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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 4cb8618d7f4fe0fb8f002651bc570a710cf7e3e1 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 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 Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]114 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]115 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
117 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
118 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]119 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
120 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
121 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]122 </ol>
123 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]124 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]125 <ol>
126 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
127 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
129 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
130 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]131 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
132 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
133 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]135 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
136 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]137 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]138 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#otherops">Other Operations</a>
140 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]141 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
142 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]144 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]146 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]147 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]149 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]151 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]152 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
154 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]155 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
156 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 </ol>
159 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
161 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]162 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
163 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]167 <li><a href="#int_codegen">Code Generator Intrinsics</a>
168 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]169 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
170 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
172 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
173 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
174 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
175 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]176 </ol>
177 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]178 <li><a href="#int_libc">Standard C Library Intrinsics</a>
179 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]180 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
181 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]185 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
186 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]188 </ol>
189 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]190 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]191 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]192 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]193 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
194 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]196 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
197 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]198 </ol>
199 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]200 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]201 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]202 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]203 <ol>
204 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]205 </ol>
206 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]207 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]208 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]209 <li><a href="#int_var_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]210 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]211 <li><a href="#int_annotation">
Tanya Lattner91d0b882007-09-22 00:01:26 +0000[diff] [blame]212 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame^]213 <li><a href="#int_trap">
214 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]215 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]216 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]219</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]220
221<div class="doc_author">
222 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
223 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]224</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]226<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227<div class="doc_section"> <a name="abstract">Abstract </a></div>
228<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]230<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]231<p>This document is a reference manual for the LLVM assembly language.
232LLVM is an SSA based representation that provides type safety,
233low-level operations, flexibility, and the capability of representing
234'all' high-level languages cleanly. It is the common code
235representation used throughout all phases of the LLVM compilation
236strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]237</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]239<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<div class="doc_section"> <a name="introduction">Introduction</a> </div>
241<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]245<p>The LLVM code representation is designed to be used in three
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]246different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]247representation (suitable for fast loading by a Just-In-Time compiler),
248and as a human readable assembly language representation. This allows
249LLVM to provide a powerful intermediate representation for efficient
250compiler transformations and analysis, while providing a natural means
251to debug and visualize the transformations. The three different forms
252of LLVM are all equivalent. This document describes the human readable
253representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]255<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256while being expressive, typed, and extensible at the same time. It
257aims to be a "universal IR" of sorts, by being at a low enough level
258that high-level ideas may be cleanly mapped to it (similar to how
259microprocessors are "universal IR's", allowing many source languages to
260be mapped to them). By providing type information, LLVM can be used as
261the target of optimizations: for example, through pointer analysis, it
262can be proven that a C automatic variable is never accessed outside of
263the current function... allowing it to be promoted to a simple SSA
264value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]266</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]267
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]268<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]269<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]270
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]271<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]273<p>It is important to note that this document describes 'well formed'
274LLVM assembly language. There is a difference between what the parser
275accepts and what is considered 'well formed'. For example, the
276following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]278<div class="doc_code">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]279<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]280%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]282</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]283
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]284<p>...because the definition of <tt>%x</tt> does not dominate all of
285its uses. The LLVM infrastructure provides a verification pass that may
286be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]287automatically run by the parser after parsing input assembly and by
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]288the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]289by the verifier pass indicate bugs in transformation passes or input to
290the parser.</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]293<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]295<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]299<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]300
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]301 <p>LLVM identifiers come in two basic types: global and local. Global
302 identifiers (functions, global variables) begin with the @ character. Local
303 identifiers (register names, types) begin with the % character. Additionally,
304 there are three different formats for identifiers, for different purposes:
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]305
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]306<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]307 <li>Named values are represented as a string of characters with their prefix.
308 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
309 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]310 Identifiers which require other characters in their names can be surrounded
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]311 with quotes. In this way, anything except a <tt>&quot;</tt> character can
312 be used in a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]313
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]314 <li>Unnamed values are represented as an unsigned numeric value with their
315 prefix. For example, %12, @2, %44.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]316
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]317 <li>Constants, which are described in a <a href="#constants">section about
318 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]320
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]321<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]322don't need to worry about name clashes with reserved words, and the set of
323reserved words may be expanded in the future without penalty. Additionally,
324unnamed identifiers allow a compiler to quickly come up with a temporary
325variable without having to avoid symbol table conflicts.</p>
326
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]327<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]328languages. There are keywords for different opcodes
329('<tt><a href="#i_add">add</a></tt>',
330 '<tt><a href="#i_bitcast">bitcast</a></tt>',
331 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]332href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333and others. These reserved words cannot conflict with variable names, because
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]334none of them start with a prefix character ('%' or '@').</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
336<p>Here is an example of LLVM code to multiply the integer variable
337'<tt>%X</tt>' by 8:</p>
338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]340
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]341<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]343%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]345</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]347<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]348
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]349<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]350<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]351%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]352</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]353</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]354
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]355<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]356
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]357<div class="doc_code">
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]358<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]359<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
360<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
361%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]363</div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]364
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]365<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
366important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]367
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]368<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]369
370 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
371 line.</li>
372
373 <li>Unnamed temporaries are created when the result of a computation is not
374 assigned to a named value.</li>
375
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]376 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]377
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]378</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]379
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]380<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]381demonstrating instructions, we will follow an instruction with a comment that
382defines the type and name of value produced. Comments are shown in italic
383text.</p>
384
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]385</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386
387<!-- *********************************************************************** -->
388<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
389<!-- *********************************************************************** -->
390
391<!-- ======================================================================= -->
392<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
393</div>
394
395<div class="doc_text">
396
397<p>LLVM programs are composed of "Module"s, each of which is a
398translation unit of the input programs. Each module consists of
399functions, global variables, and symbol table entries. Modules may be
400combined together with the LLVM linker, which merges function (and
401global variable) definitions, resolves forward declarations, and merges
402symbol table entries. Here is an example of the "hello world" module:</p>
403
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]404<div class="doc_code">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]405<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]406<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
407 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]408
409<i>; External declaration of the puts function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]410<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]411
412<i>; Definition of main function</i>
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]413define i32 @main() { <i>; i32()* </i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]414 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]415 %cast210 = <a
Chris Lattner6c0955b2007-06-12 17:01:15 +0000[diff] [blame]416 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417
418 <i>; Call puts function to write out the string to stdout...</i>
419 <a
Chris Lattnera89e5f12007-06-12 17:00:26 +0000[diff] [blame]420 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]421 <a
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]422 href="#i_ret">ret</a> i32 0<br>}<br>
423</pre>
424</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]425
426<p>This example is made up of a <a href="#globalvars">global variable</a>
427named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
428function, and a <a href="#functionstructure">function definition</a>
429for "<tt>main</tt>".</p>
430
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431<p>In general, a module is made up of a list of global values,
432where both functions and global variables are global values. Global values are
433represented by a pointer to a memory location (in this case, a pointer to an
434array of char, and a pointer to a function), and have one of the following <a
435href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]436
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437</div>
438
439<!-- ======================================================================= -->
440<div class="doc_subsection">
441 <a name="linkage">Linkage Types</a>
442</div>
443
444<div class="doc_text">
445
446<p>
447All Global Variables and Functions have one of the following types of linkage:
448</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]449
450<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]452 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]453
454 <dd>Global values with internal linkage are only directly accessible by
455 objects in the current module. In particular, linking code into a module with
456 an internal global value may cause the internal to be renamed as necessary to
457 avoid collisions. Because the symbol is internal to the module, all
458 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]459 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]460 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]461
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]462 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]463
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]464 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
465 the same name when linkage occurs. This is typically used to implement
466 inline functions, templates, or other code which must be generated in each
467 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
468 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]472
473 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
474 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]475 used for globals that may be emitted in multiple translation units, but that
476 are not guaranteed to be emitted into every translation unit that uses them.
477 One example of this are common globals in C, such as "<tt>int X;</tt>" at
478 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]479 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]480
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]481 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]482
483 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
484 pointer to array type. When two global variables with appending linkage are
485 linked together, the two global arrays are appended together. This is the
486 LLVM, typesafe, equivalent of having the system linker append together
487 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]489
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
491 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
492 until linked, if not linked, the symbol becomes null instead of being an
493 undefined reference.
494 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]495
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]496 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]497
498 <dd>If none of the above identifiers are used, the global is externally
499 visible, meaning that it participates in linkage and can be used to resolve
500 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]502</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]503
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]504 <p>
505 The next two types of linkage are targeted for Microsoft Windows platform
506 only. They are designed to support importing (exporting) symbols from (to)
507 DLLs.
508 </p>
509
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]510 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]511 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
512
513 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
514 or variable via a global pointer to a pointer that is set up by the DLL
515 exporting the symbol. On Microsoft Windows targets, the pointer name is
516 formed by combining <code>_imp__</code> and the function or variable name.
517 </dd>
518
519 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
520
521 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
522 pointer to a pointer in a DLL, so that it can be referenced with the
523 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
524 name is formed by combining <code>_imp__</code> and the function or variable
525 name.
526 </dd>
527
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]528</dl>
529
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]530<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]531variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
532variable and was linked with this one, one of the two would be renamed,
533preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
534external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]535outside of the current module.</p>
536<p>It is illegal for a function <i>declaration</i>
537to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]538or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]539<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
540linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541</div>
542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]545 <a name="callingconv">Calling Conventions</a>
546</div>
547
548<div class="doc_text">
549
550<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
551and <a href="#i_invoke">invokes</a> can all have an optional calling convention
552specified for the call. The calling convention of any pair of dynamic
553caller/callee must match, or the behavior of the program is undefined. The
554following calling conventions are supported by LLVM, and more may be added in
555the future:</p>
556
557<dl>
558 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
559
560 <dd>This calling convention (the default if no other calling convention is
561 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]562 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]563 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]564 </dd>
565
566 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
567
568 <dd>This calling convention attempts to make calls as fast as possible
569 (e.g. by passing things in registers). This calling convention allows the
570 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]571 without having to conform to an externally specified ABI. Implementations of
572 this convention should allow arbitrary tail call optimization to be supported.
573 This calling convention does not support varargs and requires the prototype of
574 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]575 </dd>
576
577 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
578
579 <dd>This calling convention attempts to make code in the caller as efficient
580 as possible under the assumption that the call is not commonly executed. As
581 such, these calls often preserve all registers so that the call does not break
582 any live ranges in the caller side. This calling convention does not support
583 varargs and requires the prototype of all callees to exactly match the
584 prototype of the function definition.
585 </dd>
586
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]587 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]588
589 <dd>Any calling convention may be specified by number, allowing
590 target-specific calling conventions to be used. Target specific calling
591 conventions start at 64.
592 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]593</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]594
595<p>More calling conventions can be added/defined on an as-needed basis, to
596support pascal conventions or any other well-known target-independent
597convention.</p>
598
599</div>
600
601<!-- ======================================================================= -->
602<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]603 <a name="visibility">Visibility Styles</a>
604</div>
605
606<div class="doc_text">
607
608<p>
609All Global Variables and Functions have one of the following visibility styles:
610</p>
611
612<dl>
613 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
614
615 <dd>On ELF, default visibility means that the declaration is visible to other
616 modules and, in shared libraries, means that the declared entity may be
617 overridden. On Darwin, default visibility means that the declaration is
618 visible to other modules. Default visibility corresponds to "external
619 linkage" in the language.
620 </dd>
621
622 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
623
624 <dd>Two declarations of an object with hidden visibility refer to the same
625 object if they are in the same shared object. Usually, hidden visibility
626 indicates that the symbol will not be placed into the dynamic symbol table,
627 so no other module (executable or shared library) can reference it
628 directly.
629 </dd>
630
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]631 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
632
633 <dd>On ELF, protected visibility indicates that the symbol will be placed in
634 the dynamic symbol table, but that references within the defining module will
635 bind to the local symbol. That is, the symbol cannot be overridden by another
636 module.
637 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]638</dl>
639
640</div>
641
642<!-- ======================================================================= -->
643<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]644 <a name="globalvars">Global Variables</a>
645</div>
646
647<div class="doc_text">
648
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]649<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]650instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]651an explicit section to be placed in, and may have an optional explicit alignment
652specified. A variable may be defined as "thread_local", which means that it
653will not be shared by threads (each thread will have a separated copy of the
654variable). A variable may be defined as a global "constant," which indicates
655that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]656optimization, allowing the global data to be placed in the read-only section of
657an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]658cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]659
660<p>
661LLVM explicitly allows <em>declarations</em> of global variables to be marked
662constant, even if the final definition of the global is not. This capability
663can be used to enable slightly better optimization of the program, but requires
664the language definition to guarantee that optimizations based on the
665'constantness' are valid for the translation units that do not include the
666definition.
