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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 2b91631e449376aae5f5cd84b5957cfae4ac5e53 / . / 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.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikovc6c98af2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]194 </ol>
195 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]196</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]197
198<div class="doc_author">
199 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
200 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]201</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]203<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204<div class="doc_section"> <a name="abstract">Abstract </a></div>
205<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]206
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]207<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208<p>This document is a reference manual for the LLVM assembly language.
209LLVM is an SSA based representation that provides type safety,
210low-level operations, flexibility, and the capability of representing
211'all' high-level languages cleanly. It is the common code
212representation used throughout all phases of the LLVM compilation
213strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]214</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]216<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217<div class="doc_section"> <a name="introduction">Introduction</a> </div>
218<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]219
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]220<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<p>The LLVM code representation is designed to be used in three
223different forms: as an in-memory compiler IR, as an on-disk bytecode
224representation (suitable for fast loading by a Just-In-Time compiler),
225and as a human readable assembly language representation. This allows
226LLVM to provide a powerful intermediate representation for efficient
227compiler transformations and analysis, while providing a natural means
228to debug and visualize the transformations. The three different forms
229of LLVM are all equivalent. This document describes the human readable
230representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]231
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]232<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]233while being expressive, typed, and extensible at the same time. It
234aims to be a "universal IR" of sorts, by being at a low enough level
235that high-level ideas may be cleanly mapped to it (similar to how
236microprocessors are "universal IR's", allowing many source languages to
237be mapped to them). By providing type information, LLVM can be used as
238the target of optimizations: for example, through pointer analysis, it
239can be proven that a C automatic variable is never accessed outside of
240the current function... allowing it to be promoted to a simple SSA
241value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]243</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]245<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]248<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]250<p>It is important to note that this document describes 'well formed'
251LLVM assembly language. There is a difference between what the parser
252accepts and what is considered 'well formed'. For example, the
253following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254
255<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]256 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]257</pre>
258
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]259<p>...because the definition of <tt>%x</tt> does not dominate all of
260its uses. The LLVM infrastructure provides a verification pass that may
261be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]262automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]263the optimizer before it outputs bytecode. The violations pointed out
264by the verifier pass indicate bugs in transformation passes or input to
265the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]266
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]267<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]269<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]270<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]271<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]273<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]275<p>LLVM uses three different forms of identifiers, for different
276purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]278<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]279 <li>Named values are represented as a string of characters with a '%' prefix.
280 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
281 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
282 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]283 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]284 in a name.</li>
285
286 <li>Unnamed values are represented as an unsigned numeric value with a '%'
287 prefix. For example, %12, %2, %44.</li>
288
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]289 <li>Constants, which are described in a <a href="#constants">section about
290 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]291</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]292
293<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
294don't need to worry about name clashes with reserved words, and the set of
295reserved words may be expanded in the future without penalty. Additionally,
296unnamed identifiers allow a compiler to quickly come up with a temporary
297variable without having to avoid symbol table conflicts.</p>
298
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]299<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]300languages. There are keywords for different opcodes
301('<tt><a href="#i_add">add</a></tt>',
302 '<tt><a href="#i_bitcast">bitcast</a></tt>',
303 '<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]304href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305and others. These reserved words cannot conflict with variable names, because
306none of them start with a '%' character.</p>
307
308<p>Here is an example of LLVM code to multiply the integer variable
309'<tt>%X</tt>' by 8:</p>
310
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]311<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]312
313<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]314 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315</pre>
316
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]317<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]318
319<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]320 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321</pre>
322
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]323<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]324
325<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]326 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
327 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
328 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329</pre>
330
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]331<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
332important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]333
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]334<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]335
336 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
337 line.</li>
338
339 <li>Unnamed temporaries are created when the result of a computation is not
340 assigned to a named value.</li>
341
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]342 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]344</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]345
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]346<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]347demonstrating instructions, we will follow an instruction with a comment that
348defines the type and name of value produced. Comments are shown in italic
349text.</p>
350
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]351</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]352
353<!-- *********************************************************************** -->
354<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
355<!-- *********************************************************************** -->
356
357<!-- ======================================================================= -->
358<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
359</div>
360
361<div class="doc_text">
362
363<p>LLVM programs are composed of "Module"s, each of which is a
364translation unit of the input programs. Each module consists of
365functions, global variables, and symbol table entries. Modules may be
366combined together with the LLVM linker, which merges function (and
367global variable) definitions, resolves forward declarations, and merges
368symbol table entries. Here is an example of the "hello world" module:</p>
369
370<pre><i>; Declare the string constant as a global constant...</i>
371<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]372 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]373
374<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]375<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376
377<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]378define i32 %main() { <i>; i32()* </i>
379 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]380 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]381 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]382
383 <i>; Call puts function to write out the string to stdout...</i>
384 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]387 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]388
389<p>This example is made up of a <a href="#globalvars">global variable</a>
390named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
391function, and a <a href="#functionstructure">function definition</a>
392for "<tt>main</tt>".</p>
393
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394<p>In general, a module is made up of a list of global values,
395where both functions and global variables are global values. Global values are
396represented by a pointer to a memory location (in this case, a pointer to an
397array of char, and a pointer to a function), and have one of the following <a
398href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]399
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]400</div>
401
402<!-- ======================================================================= -->
403<div class="doc_subsection">
404 <a name="linkage">Linkage Types</a>
405</div>
406
407<div class="doc_text">
408
409<p>
410All Global Variables and Functions have one of the following types of linkage:
411</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412
413<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]415 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
417 <dd>Global values with internal linkage are only directly accessible by
418 objects in the current module. In particular, linking code into a module with
419 an internal global value may cause the internal to be renamed as necessary to
420 avoid collisions. Because the symbol is internal to the module, all
421 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]422 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]423 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]425 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]427 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
428 the same name when linkage occurs. This is typically used to implement
429 inline functions, templates, or other code which must be generated in each
430 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
431 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]432 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]434 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]435
436 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
437 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]438 used for globals that may be emitted in multiple translation units, but that
439 are not guaranteed to be emitted into every translation unit that uses them.
440 One example of this are common globals in C, such as "<tt>int X;</tt>" at
441 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]442 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]443
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]444 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
446 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
447 pointer to array type. When two global variables with appending linkage are
448 linked together, the two global arrays are appended together. This is the
449 LLVM, typesafe, equivalent of having the system linker append together
450 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]451 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]453 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
454 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
455 until linked, if not linked, the symbol becomes null instead of being an
456 undefined reference.
457 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]458
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]459 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
461 <dd>If none of the above identifiers are used, the global is externally
462 visible, meaning that it participates in linkage and can be used to resolve
463 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]464 </dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]465</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]466
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]467 <p>
468 The next two types of linkage are targeted for Microsoft Windows platform
469 only. They are designed to support importing (exporting) symbols from (to)
470 DLLs.
471 </p>
472
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]473 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]474 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
475
476 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
477 or variable via a global pointer to a pointer that is set up by the DLL
478 exporting the symbol. On Microsoft Windows targets, the pointer name is
479 formed by combining <code>_imp__</code> and the function or variable name.
480 </dd>
481
482 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
483
484 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
485 pointer to a pointer in a DLL, so that it can be referenced with the
486 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
487 name is formed by combining <code>_imp__</code> and the function or variable
488 name.
