1595 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1596 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1597
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1598 <p>Undefined values indicate to the compiler that the program is well defined
1599 no matter what value is used, giving the compiler more freedom to optimize.
1600 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1601</div>
1602
1603<!-- ======================================================================= -->
1604<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1605</div>
1606
1607<div class="doc_text">
1608
1609<p>Constant expressions are used to allow expressions involving other constants
1610to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1611href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1612that does not have side effects (e.g. load and call are not supported). The
1613following is the syntax for constant expressions:</p>
1614
1615<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1616 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1617 <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]1618 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1619
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1620 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1621 <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]1622 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]1623
1624 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1625 <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]1626 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]1627
1628 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1629 <dd>Truncate a floating point constant to another floating point type. The
1630 size of CST must be larger than the size of TYPE. Both types must be
1631 floating point.</dd>
1632
1633 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1634 <dd>Floating point extend a constant to another type. The size of CST must be
1635 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1636
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1637 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1638 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1639 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1640 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1641 of the same number of elements. If the value won't fit in the integer type,
1642 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1643
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1644 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1645 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1646 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1647 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1648 of the same number of elements. If the value won't fit in the integer type,
1649 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1650
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1651 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1652 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1653 constant. TYPE must be a scalar or vector floating point type. CST must be of
1654 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1655 of the same number of elements. If the value won't fit in the floating point
1656 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1657
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1658 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1659 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1660 constant. TYPE must be a scalar or vector floating point type. CST must be of
1661 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1662 of the same number of elements. If the value won't fit in the floating point
1663 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1664
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1665 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1666 <dd>Convert a pointer typed constant to the corresponding integer constant
1667 TYPE must be an integer type. CST must be of pointer type. The CST value is
1668 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1669
1670 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1671 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1672 pointer type. CST must be of integer type. The CST value is zero extended,
1673 truncated, or unchanged to make it fit in a pointer size. This one is
1674 <i>really</i> dangerous!</dd>
1675
1676 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1677 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1678 identical (same number of bits). The conversion is done as if the CST value
1679 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]1680 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1681 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]1682 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1683 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1684
1685 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1686
1687 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1688 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1689 instruction, the index list may have zero or more indexes, which are required
1690 to make sense for the type of "CSTPTR".</dd>
1691
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1692 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1693
1694 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1695 constants.</dd>
1696
1697 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1698 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1699
1700 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1701 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1702
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]1703 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1704 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1705
1706 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1707 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1708
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1709 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1710
1711 <dd>Perform the <a href="#i_extractelement">extractelement
1712 operation</a> on constants.
1713
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1714 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1715
1716 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1717 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1718
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1719
1720 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1721
1722 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1723 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1724
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1725 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1726
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1727 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1728 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1729 binary</a> operations. The constraints on operands are the same as those for
1730 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1731 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1732</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1733</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1734
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1735<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1736<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1737<!-- *********************************************************************** -->
1738
1739<!-- ======================================================================= -->
1740<div class="doc_subsection">
1741<a name="inlineasm">Inline Assembler Expressions</a>
1742</div>
1743
1744<div class="doc_text">
1745
1746<p>
1747LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1748Module-Level Inline Assembly</a>) through the use of a special value. This
1749value represents the inline assembler as a string (containing the instructions
1750to emit), a list of operand constraints (stored as a string), and a flag that
1751indicates whether or not the inline asm expression has side effects. An example
1752inline assembler expression is:
1753</p>
1754
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1755<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1756<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1757i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1758</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1759</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1760
1761<p>
1762Inline assembler expressions may <b>only</b> be used as the callee operand of
1763a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1764</p>
1765
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1766<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1767<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1768%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]1769</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1770</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1771
1772<p>
1773Inline asms with side effects not visible in the constraint list must be marked
1774as having side effects. This is done through the use of the
1775'<tt>sideeffect</tt>' keyword, like so:
1776</p>
1777
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1778<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1779<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1780call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1781</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1782</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1783
1784<p>TODO: The format of the asm and constraints string still need to be
1785documented here. Constraints on what can be done (e.g. duplication, moving, etc
1786need to be documented).
1787</p>
1788
1789</div>
1790
1791<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1792<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1793<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1795<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1796
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1797<p>The LLVM instruction set consists of several different
1798classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1799instructions</a>, <a href="#binaryops">binary instructions</a>,
1800<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1801 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1802instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1804</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1806<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1807<div class="doc_subsection"> <a name="terminators">Terminator
1808Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1809
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1810<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1811
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1812<p>As mentioned <a href="#functionstructure">previously</a>, every
1813basic block in a program ends with a "Terminator" instruction, which
1814indicates which block should be executed after the current block is
1815finished. These terminator instructions typically yield a '<tt>void</tt>'
1816value: they produce control flow, not values (the one exception being
1817the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1818<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1819 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1820instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1821the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1822 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1823 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1824
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1825</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1826
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1827<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1828<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1829Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1830<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1831<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1832<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]1833 ret void <i>; Return from void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1834 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]1835</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1838
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1839<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1840value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1841<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1842returns value(s) and then causes control flow, and one that just causes
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1843control flow to occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1844
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Arguments:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1846
1847<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1848The type of each return value must be a '<a href="#t_firstclass">first
1849class</a>' type. Note that a function is not <a href="#wellformed">well
1850formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1851function that returns values that do not match the return type of the
1852function.</p>
1853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1854<h5>Semantics:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1855
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1856<p>When the '<tt>ret</tt>' instruction is executed, control flow
1857returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1858 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1859the instruction after the call. If the caller was an "<a
1860 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1861at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1862returns a value, that value shall set the call or invoke instruction's
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1863return value. If the instruction returns multiple values then these
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1864values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1865</a>' instruction.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1866
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1867<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1868
1869<pre>
1870 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1871 ret void <i>; Return from a void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1872 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1873</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1874</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1875<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1876<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1877<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1878<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1879<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]1880</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1881<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1882<p>The '<tt>br</tt>' instruction is used to cause control flow to
1883transfer to a different basic block in the current function. There are
1884two forms of this instruction, corresponding to a conditional branch
1885and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1887<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1888single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1889unconditional form of the '<tt>br</tt>' instruction takes a single
1890'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1891<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1892<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1893argument is evaluated. If the value is <tt>true</tt>, control flows
1894to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1895control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1896<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1897<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]1898 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]1899</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1900<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1901<div class="doc_subsubsection">
1902 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1903</div>
1904
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1905<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1906<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1907
1908<pre>
1909 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1910</pre>
1911
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1912<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1913
1914<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1915several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1916instruction, allowing a branch to occur to one of many possible
1917destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1918
1919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1920<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1921
1922<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1923comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1924an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1925table is not allowed to contain duplicate constant entries.</p>
1926
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1928
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1929<p>The <tt>switch</tt> instruction specifies a table of values and
1930destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1931table is searched for the given value. If the value is found, control flow is
1932transfered to the corresponding destination; otherwise, control flow is
1933transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1934
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1935<h5>Implementation:</h5>
1936
1937<p>Depending on properties of the target machine and the particular
1938<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1939ways. For example, it could be generated as a series of chained conditional
1940branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1941
1942<h5>Example:</h5>
1943
1944<pre>
1945 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1946 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1947 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1948
1949 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1950 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1951
1952 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1953 switch i32 %val, label %otherwise [ i32 0, label %onzero
1954 i32 1, label %onone
1955 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1956</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1957</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1958
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1959<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1960<div class="doc_subsubsection">
1961 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1962</div>
1963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1964<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1966<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1967
1968<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1969 &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]1970 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1971</pre>
1972
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1973<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1974
1975<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1976function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1977'<tt>normal</tt>' label or the
1978'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1979"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1980"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1981href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1982continued at the dynamically nearest "exception" label. If the callee function
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1983returns multiple values then individual return values are only accessible through
1984a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1985
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1986<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1987
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1988<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1989
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1990<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1991 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1992 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1993 convention</a> the call should use. If none is specified, the call defaults
1994 to using C calling conventions.
1995 </li>
1996 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1997 function value being invoked. In most cases, this is a direct function
1998 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1999 an arbitrary pointer to function value.
2000 </li>
2001
2002 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2003 function to be invoked. </li>
2004
2005 <li>'<tt>function args</tt>': argument list whose types match the function
2006 signature argument types. If the function signature indicates the function
2007 accepts a variable number of arguments, the extra arguments can be
2008 specified. </li>
2009
2010 <li>'<tt>normal label</tt>': the label reached when the called function
2011 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2012
2013 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2014 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2015
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2016</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2017
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2018<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2019
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2020<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2021href="#i_call">call</a></tt>' instruction in most regards. The primary
2022difference is that it establishes an association with a label, which is used by
2023the runtime library to unwind the stack.</p>
2024
2025<p>This instruction is used in languages with destructors to ensure that proper
2026cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2027exception. Additionally, this is important for implementation of
2028'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2029
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2030<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2031<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2032 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2033 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2034 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2035 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2036</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2037</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2038
2039
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2040<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2041
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2042<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2043Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2044
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2045<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2046
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2047<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2048<pre>
2049 unwind
2050</pre>
2051
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2052<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2053
2054<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2055at the first callee in the dynamic call stack which used an <a
2056href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2057primarily used to implement exception handling.</p>
2058
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2059<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2060
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2061<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2062immediately halt. The dynamic call stack is then searched for the first <a
2063href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2064execution continues at the "exceptional" destination block specified by the
2065<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2066dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2067</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2068
2069<!-- _______________________________________________________________________ -->
2070
2071<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2072Instruction</a> </div>
2073
2074<div class="doc_text">
2075
2076<h5>Syntax:</h5>
2077<pre>
2078 unreachable
2079</pre>
2080
2081<h5>Overview:</h5>
2082
2083<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2084instruction is used to inform the optimizer that a particular portion of the
2085code is not reachable. This can be used to indicate that the code after a
2086no-return function cannot be reached, and other facts.</p>
2087
2088<h5>Semantics:</h5>
2089
2090<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2091</div>
2092
2093
2094
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2095<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2096<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2097<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2098<p>Binary operators are used to do most of the computation in a
Chris Lattner81f92972008-04-01 18:47:32 +0000[diff] [blame]2099program. They require two operands of the same type, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2100produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2101multiple 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]2102The result value has the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2103<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2104</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2105<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2106<div class="doc_subsubsection">
2107 <a name="i_add">'<tt>add</tt>' Instruction</a>
2108</div>
2109
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2110<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2111
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2112<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2113
2114<pre>
2115 &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]2116</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2118<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2119
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2120<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2122<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2123
2124<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2125 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2126 <a href="#t_vector">vector</a> values. Both arguments must have identical
2127 types.</p>
2128
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2130
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2131<p>The value produced is the integer or floating point sum of the two
2132operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2133
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2134<p>If an integer sum has unsigned overflow, the result returned is the
2135mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2136the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2137
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2138<p>Because LLVM integers use a two's complement representation, this
2139instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2140
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2141<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2142
2143<pre>