667</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]668
669<p>As SSA values, global variables define pointer values that are in
670scope (i.e. they dominate) all basic blocks in the program. Global
671variables always define a pointer to their "content" type because they
672describe a region of memory, and all memory objects in LLVM are
673accessed through pointers.</p>
674
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]675<p>A global variable may be declared to reside in a target-specifc numbered
676address space. For targets that support them, address spaces may affect how
677optimizations are performed and/or what target instructions are used to access
Christopher Lambd49e18d2007-12-12 08:44:39 +0000[diff] [blame]678the variable. The default address space is zero. The address space qualifier
679must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]680
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]681<p>LLVM allows an explicit section to be specified for globals. If the target
682supports it, it will emit globals to the section specified.</p>
683
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]684<p>An explicit alignment may be specified for a global. If not present, or if
685the alignment is set to zero, the alignment of the global is set by the target
686to whatever it feels convenient. If an explicit alignment is specified, the
687global is forced to have at least that much alignment. All alignments must be
688a power of 2.</p>
689
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]690<p>For example, the following defines a global in a numbered address space with
691an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]692
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]693<div class="doc_code">
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]694<pre>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]695@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]696</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]697</div>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]698
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]699</div>
700
701
702<!-- ======================================================================= -->
703<div class="doc_subsection">
704 <a name="functionstructure">Functions</a>
705</div>
706
707<div class="doc_text">
708
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]709<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
710an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]711<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]712<a href="#callingconv">calling convention</a>, a return type, an optional
713<a href="#paramattrs">parameter attribute</a> for the return type, a function
714name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]715<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]716optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]717opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]718
719LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
720optional <a href="#linkage">linkage type</a>, an optional
721<a href="#visibility">visibility style</a>, an optional
722<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]723<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]724name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksene754abe2007-12-10 03:30:21 +0000[diff] [blame]725<a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]726
727<p>A function definition contains a list of basic blocks, forming the CFG for
728the function. Each basic block may optionally start with a label (giving the
729basic block a symbol table entry), contains a list of instructions, and ends
730with a <a href="#terminators">terminator</a> instruction (such as a branch or
731function return).</p>
732
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]733<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]734executed on entrance to the function, and it is not allowed to have predecessor
735basic blocks (i.e. there can not be any branches to the entry block of a
736function). Because the block can have no predecessors, it also cannot have any
737<a href="#i_phi">PHI nodes</a>.</p>
738
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]739<p>LLVM allows an explicit section to be specified for functions. If the target
740supports it, it will emit functions to the section specified.</p>
741
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]742<p>An explicit alignment may be specified for a function. If not present, or if
743the alignment is set to zero, the alignment of the function is set by the target
744to whatever it feels convenient. If an explicit alignment is specified, the
745function is forced to have at least that much alignment. All alignments must be
746a power of 2.</p>
747
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]748</div>
749
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
753 <a name="aliasstructure">Aliases</a>
754</div>
755<div class="doc_text">
756 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]757 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]758 optional <a href="#linkage">linkage type</a>, and an
759 optional <a href="#visibility">visibility style</a>.</p>
760
761 <h5>Syntax:</h5>
762
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]763<div class="doc_code">
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]764<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]765@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]766</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]767</div>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]768
769</div>
770
771
772
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]773<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
775<div class="doc_text">
776 <p>The return type and each parameter of a function type may have a set of
777 <i>parameter attributes</i> associated with them. Parameter attributes are
778 used to communicate additional information about the result or parameters of
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]779 a function. Parameter attributes are considered to be part of the function,
780 not of the function type, so functions with different parameter attributes
781 can have the same function type.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]782
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]783 <p>Parameter attributes are simple keywords that follow the type specified. If
784 multiple parameter attributes are needed, they are space separated. For
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]785 example:</p>
786
787<div class="doc_code">
788<pre>
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]789declare i32 @printf(i8* noalias , ...) nounwind
790declare i32 @atoi(i8*) nounwind readonly
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]791</pre>
792</div>
793
Duncan Sandsdc024672007-11-27 13:23:08 +0000[diff] [blame]794 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
795 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]796
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]797 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]798 <dl>
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]799 <dt><tt>zeroext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]800 <dd>This indicates that the parameter should be zero extended just before
801 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]802
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]803 <dt><tt>signext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]804 <dd>This indicates that the parameter should be sign extended just before
805 a call to this function.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]806
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]807 <dt><tt>inreg</tt></dt>
808 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]809 possible) during assembling function call. Support for this attribute is
810 target-specific</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]811
812 <dt><tt>byval</tt></dt>
Chris Lattner0747baa2008-01-15 04:34:22 +0000[diff] [blame]813 <dd>This indicates that the pointer parameter should really be passed by
814 value to the function. The attribute implies that a hidden copy of the
815 pointee is made between the caller and the callee, so the callee is unable
816 to modify the value in the callee. This attribute is only valid on llvm
817 pointer arguments. It is generally used to pass structs and arrays by
818 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]819
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]820 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]821 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]822 that is the return value of the function in the source program.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]823
Zhou Shengfebca342007-06-05 05:28:26 +0000[diff] [blame]824 <dt><tt>noalias</tt></dt>
825 <dd>This indicates that the parameter not alias any other object or any
826 other "noalias" objects during the function call.
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]827
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]828 <dt><tt>noreturn</tt></dt>
829 <dd>This function attribute indicates that the function never returns. This
830 indicates to LLVM that every call to this function should be treated as if
831 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]832
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]833 <dt><tt>nounwind</tt></dt>
834 <dd>This function attribute indicates that the function type does not use
835 the unwind instruction and does not allow stack unwinding to propagate
836 through it.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]837
Duncan Sands50f19f52007-07-27 19:57:41 +0000[diff] [blame]838 <dt><tt>nest</tt></dt>
839 <dd>This indicates that the parameter can be excised using the
840 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]841 <dt><tt>readonly</tt></dt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]842 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsed4a2f12007-11-22 20:23:04 +0000[diff] [blame]843 except for producing a return value or throwing an exception. The value
844 returned must only depend on the function arguments and/or global variables.
845 It may use values obtained by dereferencing pointers.</dd>
846 <dt><tt>readnone</tt></dt>
847 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sandsf04d5842007-11-14 21:14:02 +0000[diff] [blame]848 function, but in addition it is not allowed to dereference any pointer arguments
849 or global variables.
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]850 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]851
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]852</div>
853
854<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]855<div class="doc_subsection">
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]856 <a name="gc">Garbage Collector Names</a>
857</div>
858
859<div class="doc_text">
860<p>Each function may specify a garbage collector name, which is simply a
861string.</p>
862
863<div class="doc_code"><pre
864>define void @f() gc "name" { ...</pre></div>
865
866<p>The compiler declares the supported values of <i>name</i>. Specifying a
867collector which will cause the compiler to alter its output in order to support
868the named garbage collection algorithm.</p>
869</div>
870
871<!-- ======================================================================= -->
872<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]873 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]874</div>
875
876<div class="doc_text">
877<p>
878Modules may contain "module-level inline asm" blocks, which corresponds to the
879GCC "file scope inline asm" blocks. These blocks are internally concatenated by
880LLVM and treated as a single unit, but may be separated in the .ll file if
881desired. The syntax is very simple:
882</p>
883
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]884<div class="doc_code">
885<pre>
886module asm "inline asm code goes here"
887module asm "more can go here"
888</pre>
889</div>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]890
891<p>The strings can contain any character by escaping non-printable characters.
892 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
893 for the number.
894</p>
895
896<p>
897 The inline asm code is simply printed to the machine code .s file when
898 assembly code is generated.
899</p>
900</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]901
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]902<!-- ======================================================================= -->
903<div class="doc_subsection">
904 <a name="datalayout">Data Layout</a>
905</div>
906
907<div class="doc_text">
908<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]909data is to be laid out in memory. The syntax for the data layout is simply:</p>
910<pre> target datalayout = "<i>layout specification</i>"</pre>
911<p>The <i>layout specification</i> consists of a list of specifications
912separated by the minus sign character ('-'). Each specification starts with a
913letter and may include other information after the letter to define some
914aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]915<dl>
916 <dt><tt>E</tt></dt>
917 <dd>Specifies that the target lays out data in big-endian form. That is, the
918 bits with the most significance have the lowest address location.</dd>
919 <dt><tt>e</tt></dt>
920 <dd>Specifies that hte target lays out data in little-endian form. That is,
921 the bits with the least significance have the lowest address location.</dd>
922 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
923 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
924 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
925 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
926 too.</dd>
927 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
928 <dd>This specifies the alignment for an integer type of a given bit
929 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
930 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
931 <dd>This specifies the alignment for a vector type of a given bit
932 <i>size</i>.</dd>
933 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
934 <dd>This specifies the alignment for a floating point type of a given bit
935 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
936 (double).</dd>
937 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
938 <dd>This specifies the alignment for an aggregate type of a given bit
939 <i>size</i>.</dd>
940</dl>
941<p>When constructing the data layout for a given target, LLVM starts with a
942default set of specifications which are then (possibly) overriden by the
943specifications in the <tt>datalayout</tt> keyword. The default specifications
944are given in this list:</p>
945<ul>
946 <li><tt>E</tt> - big endian</li>
947 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
948 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
949 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
950 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
951 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
952 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
953 alignment of 64-bits</li>
954 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
955 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
956 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
957 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
958 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
959</ul>
960<p>When llvm is determining the alignment for a given type, it uses the
961following rules:
962<ol>
963 <li>If the type sought is an exact match for one of the specifications, that
964 specification is used.</li>
965 <li>If no match is found, and the type sought is an integer type, then the
966 smallest integer type that is larger than the bitwidth of the sought type is
967 used. If none of the specifications are larger than the bitwidth then the the
968 largest integer type is used. For example, given the default specifications
969 above, the i7 type will use the alignment of i8 (next largest) while both
970 i65 and i256 will use the alignment of i64 (largest specified).</li>
971 <li>If no match is found, and the type sought is a vector type, then the
972 largest vector type that is smaller than the sought vector type will be used
973 as a fall back. This happens because <128 x double> can be implemented in
974 terms of 64 <2 x double>, for example.</li>
975</ol>
976</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]977
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]978<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]979<div class="doc_section"> <a name="typesystem">Type System</a> </div>
980<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]981
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]982<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]983
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]984<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]985intermediate representation. Being typed enables a number of
986optimizations to be performed on the IR directly, without having to do
987extra analyses on the side before the transformation. A strong type
988system makes it easier to read the generated code and enables novel
989analyses and transformations that are not feasible to perform on normal
990three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]991
992</div>
993
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]994<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]995<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]996Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]997<div class="doc_text">
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]998<p>The types fall into a few useful
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]999classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1000
1001<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1002 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1003 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1004 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1005 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1006 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1007 </tr>
1008 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1009 <td><a href="#t_floating">floating point</a></td>
1010 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1011 </tr>
1012 <tr>
1013 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1014 <td><a href="#t_integer">integer</a>,
1015 <a href="#t_floating">floating point</a>,
1016 <a href="#t_pointer">pointer</a>,
1017 <a href="#t_vector">vector</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1018 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1019 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1020 <tr>
1021 <td><a href="#t_primitive">primitive</a></td>
1022 <td><a href="#t_label">label</a>,
1023 <a href="#t_void">void</a>,
1024 <a href="#t_integer">integer</a>,
1025 <a href="#t_floating">floating point</a>.</td>
1026 </tr>
1027 <tr>
1028 <td><a href="#t_derived">derived</a></td>
1029 <td><a href="#t_integer">integer</a>,
1030 <a href="#t_array">array</a>,
1031 <a href="#t_function">function</a>,
1032 <a href="#t_pointer">pointer</a>,
1033 <a href="#t_struct">structure</a>,
1034 <a href="#t_pstruct">packed structure</a>,
1035 <a href="#t_vector">vector</a>,
1036 <a href="#t_opaque">opaque</a>.
1037 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1038 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1039</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1040
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1041<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1042most important. Values of these types are the only ones which can be
1043produced by instructions, passed as arguments, or used as operands to
1044instructions. This means that all structures and arrays must be
1045manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1046</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1047
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1048<!-- ======================================================================= -->
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1049<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1050
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1051<div class="doc_text">
1052<p>The primitive types are the fundamental building blocks of the LLVM
1053system.</p>
1054
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1055</div>
1056
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1057<!-- _______________________________________________________________________ -->
1058<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1059
1060<div class="doc_text">
1061 <table>
1062 <tbody>
1063 <tr><th>Type</th><th>Description</th></tr>
1064 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1065 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1066 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1067 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1068 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1069 </tbody>
1070 </table>
1071</div>
1072
1073<!-- _______________________________________________________________________ -->
1074<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1075
1076<div class="doc_text">
1077<h5>Overview:</h5>
1078<p>The void type does not represent any value and has no size.</p>
1079
1080<h5>Syntax:</h5>
1081
1082<pre>
1083 void
1084</pre>
1085</div>
1086
1087<!-- _______________________________________________________________________ -->
1088<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1089
1090<div class="doc_text">
1091<h5>Overview:</h5>
1092<p>The label type represents code labels.</p>
1093
1094<h5>Syntax:</h5>
1095
1096<pre>
1097 label
1098</pre>
1099</div>
1100
1101
1102<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1103<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1104
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1105<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1106
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1107<p>The real power in LLVM comes from the derived types in the system.
1108This is what allows a programmer to represent arrays, functions,
1109pointers, and other useful types. Note that these derived types may be
1110recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1111
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1112</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1113
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1114<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1115<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1116
1117<div class="doc_text">
1118
1119<h5>Overview:</h5>
1120<p>The integer type is a very simple derived type that simply specifies an
1121arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11222^23-1 (about 8 million) can be specified.</p>
1123
1124<h5>Syntax:</h5>
1125
1126<pre>
1127 iN
1128</pre>
1129
1130<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1131value.</p>
1132
1133<h5>Examples:</h5>
1134<table class="layout">
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1135 <tbody>
1136 <tr>
1137 <td><tt>i1</tt></td>
1138 <td>a single-bit integer.</td>
1139 </tr><tr>
1140 <td><tt>i32</tt></td>
1141 <td>a 32-bit integer.</td>
1142 </tr><tr>
1143 <td><tt>i1942652</tt></td>
1144 <td>a really big integer of over 1 million bits.</td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1145 </tr>
Chris Lattnerb9488a62007-12-18 06:18:21 +0000[diff] [blame]1146 </tbody>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1147</table>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1148</div>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1149
1150<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1151<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1152
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1153<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1154
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1155<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1156
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1157<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1158sequentially in memory. The array type requires a size (number of
1159elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1160
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1161<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1162
1163<pre>
1164 [&lt;# elements&gt; x &lt;elementtype&gt;]
1165</pre>
1166
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1167<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1168be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1170<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1171<table class="layout">
1172 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1173 <td class="left"><tt>[40 x i32]</tt></td>
1174 <td class="left">Array of 40 32-bit integer values.</td>
1175 </tr>
1176 <tr class="layout">
1177 <td class="left"><tt>[41 x i32]</tt></td>
1178 <td class="left">Array of 41 32-bit integer values.</td>
1179 </tr>
1180 <tr class="layout">
1181 <td class="left"><tt>[4 x i8]</tt></td>
1182 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1183 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1184</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1185<p>Here are some examples of multidimensional arrays:</p>
1186<table class="layout">
1187 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1188 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1189 <td class="left">3x4 array of 32-bit integer values.</td>
1190 </tr>
1191 <tr class="layout">
1192 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1193 <td class="left">12x10 array of single precision floating point values.</td>
1194 </tr>
1195 <tr class="layout">
1196 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1197 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1198 </tr>
1199</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1200
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1201<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1202length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1203LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1204As a special case, however, zero length arrays are recognized to be variable
1205length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1206type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1208</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1209
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1210<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1211<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1212<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1213<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1214<p>The function type can be thought of as a function signature. It
1215consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1216Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1217(which are structures of pointers to functions), for indirect function
1218calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1219<p>
1220The return type of a function type cannot be an aggregate type.