489 </dd>
490
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491</dl>
492
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]493<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]494variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
495variable and was linked with this one, one of the two would be renamed,
496preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
497external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]498outside of the current module.</p>
499<p>It is illegal for a function <i>declaration</i>
500to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]501or <tt>extern_weak</tt>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]502<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
503linkages.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]504</div>
505
506<!-- ======================================================================= -->
507<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]508 <a name="callingconv">Calling Conventions</a>
509</div>
510
511<div class="doc_text">
512
513<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
514and <a href="#i_invoke">invokes</a> can all have an optional calling convention
515specified for the call. The calling convention of any pair of dynamic
516caller/callee must match, or the behavior of the program is undefined. The
517following calling conventions are supported by LLVM, and more may be added in
518the future:</p>
519
520<dl>
521 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
522
523 <dd>This calling convention (the default if no other calling convention is
524 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]525 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]526 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]527 </dd>
528
529 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
530
531 <dd>This calling convention attempts to make calls as fast as possible
532 (e.g. by passing things in registers). This calling convention allows the
533 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]534 without having to conform to an externally specified ABI. Implementations of
535 this convention should allow arbitrary tail call optimization to be supported.
536 This calling convention does not support varargs and requires the prototype of
537 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]538 </dd>
539
540 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
541
542 <dd>This calling convention attempts to make code in the caller as efficient
543 as possible under the assumption that the call is not commonly executed. As
544 such, these calls often preserve all registers so that the call does not break
545 any live ranges in the caller side. This calling convention does not support
546 varargs and requires the prototype of all callees to exactly match the
547 prototype of the function definition.
548 </dd>
549
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]550 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]551
552 <dd>Any calling convention may be specified by number, allowing
553 target-specific calling conventions to be used. Target specific calling
554 conventions start at 64.
555 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]556</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]557
558<p>More calling conventions can be added/defined on an as-needed basis, to
559support pascal conventions or any other well-known target-independent
560convention.</p>
561
562</div>
563
564<!-- ======================================================================= -->
565<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]566 <a name="visibility">Visibility Styles</a>
567</div>
568
569<div class="doc_text">
570
571<p>
572All Global Variables and Functions have one of the following visibility styles:
573</p>
574
575<dl>
576 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
577
578 <dd>On ELF, default visibility means that the declaration is visible to other
579 modules and, in shared libraries, means that the declared entity may be
580 overridden. On Darwin, default visibility means that the declaration is
581 visible to other modules. Default visibility corresponds to "external
582 linkage" in the language.
583 </dd>
584
585 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
586
587 <dd>Two declarations of an object with hidden visibility refer to the same
588 object if they are in the same shared object. Usually, hidden visibility
589 indicates that the symbol will not be placed into the dynamic symbol table,
590 so no other module (executable or shared library) can reference it
591 directly.
592 </dd>
593
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]594 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
595
596 <dd>On ELF, protected visibility indicates that the symbol will be placed in
597 the dynamic symbol table, but that references within the defining module will
598 bind to the local symbol. That is, the symbol cannot be overridden by another
599 module.
600 </dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]601</dl>
602
603</div>
604
605<!-- ======================================================================= -->
606<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]607 <a name="globalvars">Global Variables</a>
608</div>
609
610<div class="doc_text">
611
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]612<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]613instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]614an explicit section to be placed in, and may have an optional explicit alignment
615specified. A variable may be defined as "thread_local", which means that it
616will not be shared by threads (each thread will have a separated copy of the
617variable). A variable may be defined as a global "constant," which indicates
618that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]619optimization, allowing the global data to be placed in the read-only section of
620an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]621cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]622
623<p>
624LLVM explicitly allows <em>declarations</em> of global variables to be marked
625constant, even if the final definition of the global is not. This capability
626can be used to enable slightly better optimization of the program, but requires
627the language definition to guarantee that optimizations based on the
628'constantness' are valid for the translation units that do not include the
629definition.
630</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]631
632<p>As SSA values, global variables define pointer values that are in
633scope (i.e. they dominate) all basic blocks in the program. Global
634variables always define a pointer to their "content" type because they
635describe a region of memory, and all memory objects in LLVM are
636accessed through pointers.</p>
637
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]638<p>LLVM allows an explicit section to be specified for globals. If the target
639supports it, it will emit globals to the section specified.</p>
640
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]641<p>An explicit alignment may be specified for a global. If not present, or if
642the alignment is set to zero, the alignment of the global is set by the target
643to whatever it feels convenient. If an explicit alignment is specified, the
644global is forced to have at least that much alignment. All alignments must be
645a power of 2.</p>
646
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]647<p>For example, the following defines a global with an initializer, section,
648 and alignment:</p>
649
650<pre>
651 %G = constant float 1.0, section "foo", align 4
652</pre>
653
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]654</div>
655
656
657<!-- ======================================================================= -->
658<div class="doc_subsection">
659 <a name="functionstructure">Functions</a>
660</div>
661
662<div class="doc_text">
663
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]664<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
665an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]666<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]667<a href="#callingconv">calling convention</a>, a return type, an optional
668<a href="#paramattrs">parameter attribute</a> for the return type, a function
669name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]670<a href="#paramattrs">parameter attributes</a>), an optional section, an
671optional alignment, an opening curly brace, a list of basic blocks, and a
672closing curly brace.
673
674LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
675optional <a href="#linkage">linkage type</a>, an optional
676<a href="#visibility">visibility style</a>, an optional
677<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]678<a href="#paramattrs">parameter attribute</a> for the return type, a function
679name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]680
681<p>A function definition contains a list of basic blocks, forming the CFG for
682the function. Each basic block may optionally start with a label (giving the
683basic block a symbol table entry), contains a list of instructions, and ends
684with a <a href="#terminators">terminator</a> instruction (such as a branch or
685function return).</p>
686
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]687<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]688executed on entrance to the function, and it is not allowed to have predecessor
689basic blocks (i.e. there can not be any branches to the entry block of a
690function). Because the block can have no predecessors, it also cannot have any
691<a href="#i_phi">PHI nodes</a>.</p>
692
693<p>LLVM functions are identified by their name and type signature. Hence, two
694functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]695considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]696appropriately.</p>
697
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]698<p>LLVM allows an explicit section to be specified for functions. If the target
699supports it, it will emit functions to the section specified.</p>
700
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]701<p>An explicit alignment may be specified for a function. If not present, or if
702the alignment is set to zero, the alignment of the function is set by the target
703to whatever it feels convenient. If an explicit alignment is specified, the
704function is forced to have at least that much alignment. All alignments must be
705a power of 2.</p>
706
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]707</div>
708
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]709
710<!-- ======================================================================= -->
711<div class="doc_subsection">
712 <a name="aliasstructure">Aliases</a>
713</div>
714<div class="doc_text">
715 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikova80e1182007-04-28 13:45:00 +0000[diff] [blame]716 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]717 optional <a href="#linkage">linkage type</a>, and an
718 optional <a href="#visibility">visibility style</a>.</p>
719
720 <h5>Syntax:</h5>
721
722 <pre>
723 @&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
724 </pre>
725
726</div>
727
728
729
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]730<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]731<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
732<div class="doc_text">
733 <p>The return type and each parameter of a function type may have a set of
734 <i>parameter attributes</i> associated with them. Parameter attributes are
735 used to communicate additional information about the result or parameters of
736 a function. Parameter attributes are considered to be part of the function
737 type so two functions types that differ only by the parameter attributes
738 are different function types.</p>
739
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]740 <p>Parameter attributes are simple keywords that follow the type specified. If
741 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]742 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]743 %someFunc = i16 (i8 sext %someParam) zext
744 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]745 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]746 a different attribute (sext in the first one, zext in the second). Also note
747 that the attribute for the function result (zext) comes immediately after the
748 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]749
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]750 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]751 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]752 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]753 <dd>This indicates that the parameter should be zero extended just before
754 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]755 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]756 <dd>This indicates that the parameter should be sign extended just before
757 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]758 <dt><tt>inreg</tt></dt>
759 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]760 possible) during assembling function call. Support for this attribute is
761 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]762 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]763 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]764 that is the return value of the function in the source program.</dd>
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]765 <dt><tt>noreturn</tt></dt>
766 <dd>This function attribute indicates that the function never returns. This
767 indicates to LLVM that every call to this function should be treated as if
768 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]769 <dt><tt>nounwind</tt></dt>
770 <dd>This function attribute indicates that the function type does not use
771 the unwind instruction and does not allow stack unwinding to propagate
772 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]773 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]774
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]775</div>
776
777<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]778<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]779 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]780</div>
781
782<div class="doc_text">
783<p>
784Modules may contain "module-level inline asm" blocks, which corresponds to the
785GCC "file scope inline asm" blocks. These blocks are internally concatenated by
786LLVM and treated as a single unit, but may be separated in the .ll file if
787desired. The syntax is very simple:
788</p>
789
790<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]791 module asm "inline asm code goes here"
792 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]793</pre></div>
794
795<p>The strings can contain any character by escaping non-printable characters.