2144 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2145</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2146</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2147<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2148<div class="doc_subsubsection">
2149 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2150</div>
2151
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2152<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2153
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2154<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2155
2156<pre>
2157 &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]2158</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2159
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2160<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2161
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2162<p>The '<tt>sub</tt>' instruction returns the difference of its two
2163operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2164
2165<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2166'<tt>neg</tt>' instruction present in most other intermediate
2167representations.</p>
2168
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2169<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2170
2171<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2172 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2173 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2174 types.</p>
2175
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2176<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2177
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2178<p>The value produced is the integer or floating point difference of
2179the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2180
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2181<p>If an integer difference has unsigned overflow, the result returned is the
2182mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2183the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2184
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2185<p>Because LLVM integers use a two's complement representation, this
2186instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2188<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2189<pre>
2190 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2191 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2192</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2193</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2194
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2195<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2196<div class="doc_subsubsection">
2197 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2198</div>
2199
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2200<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2201
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2202<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2203<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]2204</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2205<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2206<p>The '<tt>mul</tt>' instruction returns the product of its two
2207operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2209<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2210
2211<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2212href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2213or <a href="#t_vector">vector</a> values. Both arguments must have identical
2214types.</p>
2215
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2216<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2217
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2218<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2219two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2220
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2221<p>If the result of an integer multiplication has unsigned overflow,
2222the result returned is the mathematical result modulo
22232<sup>n</sup>, where n is the bit width of the result.</p>
2224<p>Because LLVM integers use a two's complement representation, and the
2225result is the same width as the operands, this instruction returns the
2226correct result for both signed and unsigned integers. If a full product
2227(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2228should be sign-extended or zero-extended as appropriate to the
2229width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2230<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2231<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]2232</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2233</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2235<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2236<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2237</a></div>
2238<div class="doc_text">
2239<h5>Syntax:</h5>
2240<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2241</pre>
2242<h5>Overview:</h5>
2243<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2244operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2245
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2246<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2247
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2248<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2249<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2250values. Both arguments must have identical types.</p>
2251
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2252<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2253
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2254<p>The value produced is the unsigned integer quotient of the two operands.</p>
2255<p>Note that unsigned integer division and signed integer division are distinct
2256operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2257<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2258<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2259<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]2260</pre>
2261</div>
2262<!-- _______________________________________________________________________ -->
2263<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2264</a> </div>
2265<div class="doc_text">
2266<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2267<pre>
2268 &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]2269</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2270
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2271<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2272
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2273<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2274operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2275
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2276<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2277
2278<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2279<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2280values. Both arguments must have identical types.</p>
2281
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2282<h5>Semantics:</h5>
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2283<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]2284<p>Note that signed integer division and unsigned integer division are distinct
2285operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2286<p>Division by zero leads to undefined behavior. Overflow also leads to
2287undefined behavior; this is a rare case, but can occur, for example,
2288by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2289<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2290<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]2291</pre>
2292</div>
2293<!-- _______________________________________________________________________ -->
2294<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2295Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2296<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2297<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2298<pre>
2299 &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]2300</pre>
2301<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2302
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2303<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2304operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2305
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2306<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2307
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2308<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2309<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2310of floating point values. Both arguments must have identical types.</p>
2311
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2312<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2313
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2314<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2315
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2316<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2317
2318<pre>
2319 &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]2320</pre>
2321</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2322
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2323<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2324<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2325</div>
2326<div class="doc_text">
2327<h5>Syntax:</h5>
2328<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2329</pre>
2330<h5>Overview:</h5>
2331<p>The '<tt>urem</tt>' instruction returns the remainder from the
2332unsigned division of its two arguments.</p>
2333<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2334<p>The two arguments to the '<tt>urem</tt>' instruction must be
2335<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2336values. Both arguments must have identical types.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2337<h5>Semantics:</h5>
2338<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2339This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2340<p>Note that unsigned integer remainder and signed integer remainder are
2341distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2342<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2343<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2344<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]2345</pre>
2346
2347</div>
2348<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2349<div class="doc_subsubsection">
2350 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2351</div>
2352
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2353<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2354
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2355<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2356
2357<pre>
2358 &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]2359</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2360
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2361<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2362
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2363<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2364signed division of its two operands. This instruction can also take
2365<a href="#t_vector">vector</a> versions of the values in which case
2366the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2367
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2368<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2369
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2370<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2371<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2372values. Both arguments must have identical types.</p>
2373
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2374<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2375
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2376<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2377has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2378operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2379a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2380 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2381Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2382please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2383Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2384<p>Note that signed integer remainder and unsigned integer remainder are
2385distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2386<p>Taking the remainder of a division by zero leads to undefined behavior.
2387Overflow also leads to undefined behavior; this is a rare case, but can occur,
2388for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2389(The remainder doesn't actually overflow, but this rule lets srem be
2390implemented using instructions that return both the result of the division
2391and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2392<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2393<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]2394</pre>
2395
2396</div>
2397<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2398<div class="doc_subsubsection">
2399 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2400
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2401<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2402
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2403<h5>Syntax:</h5>
2404<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2405</pre>
2406<h5>Overview:</h5>
2407<p>The '<tt>frem</tt>' instruction returns the remainder from the
2408division of its two operands.</p>
2409<h5>Arguments:</h5>
2410<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2411<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2412of floating point values. Both arguments must have identical types.</p>
2413
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2414<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2415
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2416<p>This instruction returns the <i>remainder</i> of a division.
2417The remainder has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2418
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2419<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2420
2421<pre>
2422 &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]2423</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2424</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2425
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2426<!-- ======================================================================= -->
2427<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2428Operations</a> </div>
2429<div class="doc_text">
2430<p>Bitwise binary operators are used to do various forms of
2431bit-twiddling in a program. They are generally very efficient
2432instructions and can commonly be strength reduced from other
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2433instructions. They require two operands of the same type, execute an operation on them,
2434and 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]2435</div>
2436
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2437<!-- _______________________________________________________________________ -->
2438<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2439Instruction</a> </div>
2440<div class="doc_text">
2441<h5>Syntax:</h5>
2442<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2443</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2444
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2445<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2446
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2447<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2448the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2449
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2450<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2451
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2452<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2453 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2454unsigned value. This instruction does not support
2455<a href="#t_vector">vector</a> operands.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2456
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2457<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2458
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2459<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2460where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2461equal 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]2462
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2463<h5>Example:</h5><pre>
2464 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2465 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2466 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2467 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2468</pre>
2469</div>
2470<!-- _______________________________________________________________________ -->
2471<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2472Instruction</a> </div>
2473<div class="doc_text">
2474<h5>Syntax:</h5>
2475<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2476</pre>
2477
2478<h5>Overview:</h5>
2479<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2480operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2481
2482<h5>Arguments:</h5>
2483<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2484<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2485unsigned value. This instruction does not support
2486<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2487
2488<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2489
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2490<p>This instruction always performs a logical shift right operation. The most
2491significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2492shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2493the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2494
2495<h5>Example:</h5>
2496<pre>
2497 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2498 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2499 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2500 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2501 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2502</pre>
2503</div>
2504
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2505<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2506<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2507Instruction</a> </div>
2508<div class="doc_text">
2509
2510<h5>Syntax:</h5>
2511<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2512</pre>
2513
2514<h5>Overview:</h5>
2515<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2516operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2517
2518<h5>Arguments:</h5>
2519<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2520<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2521unsigned value. This instruction does not support
2522<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2523
2524<h5>Semantics:</h5>
2525<p>This instruction always performs an arithmetic shift right operation,
2526The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2527of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2528larger than the number of bits in <tt>var1</tt>, the result is undefined.
2529</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2530
2531<h5>Example:</h5>
2532<pre>
2533 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2534 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2535 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2536 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2537 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2538</pre>
2539</div>
2540
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2541<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2542<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2543Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2544
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2545<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2546
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2547<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2548
2549<pre>
2550 &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]2551</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2552
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2553<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2554
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2555<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2556its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2557
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2559
2560<p>The two arguments to the '<tt>and</tt>' instruction must be
2561<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2562values. Both arguments must have identical types.</p>
2563
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2564<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2565<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2566<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2567<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2568<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2569 <tbody>
2570 <tr>
2571 <td>In0</td>
2572 <td>In1</td>
2573 <td>Out</td>
2574 </tr>
2575 <tr>
2576 <td>0</td>
2577 <td>0</td>
2578 <td>0</td>
2579 </tr>
2580 <tr>
2581 <td>0</td>
2582 <td>1</td>
2583 <td>0</td>
2584 </tr>
2585 <tr>
2586 <td>1</td>
2587 <td>0</td>
2588 <td>0</td>
2589 </tr>
2590 <tr>
2591 <td>1</td>
2592 <td>1</td>
2593 <td>1</td>
2594 </tr>
2595 </tbody>
2596</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2597</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2598<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2599<pre>
2600 &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]2601 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2602 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2603</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2604</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2605<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2606<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2607<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2608<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2609<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]2610</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2611<h5>Overview:</h5>
2612<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2613or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2614<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2615
2616<p>The two arguments to the '<tt>or</tt>' instruction must be
2617<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2618values. Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2619<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2620<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2621<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2622<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2623<table border="1" cellspacing="0" cellpadding="4">
2624 <tbody>
2625 <tr>
2626 <td>In0</td>
2627 <td>In1</td>
2628 <td>Out</td>
2629 </tr>
2630 <tr>
2631 <td>0</td>
2632 <td>0</td>
2633 <td>0</td>
2634 </tr>
2635 <tr>
2636 <td>0</td>
2637 <td>1</td>
2638 <td>1</td>
2639 </tr>
2640 <tr>
2641 <td>1</td>
2642 <td>0</td>
2643 <td>1</td>
2644 </tr>
2645 <tr>
2646 <td>1</td>
2647 <td>1</td>
2648 <td>1</td>
2649 </tr>
2650 </tbody>
2651</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2652</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2654<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2655 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2656 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2657</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2658</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2659<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2660<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2661Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2662<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2663<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2664<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]2665</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2666<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2667<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2668or of its two operands. The <tt>xor</tt> is used to implement the
2669"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2670<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2671<p>The two arguments to the '<tt>xor</tt>' instruction must be
2672<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2673values. Both arguments must have identical types.</p>
2674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2675<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2677<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2678<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2679<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2680<table border="1" cellspacing="0" cellpadding="4">
2681 <tbody>
2682 <tr>
2683 <td>In0</td>
2684 <td>In1</td>
2685 <td>Out</td>
2686 </tr>
2687 <tr>
2688 <td>0</td>
2689 <td>0</td>
2690 <td>0</td>
2691 </tr>
2692 <tr>
2693 <td>0</td>
2694 <td>1</td>
2695 <td>1</td>
2696 </tr>
2697 <tr>
2698 <td>1</td>
2699 <td>0</td>
2700 <td>1</td>
2701 </tr>
2702 <tr>
2703 <td>1</td>
2704 <td>1</td>
2705 <td>0</td>
2706 </tr>
2707 </tbody>
2708</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2709</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2710<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2711<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2712<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2713 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2714 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2715 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2716</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2717</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2718
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2719<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2720<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2721 <a name="vectorops">Vector Operations</a>
2722</div>
2723
2724<div class="doc_text">
2725
2726<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2727target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2728vector-specific operations needed to process vectors effectively. While LLVM
2729does directly support these vector operations, many sophisticated algorithms
2730will want to use target-specific intrinsics to take full advantage of a specific
2731target.</p>
2732
2733</div>
2734
2735<!-- _______________________________________________________________________ -->
2736<div class="doc_subsubsection">
2737 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2738</div>
2739
2740<div class="doc_text">
2741
2742<h5>Syntax:</h5>
2743
2744<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2745 &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]2746</pre>
2747
2748<h5>Overview:</h5>
2749
2750<p>
2751The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2752element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2753</p>
2754
2755
2756<h5>Arguments:</h5>
2757
2758<p>
2759The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2760value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2761an index indicating the position from which to extract the element.
2762The index may be a variable.</p>
2763
2764<h5>Semantics:</h5>
2765
2766<p>
2767The result is a scalar of the same type as the element type of
2768<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2769<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2770results are undefined.