1221</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1222<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1223<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1224<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]1225specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1226which indicates that the function takes a variable number of arguments.
1227Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1228 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1229<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1230<table class="layout">
1231 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1232 <td class="left"><tt>i32 (i32)</tt></td>
1233 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1234 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1235 </tr><tr class="layout">
Reid Spencer9445e9a2007-07-19 23:13:04 +0000[diff] [blame]1236 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1237 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1238 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1239 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1240 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1241 <tt>float</tt>.
1242 </td>
1243 </tr><tr class="layout">
1244 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1245 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1246 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1247 which returns an integer. This is the signature for <tt>printf</tt> in
1248 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
1250 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1251</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1252
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1253</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1254<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1255<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1256<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1257<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1258<p>The structure type is used to represent a collection of data members
1259together in memory. The packing of the field types is defined to match
1260the ABI of the underlying processor. The elements of a structure may
1261be any type that has a size.</p>
1262<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1263and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1264field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1265instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1266<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1267<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1268<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1269<table class="layout">
1270 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1271 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1272 <td class="left">A triple of three <tt>i32</tt> values</td>
1273 </tr><tr class="layout">
1274 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1275 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1276 second element is a <a href="#t_pointer">pointer</a> to a
1277 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1278 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1279 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1280</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1281</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1282
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1283<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1284<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1285</div>
1286<div class="doc_text">
1287<h5>Overview:</h5>
1288<p>The packed structure type is used to represent a collection of data members
1289together in memory. There is no padding between fields. Further, the alignment
1290of a packed structure is 1 byte. The elements of a packed structure may
1291be any type that has a size.</p>
1292<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1293and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1294field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1295instruction.</p>
1296<h5>Syntax:</h5>
1297<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1298<h5>Examples:</h5>
1299<table class="layout">
1300 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1301 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1302 <td class="left">A triple of three <tt>i32</tt> values</td>
1303 </tr><tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1304 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1305 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1306 second element is a <a href="#t_pointer">pointer</a> to a
1307 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1308 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1309 </tr>
1310</table>
1311</div>
1312
1313<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1314<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1315<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1316<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1317<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]1318reference to another object, which must live in memory. Pointer types may have
1319an optional address space attribute defining the target-specific numbered
1320address space where the pointed-to object resides. The default address space is
1321zero.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1322<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1323<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1324<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1325<table class="layout">
1326 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1327 <td class="left"><tt>[4x i32]*</tt></td>
1328 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1329 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1330 </tr>
1331 <tr class="layout">
1332 <td class="left"><tt>i32 (i32 *) *</tt></td>
1333 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1334 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1335 <tt>i32</tt>.</td>
1336 </tr>
1337 <tr class="layout">
1338 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1339 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1340 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1341 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1342</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1343</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1344
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1345<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1346<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1347<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1348
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1349<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1350
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1351<p>A vector type is a simple derived type that represents a vector
1352of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1353are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1354A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1355elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1356of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1357considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1358
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1359<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1360
1361<pre>
1362 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1363</pre>
1364
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1365<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1366be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1367
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1368<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1369
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1370<table class="layout">
1371 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1372 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1373 <td class="left">Vector of 4 32-bit integer values.</td>
1374 </tr>
1375 <tr class="layout">
1376 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1377 <td class="left">Vector of 8 32-bit floating-point values.</td>
1378 </tr>
1379 <tr class="layout">
1380 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1381 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1382 </tr>
1383</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1384</div>
1385
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1386<!-- _______________________________________________________________________ -->
1387<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1388<div class="doc_text">
1389
1390<h5>Overview:</h5>
1391
1392<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksen8ac04ff2007-10-14 00:34:53 +0000[diff] [blame]1393corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1394In LLVM, opaque types can eventually be resolved to any type (not just a
1395structure type).</p>
1396
1397<h5>Syntax:</h5>
1398
1399<pre>
1400 opaque
1401</pre>
1402
1403<h5>Examples:</h5>
1404
1405<table class="layout">
1406 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1407 <td class="left"><tt>opaque</tt></td>
1408 <td class="left">An opaque type.</td>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1409 </tr>
1410</table>
1411</div>
1412
1413
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1414<!-- *********************************************************************** -->
1415<div class="doc_section"> <a name="constants">Constants</a> </div>
1416<!-- *********************************************************************** -->
1417
1418<div class="doc_text">
1419
1420<p>LLVM has several different basic types of constants. This section describes
1421them all and their syntax.</p>
1422
1423</div>
1424
1425<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1426<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1427
1428<div class="doc_text">
1429
1430<dl>
1431 <dt><b>Boolean constants</b></dt>
1432
1433 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1434 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1435 </dd>
1436
1437 <dt><b>Integer constants</b></dt>
1438
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1439 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1440 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1441 integer types.
1442 </dd>
1443
1444 <dt><b>Floating point constants</b></dt>
1445
1446 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1447 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1448 notation (see below). Floating point constants must have a <a
1449 href="#t_floating">floating point</a> type. </dd>
1450
1451 <dt><b>Null pointer constants</b></dt>
1452
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1453 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1454 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1455
1456</dl>
1457
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1458<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1459of floating point constants. For example, the form '<tt>double
14600x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14614.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1462(and the only time that they are generated by the disassembler) is when a
1463floating point constant must be emitted but it cannot be represented as a
1464decimal floating point number. For example, NaN's, infinities, and other
1465special values are represented in their IEEE hexadecimal format so that
1466assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467
1468</div>
1469
1470<!-- ======================================================================= -->
1471<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1472</div>
1473
1474<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1475<p>Aggregate constants arise from aggregation of simple constants
1476and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1477
1478<dl>
1479 <dt><b>Structure constants</b></dt>
1480
1481 <dd>Structure constants are represented with notation similar to structure
1482 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner64910ee2007-12-25 20:34:52 +0000[diff] [blame]1483 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1484 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1485 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1486 types of elements must match those specified by the type.
1487 </dd>
1488
1489 <dt><b>Array constants</b></dt>
1490
1491 <dd>Array constants are represented with notation similar to array type
1492 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1493 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1494 constants must have <a href="#t_array">array type</a>, and the number and
1495 types of elements must match those specified by the type.
1496 </dd>
1497
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1498 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1499
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1500 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1501 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1502 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1503 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1504 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1505 match those specified by the type.
1506 </dd>
1507
1508 <dt><b>Zero initialization</b></dt>
1509
1510 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1511 value to zero of <em>any</em> type, including scalar and aggregate types.
1512 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1513 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1514 initializers.
1515 </dd>
1516</dl>
1517
1518</div>
1519
1520<!-- ======================================================================= -->
1521<div class="doc_subsection">
1522 <a name="globalconstants">Global Variable and Function Addresses</a>
1523</div>
1524
1525<div class="doc_text">
1526
1527<p>The addresses of <a href="#globalvars">global variables</a> and <a
1528href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1529constants. These constants are explicitly referenced when the <a
1530href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1531href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1532file:</p>
1533
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1534<div class="doc_code">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535<pre>
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]1536@X = global i32 17
1537@Y = global i32 42
1538@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1539</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1540</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1541
1542</div>
1543
1544<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1545<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1546<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1547 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1548 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1549 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1550
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1551 <p>Undefined values indicate to the compiler that the program is well defined
1552 no matter what value is used, giving the compiler more freedom to optimize.
1553 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1554</div>
1555
1556<!-- ======================================================================= -->
1557<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1558</div>
1559
1560<div class="doc_text">
1561
1562<p>Constant expressions are used to allow expressions involving other constants
1563to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1564href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1565that does not have side effects (e.g. load and call are not supported). The
1566following is the syntax for constant expressions:</p>
1567
1568<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1569 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1570 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1571 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1572
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1573 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1574 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1575 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1576
1577 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1578 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1579 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1580
1581 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1582 <dd>Truncate a floating point constant to another floating point type. The
1583 size of CST must be larger than the size of TYPE. Both types must be
1584 floating point.</dd>
1585
1586 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1587 <dd>Floating point extend a constant to another type. The size of CST must be
1588 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1589
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]1590 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1591 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1592 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1593 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1594 of the same number of elements. If the value won't fit in the integer type,
1595 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1596
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1597 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1598 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1599 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1600 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1601 of the same number of elements. If the value won't fit in the integer type,
1602 the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1603
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1604 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1605 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1606 constant. TYPE must be a scalar or vector floating point type. CST must be of
1607 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1608 of the same number of elements. If the value won't fit in the floating point
1609 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1610
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1611 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1612 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]1613 constant. TYPE must be a scalar or vector floating point type. CST must be of
1614 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1615 of the same number of elements. If the value won't fit in the floating point
1616 type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1617
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1618 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1619 <dd>Convert a pointer typed constant to the corresponding integer constant
1620 TYPE must be an integer type. CST must be of pointer type. The CST value is
1621 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1622
1623 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1624 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1625 pointer type. CST must be of integer type. The CST value is zero extended,
1626 truncated, or unchanged to make it fit in a pointer size. This one is
1627 <i>really</i> dangerous!</dd>
1628
1629 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1630 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1631 identical (same number of bits). The conversion is done as if the CST value
1632 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1633 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1634 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1635 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1636 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1637
1638 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1639
1640 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1641 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1642 instruction, the index list may have zero or more indexes, which are required
1643 to make sense for the type of "CSTPTR".</dd>
1644
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1645 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1646
1647 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1648 constants.</dd>
1649
1650 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1651 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1652
1653 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1654 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1655
1656 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1657
1658 <dd>Perform the <a href="#i_extractelement">extractelement
1659 operation</a> on constants.
1660
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1661 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1662
1663 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1664 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1665
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1666
1667 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1668
1669 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1670 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1671
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1672 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1673
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1674 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1675 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1676 binary</a> operations. The constraints on operands are the same as those for
1677 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1678 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1679</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1680</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1681
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1682<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1683<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1684<!-- *********************************************************************** -->
1685
1686<!-- ======================================================================= -->
1687<div class="doc_subsection">
1688<a name="inlineasm">Inline Assembler Expressions</a>
1689</div>
1690
1691<div class="doc_text">
1692
1693<p>
1694LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1695Module-Level Inline Assembly</a>) through the use of a special value. This
1696value represents the inline assembler as a string (containing the instructions
1697to emit), a list of operand constraints (stored as a string), and a flag that
1698indicates whether or not the inline asm expression has side effects. An example
1699inline assembler expression is:
1700</p>
1701
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1702<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1703<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1704i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1705</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1706</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1707
1708<p>
1709Inline assembler expressions may <b>only</b> be used as the callee operand of
1710a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1711</p>
1712
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1713<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1714<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1715%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1716</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1717</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1718
1719<p>
1720Inline asms with side effects not visible in the constraint list must be marked
1721as having side effects. This is done through the use of the
1722'<tt>sideeffect</tt>' keyword, like so:
1723</p>
1724
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1725<div class="doc_code">
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1726<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1727call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1728</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1729</div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1730
1731<p>TODO: The format of the asm and constraints string still need to be
1732documented here. Constraints on what can be done (e.g. duplication, moving, etc
1733need to be documented).
1734</p>
1735
1736</div>
1737
1738<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1739<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1740<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1741
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1742<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1743
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1744<p>The LLVM instruction set consists of several different
1745classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1746instructions</a>, <a href="#binaryops">binary instructions</a>,
1747<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1748 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1749instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1750
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1751</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1752
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1754<div class="doc_subsection"> <a name="terminators">Terminator
1755Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1756
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1758
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1759<p>As mentioned <a href="#functionstructure">previously</a>, every
1760basic block in a program ends with a "Terminator" instruction, which
1761indicates which block should be executed after the current block is
1762finished. These terminator instructions typically yield a '<tt>void</tt>'
1763value: they produce control flow, not values (the one exception being
1764the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1765<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1767instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1768the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1769 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1770 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1771
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1772</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1774<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1775<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1776Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1777<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1778<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1779<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1780 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1781</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1782<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1783<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1784value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1785<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1786returns a value and then causes control flow, and one that just causes
1787control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1788<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1789<p>The '<tt>ret</tt>' instruction may return any '<a
1790 href="#t_firstclass">first class</a>' type. Notice that a function is
1791not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1792instruction inside of the function that returns a value that does not
1793match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<p>When the '<tt>ret</tt>' instruction is executed, control flow
1796returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1797 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1798the instruction after the call. If the caller was an "<a
1799 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1800at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1801returns a value, that value shall set the call or invoke instruction's
1802return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1803<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1804<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1805 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1806</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1807</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1810<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1812<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1813</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1814<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1815<p>The '<tt>br</tt>' instruction is used to cause control flow to
1816transfer to a different basic block in the current function. There are
1817two forms of this instruction, corresponding to a conditional branch
1818and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1820<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1821single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1822unconditional form of the '<tt>br</tt>' instruction takes a single
1823'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1825<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1826argument is evaluated. If the value is <tt>true</tt>, control flows
1827to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1828control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1830<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1831 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1832</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1833<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1834<div class="doc_subsubsection">
1835 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1836</div>
1837
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1838<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1840
1841<pre>
1842 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1843</pre>
1844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1846
1847<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1848several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1849instruction, allowing a branch to occur to one of many possible
1850destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1851
1852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1853<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1854
1855<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1856comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1857an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1858table is not allowed to contain duplicate constant entries.</p>
1859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1860<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1861
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1862<p>The <tt>switch</tt> instruction specifies a table of values and
1863destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1864table is searched for the given value. If the value is found, control flow is
1865transfered to the corresponding destination; otherwise, control flow is
1866transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1867
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1868<h5>Implementation:</h5>
1869
1870<p>Depending on properties of the target machine and the particular
1871<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1872ways. For example, it could be generated as a series of chained conditional
1873branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1874
1875<h5>Example:</h5>
1876
1877<pre>
1878 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1879 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1880 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1881
1882 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1883 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1884
1885 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1886 switch i32 %val, label %otherwise [ i32 0, label %onzero
1887 i32 1, label %onone
1888 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1889</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1890</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1891
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1893<div class="doc_subsubsection">
1894 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1895</div>
1896
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1897<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1898
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1899<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1900
1901<pre>
1902 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1903 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1904</pre>
1905
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1906<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1907
1908<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1909function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1910'<tt>normal</tt>' label or the
1911'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1912"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1913"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1914href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1915continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1916
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1917<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1918
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1919<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1921<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1922 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1923 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1924 convention</a> the call should use. If none is specified, the call defaults
1925 to using C calling conventions.