796 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
797 for the number.
798</p>
799
800<p>
801 The inline asm code is simply printed to the machine code .s file when
802 assembly code is generated.
803</p>
804</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]805
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]806<!-- ======================================================================= -->
807<div class="doc_subsection">
808 <a name="datalayout">Data Layout</a>
809</div>
810
811<div class="doc_text">
812<p>A module may specify a target specific data layout string that specifies how
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]813data is to be laid out in memory. The syntax for the data layout is simply:</p>
814<pre> target datalayout = "<i>layout specification</i>"</pre>
815<p>The <i>layout specification</i> consists of a list of specifications
816separated by the minus sign character ('-'). Each specification starts with a
817letter and may include other information after the letter to define some
818aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]819<dl>
820 <dt><tt>E</tt></dt>
821 <dd>Specifies that the target lays out data in big-endian form. That is, the
822 bits with the most significance have the lowest address location.</dd>
823 <dt><tt>e</tt></dt>
824 <dd>Specifies that hte target lays out data in little-endian form. That is,
825 the bits with the least significance have the lowest address location.</dd>
826 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
827 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
828 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
829 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
830 too.</dd>
831 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
832 <dd>This specifies the alignment for an integer type of a given bit
833 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
834 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
835 <dd>This specifies the alignment for a vector type of a given bit
836 <i>size</i>.</dd>
837 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
838 <dd>This specifies the alignment for a floating point type of a given bit
839 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
840 (double).</dd>
841 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
842 <dd>This specifies the alignment for an aggregate type of a given bit
843 <i>size</i>.</dd>
844</dl>
845<p>When constructing the data layout for a given target, LLVM starts with a
846default set of specifications which are then (possibly) overriden by the
847specifications in the <tt>datalayout</tt> keyword. The default specifications
848are given in this list:</p>
849<ul>
850 <li><tt>E</tt> - big endian</li>
851 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
852 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
853 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
854 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
855 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
856 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
857 alignment of 64-bits</li>
858 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
859 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
860 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
861 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
862 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
863</ul>
864<p>When llvm is determining the alignment for a given type, it uses the
865following rules:
866<ol>
867 <li>If the type sought is an exact match for one of the specifications, that
868 specification is used.</li>
869 <li>If no match is found, and the type sought is an integer type, then the
870 smallest integer type that is larger than the bitwidth of the sought type is
871 used. If none of the specifications are larger than the bitwidth then the the
872 largest integer type is used. For example, given the default specifications
873 above, the i7 type will use the alignment of i8 (next largest) while both
874 i65 and i256 will use the alignment of i64 (largest specified).</li>
875 <li>If no match is found, and the type sought is a vector type, then the
876 largest vector type that is smaller than the sought vector type will be used
877 as a fall back. This happens because <128 x double> can be implemented in
878 terms of 64 <2 x double>, for example.</li>
879</ol>
880</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]881
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]882<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]883<div class="doc_section"> <a name="typesystem">Type System</a> </div>
884<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]885
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]886<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]887
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]888<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]889intermediate representation. Being typed enables a number of
890optimizations to be performed on the IR directly, without having to do
891extra analyses on the side before the transformation. A strong type
892system makes it easier to read the generated code and enables novel
893analyses and transformations that are not feasible to perform on normal
894three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]895
896</div>
897
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]898<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]899<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]900<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]901<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]902system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]903
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]904<table class="layout">
905 <tr class="layout">
906 <td class="left">
907 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]909 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]910 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]911 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]912 </tbody>
913 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]914 </td>
915 <td class="right">
916 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]917 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]918 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame^]919 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]920 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]921 </tbody>
922 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]923 </td>
924 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]925</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]926</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]927
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]928<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]929<div class="doc_subsubsection"> <a name="t_classifications">Type
930Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]931<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]932<p>These different primitive types fall into a few useful
933classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]934
935<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]936 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]937 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]938 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]939 <td><a name="t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame^]940 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]941 </tr>
942 <tr>
943 <td><a name="t_floating">floating point</a></td>
944 <td><tt>float, double</tt></td>
945 </tr>
946 <tr>
947 <td><a name="t_firstclass">first class</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame^]948 <td><tt>i1, ..., float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]949 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]950 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]951 </tr>
952 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]953</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]954
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]955<p>The <a href="#t_firstclass">first class</a> types are perhaps the
956most important. Values of these types are the only ones which can be
957produced by instructions, passed as arguments, or used as operands to
958instructions. This means that all structures and arrays must be
959manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]960</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]961
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]962<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]963<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]964
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]965<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]966
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]967<p>The real power in LLVM comes from the derived types in the system.
968This is what allows a programmer to represent arrays, functions,
969pointers, and other useful types. Note that these derived types may be
970recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]971
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]972</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]973
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]974<!-- _______________________________________________________________________ -->
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame^]975<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
976
977<div class="doc_text">
978
979<h5>Overview:</h5>
980<p>The integer type is a very simple derived type that simply specifies an
981arbitrary bit width for the integer type desired. Any bit width from 1 bit to
9822^23-1 (about 8 million) can be specified.</p>
983
984<h5>Syntax:</h5>
985
986<pre>
987 iN
988</pre>
989
990<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
991value.</p>
992
993<h5>Examples:</h5>
994<table class="layout">
995 <tr class="layout">
996 <td class="left">
997 <tt>i1</tt><br/>
998 <tt>i4</tt><br/>
999 <tt>i8</tt><br/>
1000 <tt>i16</tt><br/>
1001 <tt>i32</tt><br/>
1002 <tt>i42</tt><br/>
1003 <tt>i64</tt><br/>
1004 <tt>i1942652</tt><br/>
1005 </td>
1006 <td class="left">
1007 A boolean integer of 1 bit<br/>
1008 A nibble sized integer of 4 bits.<br/>
1009 A byte sized integer of 8 bits.<br/>
1010 A half word sized integer of 16 bits.<br/>
1011 A word sized integer of 32 bits.<br/>
1012 An integer whose bit width is the answer. <br/>
1013 A double word sized integer of 64 bits.<br/>
1014 A really big integer of over 1 million bits.<br/>
1015 </td>
1016 </tr>
1017</table>
1018
1019<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1021
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1022<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1023
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1024<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1025
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1026<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1027sequentially in memory. The array type requires a size (number of
1028elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1029
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1030<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1031
1032<pre>
1033 [&lt;# elements&gt; x &lt;elementtype&gt;]
1034</pre>
1035
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1036<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1037be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1038
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1039<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1040<table class="layout">
1041 <tr class="layout">
1042 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1043 <tt>[40 x i32 ]</tt><br/>
1044 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1045 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1046 </td>
1047 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1048 Array of 40 32-bit integer values.<br/>
1049 Array of 41 32-bit integer values.<br/>
1050 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1051 </td>
1052 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1053</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1054<p>Here are some examples of multidimensional arrays:</p>
1055<table class="layout">
1056 <tr class="layout">
1057 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1058 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1059 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1060 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1061 </td>
1062 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1063 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1064 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1065 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1066 </td>
1067 </tr>
1068</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1069
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1070<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1071length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1072LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1073As a special case, however, zero length arrays are recognized to be variable
1074length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1075type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1076
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1077</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1078
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1079<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1080<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1081<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1082<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1083<p>The function type can be thought of as a function signature. It
1084consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1085Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1086(which are structures of pointers to functions), for indirect function
1087calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1088<p>
1089The return type of a function type cannot be an aggregate type.