2771</p>
2772
2773<h5>Example:</h5>
2774
2775<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2776 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2777</pre>
2778</div>
2779
2780
2781<!-- _______________________________________________________________________ -->
2782<div class="doc_subsubsection">
2783 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2784</div>
2785
2786<div class="doc_text">
2787
2788<h5>Syntax:</h5>
2789
2790<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]2791 &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]2792</pre>
2793
2794<h5>Overview:</h5>
2795
2796<p>
2797The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2798element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2799</p>
2800
2801
2802<h5>Arguments:</h5>
2803
2804<p>
2805The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2806value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2807scalar value whose type must equal the element type of the first
2808operand. The third operand is an index indicating the position at
2809which to insert the value. The index may be a variable.</p>
2810
2811<h5>Semantics:</h5>
2812
2813<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2814The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2815element values are those of <tt>val</tt> except at position
2816<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2817exceeds the length of <tt>val</tt>, the results are undefined.
2818</p>
2819
2820<h5>Example:</h5>
2821
2822<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2823 %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]2824</pre>
2825</div>
2826
2827<!-- _______________________________________________________________________ -->
2828<div class="doc_subsubsection">
2829 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2830</div>
2831
2832<div class="doc_text">
2833
2834<h5>Syntax:</h5>
2835
2836<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2837 &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]2838</pre>
2839
2840<h5>Overview:</h5>
2841
2842<p>
2843The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2844from two input vectors, returning a vector of the same type.
2845</p>
2846
2847<h5>Arguments:</h5>
2848
2849<p>
2850The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2851with types that match each other and types that match the result of the
2852instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2853of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2854</p>
2855
2856<p>
2857The shuffle mask operand is required to be a constant vector with either
2858constant integer or undef values.
2859</p>
2860
2861<h5>Semantics:</h5>
2862
2863<p>
2864The elements of the two input vectors are numbered from left to right across
2865both of the vectors. The shuffle mask operand specifies, for each element of
2866the result vector, which element of the two input registers the result element
2867gets. The element selector may be undef (meaning "don't care") and the second
2868operand may be undef if performing a shuffle from only one vector.
2869</p>
2870
2871<h5>Example:</h5>
2872
2873<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2874 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2875 &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]2876 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2877 &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]2878</pre>
2879</div>
2880
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2881
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2882<!-- ======================================================================= -->
2883<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2884 <a name="aggregateops">Aggregate Operations</a>
2885</div>
2886
2887<div class="doc_text">
2888
2889<p>LLVM supports several instructions for working with aggregate values.
2890</p>
2891
2892</div>
2893
2894<!-- _______________________________________________________________________ -->
2895<div class="doc_subsubsection">
2896 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2897</div>
2898
2899<div class="doc_text">
2900
2901<h5>Syntax:</h5>
2902
2903<pre>
2904 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2905</pre>
2906
2907<h5>Overview:</h5>
2908
2909<p>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2910The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2911or array element from an aggregate value.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2912</p>
2913
2914
2915<h5>Arguments:</h5>
2916
2917<p>
2918The first operand of an '<tt>extractvalue</tt>' instruction is a
2919value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2920type. The operands are constant indices to specify which value to extract
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]2921in a similar manner as indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2922'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2923</p>
2924
2925<h5>Semantics:</h5>
2926
2927<p>
2928The result is the value at the position in the aggregate specified by
2929the index operands.
2930</p>
2931
2932<h5>Example:</h5>
2933
2934<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]2935 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2936</pre>
2937</div>
2938
2939
2940<!-- _______________________________________________________________________ -->
2941<div class="doc_subsubsection">
2942 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2943</div>
2944
2945<div class="doc_text">
2946
2947<h5>Syntax:</h5>
2948
2949<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]2950 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2951</pre>
2952
2953<h5>Overview:</h5>
2954
2955<p>
2956The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2957into a struct field or array element in an aggregate.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2958</p>
2959
2960
2961<h5>Arguments:</h5>
2962
2963<p>
2964The first operand of an '<tt>insertvalue</tt>' instruction is a
2965value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2966The second operand is a first-class value to insert.
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame]2967The following operands are constant indices
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]2968indicating the position at which to insert the value in a similar manner as
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2969indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2970'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2971The value to insert must have the same type as the value identified
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2972by the indices.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2973
2974<h5>Semantics:</h5>
2975
2976<p>
2977The result is an aggregate of the same type as <tt>val</tt>. Its
2978value is that of <tt>val</tt> except that the value at the position
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2979specified by the indices is that of <tt>elt</tt>.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2980</p>
2981
2982<h5>Example:</h5>
2983
2984<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]2985 %result = insertvalue {i32, float} %agg, 1, 0 <i>; yields {i32, float}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2986</pre>
2987</div>
2988
2989
2990<!-- ======================================================================= -->
2991<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2992 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2993</div>
2994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2995<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2996
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2997<p>A key design point of an SSA-based representation is how it
2998represents memory. In LLVM, no memory locations are in SSA form, which
2999makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3000allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3001
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3002</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3003
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3004<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3005<div class="doc_subsubsection">
3006 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3007</div>
3008
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3009<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3010
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3011<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3012
3013<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3014 &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]3015</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3017<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3018
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3019<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3020heap and returns a pointer to it. The object is always allocated in the generic
3021address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3022
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3023<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3024
3025<p>The '<tt>malloc</tt>' instruction allocates
3026<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]3027bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3028appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3029number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3030If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3031be aligned to at least that boundary. If not specified, or if zero, the target can
3032choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3033
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3034<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3035
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3036<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3037
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3038<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3039a pointer is returned. The result of a zero byte allocattion is undefined. The
3040result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3041
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3042<h5>Example:</h5>
3043
3044<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3045 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3046
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3047 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3048 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3049 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3050 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3051 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3052</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3053</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3054
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3055<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3056<div class="doc_subsubsection">
3057 <a name="i_free">'<tt>free</tt>' Instruction</a>
3058</div>
3059
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3060<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3061
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3062<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3063
3064<pre>
3065 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3066</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3067
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3068<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3069
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3070<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3071memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3073<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3074
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3075<p>'<tt>value</tt>' shall be a pointer value that points to a value
3076that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3077instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3078
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3079<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3080
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3081<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner0f103e12008-04-19 22:41:32 +0000[diff] [blame]3082after this instruction executes. If the pointer is null, the operation
3083is a noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3086
3087<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3088 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3089 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3090</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3091</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3092
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3093<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3094<div class="doc_subsubsection">
3095 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3096</div>
3097
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3098<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3099
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3100<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3101
3102<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3103 &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]3104</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3105
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3107
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3108<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3109currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3110returns to its caller. The object is always allocated in the generic address
3111space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3112
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3113<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3114
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3115<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3116bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3117appropriate type to the program. If "NumElements" is specified, it is the
3118number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3119If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3120to be aligned to at least that boundary. If not specified, or if zero, the target
3121can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3122
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3123<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3125<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3126
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3127<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3128there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3129memory is automatically released when the function returns. The '<tt>alloca</tt>'
3130instruction is commonly used to represent automatic variables that must
3131have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]3132 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]3133instructions), the memory is reclaimed. Allocating zero bytes
3134is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3135
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3136<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3137
3138<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3139 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3140 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3141 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3142 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3143</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3144</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3145
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3146<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3147<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3148Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3149<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3150<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3151<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]3152<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3153<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3154<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3155<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3156address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]3157 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3158marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3159the number or order of execution of this <tt>load</tt> with other
3160volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3161instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3162<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3163The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3164(that is, the alignment of the memory address). A value of 0 or an
3165omitted "align" argument means that the operation has the preferential
3166alignment for the target. It is the responsibility of the code emitter
3167to ensure that the alignment information is correct. Overestimating
3168the alignment results in an undefined behavior. Underestimating the
3169alignment may produce less efficient code. An alignment of 1 is always
3170safe.
3171</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3172<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3173<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3174<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3175<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3176 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3177 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3178 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3179</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3180</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3181<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3182<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3183Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]3184<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3185<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3186<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3187 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]3188</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3189<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3190<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3191<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3192<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3193to 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]3194operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3195of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3196operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3197optimizer is not allowed to modify the number or order of execution of
3198this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3199 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3200<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3201The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3202(that is, the alignment of the memory address). A value of 0 or an
3203omitted "align" argument means that the operation has the preferential
3204alignment for the target. It is the responsibility of the code emitter
3205to ensure that the alignment information is correct. Overestimating
3206the alignment results in an undefined behavior. Underestimating the
3207alignment may produce less efficient code. An alignment of 1 is always
3208safe.
3209</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3210<h5>Semantics:</h5>
3211<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3212at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3213<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3214<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]3215 store i32 3, i32* %ptr <i>; yields {void}</i>
3216 %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]3217</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3218</div>
3219
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3220<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3221<div class="doc_subsubsection">
3222 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3223</div>
3224
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3225<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3226<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3227<pre>
3228 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3229</pre>
3230
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3231<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3232
3233<p>
3234The '<tt>getelementptr</tt>' instruction is used to get the address of a
3235subelement of an aggregate data structure.</p>
3236
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3237<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3238
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3239<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3240elements of the aggregate object to index to. The actual types of the arguments
3241provided depend on the type of the first pointer argument. The
3242'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3243levels 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]3244structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3245into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3246values will be sign extended to 64-bits if required.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3247
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3248<p>For example, let's consider a C code fragment and how it gets
3249compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3250
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3251<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3252<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3253struct RT {
3254 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3255 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3256 char C;
3257};
3258struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3259 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3260 double Y;
3261 struct RT Z;
3262};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3263
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3264int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3265 return &amp;s[1].Z.B[5][13];
3266}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3267</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3268</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3269
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3270<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3271
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3272<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3273<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3274%RT = type { i8 , [10 x [20 x i32]], i8 }
3275%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3276
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3277define i32* %foo(%ST* %s) {
3278entry:
3279 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3280 ret i32* %reg
3281}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3282</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3283</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3284
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3285<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3286
3287<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3288on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3289and <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]3290<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]3291to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3292structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3293
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3294<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]3295type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3296}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3297the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3298i8 }</tt>' type, another structure. The third index indexes into the second
3299element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3300array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3301'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3302to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3303
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3304<p>Note that it is perfectly legal to index partially through a
3305structure, returning a pointer to an inner element. Because of this,
3306the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3307
3308<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3309 define i32* %foo(%ST* %s) {
3310 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3311 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3312 %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]3313 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3314 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3315 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3316 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3317</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3318
3319<p>Note that it is undefined to access an array out of bounds: array and
3320pointer indexes must always be within the defined bounds of the array type.