1926 </li>
1927 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1928 function value being invoked. In most cases, this is a direct function
1929 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1930 an arbitrary pointer to function value.
1931 </li>
1932
1933 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1934 function to be invoked. </li>
1935
1936 <li>'<tt>function args</tt>': argument list whose types match the function
1937 signature argument types. If the function signature indicates the function
1938 accepts a variable number of arguments, the extra arguments can be
1939 specified. </li>
1940
1941 <li>'<tt>normal label</tt>': the label reached when the called function
1942 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1943
1944 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1945 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1946
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1947</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1951<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1952href="#i_call">call</a></tt>' instruction in most regards. The primary
1953difference is that it establishes an association with a label, which is used by
1954the runtime library to unwind the stack.</p>
1955
1956<p>This instruction is used in languages with destructors to ensure that proper
1957cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1958exception. Additionally, this is important for implementation of
1959'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1960
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1961<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1962<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1963 %retval = invoke i32 %Test(i32 15) to label %Continue
1964 unwind label %TestCleanup <i>; {i32}:retval set</i>
1965 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1966 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1967</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1968</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1969
1970
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1971<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1972
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1973<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1974Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1975
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1976<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1977
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1978<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1979<pre>
1980 unwind
1981</pre>
1982
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1983<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1984
1985<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1986at the first callee in the dynamic call stack which used an <a
1987href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1988primarily used to implement exception handling.</p>
1989
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1990<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1991
1992<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1993immediately halt. The dynamic call stack is then searched for the first <a
1994href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1995execution continues at the "exceptional" destination block specified by the
1996<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1997dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1998</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1999
2000<!-- _______________________________________________________________________ -->
2001
2002<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2003Instruction</a> </div>
2004
2005<div class="doc_text">
2006
2007<h5>Syntax:</h5>
2008<pre>
2009 unreachable
2010</pre>
2011
2012<h5>Overview:</h5>
2013
2014<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2015instruction is used to inform the optimizer that a particular portion of the
2016code is not reachable. This can be used to indicate that the code after a
2017no-return function cannot be reached, and other facts.</p>
2018
2019<h5>Semantics:</h5>
2020
2021<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2022</div>
2023
2024
2025
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2026<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2027<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2028<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2029<p>Binary operators are used to do most of the computation in a
2030program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2031produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2032multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2033The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2034necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2035<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2036</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2038<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2039Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2040<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2041<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2042<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2045<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2046<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2047<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2048 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2049 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2050Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2051<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2052<p>The value produced is the integer or floating point sum of the two
2053operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2054<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2055<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2056</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2057</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2058<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2059<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2060Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2061<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2062<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2063<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2064</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2066<p>The '<tt>sub</tt>' instruction returns the difference of its two
2067operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2068<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2069instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2071<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2072 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2073values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2074This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2075Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2076<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2077<p>The value produced is the integer or floating point difference of
2078the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2079<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2080<pre>
2081 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2082 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2083</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2084</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2085<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2086<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2087Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2088<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2089<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2090<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2091</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2092<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2093<p>The '<tt>mul</tt>' instruction returns the product of its two
2094operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2095<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2096<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2097 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2098values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2099This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2100Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2102<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2103two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]2104<p>Because the operands are the same width, the result of an integer
2105multiplication is the same whether the operands should be deemed unsigned or
2106signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2107<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2108<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2109</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2110</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2111<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2112<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2113</a></div>
2114<div class="doc_text">
2115<h5>Syntax:</h5>
2116<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2117</pre>
2118<h5>Overview:</h5>
2119<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2120operands.</p>
2121<h5>Arguments:</h5>
2122<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2123<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2124types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2125of the values in which case the elements must be integers.</p>
2126<h5>Semantics:</h5>
2127<p>The value produced is the unsigned integer quotient of the two operands. This
2128instruction always performs an unsigned division operation, regardless of
2129whether the arguments are unsigned or not.</p>
2130<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2131<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2132</pre>
2133</div>
2134<!-- _______________________________________________________________________ -->
2135<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2136</a> </div>
2137<div class="doc_text">
2138<h5>Syntax:</h5>
2139<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2140</pre>
2141<h5>Overview:</h5>
2142<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2143operands.</p>
2144<h5>Arguments:</h5>
2145<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2146<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2147types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2148of the values in which case the elements must be integers.</p>
2149<h5>Semantics:</h5>
2150<p>The value produced is the signed integer quotient of the two operands. This
2151instruction always performs a signed division operation, regardless of whether
2152the arguments are signed or not.</p>
2153<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2154<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2155</pre>
2156</div>
2157<!-- _______________________________________________________________________ -->
2158<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2159Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2160<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2161<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2162<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2163</pre>
2164<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2165<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2166operands.</p>
2167<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2168<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2169<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2170identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2171versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2172<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2173<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2174<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2175<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2176</pre>
2177</div>
2178<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2179<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2180</div>
2181<div class="doc_text">
2182<h5>Syntax:</h5>
2183<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2184</pre>
2185<h5>Overview:</h5>
2186<p>The '<tt>urem</tt>' instruction returns the remainder from the
2187unsigned division of its two arguments.</p>
2188<h5>Arguments:</h5>
2189<p>The two arguments to the '<tt>urem</tt>' instruction must be
2190<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2191types. This instruction can also take <a href="#t_vector">vector</a> versions
2192of the values in which case the elements must be integers.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2193<h5>Semantics:</h5>
2194<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2195This instruction always performs an unsigned division to get the remainder,
2196regardless of whether the arguments are unsigned or not.</p>
2197<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2198<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2199</pre>
2200
2201</div>
2202<!-- _______________________________________________________________________ -->
2203<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2204Instruction</a> </div>
2205<div class="doc_text">
2206<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2207<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2208</pre>
2209<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2210<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2211signed division of its two operands. This instruction can also take
2212<a href="#t_vector">vector</a> versions of the values in which case
2213the elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]2214
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2215<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2216<p>The two arguments to the '<tt>srem</tt>' instruction must be
2217<a href="#t_integer">integer</a> values. Both arguments must have identical
2218types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2219<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2220<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2221has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2222operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2223a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2224 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2225Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2226please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2227Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2228<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2229<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2230</pre>
2231
2232</div>
2233<!-- _______________________________________________________________________ -->
2234<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2235Instruction</a> </div>
2236<div class="doc_text">
2237<h5>Syntax:</h5>
2238<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2239</pre>
2240<h5>Overview:</h5>
2241<p>The '<tt>frem</tt>' instruction returns the remainder from the
2242division of its two operands.</p>
2243<h5>Arguments:</h5>
2244<p>The two arguments to the '<tt>frem</tt>' instruction must be
2245<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman80176312007-11-05 23:35:22 +0000[diff] [blame]2246identical types. This instruction can also take <a href="#t_vector">vector</a>
2247versions of floating point values.</p>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2248<h5>Semantics:</h5>
2249<p>This instruction returns the <i>remainder</i> of a division.</p>
2250<h5>Example:</h5>
2251<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2252</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2253</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2254
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2255<!-- ======================================================================= -->
2256<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2257Operations</a> </div>
2258<div class="doc_text">
2259<p>Bitwise binary operators are used to do various forms of
2260bit-twiddling in a program. They are generally very efficient
2261instructions and can commonly be strength reduced from other
2262instructions. They require two operands, execute an operation on them,
2263and produce a single value. The resulting value of the bitwise binary
2264operators is always the same type as its first operand.</p>
2265</div>
2266
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2267<!-- _______________________________________________________________________ -->
2268<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2269Instruction</a> </div>
2270<div class="doc_text">
2271<h5>Syntax:</h5>
2272<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2273</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2274
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2275<h5>Overview:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2276
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2277<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2278the left a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2279
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2280<h5>Arguments:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2281
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2282<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2283 href="#t_integer">integer</a> type.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2284
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2285<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2286
2287<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2288<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2289of bits in <tt>var1</tt>, the result is undefined.</p>
2290
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2291<h5>Example:</h5><pre>
2292 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2293 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2294 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2295 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2296</pre>
2297</div>
2298<!-- _______________________________________________________________________ -->
2299<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2300Instruction</a> </div>
2301<div class="doc_text">
2302<h5>Syntax:</h5>
2303<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2304</pre>
2305
2306<h5>Overview:</h5>
2307<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2308operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2309
2310<h5>Arguments:</h5>
2311<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2312<a href="#t_integer">integer</a> type.</p>
2313
2314<h5>Semantics:</h5>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2315
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2316<p>This instruction always performs a logical shift right operation. The most
2317significant bits of the result will be filled with zero bits after the
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2318shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2319the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2320
2321<h5>Example:</h5>
2322<pre>
2323 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2324 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2325 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2326 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2327 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2328</pre>
2329</div>
2330
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2331<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2332<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2333Instruction</a> </div>
2334<div class="doc_text">
2335
2336<h5>Syntax:</h5>
2337<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2338</pre>
2339
2340<h5>Overview:</h5>
2341<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2342operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2343
2344<h5>Arguments:</h5>
2345<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2346<a href="#t_integer">integer</a> type.</p>
2347
2348<h5>Semantics:</h5>
2349<p>This instruction always performs an arithmetic shift right operation,
2350The most significant bits of the result will be filled with the sign bit
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2351of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2352larger than the number of bits in <tt>var1</tt>, the result is undefined.
2353</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2354
2355<h5>Example:</h5>
2356<pre>
2357 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2358 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2359 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2360 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]2361 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2362</pre>
2363</div>
2364
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2365<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2366<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2367Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2368<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2369<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2370<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2371</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2372<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2373<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2374its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2375<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2376<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2377 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2378identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2379<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2380<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2381<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2382<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2383<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2384 <tbody>
2385 <tr>
2386 <td>In0</td>
2387 <td>In1</td>
2388 <td>Out</td>
2389 </tr>
2390 <tr>
2391 <td>0</td>
2392 <td>0</td>
2393 <td>0</td>
2394 </tr>
2395 <tr>
2396 <td>0</td>
2397 <td>1</td>
2398 <td>0</td>
2399 </tr>
2400 <tr>
2401 <td>1</td>
2402 <td>0</td>
2403 <td>0</td>
2404 </tr>
2405 <tr>
2406 <td>1</td>
2407 <td>1</td>
2408 <td>1</td>
2409 </tr>
2410 </tbody>
2411</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2412</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2413<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2414<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2415 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2416 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2417</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2418</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2419<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2420<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2421<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2423<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2424</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2425<h5>Overview:</h5>
2426<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2427or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2428<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2429<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2430 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2431identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2433<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2434<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2435<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2436<table border="1" cellspacing="0" cellpadding="4">
2437 <tbody>
2438 <tr>
2439 <td>In0</td>
2440 <td>In1</td>
2441 <td>Out</td>
2442 </tr>
2443 <tr>
2444 <td>0</td>
2445 <td>0</td>
2446 <td>0</td>
2447 </tr>
2448 <tr>
2449 <td>0</td>
2450 <td>1</td>
2451 <td>1</td>
2452 </tr>
2453 <tr>
2454 <td>1</td>
2455 <td>0</td>
2456 <td>1</td>
2457 </tr>
2458 <tr>
2459 <td>1</td>
2460 <td>1</td>
2461 <td>1</td>
2462 </tr>
2463 </tbody>
2464</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2465</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2466<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2467<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2468 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2469 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2470</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2471</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2472<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2473<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2474Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2475<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2476<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2477<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2478</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2480<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2481or of its two operands. The <tt>xor</tt> is used to implement the
2482"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2483<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2484<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2485 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2486identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2487<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2488<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2489<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2490<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2491<table border="1" cellspacing="0" cellpadding="4">
2492 <tbody>
2493 <tr>
2494 <td>In0</td>
2495 <td>In1</td>
2496 <td>Out</td>
2497 </tr>
2498 <tr>
2499 <td>0</td>
2500 <td>0</td>
2501 <td>0</td>
2502 </tr>
2503 <tr>
2504 <td>0</td>
2505 <td>1</td>
2506 <td>1</td>
2507 </tr>
2508 <tr>
2509 <td>1</td>
2510 <td>0</td>
2511 <td>1</td>
2512 </tr>
2513 <tr>
2514 <td>1</td>
2515 <td>1</td>
2516 <td>0</td>
2517 </tr>
2518 </tbody>
2519</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2520</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2521<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2522<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2523<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2524 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2525 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2526 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2528</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2530<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2531<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2532 <a name="vectorops">Vector Operations</a>
2533</div>
2534
2535<div class="doc_text">
2536
2537<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2538target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2539vector-specific operations needed to process vectors effectively. While LLVM
2540does directly support these vector operations, many sophisticated algorithms
2541will want to use target-specific intrinsics to take full advantage of a specific
2542target.</p>
2543
2544</div>
2545
2546<!-- _______________________________________________________________________ -->
2547<div class="doc_subsubsection">
2548 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2549</div>
2550
2551<div class="doc_text">
2552
2553<h5>Syntax:</h5>
2554
2555<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2556 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2557</pre>
2558
2559<h5>Overview:</h5>
2560
2561<p>
2562The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2563element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2564</p>
2565
2566
2567<h5>Arguments:</h5>
2568
2569<p>
2570The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2571value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2572an index indicating the position from which to extract the element.
2573The index may be a variable.</p>
2574
2575<h5>Semantics:</h5>
2576
2577<p>
2578The result is a scalar of the same type as the element type of
2579<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2580<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2581results are undefined.