1090</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1091<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1092<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1093<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]1094specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1095which indicates that the function takes a variable number of arguments.
1096Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1097 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1098<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1099<table class="layout">
1100 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1101 <td class="left"><tt>i32 (i32)</tt></td>
1102 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1103 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1104 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1105 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1106 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1107 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1108 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1109 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1110 <tt>float</tt>.
1111 </td>
1112 </tr><tr class="layout">
1113 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1114 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1115 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1116 which returns an integer. This is the signature for <tt>printf</tt> in
1117 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1118 </td>
1119 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1120</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1121
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1122</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1123<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1124<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1125<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1126<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1127<p>The structure type is used to represent a collection of data members
1128together in memory. The packing of the field types is defined to match
1129the ABI of the underlying processor. The elements of a structure may
1130be any type that has a size.</p>
1131<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1132and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1133field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1134instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1135<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1136<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1137<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1138<table class="layout">
1139 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1140 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1141 <td class="left">A triple of three <tt>i32</tt> values</td>
1142 </tr><tr class="layout">
1143 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1144 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1145 second element is a <a href="#t_pointer">pointer</a> to a
1146 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1147 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1148 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1149</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1150</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1152<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1153<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1154</div>
1155<div class="doc_text">
1156<h5>Overview:</h5>
1157<p>The packed structure type is used to represent a collection of data members
1158together in memory. There is no padding between fields. Further, the alignment
1159of a packed structure is 1 byte. The elements of a packed structure may
1160be any type that has a size.</p>
1161<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1162and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1163field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1164instruction.</p>
1165<h5>Syntax:</h5>
1166<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1167<h5>Examples:</h5>
1168<table class="layout">
1169 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1170 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1171 <td class="left">A triple of three <tt>i32</tt> values</td>
1172 </tr><tr class="layout">
1173 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1174 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1175 second element is a <a href="#t_pointer">pointer</a> to a
1176 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1177 an <tt>i32</tt>.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1178 </tr>
1179</table>
1180</div>
1181
1182<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1183<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1184<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1185<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1186<p>As in many languages, the pointer type represents a pointer or
1187reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1188<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1189<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1190<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1191<table class="layout">
1192 <tr class="layout">
1193 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1194 <tt>[4x i32]*</tt><br/>
1195 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1196 </td>
1197 <td class="left">
1198 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1199 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1200 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1201 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1202 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1203 </td>
1204 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1205</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1206</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1207
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1208<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1209<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1210<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1211
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1212<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1213
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1214<p>A vector type is a simple derived type that represents a vector
1215of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1216are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1217A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1218elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1219of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1220considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1221
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1222<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1223
1224<pre>
1225 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1226</pre>
1227
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1228<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1229be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1230
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1231<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1232
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1233<table class="layout">
1234 <tr class="layout">
1235 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1236 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1237 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1238 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1239 </td>
1240 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1241 Vector of 4 32-bit integer values.<br/>
1242 Vector of 8 floating-point values.<br/>
1243 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1244 </td>
1245 </tr>
1246</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1247</div>
1248
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1249<!-- _______________________________________________________________________ -->
1250<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1251<div class="doc_text">
1252
1253<h5>Overview:</h5>
1254
1255<p>Opaque types are used to represent unknown types in the system. This
1256corresponds (for example) to the C notion of a foward declared structure type.
1257In LLVM, opaque types can eventually be resolved to any type (not just a
1258structure type).</p>
1259
1260<h5>Syntax:</h5>
1261
1262<pre>
1263 opaque
1264</pre>
1265
1266<h5>Examples:</h5>
1267
1268<table class="layout">
1269 <tr class="layout">
1270 <td class="left">
1271 <tt>opaque</tt>
1272 </td>
1273 <td class="left">
1274 An opaque type.<br/>
1275 </td>
1276 </tr>
1277</table>
1278</div>
1279
1280
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1281<!-- *********************************************************************** -->
1282<div class="doc_section"> <a name="constants">Constants</a> </div>
1283<!-- *********************************************************************** -->
1284
1285<div class="doc_text">
1286
1287<p>LLVM has several different basic types of constants. This section describes
1288them all and their syntax.</p>
1289
1290</div>
1291
1292<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1293<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1294
1295<div class="doc_text">
1296
1297<dl>
1298 <dt><b>Boolean constants</b></dt>
1299
1300 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1301 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1302 </dd>
1303
1304 <dt><b>Integer constants</b></dt>
1305
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1306 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1307 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1308 integer types.
1309 </dd>
1310
1311 <dt><b>Floating point constants</b></dt>
1312
1313 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1314 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1315 notation (see below). Floating point constants must have a <a
1316 href="#t_floating">floating point</a> type. </dd>
1317
1318 <dt><b>Null pointer constants</b></dt>
1319
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1320 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1321 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1322
1323</dl>
1324
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1325<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1326of floating point constants. For example, the form '<tt>double
13270x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13284.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1329(and the only time that they are generated by the disassembler) is when a
1330floating point constant must be emitted but it cannot be represented as a
1331decimal floating point number. For example, NaN's, infinities, and other
1332special values are represented in their IEEE hexadecimal format so that
1333assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1334
1335</div>
1336
1337<!-- ======================================================================= -->
1338<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1339</div>
1340
1341<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1342<p>Aggregate constants arise from aggregation of simple constants
1343and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1344
1345<dl>
1346 <dt><b>Structure constants</b></dt>
1347
1348 <dd>Structure constants are represented with notation similar to structure
1349 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1350 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1351 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]1352 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1353 types of elements must match those specified by the type.
1354 </dd>
1355
1356 <dt><b>Array constants</b></dt>
1357
1358 <dd>Array constants are represented with notation similar to array type
1359 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1360 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1361 constants must have <a href="#t_array">array type</a>, and the number and
1362 types of elements must match those specified by the type.
1363 </dd>
1364
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1365 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1366
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1367 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1368 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1369 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]1370 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1371 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372 match those specified by the type.
1373 </dd>
1374
1375 <dt><b>Zero initialization</b></dt>
1376
1377 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1378 value to zero of <em>any</em> type, including scalar and aggregate types.
1379 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]1380 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1381 initializers.
1382 </dd>
1383</dl>
1384
1385</div>
1386
1387<!-- ======================================================================= -->
1388<div class="doc_subsection">
1389 <a name="globalconstants">Global Variable and Function Addresses</a>
1390</div>
1391
1392<div class="doc_text">
1393
1394<p>The addresses of <a href="#globalvars">global variables</a> and <a
1395href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1396constants. These constants are explicitly referenced when the <a
1397href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1398href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1399file:</p>
1400
1401<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1402 %X = global i32 17
1403 %Y = global i32 42
1404 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1405</pre>
1406
1407</div>
1408
1409<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1410<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1411<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1412 <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]1413 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1414 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1415
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1416 <p>Undefined values indicate to the compiler that the program is well defined
1417 no matter what value is used, giving the compiler more freedom to optimize.