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3321The one exception for this rule is zero length arrays. These arrays are
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3322defined to be accessible as variable length arrays, which requires access
3323beyond the zero'th element.</p>
3324
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3325<p>The getelementptr instruction is often confusing. For some more insight
3326into how it works, see <a href="GetElementPtr.html">the getelementptr
3327FAQ</a>.</p>
3328
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3329<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3330
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3331<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3332 <i>; yields [12 x i8]*:aptr</i>
3333 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3334</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3335</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3336
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3337<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3338<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3339</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3340<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3341<p>The instructions in this category are the conversion instructions (casting)
3342which all take a single operand and a type. They perform various bit conversions
3343on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3344</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3345
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3346<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3347<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3348 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3349</div>
3350<div class="doc_text">
3351
3352<h5>Syntax:</h5>
3353<pre>
3354 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3355</pre>
3356
3357<h5>Overview:</h5>
3358<p>
3359The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3360</p>
3361
3362<h5>Arguments:</h5>
3363<p>
3364The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3365be 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]3366and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3367type. The bit size of <tt>value</tt> must be larger than the bit size of
3368<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3369
3370<h5>Semantics:</h5>
3371<p>
3372The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3373and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3374larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3375It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3376
3377<h5>Example:</h5>
3378<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3379 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3380 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3381 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3382</pre>
3383</div>
3384
3385<!-- _______________________________________________________________________ -->
3386<div class="doc_subsubsection">
3387 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3388</div>
3389<div class="doc_text">
3390
3391<h5>Syntax:</h5>
3392<pre>
3393 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3394</pre>
3395
3396<h5>Overview:</h5>
3397<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3398<tt>ty2</tt>.</p>
3399
3400
3401<h5>Arguments:</h5>
3402<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]3403<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3404also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3405<tt>value</tt> must be smaller than the bit size of the destination type,
3406<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3407
3408<h5>Semantics:</h5>
3409<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]3410bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3411
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3412<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]3413
3414<h5>Example:</h5>
3415<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3416 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3417 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection">
3423 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3424</div>
3425<div class="doc_text">
3426
3427<h5>Syntax:</h5>
3428<pre>
3429 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3430</pre>
3431
3432<h5>Overview:</h5>
3433<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3434
3435<h5>Arguments:</h5>
3436<p>
3437The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3438<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3439also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3440<tt>value</tt> must be smaller than the bit size of the destination type,
3441<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3442
3443<h5>Semantics:</h5>
3444<p>
3445The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3446bit (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]3447the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3448
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3449<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]3450
3451<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3452<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3453 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3454 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3455</pre>
3456</div>
3457
3458<!-- _______________________________________________________________________ -->
3459<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3460 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3461</div>
3462
3463<div class="doc_text">
3464
3465<h5>Syntax:</h5>
3466
3467<pre>
3468 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3469</pre>
3470
3471<h5>Overview:</h5>
3472<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3473<tt>ty2</tt>.</p>
3474
3475
3476<h5>Arguments:</h5>
3477<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3478 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3479cast it to. The size of <tt>value</tt> must be larger than the size of
3480<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3481<i>no-op cast</i>.</p>
3482
3483<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3484<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3485<a href="#t_floating">floating point</a> type to a smaller
3486<a href="#t_floating">floating point</a> type. If the value cannot fit within
3487the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3488
3489<h5>Example:</h5>
3490<pre>
3491 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3492 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3493</pre>
3494</div>
3495
3496<!-- _______________________________________________________________________ -->
3497<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3498 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3499</div>
3500<div class="doc_text">
3501
3502<h5>Syntax:</h5>
3503<pre>
3504 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3505</pre>
3506
3507<h5>Overview:</h5>
3508<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3509floating point value.</p>
3510
3511<h5>Arguments:</h5>
3512<p>The '<tt>fpext</tt>' instruction takes a
3513<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3514and a <a href="#t_floating">floating point</a> type to cast it to. The source
3515type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3516
3517<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3518<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3519<a href="#t_floating">floating point</a> type to a larger
3520<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3521used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3522<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]3523
3524<h5>Example:</h5>
3525<pre>
3526 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3527 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3528</pre>
3529</div>
3530
3531<!-- _______________________________________________________________________ -->
3532<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3533 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3534</div>
3535<div class="doc_text">
3536
3537<h5>Syntax:</h5>
3538<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3539 &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]3540</pre>
3541
3542<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3543<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3544unsigned integer equivalent of type <tt>ty2</tt>.
3545</p>
3546
3547<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3548<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]3549scalar or vector <a href="#t_floating">floating point</a> value, and a type
3550to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3551type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3552vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3553
3554<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3555<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3556<a href="#t_floating">floating point</a> operand into the nearest (rounding
3557towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3558the results are undefined.</p>
3559
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3560<h5>Example:</h5>
3561<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3562 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3563 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3564 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3565</pre>
3566</div>
3567
3568<!-- _______________________________________________________________________ -->
3569<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3570 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3571</div>
3572<div class="doc_text">
3573
3574<h5>Syntax:</h5>
3575<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3576 &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]3577</pre>
3578
3579<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3580<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3581<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]3582</p>
3583
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3584<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3585<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]3586scalar or vector <a href="#t_floating">floating point</a> value, and a type
3587to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3588type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3589vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3590
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3591<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3592<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3593<a href="#t_floating">floating point</a> operand into the nearest (rounding
3594towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3595the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3596
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3597<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3598<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3599 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3600 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3601 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3602</pre>
3603</div>
3604
3605<!-- _______________________________________________________________________ -->
3606<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3607 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3608</div>
3609<div class="doc_text">
3610
3611<h5>Syntax:</h5>
3612<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3613 &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]3614</pre>
3615
3616<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3617<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3618integer and converts that value to the <tt>ty2</tt> type.</p>
3619
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3620<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3621<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3622scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3623to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3624type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3625floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3626
3627<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3628<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3629integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3630the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3631
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3632<h5>Example:</h5>
3633<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3634 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3635 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3636</pre>
3637</div>
3638
3639<!-- _______________________________________________________________________ -->
3640<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3641 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3642</div>
3643<div class="doc_text">
3644
3645<h5>Syntax:</h5>
3646<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3647 &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]3648</pre>
3649
3650<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3651<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3652integer and converts that value to the <tt>ty2</tt> type.</p>
3653
3654<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3655<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3656scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3657to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3658type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3659floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3660
3661<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3662<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3663integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3664the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3665
3666<h5>Example:</h5>
3667<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3668 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3669 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3670</pre>
3671</div>
3672
3673<!-- _______________________________________________________________________ -->
3674<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3675 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3676</div>
3677<div class="doc_text">
3678
3679<h5>Syntax:</h5>
3680<pre>
3681 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3682</pre>
3683
3684<h5>Overview:</h5>
3685<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3686the integer type <tt>ty2</tt>.</p>
3687
3688<h5>Arguments:</h5>
3689<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3690must 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]3691<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3692
3693<h5>Semantics:</h5>
3694<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3695<tt>ty2</tt> by interpreting the pointer value as an integer and either
3696truncating or zero extending that value to the size of the integer type. If
3697<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3698<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]3699are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3700change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3701
3702<h5>Example:</h5>
3703<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3704 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3705 %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]3706</pre>
3707</div>
3708
3709<!-- _______________________________________________________________________ -->
3710<div class="doc_subsubsection">
3711 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3712</div>
3713<div class="doc_text">
3714
3715<h5>Syntax:</h5>
3716<pre>
3717 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3718</pre>
3719
3720<h5>Overview:</h5>
3721<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3722a pointer type, <tt>ty2</tt>.</p>
3723
3724<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3725<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3726value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3727<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3728
3729<h5>Semantics:</h5>
3730<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3731<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3732the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3733size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3734the size of a pointer then a zero extension is done. If they are the same size,
3735nothing is done (<i>no-op cast</i>).</p>
3736
3737<h5>Example:</h5>
3738<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3739 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3740 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3741 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3742</pre>
3743</div>
3744
3745<!-- _______________________________________________________________________ -->
3746<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3747 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3748</div>
3749<div class="doc_text">
3750
3751<h5>Syntax:</h5>
3752<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3753 &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]3754</pre>
3755
3756<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3757
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3758<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3759<tt>ty2</tt> without changing any bits.</p>
3760
3761<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3762
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3763<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3764a first class value, and a type to cast it to, which must also be a <a
3765 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3766and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3767type is a pointer, the destination type must also be a pointer. This
3768instruction supports bitwise conversion of vectors to integers and to vectors
3769of other types (as long as they have the same size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3770
3771<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3772<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3773<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3774this conversion. The conversion is done as if the <tt>value</tt> had been
3775stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3776converted to other pointer types with this instruction. To convert pointers to
3777other types, use the <a href="#i_inttoptr">inttoptr</a> or
3778<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3779
3780<h5>Example:</h5>
3781<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3782 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3783 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3784 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3785</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3786</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3787
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3788<!-- ======================================================================= -->
3789<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3790<div class="doc_text">
3791<p>The instructions in this category are the "miscellaneous"
3792instructions, which defy better classification.</p>
3793</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3794
3795<!-- _______________________________________________________________________ -->
3796<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3797</div>
3798<div class="doc_text">
3799<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3800<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]3801</pre>
3802<h5>Overview:</h5>
3803<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3804of its two integer or pointer operands.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3805<h5>Arguments:</h5>
3806<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3807the condition code indicating the kind of comparison to perform. It is not
3808a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3809<ol>
3810 <li><tt>eq</tt>: equal</li>
3811 <li><tt>ne</tt>: not equal </li>
3812 <li><tt>ugt</tt>: unsigned greater than</li>
3813 <li><tt>uge</tt>: unsigned greater or equal</li>
3814 <li><tt>ult</tt>: unsigned less than</li>
3815 <li><tt>ule</tt>: unsigned less or equal</li>
3816 <li><tt>sgt</tt>: signed greater than</li>
3817 <li><tt>sge</tt>: signed greater or equal</li>
3818 <li><tt>slt</tt>: signed less than</li>
3819 <li><tt>sle</tt>: signed less or equal</li>
3820</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3821<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3822<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3823<h5>Semantics:</h5>
3824<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3825the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3826yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3827<ol>
3828 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3829 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3830 </li>
3831 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3832 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3833 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3834 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3835 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3836 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3837 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3838 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3839 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3840 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3841 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3842 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3843 <li><tt>sge</tt>: interprets the operands as signed values and yields
3844 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3845 <li><tt>slt</tt>: interprets the operands as signed values and yields
3846 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3847 <li><tt>sle</tt>: interprets the operands as signed values and yields
3848 <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]3849</ol>
3850<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3851values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3852
3853<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3854<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3855 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3856 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3857 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3858 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3859 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3860</pre>
3861</div>
3862
3863<!-- _______________________________________________________________________ -->
3864<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3865</div>
3866<div class="doc_text">
3867<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3868<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]3869</pre>
3870<h5>Overview:</h5>
3871<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3872of its floating point operands.</p>
3873<h5>Arguments:</h5>
3874<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3875the condition code indicating the kind of comparison to perform. It is not
3876a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3877<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3878 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3879 <li><tt>oeq</tt>: ordered and equal</li>
3880 <li><tt>ogt</tt>: ordered and greater than </li>
3881 <li><tt>oge</tt>: ordered and greater than or equal</li>
3882 <li><tt>olt</tt>: ordered and less than </li>
3883 <li><tt>ole</tt>: ordered and less than or equal</li>
3884 <li><tt>one</tt>: ordered and not equal</li>
3885 <li><tt>ord</tt>: ordered (no nans)</li>
3886 <li><tt>ueq</tt>: unordered or equal</li>
3887 <li><tt>ugt</tt>: unordered or greater than </li>
3888 <li><tt>uge</tt>: unordered or greater than or equal</li>
3889 <li><tt>ult</tt>: unordered or less than </li>
3890 <li><tt>ule</tt>: unordered or less than or equal</li>
3891 <li><tt>une</tt>: unordered or not equal</li>
3892 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3893 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3894</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3895<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3896<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3897<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3898<a href="#t_floating">floating point</a> typed. They must have identical
3899types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3900<h5>Semantics:</h5>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3901<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3902according to the condition code given as <tt>cond</tt>. The comparison performed
3903always yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3904<ol>
3905 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3906 <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]3907 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3908 <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]3909 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3910 <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]3911 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3912 <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]3913 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3914 <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]3915 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3916 <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]3917 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3918 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3919 <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]3920 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3921 <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]3922 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3923 <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]3924 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3925 <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]3926 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3927 <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]3928 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3929 <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]3930 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3931 <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]3932 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3933</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3934
3935<h5>Example:</h5>
3936<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3937 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3938 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3939 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3940</pre>
3941</div>
3942
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3943<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3944<div class="doc_subsubsection">
3945 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3946</div>
3947<div class="doc_text">
3948<h5>Syntax:</h5>
3949<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3950</pre>
3951<h5>Overview:</h5>
3952<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3953element-wise comparison of its two integer vector operands.</p>
3954<h5>Arguments:</h5>
3955<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3956the condition code indicating the kind of comparison to perform. It is not
3957a value, just a keyword. The possible condition code are:
3958<ol>
3959 <li><tt>eq</tt>: equal</li>
3960 <li><tt>ne</tt>: not equal </li>
3961 <li><tt>ugt</tt>: unsigned greater than</li>
3962 <li><tt>uge</tt>: unsigned greater or equal</li>
3963 <li><tt>ult</tt>: unsigned less than</li>
3964 <li><tt>ule</tt>: unsigned less or equal</li>
3965 <li><tt>sgt</tt>: signed greater than</li>
3966 <li><tt>sge</tt>: signed greater or equal</li>
3967 <li><tt>slt</tt>: signed less than</li>
3968 <li><tt>sle</tt>: signed less or equal</li>
3969</ol>
3970<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3971<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3972<h5>Semantics:</h5>
3973<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3974according to the condition code given as <tt>cond</tt>. The comparison yields a
3975<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3976identical type as the values being compared. The most significant bit in each
3977element is 1 if the element-wise comparison evaluates to true, and is 0
3978otherwise. All other bits of the result are undefined. The condition codes
3979are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3980instruction</a>.