2582</p>
2583
2584<h5>Example:</h5>
2585
2586<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2587 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2588</pre>
2589</div>
2590
2591
2592<!-- _______________________________________________________________________ -->
2593<div class="doc_subsubsection">
2594 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2595</div>
2596
2597<div class="doc_text">
2598
2599<h5>Syntax:</h5>
2600
2601<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2602 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2603</pre>
2604
2605<h5>Overview:</h5>
2606
2607<p>
2608The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2609element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2610</p>
2611
2612
2613<h5>Arguments:</h5>
2614
2615<p>
2616The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2617value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2618scalar value whose type must equal the element type of the first
2619operand. The third operand is an index indicating the position at
2620which to insert the value. The index may be a variable.</p>
2621
2622<h5>Semantics:</h5>
2623
2624<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2625The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2626element values are those of <tt>val</tt> except at position
2627<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2628exceeds the length of <tt>val</tt>, the results are undefined.
2629</p>
2630
2631<h5>Example:</h5>
2632
2633<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2634 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2635</pre>
2636</div>
2637
2638<!-- _______________________________________________________________________ -->
2639<div class="doc_subsubsection">
2640 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2641</div>
2642
2643<div class="doc_text">
2644
2645<h5>Syntax:</h5>
2646
2647<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2648 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2649</pre>
2650
2651<h5>Overview:</h5>
2652
2653<p>
2654The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2655from two input vectors, returning a vector of the same type.
2656</p>
2657
2658<h5>Arguments:</h5>
2659
2660<p>
2661The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2662with types that match each other and types that match the result of the
2663instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2664of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2665</p>
2666
2667<p>
2668The shuffle mask operand is required to be a constant vector with either
2669constant integer or undef values.
2670</p>
2671
2672<h5>Semantics:</h5>
2673
2674<p>
2675The elements of the two input vectors are numbered from left to right across
2676both of the vectors. The shuffle mask operand specifies, for each element of
2677the result vector, which element of the two input registers the result element
2678gets. The element selector may be undef (meaning "don't care") and the second
2679operand may be undef if performing a shuffle from only one vector.
2680</p>
2681
2682<h5>Example:</h5>
2683
2684<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2685 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2686 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2687 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2688 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2689</pre>
2690</div>
2691
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2692
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2693<!-- ======================================================================= -->
2694<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2695 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2696</div>
2697
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2698<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2699
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2700<p>A key design point of an SSA-based representation is how it
2701represents memory. In LLVM, no memory locations are in SSA form, which
2702makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2703allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2704
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2705</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2707<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2708<div class="doc_subsubsection">
2709 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2710</div>
2711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2712<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2714<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2715
2716<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2717 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2718</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2719
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2720<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2721
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2722<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2723heap and returns a pointer to it. The object is always allocated in the generic
2724address space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2725
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2726<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2727
2728<p>The '<tt>malloc</tt>' instruction allocates
2729<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2730bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2731appropriate type to the program. If "NumElements" is specified, it is the
2732number of elements allocated. If an alignment is specified, the value result
2733of the allocation is guaranteed to be aligned to at least that boundary. If
2734not specified, or if zero, the target can choose to align the allocation on any
2735convenient boundary.</p>
2736
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2737<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2738
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2739<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2740
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2741<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2742a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2743
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2744<h5>Example:</h5>
2745
2746<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2747 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2748
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]2749 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2750 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2751 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2752 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2753 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2754</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2755</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2758<div class="doc_subsubsection">
2759 <a name="i_free">'<tt>free</tt>' Instruction</a>
2760</div>
2761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2762<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2763
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2764<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2765
2766<pre>
2767 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2768</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2769
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2770<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2771
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2772<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2773memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2775<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2776
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2777<p>'<tt>value</tt>' shall be a pointer value that points to a value
2778that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2779instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2781<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2782
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2783<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2784after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2785
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2786<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2787
2788<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2789 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2790 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2791</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2792</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2794<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2795<div class="doc_subsubsection">
2796 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2797</div>
2798
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2799<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2800
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2801<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2802
2803<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2804 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2805</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2806
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2807<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2808
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2809<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2810currently executing function, to be automatically released when this function
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]2811returns to its caller. The object is always allocated in the generic address
2812space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2815
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2816<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2817bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2818appropriate type to the program. If "NumElements" is specified, it is the
2819number of elements allocated. If an alignment is specified, the value result
2820of the allocation is guaranteed to be aligned to at least that boundary. If
2821not specified, or if zero, the target can choose to align the allocation on any
2822convenient boundary.</p>
2823
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2824<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2825
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2826<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2827
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2828<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2829memory is automatically released when the function returns. The '<tt>alloca</tt>'
2830instruction is commonly used to represent automatic variables that must
2831have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2832 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2833instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2834
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2835<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2836
2837<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2838 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2839 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2840 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2841 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2842</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2843</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2844
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2845<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2846<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2847Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2848<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2849<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2850<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2851<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2852<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2853<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2854<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2855address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2856 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2857marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2858the number or order of execution of this <tt>load</tt> with other
2859volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2860instructions. </p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2861<p>
2862The optional "align" argument specifies the alignment of the operation
2863(that is, the alignment of the memory address). A value of 0 or an
2864omitted "align" argument means that the operation has the preferential
2865alignment for the target. It is the responsibility of the code emitter
2866to ensure that the alignment information is correct. Overestimating
2867the alignment results in an undefined behavior. Underestimating the
2868alignment may produce less efficient code. An alignment of 1 is always
2869safe.
2870</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2871<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2872<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2873<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2874<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2875 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2876 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2877 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2878</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2879</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2880<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2881<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2882Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2883<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2884<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2885<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2886 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2887</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2888<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2889<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2890<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2891<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2892to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2893operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2894operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2895optimizer is not allowed to modify the number or order of execution of
2896this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2897 href="#i_store">store</a></tt> instructions.</p>
Chris Lattnera31d1d72008-01-06 21:04:43 +0000[diff] [blame]2898<p>
2899The optional "align" argument specifies the alignment of the operation
2900(that is, the alignment of the memory address). A value of 0 or an
2901omitted "align" argument means that the operation has the preferential
2902alignment for the target. It is the responsibility of the code emitter
2903to ensure that the alignment information is correct. Overestimating
2904the alignment results in an undefined behavior. Underestimating the
2905alignment may produce less efficient code. An alignment of 1 is always
2906safe.
2907</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2908<h5>Semantics:</h5>
2909<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2910at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2911<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2912<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]2913 store i32 3, i32* %ptr <i>; yields {void}</i>
2914 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2915</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2916</div>
2917
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2918<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2919<div class="doc_subsubsection">
2920 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2921</div>
2922
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2923<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2924<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2925<pre>
2926 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2927</pre>
2928
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2929<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2930
2931<p>
2932The '<tt>getelementptr</tt>' instruction is used to get the address of a
2933subelement of an aggregate data structure.</p>
2934
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2935<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2936
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2937<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2938elements of the aggregate object to index to. The actual types of the arguments
2939provided depend on the type of the first pointer argument. The
2940'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2941levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2942structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2943into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2944be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2945
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2946<p>For example, let's consider a C code fragment and how it gets
2947compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2948
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2949<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2950<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2951struct RT {
2952 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2953 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2954 char C;
2955};
2956struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2957 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2958 double Y;
2959 struct RT Z;
2960};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2961
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]2962int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2963 return &amp;s[1].Z.B[5][13];
2964}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2965</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2966</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2967
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2968<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2969
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2970<div class="doc_code">
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2971<pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2972%RT = type { i8 , [10 x [20 x i32]], i8 }
2973%ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2974
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2975define i32* %foo(%ST* %s) {
2976entry:
2977 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2978 ret i32* %reg
2979}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2980</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2981</div>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2982
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2983<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2984
2985<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2986on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2987and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2988<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2989to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2990<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2991
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2992<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2993type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2994}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2995the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2996i8 }</tt>' type, another structure. The third index indexes into the second
2997element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2998array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2999'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3000to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3001
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3002<p>Note that it is perfectly legal to index partially through a
3003structure, returning a pointer to an inner element. Because of this,
3004the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3005
3006<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3007 define i32* %foo(%ST* %s) {
3008 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3009 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3010 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3011 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3012 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3013 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3014 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3015</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3016
3017<p>Note that it is undefined to access an array out of bounds: array and
3018pointer indexes must always be within the defined bounds of the array type.
3019The one exception for this rules is zero length arrays. These arrays are
3020defined to be accessible as variable length arrays, which requires access
3021beyond the zero'th element.</p>
3022
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]3023<p>The getelementptr instruction is often confusing. For some more insight
3024into how it works, see <a href="GetElementPtr.html">the getelementptr
3025FAQ</a>.</p>
3026
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3027<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]3028
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3029<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3030 <i>; yields [12 x i8]*:aptr</i>
3031 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3032</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]3033</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]3034
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3035<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3036<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3037</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3038<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3039<p>The instructions in this category are the conversion instructions (casting)
3040which all take a single operand and a type. They perform various bit conversions
3041on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3042</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3043
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3044<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3045<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3046 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3047</div>
3048<div class="doc_text">
3049
3050<h5>Syntax:</h5>
3051<pre>
3052 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3053</pre>
3054
3055<h5>Overview:</h5>
3056<p>
3057The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3058</p>
3059
3060<h5>Arguments:</h5>
3061<p>
3062The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3063be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3064and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3065type. The bit size of <tt>value</tt> must be larger than the bit size of
3066<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3067
3068<h5>Semantics:</h5>
3069<p>
3070The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3071and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3072larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3073It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074
3075<h5>Example:</h5>
3076<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3077 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3078 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3079 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3080</pre>
3081</div>
3082
3083<!-- _______________________________________________________________________ -->
3084<div class="doc_subsubsection">
3085 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3086</div>
3087<div class="doc_text">
3088
3089<h5>Syntax:</h5>
3090<pre>
3091 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3092</pre>
3093
3094<h5>Overview:</h5>
3095<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3096<tt>ty2</tt>.</p>
3097
3098
3099<h5>Arguments:</h5>
3100<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3101<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3102also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3103<tt>value</tt> must be smaller than the bit size of the destination type,
3104<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3105
3106<h5>Semantics:</h5>
3107<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]3108bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3109
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]3110<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111
3112<h5>Example:</h5>
3113<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3114 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3115 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3116</pre>
3117</div>
3118
3119<!-- _______________________________________________________________________ -->
3120<div class="doc_subsubsection">
3121 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3122</div>
3123<div class="doc_text">
3124
3125<h5>Syntax:</h5>
3126<pre>
3127 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3128</pre>
3129
3130<h5>Overview:</h5>
3131<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3132
3133<h5>Arguments:</h5>
3134<p>
3135The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3136<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3137also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3138<tt>value</tt> must be smaller than the bit size of the destination type,
3139<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3140
3141<h5>Semantics:</h5>
3142<p>
3143The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3144bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerd1d25172007-05-24 19:13:27 +0000[diff] [blame]3145the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3146
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3147<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3148
3149<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3150<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3151 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3152 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3153</pre>
3154</div>
3155
3156<!-- _______________________________________________________________________ -->
3157<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3158 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3159</div>
3160
3161<div class="doc_text">
3162
3163<h5>Syntax:</h5>
3164
3165<pre>
3166 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3167</pre>
3168
3169<h5>Overview:</h5>
3170<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3171<tt>ty2</tt>.</p>
3172
3173
3174<h5>Arguments:</h5>
3175<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3176 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3177cast it to. The size of <tt>value</tt> must be larger than the size of
3178<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3179<i>no-op cast</i>.</p>
3180
3181<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3182<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3183<a href="#t_floating">floating point</a> type to a smaller
3184<a href="#t_floating">floating point</a> type. If the value cannot fit within
3185the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]3186
3187<h5>Example:</h5>
3188<pre>
3189 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3190 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3191</pre>
3192</div>
3193
3194<!-- _______________________________________________________________________ -->
3195<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3196 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3197</div>
3198<div class="doc_text">
3199
3200<h5>Syntax:</h5>
3201<pre>
3202 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3203</pre>
3204
3205<h5>Overview:</h5>
3206<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3207floating point value.</p>
3208
3209<h5>Arguments:</h5>
3210<p>The '<tt>fpext</tt>' instruction takes a
3211<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3212and a <a href="#t_floating">floating point</a> type to cast it to. The source
3213type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3214
3215<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3216<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3217<a href="#t_floating">floating point</a> type to a larger
3218<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3219used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3220<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3221
3222<h5>Example:</h5>
3223<pre>
3224 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3225 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3226</pre>
3227</div>
3228
3229<!-- _______________________________________________________________________ -->
3230<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3231 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3232</div>
3233<div class="doc_text">
3234
3235<h5>Syntax:</h5>
3236<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3237 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3238</pre>
3239
3240<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3241<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3242unsigned integer equivalent of type <tt>ty2</tt>.