1418 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1419</div>
1420
1421<!-- ======================================================================= -->
1422<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1423</div>
1424
1425<div class="doc_text">
1426
1427<p>Constant expressions are used to allow expressions involving other constants
1428to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1429href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1430that does not have side effects (e.g. load and call are not supported). The
1431following is the syntax for constant expressions:</p>
1432
1433<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1434 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1435 <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]1436 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1437
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1438 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1439 <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]1440 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]1441
1442 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1443 <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]1444 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]1445
1446 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1447 <dd>Truncate a floating point constant to another floating point type. The
1448 size of CST must be larger than the size of TYPE. Both types must be
1449 floating point.</dd>
1450
1451 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1452 <dd>Floating point extend a constant to another type. The size of CST must be
1453 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1454
1455 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1456 <dd>Convert a floating point constant to the corresponding unsigned integer
1457 constant. TYPE must be an integer type. CST must be floating point. If the
1458 value won't fit in the integer type, the results are undefined.</dd>
1459
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1460 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1461 <dd>Convert a floating point constant to the corresponding signed integer
1462 constant. TYPE must be an integer type. CST must be floating point. If the
1463 value won't fit in the integer type, the results are undefined.</dd>
1464
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1465 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1466 <dd>Convert an unsigned integer constant to the corresponding floating point
1467 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1468 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1469
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1470 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1471 <dd>Convert a signed integer constant to the corresponding floating point
1472 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]1473 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1474
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1475 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1476 <dd>Convert a pointer typed constant to the corresponding integer constant
1477 TYPE must be an integer type. CST must be of pointer type. The CST value is
1478 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1479
1480 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1481 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1482 pointer type. CST must be of integer type. The CST value is zero extended,
1483 truncated, or unchanged to make it fit in a pointer size. This one is
1484 <i>really</i> dangerous!</dd>
1485
1486 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1487 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1488 identical (same number of bits). The conversion is done as if the CST value
1489 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]1490 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1491 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]1492 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1493 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1494
1495 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1496
1497 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1498 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1499 instruction, the index list may have zero or more indexes, which are required
1500 to make sense for the type of "CSTPTR".</dd>
1501
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1502 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1503
1504 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1505 constants.</dd>
1506
1507 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1508 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1509
1510 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1511 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1512
1513 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1514
1515 <dd>Perform the <a href="#i_extractelement">extractelement
1516 operation</a> on constants.
1517
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1518 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1519
1520 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1521 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1522
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1523
1524 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1525
1526 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1527 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1528
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1529 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1530
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1531 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1532 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1533 binary</a> operations. The constraints on operands are the same as those for
1534 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1535 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1540<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1541<!-- *********************************************************************** -->
1542
1543<!-- ======================================================================= -->
1544<div class="doc_subsection">
1545<a name="inlineasm">Inline Assembler Expressions</a>
1546</div>
1547
1548<div class="doc_text">
1549
1550<p>
1551LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1552Module-Level Inline Assembly</a>) through the use of a special value. This
1553value represents the inline assembler as a string (containing the instructions
1554to emit), a list of operand constraints (stored as a string), and a flag that
1555indicates whether or not the inline asm expression has side effects. An example
1556inline assembler expression is:
1557</p>
1558
1559<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1560 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1561</pre>
1562
1563<p>
1564Inline assembler expressions may <b>only</b> be used as the callee operand of
1565a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1566</p>
1567
1568<pre>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]1569 %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]1570</pre>
1571
1572<p>
1573Inline asms with side effects not visible in the constraint list must be marked
1574as having side effects. This is done through the use of the
1575'<tt>sideeffect</tt>' keyword, like so:
1576</p>
1577
1578<pre>
1579 call void asm sideeffect "eieio", ""()
1580</pre>
1581
1582<p>TODO: The format of the asm and constraints string still need to be
1583documented here. Constraints on what can be done (e.g. duplication, moving, etc
1584need to be documented).
1585</p>
1586
1587</div>
1588
1589<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1591<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1593<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1594
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1595<p>The LLVM instruction set consists of several different
1596classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1597instructions</a>, <a href="#binaryops">binary instructions</a>,
1598<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1599 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1600instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1601
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1602</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1605<div class="doc_subsection"> <a name="terminators">Terminator
1606Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1607
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1608<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1609
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1610<p>As mentioned <a href="#functionstructure">previously</a>, every
1611basic block in a program ends with a "Terminator" instruction, which
1612indicates which block should be executed after the current block is
1613finished. These terminator instructions typically yield a '<tt>void</tt>'
1614value: they produce control flow, not values (the one exception being
1615the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1616<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1617 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1618instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1619the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1620 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1621 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1623</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1626<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1627Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1628<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1629<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1630<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]1631 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1632</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1634<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1635value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1636<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1637returns a value and then causes control flow, and one that just causes
1638control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1639<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1640<p>The '<tt>ret</tt>' instruction may return any '<a
1641 href="#t_firstclass">first class</a>' type. Notice that a function is
1642not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1643instruction inside of the function that returns a value that does not
1644match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1646<p>When the '<tt>ret</tt>' instruction is executed, control flow
1647returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1648 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1649the instruction after the call. If the caller was an "<a
1650 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1651at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1652returns a value, that value shall set the call or invoke instruction's
1653return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1655<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1656 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1657</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1658</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1659<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1660<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1661<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1662<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1663<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]1664</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<p>The '<tt>br</tt>' instruction is used to cause control flow to
1667transfer to a different basic block in the current function. There are
1668two forms of this instruction, corresponding to a conditional branch
1669and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1671<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1672single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1673unconditional form of the '<tt>br</tt>' instruction takes a single
1674'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1676<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1677argument is evaluated. If the value is <tt>true</tt>, control flows
1678to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1679control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1680<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1681<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]1682 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]1683</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1684<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1685<div class="doc_subsubsection">
1686 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1687</div>
1688
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1689<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1690<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1691
1692<pre>
1693 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1694</pre>
1695
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1696<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1697
1698<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1699several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1700instruction, allowing a branch to occur to one of many possible
1701destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1702
1703
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1705
1706<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1707comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1708an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1709table is not allowed to contain duplicate constant entries.</p>
1710
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1712
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713<p>The <tt>switch</tt> instruction specifies a table of values and
1714destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1715table is searched for the given value. If the value is found, control flow is
1716transfered to the corresponding destination; otherwise, control flow is
1717transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1718
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1719<h5>Implementation:</h5>
1720
1721<p>Depending on properties of the target machine and the particular
1722<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1723ways. For example, it could be generated as a series of chained conditional
1724branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1725
1726<h5>Example:</h5>
1727
1728<pre>
1729 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1730 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1731 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1732
1733 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1734 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1735
1736 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1737 switch i32 %val, label %otherwise [ i32 0, label %onzero
1738 i32 1, label %onone
1739 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1741</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1742
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1743<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1744<div class="doc_subsubsection">
1745 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1746</div>
1747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1748<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1751
1752<pre>
1753 &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]1754 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1755</pre>
1756
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1757<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1758
1759<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1760function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1761'<tt>normal</tt>' label or the
1762'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1763"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1764"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1765href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1766continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1768<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1769
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1770<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1771
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1773 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]1774 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1775 convention</a> the call should use. If none is specified, the call defaults
1776 to using C calling conventions.
1777 </li>
1778 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1779 function value being invoked. In most cases, this is a direct function
1780 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1781 an arbitrary pointer to function value.