3981
3982<h5>Example:</h5>
3983<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3984 &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>
3985 &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]3986</pre>
3987</div>
3988
3989<!-- _______________________________________________________________________ -->
3990<div class="doc_subsubsection">
3991 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
3992</div>
3993<div class="doc_text">
3994<h5>Syntax:</h5>
3995<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
3996<h5>Overview:</h5>
3997<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
3998element-wise comparison of its two floating point vector operands. The output
3999elements have the same width as the input elements.</p>
4000<h5>Arguments:</h5>
4001<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4002the condition code indicating the kind of comparison to perform. It is not
4003a value, just a keyword. The possible condition code are:
4004<ol>
4005 <li><tt>false</tt>: no comparison, always returns false</li>
4006 <li><tt>oeq</tt>: ordered and equal</li>
4007 <li><tt>ogt</tt>: ordered and greater than </li>
4008 <li><tt>oge</tt>: ordered and greater than or equal</li>
4009 <li><tt>olt</tt>: ordered and less than </li>
4010 <li><tt>ole</tt>: ordered and less than or equal</li>
4011 <li><tt>one</tt>: ordered and not equal</li>
4012 <li><tt>ord</tt>: ordered (no nans)</li>
4013 <li><tt>ueq</tt>: unordered or equal</li>
4014 <li><tt>ugt</tt>: unordered or greater than </li>
4015 <li><tt>uge</tt>: unordered or greater than or equal</li>
4016 <li><tt>ult</tt>: unordered or less than </li>
4017 <li><tt>ule</tt>: unordered or less than or equal</li>
4018 <li><tt>une</tt>: unordered or not equal</li>
4019 <li><tt>uno</tt>: unordered (either nans)</li>
4020 <li><tt>true</tt>: no comparison, always returns true</li>
4021</ol>
4022<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4023<a href="#t_floating">floating point</a> typed. They must also be identical
4024types.</p>
4025<h5>Semantics:</h5>
4026<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4027according to the condition code given as <tt>cond</tt>. The comparison yields a
4028<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4029an identical number of elements as the values being compared, and each element
4030having identical with to the width of the floating point elements. The most
4031significant bit in each element is 1 if the element-wise comparison evaluates to
4032true, and is 0 otherwise. All other bits of the result are undefined. The
4033condition codes are evaluated identically to the
4034<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4035
4036<h5>Example:</h5>
4037<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4038 &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>
4039 &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]4040</pre>
4041</div>
4042
4043<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4044<div class="doc_subsubsection">
4045 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4046</div>
4047
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4048<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4049
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4050<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4051
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4052<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4053<h5>Overview:</h5>
4054<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4055the SSA graph representing the function.</p>
4056<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4057
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4058<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4059field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4060as arguments, with one pair for each predecessor basic block of the
4061current block. Only values of <a href="#t_firstclass">first class</a>
4062type may be used as the value arguments to the PHI node. Only labels
4063may be used as the label arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4064
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4065<p>There must be no non-phi instructions between the start of a basic
4066block and the PHI instructions: i.e. PHI instructions must be first in
4067a basic block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4068
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4069<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4070
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4071<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4072specified by the pair corresponding to the predecessor basic block that executed
4073just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4074
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4075<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4076<pre>
4077Loop: ; Infinite loop that counts from 0 on up...
4078 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4079 %nextindvar = add i32 %indvar, 1
4080 br label %Loop
4081</pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4082</div>
4083
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4084<!-- _______________________________________________________________________ -->
4085<div class="doc_subsubsection">
4086 <a name="i_select">'<tt>select</tt>' Instruction</a>
4087</div>
4088
4089<div class="doc_text">
4090
4091<h5>Syntax:</h5>
4092
4093<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4094 &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]4095</pre>
4096
4097<h5>Overview:</h5>
4098
4099<p>
4100The '<tt>select</tt>' instruction is used to choose one value based on a
4101condition, without branching.
4102</p>
4103
4104
4105<h5>Arguments:</h5>
4106
4107<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4108The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4109condition, and two values of the same <a href="#t_firstclass">first class</a>
4110type. If the val1/val2 are vectors, the entire vectors are selected, not
4111individual elements.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4112</p>
4113
4114<h5>Semantics:</h5>
4115
4116<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4117If the i1 condition evaluates is 1, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4118value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4119</p>
4120
4121<h5>Example:</h5>
4122
4123<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4124 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4125</pre>
4126</div>
4127
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4128
4129<!-- _______________________________________________________________________ -->
4130<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4131 <a name="i_call">'<tt>call</tt>' Instruction</a>
4132</div>
4133
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4134<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4135
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4136<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4137<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4138 &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]4139</pre>
4140
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4141<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4142
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4143<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4144
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4145<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4146
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4147<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4148
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4149<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4150 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4151 <p>The optional "tail" marker indicates whether the callee function accesses
4152 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4153 function call is eligible for tail call optimization. Note that calls may
4154 be marked "tail" even if they do not occur before a <a
4155 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4156 </li>
4157 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4158 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4159 convention</a> the call should use. If none is specified, the call defaults
4160 to using C calling conventions.
4161 </li>
4162 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4163 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4164 the type of the return value. Functions that return no value are marked
4165 <tt><a href="#t_void">void</a></tt>.</p>
4166 </li>
4167 <li>
4168 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4169 value being invoked. The argument types must match the types implied by
4170 this signature. This type can be omitted if the function is not varargs
4171 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4172 </li>
4173 <li>
4174 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4175 be invoked. In most cases, this is a direct function invocation, but
4176 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4177 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4178 </li>
4179 <li>
4180 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]4181 function signature argument types. All arguments must be of
4182 <a href="#t_firstclass">first class</a> type. If the function signature
4183 indicates the function accepts a variable number of arguments, the extra
4184 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4185 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4186</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4188<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4189
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4190<p>The '<tt>call</tt>' instruction is used to cause control flow to
4191transfer to a specified function, with its incoming arguments bound to
4192the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4193instruction in the called function, control flow continues with the
4194instruction after the function call, and the return value of the
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4195function is bound to the result argument. If the callee returns multiple
4196values then the return values of the function are only accessible through
4197the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4198
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4199<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4200
4201<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4202 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4203 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4204 %X = tail call i32 @foo() <i>; yields i32</i>
4205 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4206 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4207
4208 %struct.A = type { i32, i8 }
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4209 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4210 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4211 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4212</pre>
4213
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4214</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4215
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4216<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4217<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4218 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4219</div>
4220
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4221<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4222
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4223<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4224
4225<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4226 &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]4227</pre>
4228
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4229<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4230
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4231<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4232the "variable argument" area of a function call. It is used to implement the
4233<tt>va_arg</tt> macro in C.</p>
4234
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4235<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4236
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4237<p>This instruction takes a <tt>va_list*</tt> value and the type of
4238the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4239increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4240actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4241
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4242<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4243
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4244<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4245type from the specified <tt>va_list</tt> and causes the
4246<tt>va_list</tt> to point to the next argument. For more information,
4247see the variable argument handling <a href="#int_varargs">Intrinsic
4248Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4249
4250<p>It is legal for this instruction to be called in a function which does not
4251take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4252function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4253
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4254<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4255href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4256argument.</p>
4257
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4258<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4259
4260<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4262</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4263
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4264<!-- _______________________________________________________________________ -->
4265<div class="doc_subsubsection">
4266 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4267</div>
4268
4269<div class="doc_text">
4270
4271<h5>Syntax:</h5>
4272<pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4273 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4274</pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4275
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4276<h5>Overview:</h5>
4277
4278<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4279from a '<tt><a href="#i_call">call</a></tt>'
4280or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4281results.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4282
4283<h5>Arguments:</h5>
4284
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4285<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattner1a640a62008-04-23 04:06:52 +0000[diff] [blame]4286first argument, or an undef value. The value must have <a
4287href="#t_struct">structure type</a>. The second argument is a constant
4288unsigned index value which must be in range for the number of values returned
4289by the call.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4290
4291<h5>Semantics:</h5>
4292
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4293<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4294'<tt>index</tt>' from the aggregate value.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4295
4296<h5>Example:</h5>
4297
4298<pre>
4299 %struct.A = type { i32, i8 }
4300
4301 %r = call %struct.A @foo()
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4302 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4303 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4304 add i32 %gr, 42
4305 add i8 %gr1, 41
4306</pre>
4307
4308</div>
4309
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4310<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4311<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4312<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4313
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4314<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4315
4316<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4317well known names and semantics and are required to follow certain restrictions.
4318Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4319language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]4320adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4321
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4322<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4323prefix is reserved in LLVM for intrinsic names; thus, function names may not
4324begin with this prefix. Intrinsic functions must always be external functions:
4325you cannot define the body of intrinsic functions. Intrinsic functions may
4326only be used in call or invoke instructions: it is illegal to take the address
4327of an intrinsic function. Additionally, because intrinsic functions are part
4328of the LLVM language, it is required if any are added that they be documented
4329here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4330
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4331<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4332a family of functions that perform the same operation but on different data
4333types. Because LLVM can represent over 8 million different integer types,
4334overloading is used commonly to allow an intrinsic function to operate on any
4335integer type. One or more of the argument types or the result type can be
4336overloaded to accept any integer type. Argument types may also be defined as
4337exactly matching a previous argument's type or the result type. This allows an
4338intrinsic function which accepts multiple arguments, but needs all of them to
4339be of the same type, to only be overloaded with respect to a single argument or
4340the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4341
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4342<p>Overloaded intrinsics will have the names of its overloaded argument types
4343encoded into its function name, each preceded by a period. Only those types
4344which are overloaded result in a name suffix. Arguments whose type is matched
4345against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4346take an integer of any width and returns an integer of exactly the same integer
4347width. This leads to a family of functions such as
4348<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4349Only one type, the return type, is overloaded, and only one type suffix is
4350required. Because the argument's type is matched against the return type, it
4351does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4352
4353<p>To learn how to add an intrinsic function, please see the
4354<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4355</p>
4356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4357</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4358
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4359<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4360<div class="doc_subsection">
4361 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4362</div>
4363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4364<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4365
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4366<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4367 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4368intrinsic functions. These functions are related to the similarly
4369named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4370
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4371<p>All of these functions operate on arguments that use a
4372target-specific value type "<tt>va_list</tt>". The LLVM assembly
4373language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4374transformations should be prepared to handle these functions regardless of
4375the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4376
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]4377<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]4378instruction and the variable argument handling intrinsic functions are
4379used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4380
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4381<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4382<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4383define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4384 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4385 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4386 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4387 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4388
4389 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4390 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4391
4392 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4393 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4394 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4395 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4396 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4397
4398 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4399 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4400 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4401}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4402
4403declare void @llvm.va_start(i8*)
4404declare void @llvm.va_copy(i8*, i8*)
4405declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4406</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4407</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4408
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4409</div>
4410
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4411<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4412<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4413 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4414</div>
4415
4416
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4417<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4418<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4419<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4420<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4421<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4422<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4423href="#i_va_arg">va_arg</a></tt>.</p>
4424
4425<h5>Arguments:</h5>
4426
4427<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4428
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4429<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4430
4431<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4432macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4433<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]4434<tt>va_arg</tt> will produce the first variable argument passed to the function.