3243</p>
3244
3245<h5>Arguments:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3246<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3247scalar or vector <a href="#t_floating">floating point</a> value, and a type
3248to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3249type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3250vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3251
3252<h5>Semantics:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3253<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3254<a href="#t_floating">floating point</a> operand into the nearest (rounding
3255towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3256the results are undefined.</p>
3257
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3258<h5>Example:</h5>
3259<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3260 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3261 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]3262 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3263</pre>
3264</div>
3265
3266<!-- _______________________________________________________________________ -->
3267<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3268 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3269</div>
3270<div class="doc_text">
3271
3272<h5>Syntax:</h5>
3273<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3274 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3275</pre>
3276
3277<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3278<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3279<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3280</p>
3281
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3282<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3283<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3284scalar or vector <a href="#t_floating">floating point</a> value, and a type
3285to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3286type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3287vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3288
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3289<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3290<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3291<a href="#t_floating">floating point</a> operand into the nearest (rounding
3292towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3293the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3294
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3295<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3296<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3297 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]3298 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3299 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3300</pre>
3301</div>
3302
3303<!-- _______________________________________________________________________ -->
3304<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3305 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3306</div>
3307<div class="doc_text">
3308
3309<h5>Syntax:</h5>
3310<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3311 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3312</pre>
3313
3314<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3315<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3316integer and converts that value to the <tt>ty2</tt> type.</p>
3317
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3318<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3319<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3320scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3321to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3322type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3323floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3324
3325<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3326<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3327integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3328the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3329
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3330<h5>Example:</h5>
3331<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3332 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3333 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3334</pre>
3335</div>
3336
3337<!-- _______________________________________________________________________ -->
3338<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3339 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3340</div>
3341<div class="doc_text">
3342
3343<h5>Syntax:</h5>
3344<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3345 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3346</pre>
3347
3348<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3349<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3350integer and converts that value to the <tt>ty2</tt> type.</p>
3351
3352<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]3353<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3354scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3355to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3356type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3357floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3358
3359<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3360<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3361integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3362the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3363
3364<h5>Example:</h5>
3365<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3366 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3367 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3368</pre>
3369</div>
3370
3371<!-- _______________________________________________________________________ -->
3372<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3373 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3374</div>
3375<div class="doc_text">
3376
3377<h5>Syntax:</h5>
3378<pre>
3379 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3380</pre>
3381
3382<h5>Overview:</h5>
3383<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3384the integer type <tt>ty2</tt>.</p>
3385
3386<h5>Arguments:</h5>
3387<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3388must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3389<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3390
3391<h5>Semantics:</h5>
3392<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3393<tt>ty2</tt> by interpreting the pointer value as an integer and either
3394truncating or zero extending that value to the size of the integer type. If
3395<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3396<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3397are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3398change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3399
3400<h5>Example:</h5>
3401<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3402 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3403 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3404</pre>
3405</div>
3406
3407<!-- _______________________________________________________________________ -->
3408<div class="doc_subsubsection">
3409 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3410</div>
3411<div class="doc_text">
3412
3413<h5>Syntax:</h5>
3414<pre>
3415 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3416</pre>
3417
3418<h5>Overview:</h5>
3419<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3420a pointer type, <tt>ty2</tt>.</p>
3421
3422<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3423<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3424value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3425<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3426
3427<h5>Semantics:</h5>
3428<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3429<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3430the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3431size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3432the size of a pointer then a zero extension is done. If they are the same size,
3433nothing is done (<i>no-op cast</i>).</p>
3434
3435<h5>Example:</h5>
3436<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3437 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3438 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3439 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3440</pre>
3441</div>
3442
3443<!-- _______________________________________________________________________ -->
3444<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3445 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3446</div>
3447<div class="doc_text">
3448
3449<h5>Syntax:</h5>
3450<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3451 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3452</pre>
3453
3454<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3455<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3456<tt>ty2</tt> without changing any bits.</p>
3457
3458<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3459<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3460a first class value, and a type to cast it to, which must also be a <a
3461 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3462and the destination type, <tt>ty2</tt>, must be identical. If the source
3463type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3464
3465<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3466<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3467<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3468this conversion. The conversion is done as if the <tt>value</tt> had been
3469stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3470converted to other pointer types with this instruction. To convert pointers to
3471other types, use the <a href="#i_inttoptr">inttoptr</a> or
3472<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3473
3474<h5>Example:</h5>
3475<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3476 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3477 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3478 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3479</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3480</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3481
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3482<!-- ======================================================================= -->
3483<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3484<div class="doc_text">
3485<p>The instructions in this category are the "miscellaneous"
3486instructions, which defy better classification.</p>
3487</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3488
3489<!-- _______________________________________________________________________ -->
3490<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3491</div>
3492<div class="doc_text">
3493<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3494<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3495</pre>
3496<h5>Overview:</h5>
3497<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3498of its two integer operands.</p>
3499<h5>Arguments:</h5>
3500<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3501the condition code indicating the kind of comparison to perform. It is not
3502a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3503<ol>
3504 <li><tt>eq</tt>: equal</li>
3505 <li><tt>ne</tt>: not equal </li>
3506 <li><tt>ugt</tt>: unsigned greater than</li>
3507 <li><tt>uge</tt>: unsigned greater or equal</li>
3508 <li><tt>ult</tt>: unsigned less than</li>
3509 <li><tt>ule</tt>: unsigned less or equal</li>
3510 <li><tt>sgt</tt>: signed greater than</li>
3511 <li><tt>sge</tt>: signed greater or equal</li>
3512 <li><tt>slt</tt>: signed less than</li>
3513 <li><tt>sle</tt>: signed less or equal</li>
3514</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3515<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3516<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3517<h5>Semantics:</h5>
3518<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3519the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3520yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3521<ol>
3522 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3523 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3524 </li>
3525 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3526 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3527 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3528 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3529 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3530 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3531 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3532 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3533 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3534 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3535 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3536 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3537 <li><tt>sge</tt>: interprets the operands as signed values and yields
3538 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3539 <li><tt>slt</tt>: interprets the operands as signed values and yields
3540 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3541 <li><tt>sle</tt>: interprets the operands as signed values and yields
3542 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3543</ol>
3544<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3545values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3546
3547<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3548<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3549 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3550 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3551 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3552 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3553 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3554</pre>
3555</div>
3556
3557<!-- _______________________________________________________________________ -->
3558<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3559</div>
3560<div class="doc_text">
3561<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3562<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3563</pre>
3564<h5>Overview:</h5>
3565<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3566of its floating point operands.</p>
3567<h5>Arguments:</h5>
3568<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3569the condition code indicating the kind of comparison to perform. It is not
3570a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3571<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3572 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3573 <li><tt>oeq</tt>: ordered and equal</li>
3574 <li><tt>ogt</tt>: ordered and greater than </li>
3575 <li><tt>oge</tt>: ordered and greater than or equal</li>
3576 <li><tt>olt</tt>: ordered and less than </li>
3577 <li><tt>ole</tt>: ordered and less than or equal</li>
3578 <li><tt>one</tt>: ordered and not equal</li>
3579 <li><tt>ord</tt>: ordered (no nans)</li>
3580 <li><tt>ueq</tt>: unordered or equal</li>
3581 <li><tt>ugt</tt>: unordered or greater than </li>
3582 <li><tt>uge</tt>: unordered or greater than or equal</li>
3583 <li><tt>ult</tt>: unordered or less than </li>
3584 <li><tt>ule</tt>: unordered or less than or equal</li>
3585 <li><tt>une</tt>: unordered or not equal</li>
3586 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3587 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3588</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3589<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3590<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3591<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3592<a href="#t_floating">floating point</a> typed. They must have identical
3593types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3594<h5>Semantics:</h5>
3595<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3596the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3597yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3598<ol>
3599 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3600 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3601 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3602 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3603 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3604 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3605 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3606 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3607 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3608 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3609 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3610 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3611 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3612 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3613 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3614 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3615 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3616 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3617 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3618 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3619 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3620 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3621 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3622 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3623 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3624 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3625 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3626 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3627</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3628
3629<h5>Example:</h5>
3630<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3631 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3632 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3633 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3634</pre>
3635</div>
3636
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3637<!-- _______________________________________________________________________ -->
3638<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3639Instruction</a> </div>
3640<div class="doc_text">
3641<h5>Syntax:</h5>
3642<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3643<h5>Overview:</h5>
3644<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3645the SSA graph representing the function.</p>
3646<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3647<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3648field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3649as arguments, with one pair for each predecessor basic block of the
3650current block. Only values of <a href="#t_firstclass">first class</a>
3651type may be used as the value arguments to the PHI node. Only labels
3652may be used as the label arguments.</p>
3653<p>There must be no non-phi instructions between the start of a basic
3654block and the PHI instructions: i.e. PHI instructions must be first in
3655a basic block.</p>
3656<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3657<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3658specified by the pair corresponding to the predecessor basic block that executed
3659just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3660<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3661<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3662</div>
3663
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3664<!-- _______________________________________________________________________ -->
3665<div class="doc_subsubsection">
3666 <a name="i_select">'<tt>select</tt>' Instruction</a>
3667</div>
3668
3669<div class="doc_text">
3670
3671<h5>Syntax:</h5>
3672
3673<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3674 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3675</pre>
3676
3677<h5>Overview:</h5>
3678
3679<p>
3680The '<tt>select</tt>' instruction is used to choose one value based on a
3681condition, without branching.
3682</p>
3683
3684
3685<h5>Arguments:</h5>
3686
3687<p>
3688The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
3689</p>
3690
3691<h5>Semantics:</h5>
3692
3693<p>
3694If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3695value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3696</p>
3697
3698<h5>Example:</h5>
3699
3700<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3701 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3702</pre>
3703</div>
3704
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3705
3706<!-- _______________________________________________________________________ -->
3707<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3708 <a name="i_call">'<tt>call</tt>' Instruction</a>
3709</div>
3710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3711<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3712
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3713<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3714<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3715 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3716</pre>
3717
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3718<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3719
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3720<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3721
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3722<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3723
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3724<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3725
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3726<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3727 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3728 <p>The optional "tail" marker indicates whether the callee function accesses
3729 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3730 function call is eligible for tail call optimization. Note that calls may
3731 be marked "tail" even if they do not occur before a <a
3732 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3733 </li>
3734 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3735 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3736 convention</a> the call should use. If none is specified, the call defaults
3737 to using C calling conventions.
3738 </li>
3739 <li>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3740 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3741 the type of the return value. Functions that return no value are marked
3742 <tt><a href="#t_void">void</a></tt>.</p>
3743 </li>
3744 <li>
3745 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3746 value being invoked. The argument types must match the types implied by
3747 this signature. This type can be omitted if the function is not varargs
3748 and if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3749 </li>
3750 <li>
3751 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3752 be invoked. In most cases, this is a direct function invocation, but
3753 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3754 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3755 </li>
3756 <li>
3757 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3758 function signature argument types. All arguments must be of
3759 <a href="#t_firstclass">first class</a> type. If the function signature
3760 indicates the function accepts a variable number of arguments, the extra
3761 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3762 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3763</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3765<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3766
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3767<p>The '<tt>call</tt>' instruction is used to cause control flow to
3768transfer to a specified function, with its incoming arguments bound to
3769the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3770instruction in the called function, control flow continues with the
3771instruction after the function call, and the return value of the
3772function is bound to the result argument. This is a simpler case of
3773the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3774
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3775<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3776
3777<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]3778 %retval = call i32 @test(i32 %argc)
3779 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3780 %X = tail call i32 @foo()
3781 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3782 %Z = call void %foo(i8 97 signext)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3783</pre>
3784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3785</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3786
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3787<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3788<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3789 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3790</div>
3791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3792<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3793
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3794<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3795
3796<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3797 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3798</pre>
3799
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3800<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3801
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3802<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3803the "variable argument" area of a function call. It is used to implement the
3804<tt>va_arg</tt> macro in C.</p>
3805
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3806<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3807
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3808<p>This instruction takes a <tt>va_list*</tt> value and the type of
3809the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3810increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3811actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3812
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3813<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3814
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3815<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3816type from the specified <tt>va_list</tt> and causes the
3817<tt>va_list</tt> to point to the next argument. For more information,
3818see the variable argument handling <a href="#int_varargs">Intrinsic
3819Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3820
3821<p>It is legal for this instruction to be called in a function which does not
3822take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3823function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3824
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3825<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3826href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3827argument.</p>
3828
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3829<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3830
3831<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3832
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3833</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3834
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3835<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3836<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3837<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3838
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3839<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3840
3841<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3842well known names and semantics and are required to follow certain restrictions.
3843Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3844language that does not require changing all of the transformations in LLVM when
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]3845adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3846
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3847<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3848prefix is reserved in LLVM for intrinsic names; thus, function names may not
3849begin with this prefix. Intrinsic functions must always be external functions:
3850you cannot define the body of intrinsic functions. Intrinsic functions may
3851only be used in call or invoke instructions: it is illegal to take the address
3852of an intrinsic function. Additionally, because intrinsic functions are part
3853of the LLVM language, it is required if any are added that they be documented
3854here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3855
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3856<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3857a family of functions that perform the same operation but on different data
3858types. Because LLVM can represent over 8 million different integer types,
3859overloading is used commonly to allow an intrinsic function to operate on any
3860integer type. One or more of the argument types or the result type can be
3861overloaded to accept any integer type. Argument types may also be defined as
3862exactly matching a previous argument's type or the result type. This allows an
3863intrinsic function which accepts multiple arguments, but needs all of them to
3864be of the same type, to only be overloaded with respect to a single argument or
3865the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3866
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]3867<p>Overloaded intrinsics will have the names of its overloaded argument types
3868encoded into its function name, each preceded by a period. Only those types
3869which are overloaded result in a name suffix. Arguments whose type is matched
3870against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3871take an integer of any width and returns an integer of exactly the same integer
3872width. This leads to a family of functions such as
3873<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3874Only one type, the return type, is overloaded, and only one type suffix is
3875required. Because the argument's type is matched against the return type, it
3876does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3877
3878<p>To learn how to add an intrinsic function, please see the
3879<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3880</p>
3881
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3882</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3883
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3884<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3885<div class="doc_subsection">
3886 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3887</div>
3888
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3889<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3890
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3891<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3892 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3893intrinsic functions. These functions are related to the similarly
3894named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3895
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3896<p>All of these functions operate on arguments that use a
3897target-specific value type "<tt>va_list</tt>". The LLVM assembly
3898language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3899transformations should be prepared to handle these functions regardless of
3900the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3901
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3902<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3903instruction and the variable argument handling intrinsic functions are
3904used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3905
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3906<div class="doc_code">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3907<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3908define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3909 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3910 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3911 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3912 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3913
3914 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3915 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3916
3917 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3918 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3919 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3920 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3921 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3922
3923 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3924 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3925 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3926}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3927
3928declare void @llvm.va_start(i8*)
3929declare void @llvm.va_copy(i8*, i8*)
3930declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3931</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3932</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3933
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]3934</div>
3935
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3936<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3937<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3938 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3939</div>
3940
3941
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3942<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3943<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3944<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3945<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3946<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3947<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3948href="#i_va_arg">va_arg</a></tt>.</p>
3949
3950<h5>Arguments:</h5>
3951
3952<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3953
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3954<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3955
3956<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3957macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3958<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3959<tt>va_arg</tt> will produce the first variable argument passed to the function.