1782 </li>
1783
1784 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1785 function to be invoked. </li>
1786
1787 <li>'<tt>function args</tt>': argument list whose types match the function
1788 signature argument types. If the function signature indicates the function
1789 accepts a variable number of arguments, the extra arguments can be
1790 specified. </li>
1791
1792 <li>'<tt>normal label</tt>': the label reached when the called function
1793 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1794
1795 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1796 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1797
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1801
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1802<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1803href="#i_call">call</a></tt>' instruction in most regards. The primary
1804difference is that it establishes an association with a label, which is used by
1805the runtime library to unwind the stack.</p>
1806
1807<p>This instruction is used in languages with destructors to ensure that proper
1808cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1809exception. Additionally, this is important for implementation of
1810'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1812<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1813<pre>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]1814 %retval = invoke i32 %Test(i32 15) to label %Continue
1815 unwind label %TestCleanup <i>; {i32}:retval set</i>
1816 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1817 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1819</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1820
1821
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1823
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1825Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1826
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1827<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1828
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1829<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1830<pre>
1831 unwind
1832</pre>
1833
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1834<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1835
1836<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1837at the first callee in the dynamic call stack which used an <a
1838href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1839primarily used to implement exception handling.</p>
1840
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1841<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1842
1843<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1844immediately halt. The dynamic call stack is then searched for the first <a
1845href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1846execution continues at the "exceptional" destination block specified by the
1847<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1848dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1849</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1850
1851<!-- _______________________________________________________________________ -->
1852
1853<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1854Instruction</a> </div>
1855
1856<div class="doc_text">
1857
1858<h5>Syntax:</h5>
1859<pre>
1860 unreachable
1861</pre>
1862
1863<h5>Overview:</h5>
1864
1865<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1866instruction is used to inform the optimizer that a particular portion of the
1867code is not reachable. This can be used to indicate that the code after a
1868no-return function cannot be reached, and other facts.</p>
1869
1870<h5>Semantics:</h5>
1871
1872<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1873</div>
1874
1875
1876
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1879<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1880<p>Binary operators are used to do most of the computation in a
1881program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1882produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1883multiple 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]1884The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1886<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1888<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1889<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1890Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1891<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1893<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]1894</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1896<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1897<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1898<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1899 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1900 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]1901Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1902<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1903<p>The value produced is the integer or floating point sum of the two
1904operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1905<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1906<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]1907</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1908</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1910<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1911Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1912<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1913<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1914<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]1915</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1917<p>The '<tt>sub</tt>' instruction returns the difference of its two
1918operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1919<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1920instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1921<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1922<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1923 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1924values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1925This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1926Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1928<p>The value produced is the integer or floating point difference of
1929the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1931<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1932 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1933</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1934</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1935<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1936<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1937Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1938<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1939<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1940<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]1941</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1942<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943<p>The '<tt>mul</tt>' instruction returns the product of its two
1944operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1945<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1946<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1948values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1949This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1950Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1952<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1953two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1954<p>Because the operands are the same width, the result of an integer
1955multiplication is the same whether the operands should be deemed unsigned or
1956signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1958<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]1959</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1960</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1961<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1962<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1963</a></div>
1964<div class="doc_text">
1965<h5>Syntax:</h5>
1966<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1967</pre>
1968<h5>Overview:</h5>
1969<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1970operands.</p>
1971<h5>Arguments:</h5>
1972<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1973<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1974types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1975of the values in which case the elements must be integers.</p>
1976<h5>Semantics:</h5>
1977<p>The value produced is the unsigned integer quotient of the two operands. This
1978instruction always performs an unsigned division operation, regardless of
1979whether the arguments are unsigned or not.</p>
1980<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1981<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]1982</pre>
1983</div>
1984<!-- _______________________________________________________________________ -->
1985<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1986</a> </div>
1987<div class="doc_text">
1988<h5>Syntax:</h5>
1989<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1990</pre>
1991<h5>Overview:</h5>
1992<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1993operands.</p>
1994<h5>Arguments:</h5>
1995<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1996<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1997types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1998of the values in which case the elements must be integers.</p>
1999<h5>Semantics:</h5>
2000<p>The value produced is the signed integer quotient of the two operands. This
2001instruction always performs a signed division operation, regardless of whether
2002the arguments are signed or not.</p>
2003<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2004<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]2005</pre>
2006</div>
2007<!-- _______________________________________________________________________ -->
2008<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2009Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2010<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2011<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2012<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]2013</pre>
2014<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2015<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016operands.</p>
2017<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2018<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2019<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2020identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2021versions of floating point values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2022<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2023<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2024<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]2025<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]2026</pre>
2027</div>
2028<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2029<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2030</div>
2031<div class="doc_text">
2032<h5>Syntax:</h5>
2033<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2034</pre>
2035<h5>Overview:</h5>
2036<p>The '<tt>urem</tt>' instruction returns the remainder from the
2037unsigned division of its two arguments.</p>
2038<h5>Arguments:</h5>
2039<p>The two arguments to the '<tt>urem</tt>' instruction must be
2040<a href="#t_integer">integer</a> values. Both arguments must have identical
2041types.</p>
2042<h5>Semantics:</h5>
2043<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2044This instruction always performs an unsigned division to get the remainder,
2045regardless of whether the arguments are unsigned or not.</p>
2046<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2047<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]2048</pre>
2049
2050</div>
2051<!-- _______________________________________________________________________ -->
2052<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2053Instruction</a> </div>
2054<div class="doc_text">
2055<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2056<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]2057</pre>
2058<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2059<p>The '<tt>srem</tt>' instruction returns the remainder from the
2060signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2061<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2062<p>The two arguments to the '<tt>srem</tt>' instruction must be
2063<a href="#t_integer">integer</a> values. Both arguments must have identical
2064types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2065<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2066<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2067has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2068operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2069a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2070 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2071Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2072please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2073Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2074<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2075<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]2076</pre>
2077
2078</div>
2079<!-- _______________________________________________________________________ -->
2080<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2081Instruction</a> </div>
2082<div class="doc_text">
2083<h5>Syntax:</h5>
2084<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2085</pre>
2086<h5>Overview:</h5>
2087<p>The '<tt>frem</tt>' instruction returns the remainder from the
2088division of its two operands.</p>
2089<h5>Arguments:</h5>
2090<p>The two arguments to the '<tt>frem</tt>' instruction must be
2091<a href="#t_floating">floating point</a> values. Both arguments must have
2092identical types.</p>
2093<h5>Semantics:</h5>
2094<p>This instruction returns the <i>remainder</i> of a division.</p>
2095<h5>Example:</h5>
2096<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]2097</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2098</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2099