4435Unlike 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]4436last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4438</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4439
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4440<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4441<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4442 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4443</div>
4444
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4445<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4446<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4447<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4448<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4449
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4450<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4451which 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]4452or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4453
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4454<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4455
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4456<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]4457
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4458<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4459
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4460<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]4461macro available in C. In a target-dependent way, it destroys the
4462<tt>va_list</tt> element to which the argument points. Calls to <a
4463href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4464<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4465<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4467</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4468
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4469<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4470<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4471 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4472</div>
4473
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4474<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4475
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4476<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4477
4478<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4479 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4480</pre>
4481
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4482<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4483
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4484<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4485from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4486
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4487<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4488
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4489<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]4490The 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]4491
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4492
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4493<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4494
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4495<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4496macro available in C. In a target-dependent way, it copies the source
4497<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4498intrinsic is necessary because the <tt><a href="#int_va_start">
4499llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4500example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4501
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4502</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4503
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4504<!-- ======================================================================= -->
4505<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4506 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4507</div>
4508
4509<div class="doc_text">
4510
4511<p>
4512LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4513Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4514These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4515stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4516href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4517Front-ends for type-safe garbage collected languages should generate these
4518intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4519href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4520</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4521
4522<p>The garbage collection intrinsics only operate on objects in the generic
4523 address space (address space zero).</p>
4524
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4525</div>
4526
4527<!-- _______________________________________________________________________ -->
4528<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4529 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4530</div>
4531
4532<div class="doc_text">
4533
4534<h5>Syntax:</h5>
4535
4536<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4537 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4538</pre>
4539
4540<h5>Overview:</h5>
4541
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4542<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]4543the code generator, and allows some metadata to be associated with it.</p>
4544
4545<h5>Arguments:</h5>
4546
4547<p>The first argument specifies the address of a stack object that contains the
4548root pointer. The second pointer (which must be either a constant or a global
4549value address) contains the meta-data to be associated with the root.</p>
4550
4551<h5>Semantics:</h5>
4552
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]4553<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]4554location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4555the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4556intrinsic may only be used in a function which <a href="#gc">specifies a GC
4557algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4558
4559</div>
4560
4561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4564 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4565</div>
4566
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570
4571<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4572 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4573</pre>
4574
4575<h5>Overview:</h5>
4576
4577<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4578locations, allowing garbage collector implementations that require read
4579barriers.</p>
4580
4581<h5>Arguments:</h5>
4582
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4583<p>The second argument is the address to read from, which should be an address
4584allocated from the garbage collector. The first object is a pointer to the
4585start of the referenced object, if needed by the language runtime (otherwise
4586null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4587
4588<h5>Semantics:</h5>
4589
4590<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4591instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4592garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4593may only be used in a function which <a href="#gc">specifies a GC
4594algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4595
4596</div>
4597
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4601 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4602</div>
4603
4604<div class="doc_text">
4605
4606<h5>Syntax:</h5>
4607
4608<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4609 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4610</pre>
4611
4612<h5>Overview:</h5>
4613
4614<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4615locations, allowing garbage collector implementations that require write
4616barriers (such as generational or reference counting collectors).</p>
4617
4618<h5>Arguments:</h5>
4619
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4620<p>The first argument is the reference to store, the second is the start of the
4621object to store it to, and the third is the address of the field of Obj to
4622store to. If the runtime does not require a pointer to the object, Obj may be
4623null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
4626
4627<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4628instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4629garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4630may only be used in a function which <a href="#gc">specifies a GC
4631algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4632
4633</div>
4634
4635
4636
4637<!-- ======================================================================= -->
4638<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4639 <a name="int_codegen">Code Generator Intrinsics</a>
4640</div>
4641
4642<div class="doc_text">
4643<p>
4644These intrinsics are provided by LLVM to expose special features that may only
4645be implemented with code generator support.
4646</p>
4647
4648</div>
4649
4650<!-- _______________________________________________________________________ -->
4651<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4652 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4653</div>
4654
4655<div class="doc_text">
4656
4657<h5>Syntax:</h5>
4658<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4659 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4660</pre>
4661
4662<h5>Overview:</h5>
4663
4664<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4665The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4666target-specific value indicating the return address of the current function
4667or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4668</p>
4669
4670<h5>Arguments:</h5>
4671
4672<p>
4673The argument to this intrinsic indicates which function to return the address
4674for. Zero indicates the calling function, one indicates its caller, etc. The
4675argument is <b>required</b> to be a constant integer value.
4676</p>
4677
4678<h5>Semantics:</h5>
4679
4680<p>
4681The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4682the return address of the specified call frame, or zero if it cannot be
4683identified. The value returned by this intrinsic is likely to be incorrect or 0
4684for arguments other than zero, so it should only be used for debugging purposes.
4685</p>
4686
4687<p>
4688Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4689aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4690source-language caller.
4691</p>
4692</div>
4693
4694
4695<!-- _______________________________________________________________________ -->
4696<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4697 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4698</div>
4699
4700<div class="doc_text">
4701
4702<h5>Syntax:</h5>
4703<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4704 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4705</pre>
4706
4707<h5>Overview:</h5>
4708
4709<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4710The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4711target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4712</p>
4713
4714<h5>Arguments:</h5>
4715
4716<p>
4717The argument to this intrinsic indicates which function to return the frame
4718pointer for. Zero indicates the calling function, one indicates its caller,
4719etc. The argument is <b>required</b> to be a constant integer value.
4720</p>
4721
4722<h5>Semantics:</h5>
4723
4724<p>
4725The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4726the frame address of the specified call frame, or zero if it cannot be
4727identified. The value returned by this intrinsic is likely to be incorrect or 0
4728for arguments other than zero, so it should only be used for debugging purposes.
4729</p>
4730
4731<p>
4732Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4733aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4734source-language caller.
4735</p>
4736</div>
4737
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4738<!-- _______________________________________________________________________ -->
4739<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4740 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4741</div>
4742
4743<div class="doc_text">
4744
4745<h5>Syntax:</h5>
4746<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4747 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4748</pre>
4749
4750<h5>Overview:</h5>
4751
4752<p>
4753The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4754the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4755<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4756features like scoped automatic variable sized arrays in C99.
4757</p>
4758
4759<h5>Semantics:</h5>
4760
4761<p>
4762This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4763href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4764<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4765<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4766state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4767practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4768that were allocated after the <tt>llvm.stacksave</tt> was executed.
4769</p>
4770
4771</div>
4772
4773<!-- _______________________________________________________________________ -->
4774<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4775 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4776</div>
4777
4778<div class="doc_text">
4779
4780<h5>Syntax:</h5>
4781<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4782 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4783</pre>
4784
4785<h5>Overview:</h5>
4786
4787<p>
4788The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4789the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4790href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4791useful for implementing language features like scoped automatic variable sized
4792arrays in C99.
4793</p>
4794
4795<h5>Semantics:</h5>
4796
4797<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4798See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4799</p>
4800
4801</div>
4802
4803
4804<!-- _______________________________________________________________________ -->
4805<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4806 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4807</div>
4808
4809<div class="doc_text">
4810
4811<h5>Syntax:</h5>
4812<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4813 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]4814</pre>
4815
4816<h5>Overview:</h5>
4817
4818
4819<p>
4820The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4821a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4822no
4823effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4824characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4825</p>
4826
4827<h5>Arguments:</h5>
4828
4829<p>
4830<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4831determining if the fetch should be for a read (0) or write (1), and
4832<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4833locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4834<tt>locality</tt> arguments must be constant integers.
4835</p>
4836
4837<h5>Semantics:</h5>
4838
4839<p>
4840This intrinsic does not modify the behavior of the program. In particular,
4841prefetches cannot trap and do not produce a value. On targets that support this
4842intrinsic, the prefetch can provide hints to the processor cache for better
4843performance.
4844</p>
4845
4846</div>
4847
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4848<!-- _______________________________________________________________________ -->
4849<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4850 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4851</div>
4852
4853<div class="doc_text">
4854
4855<h5>Syntax:</h5>
4856<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4857 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4858</pre>
4859
4860<h5>Overview:</h5>
4861
4862
4863<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4864The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4865(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4866code to simulators and other tools. The method is target specific, but it is
4867expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4868The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4869after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4870optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4871correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4872</p>
4873
4874<h5>Arguments:</h5>
4875
4876<p>
4877<tt>id</tt> is a numerical id identifying the marker.
4878</p>
4879
4880<h5>Semantics:</h5>
4881
4882<p>
4883This intrinsic does not modify the behavior of the program. Backends that do not
4884support this intrinisic may ignore it.
4885</p>
4886
4887</div>
4888
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4889<!-- _______________________________________________________________________ -->
4890<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4891 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4892</div>
4893
4894<div class="doc_text">
4895
4896<h5>Syntax:</h5>
4897<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4898 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4899</pre>
4900
4901<h5>Overview:</h5>
4902
4903
4904<p>
4905The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4906counter register (or similar low latency, high accuracy clocks) on those targets
4907that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4908As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4909should only be used for small timings.
4910</p>
4911
4912<h5>Semantics:</h5>
4913
4914<p>
4915When directly supported, reading the cycle counter should not modify any memory.
4916Implementations are allowed to either return a application specific value or a
4917system wide value. On backends without support, this is lowered to a constant 0.
4918</p>
4919
4920</div>
4921
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4922<!-- ======================================================================= -->
4923<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4924 <a name="int_libc">Standard C Library Intrinsics</a>
4925</div>
4926
4927<div class="doc_text">
4928<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4929LLVM provides intrinsics for a few important standard C library functions.
4930These intrinsics allow source-language front-ends to pass information about the
4931alignment of the pointer arguments to the code generator, providing opportunity
4932for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4933</p>
4934
4935</div>
4936
4937<!-- _______________________________________________________________________ -->
4938<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4939 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4940</div>
4941
4942<div class="doc_text">
4943
4944<h5>Syntax:</h5>
4945<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4946 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4947 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4948 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4949 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4950</pre>
4951
4952<h5>Overview:</h5>
4953
4954<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4955The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4956location to the destination location.
4957</p>
4958
4959<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4960Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4961intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4962</p>
4963
4964<h5>Arguments:</h5>
4965
4966<p>
4967The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4968the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4969specifying the number of bytes to copy, and the fourth argument is the alignment
4970of the source and destination locations.
4971</p>
4972
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4973<p>
4974If 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]4975the caller guarantees that both the source and destination pointers are aligned
4976to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4977</p>
4978
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4979<h5>Semantics:</h5>
4980
4981<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4982The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4983location to the destination location, which are not allowed to overlap. It
4984copies "len" bytes of memory over. If the argument is known to be aligned to
4985some boundary, this can be specified as the fourth argument, otherwise it should
4986be set to 0 or 1.
4987</p>
4988</div>
4989
4990
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4991<!-- _______________________________________________________________________ -->
4992<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4993 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4994</div>
4995
4996<div class="doc_text">
4997
4998<h5>Syntax:</h5>
4999<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5000 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5001 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5002 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5003 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5004</pre>
5005
5006<h5>Overview:</h5>
5007
5008<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5009The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5010location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]5011'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5012</p>
5013
5014<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5015Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5016intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5017</p>
5018
5019<h5>Arguments:</h5>
5020
5021<p>
5022The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5023the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5024specifying the number of bytes to copy, and the fourth argument is the alignment
5025of the source and destination locations.