3960Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3961last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3963</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3964
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3965<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3966<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3967 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3968</div>
3969
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3970<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3971<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3972<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3973<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3974
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3975<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3976which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3977or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3978
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3979<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3980
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3981<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3982
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3983<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3984
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3985<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3986macro available in C. In a target-dependent way, it destroys the
3987<tt>va_list</tt> element to which the argument points. Calls to <a
3988href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3989<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3990<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3991
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3992</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3993
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3994<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3995<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3996 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3997</div>
3998
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3999<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4000
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4001<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4002
4003<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4004 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4005</pre>
4006
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4007<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4008
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4009<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4010from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4011
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4012<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4013
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4014<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]4015The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]4016
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4017
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]4018<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4019
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]4020<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4021macro available in C. In a target-dependent way, it copies the source
4022<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4023intrinsic is necessary because the <tt><a href="#int_va_start">
4024llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4025example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4026
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4027</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4028
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4029<!-- ======================================================================= -->
4030<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4031 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4032</div>
4033
4034<div class="doc_text">
4035
4036<p>
4037LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4038Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4039These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4040stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4041href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4042Front-ends for type-safe garbage collected languages should generate these
4043intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4044href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4045</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]4046
4047<p>The garbage collection intrinsics only operate on objects in the generic
4048 address space (address space zero).</p>
4049
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4050</div>
4051
4052<!-- _______________________________________________________________________ -->
4053<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4054 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4055</div>
4056
4057<div class="doc_text">
4058
4059<h5>Syntax:</h5>
4060
4061<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4062 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4063</pre>
4064
4065<h5>Overview:</h5>
4066
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]4067<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4068the code generator, and allows some metadata to be associated with it.</p>
4069
4070<h5>Arguments:</h5>
4071
4072<p>The first argument specifies the address of a stack object that contains the
4073root pointer. The second pointer (which must be either a constant or a global
4074value address) contains the meta-data to be associated with the root.</p>
4075
4076<h5>Semantics:</h5>
4077
4078<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4079location. At compile-time, the code generator generates information to allow
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4080the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4081intrinsic may only be used in a function which <a href="#gc">specifies a GC
4082algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4083
4084</div>
4085
4086
4087<!-- _______________________________________________________________________ -->
4088<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4089 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4090</div>
4091
4092<div class="doc_text">
4093
4094<h5>Syntax:</h5>
4095
4096<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4097 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4098</pre>
4099
4100<h5>Overview:</h5>
4101
4102<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4103locations, allowing garbage collector implementations that require read
4104barriers.</p>
4105
4106<h5>Arguments:</h5>
4107
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4108<p>The second argument is the address to read from, which should be an address
4109allocated from the garbage collector. The first object is a pointer to the
4110start of the referenced object, if needed by the language runtime (otherwise
4111null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4112
4113<h5>Semantics:</h5>
4114
4115<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4116instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4117garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4118may only be used in a function which <a href="#gc">specifies a GC
4119algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4120
4121</div>
4122
4123
4124<!-- _______________________________________________________________________ -->
4125<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4126 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4127</div>
4128
4129<div class="doc_text">
4130
4131<h5>Syntax:</h5>
4132
4133<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4134 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4135</pre>
4136
4137<h5>Overview:</h5>
4138
4139<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4140locations, allowing garbage collector implementations that require write
4141barriers (such as generational or reference counting collectors).</p>
4142
4143<h5>Arguments:</h5>
4144
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]4145<p>The first argument is the reference to store, the second is the start of the
4146object to store it to, and the third is the address of the field of Obj to
4147store to. If the runtime does not require a pointer to the object, Obj may be
4148null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4149
4150<h5>Semantics:</h5>
4151
4152<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4153instruction, but may be replaced with substantially more complex code by the
Gordon Henriksene1433f22007-12-25 02:31:26 +0000[diff] [blame]4154garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4155may only be used in a function which <a href="#gc">specifies a GC
4156algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]4157
4158</div>
4159
4160
4161
4162<!-- ======================================================================= -->
4163<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4164 <a name="int_codegen">Code Generator Intrinsics</a>
4165</div>
4166
4167<div class="doc_text">
4168<p>
4169These intrinsics are provided by LLVM to expose special features that may only
4170be implemented with code generator support.
4171</p>
4172
4173</div>
4174
4175<!-- _______________________________________________________________________ -->
4176<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4177 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4178</div>
4179
4180<div class="doc_text">
4181
4182<h5>Syntax:</h5>
4183<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4184 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4185</pre>
4186
4187<h5>Overview:</h5>
4188
4189<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4190The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4191target-specific value indicating the return address of the current function
4192or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4193</p>
4194
4195<h5>Arguments:</h5>
4196
4197<p>
4198The argument to this intrinsic indicates which function to return the address
4199for. Zero indicates the calling function, one indicates its caller, etc. The
4200argument is <b>required</b> to be a constant integer value.
4201</p>
4202
4203<h5>Semantics:</h5>
4204
4205<p>
4206The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4207the return address of the specified call frame, or zero if it cannot be
4208identified. The value returned by this intrinsic is likely to be incorrect or 0
4209for arguments other than zero, so it should only be used for debugging purposes.
4210</p>
4211
4212<p>
4213Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4214aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4215source-language caller.
4216</p>
4217</div>
4218
4219
4220<!-- _______________________________________________________________________ -->
4221<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4222 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4223</div>
4224
4225<div class="doc_text">
4226
4227<h5>Syntax:</h5>
4228<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4229 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4230</pre>
4231
4232<h5>Overview:</h5>
4233
4234<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4235The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4236target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4237</p>
4238
4239<h5>Arguments:</h5>
4240
4241<p>
4242The argument to this intrinsic indicates which function to return the frame
4243pointer for. Zero indicates the calling function, one indicates its caller,
4244etc. The argument is <b>required</b> to be a constant integer value.
4245</p>
4246
4247<h5>Semantics:</h5>
4248
4249<p>
4250The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4251the frame address of the specified call frame, or zero if it cannot be
4252identified. The value returned by this intrinsic is likely to be incorrect or 0
4253for arguments other than zero, so it should only be used for debugging purposes.
4254</p>
4255
4256<p>
4257Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4258aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4259source-language caller.
4260</p>
4261</div>
4262
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4263<!-- _______________________________________________________________________ -->
4264<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4265 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4266</div>
4267
4268<div class="doc_text">
4269
4270<h5>Syntax:</h5>
4271<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4272 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4273</pre>
4274
4275<h5>Overview:</h5>
4276
4277<p>
4278The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4279the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4280<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4281features like scoped automatic variable sized arrays in C99.
4282</p>
4283
4284<h5>Semantics:</h5>
4285
4286<p>
4287This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4288href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4289<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4290<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4291state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4292practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4293that were allocated after the <tt>llvm.stacksave</tt> was executed.
4294</p>
4295
4296</div>
4297
4298<!-- _______________________________________________________________________ -->
4299<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4300 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4301</div>
4302
4303<div class="doc_text">
4304
4305<h5>Syntax:</h5>
4306<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4307 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4308</pre>
4309
4310<h5>Overview:</h5>
4311
4312<p>
4313The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4314the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4315href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4316useful for implementing language features like scoped automatic variable sized
4317arrays in C99.
4318</p>
4319
4320<h5>Semantics:</h5>
4321
4322<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4323See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4324</p>
4325
4326</div>
4327
4328
4329<!-- _______________________________________________________________________ -->
4330<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4331 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4332</div>
4333
4334<div class="doc_text">
4335
4336<h5>Syntax:</h5>
4337<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4338 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4339</pre>
4340
4341<h5>Overview:</h5>
4342
4343
4344<p>
4345The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4346a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4347no
4348effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4349characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4350</p>
4351
4352<h5>Arguments:</h5>
4353
4354<p>
4355<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4356determining if the fetch should be for a read (0) or write (1), and
4357<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4358locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4359<tt>locality</tt> arguments must be constant integers.
4360</p>
4361
4362<h5>Semantics:</h5>
4363
4364<p>
4365This intrinsic does not modify the behavior of the program. In particular,
4366prefetches cannot trap and do not produce a value. On targets that support this
4367intrinsic, the prefetch can provide hints to the processor cache for better
4368performance.
4369</p>
4370
4371</div>
4372
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4373<!-- _______________________________________________________________________ -->
4374<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4375 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4376</div>
4377
4378<div class="doc_text">
4379
4380<h5>Syntax:</h5>
4381<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]4382 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4383</pre>
4384
4385<h5>Overview:</h5>
4386
4387
4388<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4389The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4390(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4391code to simulators and other tools. The method is target specific, but it is
4392expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4393The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4394after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4395optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4396correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4397</p>
4398
4399<h5>Arguments:</h5>
4400
4401<p>
4402<tt>id</tt> is a numerical id identifying the marker.
4403</p>
4404
4405<h5>Semantics:</h5>
4406
4407<p>
4408This intrinsic does not modify the behavior of the program. Backends that do not
4409support this intrinisic may ignore it.
4410</p>
4411
4412</div>
4413
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4416 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4417</div>
4418
4419<div class="doc_text">
4420
4421<h5>Syntax:</h5>
4422<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4423 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4424</pre>
4425
4426<h5>Overview:</h5>
4427
4428
4429<p>
4430The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4431counter register (or similar low latency, high accuracy clocks) on those targets
4432that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4433As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4434should only be used for small timings.
4435</p>
4436
4437<h5>Semantics:</h5>
4438
4439<p>
4440When directly supported, reading the cycle counter should not modify any memory.
4441Implementations are allowed to either return a application specific value or a
4442system wide value. On backends without support, this is lowered to a constant 0.
4443</p>
4444
4445</div>
4446
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4447<!-- ======================================================================= -->
4448<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4449 <a name="int_libc">Standard C Library Intrinsics</a>
4450</div>
4451
4452<div class="doc_text">
4453<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4454LLVM provides intrinsics for a few important standard C library functions.
4455These intrinsics allow source-language front-ends to pass information about the
4456alignment of the pointer arguments to the code generator, providing opportunity
4457for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4458</p>
4459
4460</div>
4461
4462<!-- _______________________________________________________________________ -->
4463<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4464 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4465</div>
4466
4467<div class="doc_text">
4468
4469<h5>Syntax:</h5>
4470<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4471 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4472 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4473 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4474 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4475</pre>
4476
4477<h5>Overview:</h5>
4478
4479<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4480The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4481location to the destination location.
4482</p>
4483
4484<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4485Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4486intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4487</p>
4488
4489<h5>Arguments:</h5>
4490
4491<p>
4492The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4493the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4494specifying the number of bytes to copy, and the fourth argument is the alignment
4495of the source and destination locations.
4496</p>
4497
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4498<p>
4499If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4500the caller guarantees that both the source and destination pointers are aligned
4501to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4502</p>
4503
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4504<h5>Semantics:</h5>
4505
4506<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4507The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4508location to the destination location, which are not allowed to overlap. It
4509copies "len" bytes of memory over. If the argument is known to be aligned to
4510some boundary, this can be specified as the fourth argument, otherwise it should
4511be set to 0 or 1.
4512</p>
4513</div>
4514
4515
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4516<!-- _______________________________________________________________________ -->
4517<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4518 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4519</div>
4520
4521<div class="doc_text">
4522
4523<h5>Syntax:</h5>
4524<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4525 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4526 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4527 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4528 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4529</pre>
4530
4531<h5>Overview:</h5>
4532
4533<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4534The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4535location to the destination location. It is similar to the
Chris Lattner4b2cbcf2008-01-06 19:51:52 +0000[diff] [blame]4536'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4537</p>
4538
4539<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4540Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4541intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4542</p>
4543
4544<h5>Arguments:</h5>
4545
4546<p>
4547The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4548the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4549specifying the number of bytes to copy, and the fourth argument is the alignment
4550of the source and destination locations.
4551</p>
4552
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4553<p>
4554If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4555the caller guarantees that the source and destination pointers are aligned to
4556that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4557</p>
4558
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4559<h5>Semantics:</h5>
4560
4561<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4562The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4563location to the destination location, which may overlap. It
4564copies "len" bytes of memory over. If the argument is known to be aligned to
4565some boundary, this can be specified as the fourth argument, otherwise it should
4566be set to 0 or 1.
4567</p>
4568</div>
4569
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4570
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4571<!-- _______________________________________________________________________ -->
4572<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4573 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4574</div>
4575
4576<div class="doc_text">
4577
4578<h5>Syntax:</h5>
4579<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4580 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4581 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4582 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4583 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4584</pre>
4585
4586<h5>Overview:</h5>
4587
4588<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4589The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4590byte value.
4591</p>
4592
4593<p>
4594Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4595does not return a value, and takes an extra alignment argument.
4596</p>
4597
4598<h5>Arguments:</h5>
4599
4600<p>
4601The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4602byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4603argument specifying the number of bytes to fill, and the fourth argument is the
4604known alignment of destination location.
4605</p>
4606
4607<p>
4608If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattnerf0afc2c2006-03-04 00:02:10 +0000[diff] [blame]4609the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4610</p>
4611
4612<h5>Semantics:</h5>
4613
4614<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4615The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4616the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4617destination location. If the argument is known to be aligned to some boundary,
4618this can be specified as the fourth argument, otherwise it should be set to 0 or
46191.
4620</p>
4621</div>
4622
4623
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4624<!-- _______________________________________________________________________ -->
4625<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4626 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4627</div>
4628
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4632<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4633floating point or vector of floating point type. Not all targets support all
4634types however.
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4635<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4636 declare float @llvm.sqrt.f32(float %Val)
4637 declare double @llvm.sqrt.f64(double %Val)
4638 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4639 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4640 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4641</pre>
4642
4643<h5>Overview:</h5>
4644
4645<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4646The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4647returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4648<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4649negative numbers (which allows for better optimization).
4650</p>
4651
4652<h5>Arguments:</h5>
4653
4654<p>
4655The argument and return value are floating point numbers of the same type.
4656</p>
4657
4658<h5>Semantics:</h5>
4659
4660<p>
Dan Gohmand6257fe2007-07-16 14:37:41 +0000[diff] [blame]4661This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4662floating point number.
4663</p>
4664</div>
4665
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4666<!-- _______________________________________________________________________ -->
4667<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4668 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4669</div>
4670
4671<div class="doc_text">
4672
4673<h5>Syntax:</h5>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4674<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4675floating point or vector of floating point type. Not all targets support all
4676types however.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4677<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]4678 declare float @llvm.powi.f32(float %Val, i32 %power)
4679 declare double @llvm.powi.f64(double %Val, i32 %power)
4680 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4681 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4682 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4683</pre>
4684
4685<h5>Overview:</h5>
4686
4687<p>
4688The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4689specified (positive or negative) power. The order of evaluation of
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4690multiplications is not defined. When a vector of floating point type is
4691used, the second argument remains a scalar integer value.