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2100<!-- ======================================================================= -->
2101<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2102Operations</a> </div>
2103<div class="doc_text">
2104<p>Bitwise binary operators are used to do various forms of
2105bit-twiddling in a program. They are generally very efficient
2106instructions and can commonly be strength reduced from other
2107instructions. They require two operands, execute an operation on them,
2108and produce a single value. The resulting value of the bitwise binary
2109operators is always the same type as its first operand.</p>
2110</div>
2111
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2112<!-- _______________________________________________________________________ -->
2113<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2114Instruction</a> </div>
2115<div class="doc_text">
2116<h5>Syntax:</h5>
2117<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2118</pre>
2119<h5>Overview:</h5>
2120<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2121the left a specified number of bits.</p>
2122<h5>Arguments:</h5>
2123<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2124 href="#t_integer">integer</a> type.</p>
2125<h5>Semantics:</h5>
2126<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2127<h5>Example:</h5><pre>
2128 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2129 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2130 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2131</pre>
2132</div>
2133<!-- _______________________________________________________________________ -->
2134<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2135Instruction</a> </div>
2136<div class="doc_text">
2137<h5>Syntax:</h5>
2138<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2139</pre>
2140
2141<h5>Overview:</h5>
2142<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2143operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2144
2145<h5>Arguments:</h5>
2146<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2147<a href="#t_integer">integer</a> type.</p>
2148
2149<h5>Semantics:</h5>
2150<p>This instruction always performs a logical shift right operation. The most
2151significant bits of the result will be filled with zero bits after the
2152shift.</p>
2153
2154<h5>Example:</h5>
2155<pre>
2156 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2157 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2158 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2159 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2160</pre>
2161</div>
2162
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2163<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2164<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2165Instruction</a> </div>
2166<div class="doc_text">
2167
2168<h5>Syntax:</h5>
2169<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2170</pre>
2171
2172<h5>Overview:</h5>
2173<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2174operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2175
2176<h5>Arguments:</h5>
2177<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2178<a href="#t_integer">integer</a> type.</p>
2179
2180<h5>Semantics:</h5>
2181<p>This instruction always performs an arithmetic shift right operation,
2182The most significant bits of the result will be filled with the sign bit
2183of <tt>var1</tt>.</p>
2184
2185<h5>Example:</h5>
2186<pre>
2187 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2188 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2189 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2190 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2191</pre>
2192</div>
2193
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2194<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2195<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2196Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2197<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2198<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2199<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]2200</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2201<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2202<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2203its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2204<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2205<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2206 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2207identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2208<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2209<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2210<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2211<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2212<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2213 <tbody>
2214 <tr>
2215 <td>In0</td>
2216 <td>In1</td>
2217 <td>Out</td>
2218 </tr>
2219 <tr>
2220 <td>0</td>
2221 <td>0</td>
2222 <td>0</td>
2223 </tr>
2224 <tr>
2225 <td>0</td>
2226 <td>1</td>
2227 <td>0</td>
2228 </tr>
2229 <tr>
2230 <td>1</td>
2231 <td>0</td>
2232 <td>0</td>
2233 </tr>
2234 <tr>
2235 <td>1</td>
2236 <td>1</td>
2237 <td>1</td>
2238 </tr>
2239 </tbody>
2240</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2241</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2242<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2243<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2244 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2245 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2246</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2247</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2248<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2249<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2250<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2251<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2252<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]2253</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2254<h5>Overview:</h5>
2255<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2256or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2257<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2258<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2259 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2260identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2261<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2262<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2263<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2264<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2265<table border="1" cellspacing="0" cellpadding="4">
2266 <tbody>
2267 <tr>
2268 <td>In0</td>
2269 <td>In1</td>
2270 <td>Out</td>
2271 </tr>
2272 <tr>
2273 <td>0</td>
2274 <td>0</td>
2275 <td>0</td>
2276 </tr>
2277 <tr>
2278 <td>0</td>
2279 <td>1</td>
2280 <td>1</td>
2281 </tr>
2282 <tr>
2283 <td>1</td>
2284 <td>0</td>
2285 <td>1</td>
2286 </tr>
2287 <tr>
2288 <td>1</td>
2289 <td>1</td>
2290 <td>1</td>
2291 </tr>
2292 </tbody>
2293</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2294</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2295<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2296<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2297 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2298 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2299</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2300</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2301<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2302<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2303Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2304<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2305<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2306<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]2307</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2308<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2309<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2310or of its two operands. The <tt>xor</tt> is used to implement the
2311"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2312<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2313<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2314 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2315identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2316<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2317<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2318<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2319<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2320<table border="1" cellspacing="0" cellpadding="4">
2321 <tbody>
2322 <tr>
2323 <td>In0</td>
2324 <td>In1</td>
2325 <td>Out</td>
2326 </tr>
2327 <tr>
2328 <td>0</td>
2329 <td>0</td>
2330 <td>0</td>
2331 </tr>
2332 <tr>
2333 <td>0</td>
2334 <td>1</td>
2335 <td>1</td>
2336 </tr>
2337 <tr>
2338 <td>1</td>
2339 <td>0</td>
2340 <td>1</td>
2341 </tr>
2342 <tr>
2343 <td>1</td>
2344 <td>1</td>
2345 <td>0</td>
2346 </tr>
2347 </tbody>
2348</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2349</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2350<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2351<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2352<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2353 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2354 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2355 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2356</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2357</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2358
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2359<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2360<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2361 <a name="vectorops">Vector Operations</a>
2362</div>
2363
2364<div class="doc_text">
2365
2366<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2367target-independent manner. These instructions cover the element-access and
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2368vector-specific operations needed to process vectors effectively. While LLVM
2369does directly support these vector operations, many sophisticated algorithms
2370will want to use target-specific intrinsics to take full advantage of a specific
2371target.</p>
2372
2373</div>
2374
2375<!-- _______________________________________________________________________ -->
2376<div class="doc_subsubsection">
2377 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2378</div>
2379
2380<div class="doc_text">
2381
2382<h5>Syntax:</h5>
2383
2384<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2385 &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]2386</pre>
2387
2388<h5>Overview:</h5>
2389
2390<p>
2391The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2392element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2393</p>
2394
2395
2396<h5>Arguments:</h5>
2397
2398<p>
2399The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2400value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2401an index indicating the position from which to extract the element.
2402The index may be a variable.</p>
2403
2404<h5>Semantics:</h5>
2405
2406<p>
2407The result is a scalar of the same type as the element type of
2408<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2409<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2410results are undefined.
2411</p>
2412
2413<h5>Example:</h5>
2414
2415<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2416 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2417</pre>
2418</div>
2419
2420
2421<!-- _______________________________________________________________________ -->
2422<div class="doc_subsubsection">
2423 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2424</div>
2425
2426<div class="doc_text">
2427
2428<h5>Syntax:</h5>
2429
2430<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2431 &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]2432</pre>
2433
2434<h5>Overview:</h5>
2435
2436<p>
2437The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2438element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2439</p>
2440
2441
2442<h5>Arguments:</h5>
2443
2444<p>
2445The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2446value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2447scalar value whose type must equal the element type of the first
2448operand. The third operand is an index indicating the position at
2449which to insert the value. The index may be a variable.</p>
2450
2451<h5>Semantics:</h5>
2452
2453<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2454The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2455element values are those of <tt>val</tt> except at position
2456<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2457exceeds the length of <tt>val</tt>, the results are undefined.
2458</p>
2459
2460<h5>Example:</h5>
2461
2462<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2463 %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]2464</pre>
2465</div>
2466
2467<!-- _______________________________________________________________________ -->
2468<div class="doc_subsubsection">
2469 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2470</div>
2471
2472<div class="doc_text">
2473
2474<h5>Syntax:</h5>
2475
2476<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2477 &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]2478</pre>
2479
2480<h5>Overview:</h5>
2481
2482<p>
2483The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2484from two input vectors, returning a vector of the same type.
2485</p>
2486
2487<h5>Arguments:</h5>
2488
2489<p>
2490The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2491with types that match each other and types that match the result of the
2492instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2493of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2494</p>
2495
2496<p>
2497The shuffle mask operand is required to be a constant vector with either
2498constant integer or undef values.
2499</p>
2500
2501<h5>Semantics:</h5>
2502
2503<p>
2504The elements of the two input vectors are numbered from left to right across
2505both of the vectors. The shuffle mask operand specifies, for each element of
2506the result vector, which element of the two input registers the result element
2507gets. The element selector may be undef (meaning "don't care") and the second
2508operand may be undef if performing a shuffle from only one vector.