5026</p>
5027
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5028<p>
5029If 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]5030the caller guarantees that the source and destination pointers are aligned to
5031that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5032</p>
5033
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5034<h5>Semantics:</h5>
5035
5036<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5037The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5038location to the destination location, which may overlap. It
5039copies "len" bytes of memory over. If the argument is known to be aligned to
5040some boundary, this can be specified as the fourth argument, otherwise it should
5041be set to 0 or 1.
5042</p>
5043</div>
5044
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5045
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5046<!-- _______________________________________________________________________ -->
5047<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5048 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5049</div>
5050
5051<div class="doc_text">
5052
5053<h5>Syntax:</h5>
5054<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5055 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5056 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5057 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5058 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5059</pre>
5060
5061<h5>Overview:</h5>
5062
5063<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5064The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5065byte value.
5066</p>
5067
5068<p>
5069Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5070does not return a value, and takes an extra alignment argument.
5071</p>
5072
5073<h5>Arguments:</h5>
5074
5075<p>
5076The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5077byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5078argument specifying the number of bytes to fill, and the fourth argument is the
5079known alignment of destination location.
5080</p>
5081
5082<p>
5083If 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]5084the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5085</p>
5086
5087<h5>Semantics:</h5>
5088
5089<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5090The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5091the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5092destination location. If the argument is known to be aligned to some boundary,
5093this can be specified as the fourth argument, otherwise it should be set to 0 or
50941.
5095</p>
5096</div>
5097
5098
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5099<!-- _______________________________________________________________________ -->
5100<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5101 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5102</div>
5103
5104<div class="doc_text">
5105
5106<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5107<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]5108floating point or vector of floating point type. Not all targets support all
5109types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5110<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5111 declare float @llvm.sqrt.f32(float %Val)
5112 declare double @llvm.sqrt.f64(double %Val)
5113 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5114 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5115 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5116</pre>
5117
5118<h5>Overview:</h5>
5119
5120<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5121The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5122returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5123<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]5124negative numbers other than -0.0 (which allows for better optimization, because
5125there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5126defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5127</p>
5128
5129<h5>Arguments:</h5>
5130
5131<p>
5132The argument and return value are floating point numbers of the same type.
5133</p>
5134
5135<h5>Semantics:</h5>
5136
5137<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]5138This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5139floating point number.
5140</p>
5141</div>
5142
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5143<!-- _______________________________________________________________________ -->
5144<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5145 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5146</div>
5147
5148<div class="doc_text">
5149
5150<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5151<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]5152floating point or vector of floating point type. Not all targets support all
5153types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5154<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5155 declare float @llvm.powi.f32(float %Val, i32 %power)
5156 declare double @llvm.powi.f64(double %Val, i32 %power)
5157 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5158 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5159 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5160</pre>
5161
5162<h5>Overview:</h5>
5163
5164<p>
5165The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5166specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5167multiplications is not defined. When a vector of floating point type is
5168used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5169</p>
5170
5171<h5>Arguments:</h5>
5172
5173<p>
5174The second argument is an integer power, and the first is a value to raise to
5175that power.
5176</p>
5177
5178<h5>Semantics:</h5>
5179
5180<p>
5181This function returns the first value raised to the second power with an
5182unspecified sequence of rounding operations.</p>
5183</div>
5184
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5185<!-- _______________________________________________________________________ -->
5186<div class="doc_subsubsection">
5187 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5188</div>
5189
5190<div class="doc_text">
5191
5192<h5>Syntax:</h5>
5193<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5194floating point or vector of floating point type. Not all targets support all
5195types however.
5196<pre>
5197 declare float @llvm.sin.f32(float %Val)
5198 declare double @llvm.sin.f64(double %Val)
5199 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5200 declare fp128 @llvm.sin.f128(fp128 %Val)
5201 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5202</pre>
5203
5204<h5>Overview:</h5>
5205
5206<p>
5207The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5208</p>
5209
5210<h5>Arguments:</h5>
5211
5212<p>
5213The argument and return value are floating point numbers of the same type.
5214</p>
5215
5216<h5>Semantics:</h5>
5217
5218<p>
5219This function returns the sine of the specified operand, returning the
5220same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5221conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5222</div>
5223
5224<!-- _______________________________________________________________________ -->
5225<div class="doc_subsubsection">
5226 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5227</div>
5228
5229<div class="doc_text">
5230
5231<h5>Syntax:</h5>
5232<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5233floating point or vector of floating point type. Not all targets support all
5234types however.
5235<pre>
5236 declare float @llvm.cos.f32(float %Val)
5237 declare double @llvm.cos.f64(double %Val)
5238 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5239 declare fp128 @llvm.cos.f128(fp128 %Val)
5240 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5241</pre>
5242
5243<h5>Overview:</h5>
5244
5245<p>
5246The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5247</p>
5248
5249<h5>Arguments:</h5>
5250
5251<p>
5252The argument and return value are floating point numbers of the same type.
5253</p>
5254
5255<h5>Semantics:</h5>
5256
5257<p>
5258This function returns the cosine of the specified operand, returning the
5259same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5260conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5261</div>
5262
5263<!-- _______________________________________________________________________ -->
5264<div class="doc_subsubsection">
5265 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5266</div>
5267
5268<div class="doc_text">
5269
5270<h5>Syntax:</h5>
5271<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5272floating point or vector of floating point type. Not all targets support all
5273types however.
5274<pre>
5275 declare float @llvm.pow.f32(float %Val, float %Power)
5276 declare double @llvm.pow.f64(double %Val, double %Power)
5277 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5278 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5279 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5280</pre>
5281
5282<h5>Overview:</h5>
5283
5284<p>
5285The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5286specified (positive or negative) power.
5287</p>
5288
5289<h5>Arguments:</h5>
5290
5291<p>
5292The second argument is a floating point power, and the first is a value to
5293raise to that power.
5294</p>
5295
5296<h5>Semantics:</h5>
5297
5298<p>
5299This function returns the first value raised to the second power,
5300returning the
5301same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5302conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5303</div>
5304
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5305
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5306<!-- ======================================================================= -->
5307<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5308 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5309</div>
5310
5311<div class="doc_text">
5312<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5313LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5314These allow efficient code generation for some algorithms.
5315</p>
5316
5317</div>
5318
5319<!-- _______________________________________________________________________ -->
5320<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5321 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5322</div>
5323
5324<div class="doc_text">
5325
5326<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5327<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5328type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5329<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5330 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5331 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5332 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5333</pre>
5334
5335<h5>Overview:</h5>
5336
5337<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]5338The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5339values with an even number of bytes (positive multiple of 16 bits). These are
5340useful for performing operations on data that is not in the target's native
5341byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5342</p>
5343
5344<h5>Semantics:</h5>
5345
5346<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5347The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5348and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5349intrinsic returns an i32 value that has the four bytes of the input i32
5350swapped, 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]5351i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5352<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5353additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5354</p>
5355
5356</div>
5357
5358<!-- _______________________________________________________________________ -->
5359<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5360 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5361</div>
5362
5363<div class="doc_text">
5364
5365<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5366<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5367width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5368<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5369 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5370 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5371 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5372 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5373 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5374</pre>
5375
5376<h5>Overview:</h5>
5377
5378<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]5379The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5380value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5381</p>
5382
5383<h5>Arguments:</h5>
5384
5385<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5386The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5387integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5388</p>
5389
5390<h5>Semantics:</h5>
5391
5392<p>
5393The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5394</p>
5395</div>
5396
5397<!-- _______________________________________________________________________ -->
5398<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5399 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5400</div>
5401
5402<div class="doc_text">
5403
5404<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5405<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5406integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5407<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5408 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5409 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5410 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5411 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5412 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5413</pre>
5414
5415<h5>Overview:</h5>
5416
5417<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5418The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5419leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5420</p>
5421
5422<h5>Arguments:</h5>
5423
5424<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5425The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5426integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5427</p>
5428
5429<h5>Semantics:</h5>
5430
5431<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5432The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5433in 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]5434of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5435</p>
5436</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5437
5438
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5439
5440<!-- _______________________________________________________________________ -->
5441<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5442 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5443</div>
5444
5445<div class="doc_text">
5446
5447<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5448<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5449integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5450<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5451 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5452 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5453 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5454 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5455 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5456</pre>
5457
5458<h5>Overview:</h5>
5459
5460<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5461The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5462trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5463</p>
5464
5465<h5>Arguments:</h5>
5466
5467<p>
5468The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5469integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5470</p>
5471
5472<h5>Semantics:</h5>
5473
5474<p>
5475The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5476in a variable. If the src == 0 then the result is the size in bits of the type
5477of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5478</p>
5479</div>
5480
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5481<!-- _______________________________________________________________________ -->
5482<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5483 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5484</div>
5485
5486<div class="doc_text">
5487
5488<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5489<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5490on any integer bit width.
5491<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5492 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5493 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5494</pre>
5495
5496<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5497<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5498range of bits from an integer value and returns them in the same bit width as
5499the original value.</p>
5500
5501<h5>Arguments:</h5>
5502<p>The first argument, <tt>%val</tt> and the result may be integer types of
5503any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5504arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5505
5506<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5507<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5508of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5509<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5510operates in forward mode.</p>
5511<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5512right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5513only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5514<ol>
5515 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5516 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5517 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5518 to determine the number of bits to retain.</li>
5519 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5520 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5521</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5522<p>In reverse mode, a similar computation is made except that the bits are
5523returned in the reverse order. So, for example, if <tt>X</tt> has the value
5524<tt>i16 0x0ACF (101011001111)</tt> and we apply
5525<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5526<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5527</div>
5528
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5529<div class="doc_subsubsection">
5530 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5531</div>
5532
5533<div class="doc_text">
5534
5535<h5>Syntax:</h5>
5536<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5537on any integer bit width.
5538<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5539 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5540 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]5541</pre>
5542
5543<h5>Overview:</h5>
5544<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5545of bits in an integer value with another integer value. It returns the integer
5546with the replaced bits.</p>
5547
5548<h5>Arguments:</h5>
5549<p>The first argument, <tt>%val</tt> and the result may be integer types of
5550any bit width but they must have the same bit width. <tt>%val</tt> is the value
5551whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5552integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5553type since they specify only a bit index.</p>
5554
5555<h5>Semantics:</h5>
5556<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5557of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5558<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5559operates in forward mode.</p>
5560<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5561truncating it down to the size of the replacement area or zero extending it
5562up to that size.</p>
5563<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5564are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5565in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5566to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5567<p>In reverse mode, a similar computation is made except that the bits are
5568reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5569<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]5570<h5>Examples:</h5>
5571<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5572 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5573 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5574 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5575 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5576 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5577</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5578</div>
5579
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5580<!-- ======================================================================= -->
5581<div class="doc_subsection">
5582 <a name="int_debugger">Debugger Intrinsics</a>
5583</div>
5584
5585<div class="doc_text">
5586<p>
5587The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5588are described in the <a
5589href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5590Debugging</a> document.
5591</p>
5592</div>
5593
5594
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5595<!-- ======================================================================= -->
5596<div class="doc_subsection">
5597 <a name="int_eh">Exception Handling Intrinsics</a>
5598</div>
5599
5600<div class="doc_text">
5601<p> The LLVM exception handling intrinsics (which all start with
5602<tt>llvm.eh.</tt> prefix), are described in the <a
5603href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5604Handling</a> document. </p>
5605</div>
5606
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5607<!-- ======================================================================= -->
5608<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5609 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5610</div>
5611
5612<div class="doc_text">
5613<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5614 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5615 the <tt>nest</tt> attribute, from a function. The result is a callable
5616 function pointer lacking the nest parameter - the caller does not need
5617 to provide a value for it. Instead, the value to use is stored in
5618 advance in a "trampoline", a block of memory usually allocated
5619 on the stack, which also contains code to splice the nest value into the
5620 argument list. This is used to implement the GCC nested function address
5621 extension.