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4692</p>
4693
4694<h5>Arguments:</h5>
4695
4696<p>
4697The second argument is an integer power, and the first is a value to raise to
4698that power.
4699</p>
4700
4701<h5>Semantics:</h5>
4702
4703<p>
4704This function returns the first value raised to the second power with an
4705unspecified sequence of rounding operations.</p>
4706</div>
4707
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4708<!-- _______________________________________________________________________ -->
4709<div class="doc_subsubsection">
4710 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4711</div>
4712
4713<div class="doc_text">
4714
4715<h5>Syntax:</h5>
4716<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4717floating point or vector of floating point type. Not all targets support all
4718types however.
4719<pre>
4720 declare float @llvm.sin.f32(float %Val)
4721 declare double @llvm.sin.f64(double %Val)
4722 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4723 declare fp128 @llvm.sin.f128(fp128 %Val)
4724 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4725</pre>
4726
4727<h5>Overview:</h5>
4728
4729<p>
4730The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4731</p>
4732
4733<h5>Arguments:</h5>
4734
4735<p>
4736The argument and return value are floating point numbers of the same type.
4737</p>
4738
4739<h5>Semantics:</h5>
4740
4741<p>
4742This function returns the sine of the specified operand, returning the
4743same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4744conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4745</div>
4746
4747<!-- _______________________________________________________________________ -->
4748<div class="doc_subsubsection">
4749 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4750</div>
4751
4752<div class="doc_text">
4753
4754<h5>Syntax:</h5>
4755<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4756floating point or vector of floating point type. Not all targets support all
4757types however.
4758<pre>
4759 declare float @llvm.cos.f32(float %Val)
4760 declare double @llvm.cos.f64(double %Val)
4761 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4762 declare fp128 @llvm.cos.f128(fp128 %Val)
4763 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4764</pre>
4765
4766<h5>Overview:</h5>
4767
4768<p>
4769The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4770</p>
4771
4772<h5>Arguments:</h5>
4773
4774<p>
4775The argument and return value are floating point numbers of the same type.
4776</p>
4777
4778<h5>Semantics:</h5>
4779
4780<p>
4781This function returns the cosine of the specified operand, returning the
4782same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4783conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4784</div>
4785
4786<!-- _______________________________________________________________________ -->
4787<div class="doc_subsubsection">
4788 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4789</div>
4790
4791<div class="doc_text">
4792
4793<h5>Syntax:</h5>
4794<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4795floating point or vector of floating point type. Not all targets support all
4796types however.
4797<pre>
4798 declare float @llvm.pow.f32(float %Val, float %Power)
4799 declare double @llvm.pow.f64(double %Val, double %Power)
4800 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4801 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4802 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4803</pre>
4804
4805<h5>Overview:</h5>
4806
4807<p>
4808The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4809specified (positive or negative) power.
4810</p>
4811
4812<h5>Arguments:</h5>
4813
4814<p>
4815The second argument is a floating point power, and the first is a value to
4816raise to that power.
4817</p>
4818
4819<h5>Semantics:</h5>
4820
4821<p>
4822This function returns the first value raised to the second power,
4823returning the
4824same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmanba83b7e2007-10-17 18:05:13 +0000[diff] [blame]4825conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]4826</div>
4827
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4828
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4829<!-- ======================================================================= -->
4830<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4831 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4832</div>
4833
4834<div class="doc_text">
4835<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4836LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4837These allow efficient code generation for some algorithms.
4838</p>
4839
4840</div>
4841
4842<!-- _______________________________________________________________________ -->
4843<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4844 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4845</div>
4846
4847<div class="doc_text">
4848
4849<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4850<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4851type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4852<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4853 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4854 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4855 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4856</pre>
4857
4858<h5>Overview:</h5>
4859
4860<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4861The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4862values with an even number of bytes (positive multiple of 16 bits). These are
4863useful for performing operations on data that is not in the target's native
4864byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4865</p>
4866
4867<h5>Semantics:</h5>
4868
4869<p>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4870The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4871and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4872intrinsic returns an i32 value that has the four bytes of the input i32
4873swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4874i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4875<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4876additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4877</p>
4878
4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4883 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4884</div>
4885
4886<div class="doc_text">
4887
4888<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4889<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4890width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4891<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4892 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4893 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4894 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4895 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4896 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4897</pre>
4898
4899<h5>Overview:</h5>
4900
4901<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4902The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4903value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4904</p>
4905
4906<h5>Arguments:</h5>
4907
4908<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4909The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4910integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4911</p>
4912
4913<h5>Semantics:</h5>
4914
4915<p>
4916The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4917</p>
4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4922 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4923</div>
4924
4925<div class="doc_text">
4926
4927<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4928<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4929integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4930<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4931 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4932 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4933 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4934 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4935 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4936</pre>
4937
4938<h5>Overview:</h5>
4939
4940<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4941The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4942leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4943</p>
4944
4945<h5>Arguments:</h5>
4946
4947<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4948The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4949integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4950</p>
4951
4952<h5>Semantics:</h5>
4953
4954<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4955The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4956in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4957of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4958</p>
4959</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4960
4961
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4962
4963<!-- _______________________________________________________________________ -->
4964<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4965 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4966</div>
4967
4968<div class="doc_text">
4969
4970<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4971<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4972integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4973<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4974 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4975 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4976 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]4977 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4978 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4979</pre>
4980
4981<h5>Overview:</h5>
4982
4983<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4984The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4985trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4986</p>
4987
4988<h5>Arguments:</h5>
4989
4990<p>
4991The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4992integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4993</p>
4994
4995<h5>Semantics:</h5>
4996
4997<p>
4998The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4999in a variable. If the src == 0 then the result is the size in bits of the type
5000of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5001</p>
5002</div>
5003
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]5004<!-- _______________________________________________________________________ -->
5005<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5006 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5007</div>
5008
5009<div class="doc_text">
5010
5011<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5012<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5013on any integer bit width.
5014<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5015 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5016 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5017</pre>
5018
5019<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5020<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5021range of bits from an integer value and returns them in the same bit width as
5022the original value.</p>
5023
5024<h5>Arguments:</h5>
5025<p>The first argument, <tt>%val</tt> and the result may be integer types of
5026any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5027arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5028
5029<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]5030<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]5031of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5032<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5033operates in forward mode.</p>
5034<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5035right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5036only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5037<ol>
5038 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5039 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5040 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5041 to determine the number of bits to retain.</li>
5042 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5043 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5044</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]5045<p>In reverse mode, a similar computation is made except that the bits are
5046returned in the reverse order. So, for example, if <tt>X</tt> has the value
5047<tt>i16 0x0ACF (101011001111)</tt> and we apply
5048<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5049<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]5050</div>
5051
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5052<div class="doc_subsubsection">
5053 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5054</div>
5055
5056<div class="doc_text">
5057
5058<h5>Syntax:</h5>
5059<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5060on any integer bit width.
5061<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]5062 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5063 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5064</pre>
5065
5066<h5>Overview:</h5>
5067<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5068of bits in an integer value with another integer value. It returns the integer
5069with the replaced bits.</p>
5070
5071<h5>Arguments:</h5>
5072<p>The first argument, <tt>%val</tt> and the result may be integer types of
5073any bit width but they must have the same bit width. <tt>%val</tt> is the value
5074whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5075integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5076type since they specify only a bit index.</p>
5077
5078<h5>Semantics:</h5>
5079<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5080of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5081<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5082operates in forward mode.</p>
5083<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5084truncating it down to the size of the replacement area or zero extending it
5085up to that size.</p>
5086<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5087are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5088in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5089to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5090<p>In reverse mode, a similar computation is made except that the bits are
5091reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5092<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5093<h5>Examples:</h5>
5094<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5095 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]5096 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5097 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5098 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]5099 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]5100</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]5101</div>
5102
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]5103<!-- ======================================================================= -->
5104<div class="doc_subsection">
5105 <a name="int_debugger">Debugger Intrinsics</a>
5106</div>
5107
5108<div class="doc_text">
5109<p>
5110The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5111are described in the <a
5112href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5113Debugging</a> document.
5114</p>
5115</div>
5116
5117
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5118<!-- ======================================================================= -->
5119<div class="doc_subsection">
5120 <a name="int_eh">Exception Handling Intrinsics</a>
5121</div>
5122
5123<div class="doc_text">
5124<p> The LLVM exception handling intrinsics (which all start with
5125<tt>llvm.eh.</tt> prefix), are described in the <a
5126href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5127Handling</a> document. </p>
5128</div>
5129
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5130<!-- ======================================================================= -->
5131<div class="doc_subsection">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5132 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5133</div>
5134
5135<div class="doc_text">
5136<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5137 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5138 the <tt>nest</tt> attribute, from a function. The result is a callable
5139 function pointer lacking the nest parameter - the caller does not need
5140 to provide a value for it. Instead, the value to use is stored in
5141 advance in a "trampoline", a block of memory usually allocated
5142 on the stack, which also contains code to splice the nest value into the
5143 argument list. This is used to implement the GCC nested function address
5144 extension.
5145</p>
5146<p>
5147 For example, if the function is
5148 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5149 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5150<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5151 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5152 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5153 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5154 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5155</pre>
Bill Wendling03295ca2007-09-22 09:23:55 +0000[diff] [blame]5156 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5157 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5158</div>
5159
5160<!-- _______________________________________________________________________ -->
5161<div class="doc_subsubsection">
5162 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5163</div>
5164<div class="doc_text">
5165<h5>Syntax:</h5>
5166<pre>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5167declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5168</pre>
5169<h5>Overview:</h5>
5170<p>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5171 This fills the memory pointed to by <tt>tramp</tt> with code
5172 and returns a function pointer suitable for executing it.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5173</p>
5174<h5>Arguments:</h5>
5175<p>
5176 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5177 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5178 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsc00c2ba2007-08-22 23:39:54 +0000[diff] [blame]5179 intrinsic. Note that the size and the alignment are target-specific - LLVM
5180 currently provides no portable way of determining them, so a front-end that
5181 generates this intrinsic needs to have some target-specific knowledge.
5182 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5183</p>
5184<h5>Semantics:</h5>
5185<p>
5186 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5187 dependent code, turning it into a function. A pointer to this function is
5188 returned, but needs to be bitcast to an
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5189 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]5190 before being called. The new function's signature is the same as that of
5191 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5192 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5193 of pointer type. Calling the new function is equivalent to calling
5194 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5195 missing <tt>nest</tt> argument. If, after calling
5196 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5197 modified, then the effect of any later call to the returned function pointer is
5198 undefined.
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]5199</p>
5200</div>
5201
5202<!-- ======================================================================= -->
5203<div class="doc_subsection">
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5204 <a name="int_general">General Intrinsics</a>
5205</div>
5206
5207<div class="doc_text">
5208<p> This class of intrinsics is designed to be generic and has
5209no specific purpose. </p>
5210</div>
5211
5212<!-- _______________________________________________________________________ -->
5213<div class="doc_subsubsection">
5214 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5215</div>
5216
5217<div class="doc_text">
5218
5219<h5>Syntax:</h5>
5220<pre>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5221 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5222</pre>
5223
5224<h5>Overview:</h5>
5225
5226<p>
5227The '<tt>llvm.var.annotation</tt>' intrinsic
5228</p>
5229
5230<h5>Arguments:</h5>
5231
5232<p>
Tanya Lattnerd2e84422007-06-18 23:42:37 +0000[diff] [blame]5233The first argument is a pointer to a value, the second is a pointer to a
5234global string, the third is a pointer to a global string which is the source
5235file name, and the last argument is the line number.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5236</p>
5237
5238<h5>Semantics:</h5>
5239
5240<p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame^]5241This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5242This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame^]5243annotations. These have no other defined use, they are ignored by code
5244generation and optimization.
5245</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]5246</div>
5247
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5248<!-- _______________________________________________________________________ -->
5249<div class="doc_subsubsection">
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]5250 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5251</div>
5252
5253<div class="doc_text">
5254
5255<h5>Syntax:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5256<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5257any integer bit width.
5258</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5259<pre>
Tanya Lattnerd3989a82007-09-22 00:03:01 +0000[diff] [blame]5260 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5261 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5262 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5263 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5264 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5265</pre>
5266
5267<h5>Overview:</h5>
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5268
5269<p>
5270The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5271</p>
5272
5273<h5>Arguments:</h5>
5274
5275<p>
5276The first argument is an integer value (result of some expression),
5277the second is a pointer to a global string, the third is a pointer to a global
5278string which is the source file name, and the last argument is the line number.
Tanya Lattner39cfba62007-09-21 23:56:27 +0000[diff] [blame]5279It returns the value of the first argument.
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]5280</p>
5281
5282<h5>Semantics:</h5>
5283
5284<p>
5285This intrinsic allows annotations to be put on arbitrary expressions
5286with arbitrary strings. This can be useful for special purpose optimizations
5287that want to look for these annotations. These have no other defined use, they
5288are ignored by code generation and optimization.
5289</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]5290
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame^]5291<!-- _______________________________________________________________________ -->
5292<div class="doc_subsubsection">
5293 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5294</div>
5295
5296<div class="doc_text">
5297
5298<h5>Syntax:</h5>
5299<pre>
5300 declare void @llvm.trap()
5301</pre>
5302
5303<h5>Overview:</h5>
5304
5305<p>
5306The '<tt>llvm.trap</tt>' intrinsic
5307</p>
5308
5309<h5>Arguments:</h5>
5310
5311<p>
5312None
5313</p>
5314
5315<h5>Semantics:</h5>
5316
5317<p>
5318This intrinsics is lowered to the target dependent trap instruction. If the
5319target does not have a trap instruction, this intrinsic will be lowered to the
5320call of the abort() function.
5321</p>
5322</div>
5323
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5324<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5325<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5326<address>
5327 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5328 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5329 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5330 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5331
5332 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]5333 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]5334 Last modified: $Date$
5335</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]5336
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5337</body>
5338</html>