5622</p>
5623<p>
5624 For example, if the function is
5625 <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]5626 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]5627<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5628 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5629 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5630 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5631 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5632</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5633 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5634 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5635</div>
5636
5637<!-- _______________________________________________________________________ -->
5638<div class="doc_subsubsection">
5639 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5640</div>
5641<div class="doc_text">
5642<h5>Syntax:</h5>
5643<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5644declare 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]5645</pre>
5646<h5>Overview:</h5>
5647<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5648 This fills the memory pointed to by <tt>tramp</tt> with code
5649 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5650</p>
5651<h5>Arguments:</h5>
5652<p>
5653 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5654 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5655 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5656 intrinsic. Note that the size and the alignment are target-specific - LLVM
5657 currently provides no portable way of determining them, so a front-end that
5658 generates this intrinsic needs to have some target-specific knowledge.
5659 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]5660</p>
5661<h5>Semantics:</h5>
5662<p>
5663 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5664 dependent code, turning it into a function. A pointer to this function is
5665 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5666 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5667 before being called. The new function's signature is the same as that of
5668 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5669 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5670 of pointer type. Calling the new function is equivalent to calling
5671 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5672 missing <tt>nest</tt> argument. If, after calling
5673 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5674 modified, then the effect of any later call to the returned function pointer is
5675 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5676</p>
5677</div>
5678
5679<!-- ======================================================================= -->
5680<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5681 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5682</div>
5683
5684<div class="doc_text">
5685<p>
5686 These intrinsic functions expand the "universal IR" of LLVM to represent
5687 hardware constructs for atomic operations and memory synchronization. This
5688 provides an interface to the hardware, not an interface to the programmer. It
5689 is aimed at a low enough level to allow any programming models or APIs which
5690 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5691 hardware behavior. Just as hardware provides a "universal IR" for source
5692 languages, it also provides a starting point for developing a "universal"
5693 atomic operation and synchronization IR.
5694</p>
5695<p>
5696 These do <em>not</em> form an API such as high-level threading libraries,
5697 software transaction memory systems, atomic primitives, and intrinsic
5698 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5699 application libraries. The hardware interface provided by LLVM should allow
5700 a clean implementation of all of these APIs and parallel programming models.
5701 No one model or paradigm should be selected above others unless the hardware
5702 itself ubiquitously does so.
5703
5704</p>
5705</div>
5706
5707<!-- _______________________________________________________________________ -->
5708<div class="doc_subsubsection">
5709 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5710</div>
5711<div class="doc_text">
5712<h5>Syntax:</h5>
5713<pre>
5714declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5715i1 &lt;device&gt; )
5716
5717</pre>
5718<h5>Overview:</h5>
5719<p>
5720 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5721 specific pairs of memory access types.
5722</p>
5723<h5>Arguments:</h5>
5724<p>
5725 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5726 The first four arguments enables a specific barrier as listed below. The fith
5727 argument specifies that the barrier applies to io or device or uncached memory.
5728
5729</p>
5730 <ul>
5731 <li><tt>ll</tt>: load-load barrier</li>
5732 <li><tt>ls</tt>: load-store barrier</li>
5733 <li><tt>sl</tt>: store-load barrier</li>
5734 <li><tt>ss</tt>: store-store barrier</li>
5735 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5736 </ul>
5737<h5>Semantics:</h5>
5738<p>
5739 This intrinsic causes the system to enforce some ordering constraints upon
5740 the loads and stores of the program. This barrier does not indicate
5741 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5742 which they occur. For any of the specified pairs of load and store operations
5743 (f.ex. load-load, or store-load), all of the first operations preceding the
5744 barrier will complete before any of the second operations succeeding the
5745 barrier begin. Specifically the semantics for each pairing is as follows:
5746</p>
5747 <ul>
5748 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5749 after the barrier begins.</li>
5750
5751 <li><tt>ls</tt>: All loads before the barrier must complete before any
5752 store after the barrier begins.</li>
5753 <li><tt>ss</tt>: All stores before the barrier must complete before any
5754 store after the barrier begins.</li>
5755 <li><tt>sl</tt>: All stores before the barrier must complete before any
5756 load after the barrier begins.</li>
5757 </ul>
5758<p>
5759 These semantics are applied with a logical "and" behavior when more than one
5760 is enabled in a single memory barrier intrinsic.
5761</p>
5762<p>
5763 Backends may implement stronger barriers than those requested when they do not
5764 support as fine grained a barrier as requested. Some architectures do not
5765 need all types of barriers and on such architectures, these become noops.
5766</p>
5767<h5>Example:</h5>
5768<pre>
5769%ptr = malloc i32
5770 store i32 4, %ptr
5771
5772%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5773 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5774 <i>; guarantee the above finishes</i>
5775 store i32 8, %ptr <i>; before this begins</i>
5776</pre>
5777</div>
5778
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]5779<!-- _______________________________________________________________________ -->
5780<div class="doc_subsubsection">
5781 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5782</div>
5783<div class="doc_text">
5784<h5>Syntax:</h5>
5785<p>
5786 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5787 integer bit width. Not all targets support all bit widths however.</p>
5788
5789<pre>
5790declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5791declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5792declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5793declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5794
5795</pre>
5796<h5>Overview:</h5>
5797<p>
5798 This loads a value in memory and compares it to a given value. If they are
5799 equal, it stores a new value into the memory.
5800</p>
5801<h5>Arguments:</h5>
5802<p>
5803 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5804 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5805 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5806 this integer type. While any bit width integer may be used, targets may only
5807 lower representations they support in hardware.
5808
5809</p>
5810<h5>Semantics:</h5>
5811<p>
5812 This entire intrinsic must be executed atomically. It first loads the value
5813 in memory pointed to by <tt>ptr</tt> and compares it with the value
5814 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5815 loaded value is yielded in all cases. This provides the equivalent of an
5816 atomic compare-and-swap operation within the SSA framework.
5817</p>
5818<h5>Examples:</h5>
5819
5820<pre>
5821%ptr = malloc i32
5822 store i32 4, %ptr
5823
5824%val1 = add i32 4, 4
5825%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5826 <i>; yields {i32}:result1 = 4</i>
5827%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5828%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5829
5830%val2 = add i32 1, 1
5831%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5832 <i>; yields {i32}:result2 = 8</i>
5833%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5834
5835%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5836</pre>
5837</div>
5838
5839<!-- _______________________________________________________________________ -->
5840<div class="doc_subsubsection">
5841 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5842</div>
5843<div class="doc_text">
5844<h5>Syntax:</h5>
5845
5846<p>
5847 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5848 integer bit width. Not all targets support all bit widths however.</p>
5849<pre>
5850declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5851declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5852declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5853declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5854
5855</pre>
5856<h5>Overview:</h5>
5857<p>
5858 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5859 the value from memory. It then stores the value in <tt>val</tt> in the memory
5860 at <tt>ptr</tt>.
5861</p>
5862<h5>Arguments:</h5>
5863
5864<p>
5865 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5866 <tt>val</tt> argument and the result must be integers of the same bit width.
5867 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5868 integer type. The targets may only lower integer representations they
5869 support.
5870</p>
5871<h5>Semantics:</h5>
5872<p>
5873 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5874 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5875 equivalent of an atomic swap operation within the SSA framework.
5876
5877</p>
5878<h5>Examples:</h5>
5879<pre>
5880%ptr = malloc i32
5881 store i32 4, %ptr
5882
5883%val1 = add i32 4, 4
5884%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5885 <i>; yields {i32}:result1 = 4</i>
5886%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5887%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5888
5889%val2 = add i32 1, 1
5890%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5891 <i>; yields {i32}:result2 = 8</i>
5892
5893%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5894%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5895</pre>
5896</div>
5897
5898<!-- _______________________________________________________________________ -->
5899<div class="doc_subsubsection">
5900 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5901
5902</div>
5903<div class="doc_text">
5904<h5>Syntax:</h5>
5905<p>
5906 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5907 integer bit width. Not all targets support all bit widths however.</p>
5908<pre>
5909declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5910declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5911declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5912declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5913
5914</pre>
5915<h5>Overview:</h5>
5916<p>
5917 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5918 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5919</p>
5920<h5>Arguments:</h5>
5921<p>
5922
5923 The intrinsic takes two arguments, the first a pointer to an integer value
5924 and the second an integer value. The result is also an integer value. These
5925 integer types can have any bit width, but they must all have the same bit
5926 width. The targets may only lower integer representations they support.
5927</p>
5928<h5>Semantics:</h5>
5929<p>
5930 This intrinsic does a series of operations atomically. It first loads the
5931 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5932 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5933</p>
5934
5935<h5>Examples:</h5>
5936<pre>
5937%ptr = malloc i32
5938 store i32 4, %ptr
5939%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5940 <i>; yields {i32}:result1 = 4</i>
5941%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5942 <i>; yields {i32}:result2 = 8</i>
5943%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5944 <i>; yields {i32}:result3 = 10</i>
5945%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5946</pre>
5947</div>
5948
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5949
5950<!-- ======================================================================= -->
5951<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5952 <a name="int_general">General Intrinsics</a>
5953</div>
5954
5955<div class="doc_text">
5956<p> This class of intrinsics is designed to be generic and has
5957no specific purpose. </p>
5958</div>
5959
5960<!-- _______________________________________________________________________ -->
5961<div class="doc_subsubsection">
5962 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5963</div>
5964
5965<div class="doc_text">
5966
5967<h5>Syntax:</h5>
5968<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5969 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]5970</pre>
5971
5972<h5>Overview:</h5>
5973
5974<p>
5975The '<tt>llvm.var.annotation</tt>' intrinsic
5976</p>
5977
5978<h5>Arguments:</h5>
5979
5980<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5981The first argument is a pointer to a value, the second is a pointer to a
5982global string, the third is a pointer to a global string which is the source
5983file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5984</p>
5985
5986<h5>Semantics:</h5>
5987
5988<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5989This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5990This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5991annotations. These have no other defined use, they are ignored by code
5992generation and optimization.
5993</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5994</div>
5995
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5996<!-- _______________________________________________________________________ -->
5997<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5998 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5999</div>
6000
6001<div class="doc_text">
6002
6003<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6004<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6005any integer bit width.
6006</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6007<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]6008 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6009 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6010 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6011 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6012 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]6013</pre>
6014
6015<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6016
6017<p>
6018The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6019</p>
6020
6021<h5>Arguments:</h5>
6022
6023<p>
6024The first argument is an integer value (result of some expression),
6025the second is a pointer to a global string, the third is a pointer to a global
6026string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6027It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6028</p>
6029
6030<h5>Semantics:</h5>
6031
6032<p>
6033This intrinsic allows annotations to be put on arbitrary expressions
6034with arbitrary strings. This can be useful for special purpose optimizations
6035that want to look for these annotations. These have no other defined use, they
6036are ignored by code generation and optimization.
6037</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6038
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]6039<!-- _______________________________________________________________________ -->
6040<div class="doc_subsubsection">
6041 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6042</div>
6043
6044<div class="doc_text">
6045
6046<h5>Syntax:</h5>
6047<pre>
6048 declare void @llvm.trap()
6049</pre>
6050
6051<h5>Overview:</h5>
6052
6053<p>
6054The '<tt>llvm.trap</tt>' intrinsic
6055</p>
6056
6057<h5>Arguments:</h5>
6058
6059<p>
6060None
6061</p>
6062
6063<h5>Semantics:</h5>
6064
6065<p>
6066This intrinsics is lowered to the target dependent trap instruction. If the
6067target does not have a trap instruction, this intrinsic will be lowered to the
6068call of the abort() function.
6069</p>
6070</div>
6071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6072<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6073<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6074<address>
6075 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6076 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6077 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]6078 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6079
6080 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]6081 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6082 Last modified: $Date$
6083</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]6084
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6085</body>
6086</html>