2509</p>
2510
2511<h5>Example:</h5>
2512
2513<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2514 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2515 &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]2516 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2517 &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]2518</pre>
2519</div>
2520
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2521
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2522<!-- ======================================================================= -->
2523<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2524 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2525</div>
2526
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2527<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2528
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2529<p>A key design point of an SSA-based representation is how it
2530represents memory. In LLVM, no memory locations are in SSA form, which
2531makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2532allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2533
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2534</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2535
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2536<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2537<div class="doc_subsubsection">
2538 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2539</div>
2540
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2541<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2543<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2544
2545<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2546 &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]2547</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2548
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2549<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2550
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2551<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2552heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2555
2556<p>The '<tt>malloc</tt>' instruction allocates
2557<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2558bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2559appropriate type to the program. If "NumElements" is specified, it is the
2560number of elements allocated. If an alignment is specified, the value result
2561of the allocation is guaranteed to be aligned to at least that boundary. If
2562not specified, or if zero, the target can choose to align the allocation on any
2563convenient boundary.</p>
2564
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2565<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2568
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2569<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2570a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2571
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2572<h5>Example:</h5>
2573
2574<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2575 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2576
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2577 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2578 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2579 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2580 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2581 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2582</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2583</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2585<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586<div class="doc_subsubsection">
2587 <a name="i_free">'<tt>free</tt>' Instruction</a>
2588</div>
2589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2590<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2591
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2592<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2593
2594<pre>
2595 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2596</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2598<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2600<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2601memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2602
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2603<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2605<p>'<tt>value</tt>' shall be a pointer value that points to a value
2606that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2607instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2608
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2609<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2610
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2611<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2612after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2614<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2615
2616<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2617 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2618 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2619</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2620</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2622<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2623<div class="doc_subsubsection">
2624 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2625</div>
2626
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2627<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2628
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2629<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2630
2631<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2632 &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]2633</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2634
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2635<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2636
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2637<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2638currently executing function, to be automatically released when this function
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2639returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2640
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2641<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2642
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2643<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2644bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2645appropriate type to the program. If "NumElements" is specified, it is the
2646number of elements allocated. If an alignment is specified, the value result
2647of the allocation is guaranteed to be aligned to at least that boundary. If
2648not specified, or if zero, the target can choose to align the allocation on any
2649convenient boundary.</p>
2650
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2651<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2654
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2655<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2656memory is automatically released when the function returns. The '<tt>alloca</tt>'
2657instruction is commonly used to represent automatic variables that must
2658have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2659 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]2660instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2661
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2663
2664<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2665 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2666 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2667 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2668 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2669</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2670</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2671
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2672<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2673<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2674Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2675<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2676<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2677<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]2678<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2679<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2680<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2681<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2682address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2683 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2684marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2685the number or order of execution of this <tt>load</tt> with other
2686volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2687instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2688<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2689<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2690<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2691<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2692 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2693 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2694 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2695</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2696</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2697<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2698<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2699Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2700<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2701<h5>Syntax:</h5>
Christopher Lamb2330e4d2007-04-21 08:16:25 +0000[diff] [blame]2702<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2703 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]2704</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2705<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2706<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2707<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2708<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2709to 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]2710operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2711operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2712optimizer is not allowed to modify the number or order of execution of
2713this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2714 href="#i_store">store</a></tt> instructions.</p>
2715<h5>Semantics:</h5>
2716<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2717at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2718<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2719<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2720 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2721 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2722 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2723</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2724</div>
2725
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2726<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2727<div class="doc_subsubsection">
2728 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2729</div>
2730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2731<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2732<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2733<pre>
2734 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2735</pre>
2736
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2737<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2738
2739<p>
2740The '<tt>getelementptr</tt>' instruction is used to get the address of a
2741subelement of an aggregate data structure.</p>
2742
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2743<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2744
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2745<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2746elements of the aggregate object to index to. The actual types of the arguments
2747provided depend on the type of the first pointer argument. The
2748'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2749levels 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]2750structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2751into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2752be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2753
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2754<p>For example, let's consider a C code fragment and how it gets
2755compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2756
2757<pre>
2758 struct RT {
2759 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2760 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2761 char C;
2762 };
2763 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2764 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2765 double Y;
2766 struct RT Z;
2767 };
2768
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2769 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2770 return &amp;s[1].Z.B[5][13];
2771 }
2772</pre>
2773
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2774<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2775
2776<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2777 %RT = type { i8 , [10 x [20 x i32]], i8 }
2778 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2779
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2780 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2781 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2782 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2783 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2784 }
2785</pre>
2786
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2787<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2788
2789<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2790on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2791and <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]2792<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]2793to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2794<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2795
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2796<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]2797type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2798}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2799the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2800i8 }</tt>' type, another structure. The third index indexes into the second
2801element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2802array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2803'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2804to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2805
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2806<p>Note that it is perfectly legal to index partially through a
2807structure, returning a pointer to an inner element. Because of this,
2808the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2809
2810<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2811 define i32* %foo(%ST* %s) {
2812 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2813 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2814 %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]2815 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2816 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2817 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2818 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2819</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2820
2821<p>Note that it is undefined to access an array out of bounds: array and
2822pointer indexes must always be within the defined bounds of the array type.
2823The one exception for this rules is zero length arrays. These arrays are
2824defined to be accessible as variable length arrays, which requires access
2825beyond the zero'th element.</p>
2826
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2827<p>The getelementptr instruction is often confusing. For some more insight
2828into how it works, see <a href="GetElementPtr.html">the getelementptr
2829FAQ</a>.</p>
2830
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2831<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2832
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2833<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2834 <i>; yields [12 x i8]*:aptr</i>
2835 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2836</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2837</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2838
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2839<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2840<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2841</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2842<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2843<p>The instructions in this category are the conversion instructions (casting)
2844which all take a single operand and a type. They perform various bit conversions
2845on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2846</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2847
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2848<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2849<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2850 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2851</div>
2852<div class="doc_text">
2853
2854<h5>Syntax:</h5>
2855<pre>
2856 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2857</pre>
2858
2859<h5>Overview:</h5>
2860<p>
2861The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2862</p>
2863
2864<h5>Arguments:</h5>
2865<p>
2866The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2867be 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]2868and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2869type. The bit size of <tt>value</tt> must be larger than the bit size of
2870<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2871
2872<h5>Semantics:</h5>
2873<p>
2874The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2875and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2876larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2877It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2878
2879<h5>Example:</h5>
2880<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2881 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2882 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2883 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2884</pre>
2885</div>
2886
2887<!-- _______________________________________________________________________ -->
2888<div class="doc_subsubsection">
2889 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2890</div>
2891<div class="doc_text">
2892
2893<h5>Syntax:</h5>
2894<pre>
2895 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2896</pre>
2897
2898<h5>Overview:</h5>
2899<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2900<tt>ty2</tt>.</p>
2901
2902
2903<h5>Arguments:</h5>
2904<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]2905<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2906also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2907<tt>value</tt> must be smaller than the bit size of the destination type,
2908<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2909
2910<h5>Semantics:</h5>
2911<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2912bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2913the operand and the type are the same size, no bit filling is done and the
2914cast is considered a <i>no-op cast</i> because no bits change (only the type
2915changes).</p>
2916
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2917<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]2918
2919<h5>Example:</h5>
2920<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2921 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2922 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2923</pre>
2924</div>
2925
2926<!-- _______________________________________________________________________ -->
2927<div class="doc_subsubsection">
2928 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2929</div>
2930<div class="doc_text">
2931
2932<h5>Syntax:</h5>
2933<pre>
2934 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2935</pre>
2936
2937<h5>Overview:</h5>
2938<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2939
2940<h5>Arguments:</h5>
2941<p>
2942The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2943<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2944also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2945<tt>value</tt> must be smaller than the bit size of the destination type,
2946<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2947
2948<h5>Semantics:</h5>
2949<p>
2950The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2951bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2952the type <tt>ty2</tt>. When the the operand and the type are the same size,
2953no bit filling is done and the cast is considered a <i>no-op cast</i> because
2954no bits change (only the type changes).</p>
2955
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2956<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]2957
2958<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2959<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2960 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2961 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2962</pre>
2963</div>
2964
2965<!-- _______________________________________________________________________ -->
2966<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2967 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2968</div>
2969
2970<div class="doc_text">
2971
2972<h5>Syntax:</h5>
2973
2974<pre>
2975 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2976</pre>
2977
2978<h5>Overview:</h5>
2979<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2980<tt>ty2</tt>.</p>
2981
2982
2983<h5>Arguments:</h5>
2984<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2985 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2986cast it to. The size of <tt>value</tt> must be larger than the size of
2987<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2988<i>no-op cast</i>.</p>
2989
2990<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2991<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2992<a href="#t_floating">floating point</a> type to a smaller
2993<a href="#t_floating">floating point</a> type. If the value cannot fit within
2994the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2995
2996<h5>Example:</h5>
2997<pre>
2998 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2999 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3000</pre>
3001</div>
3002
3003<!-- _______________________________________________________________________ -->
3004<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3005 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3006</div>
3007<div class="doc_text">
3008
3009<h5>Syntax:</h5>
3010<pre>
3011 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3012</pre>
3013
3014<h5>Overview:</h5>
3015<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3016floating point value.</p>
3017
3018<h5>Arguments:</h5>
3019<p>The '<tt>fpext</tt>' instruction takes a
3020<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3021and a <a href="#t_floating">floating point</a> type to cast it to. The source
3022type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3023
3024<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3025<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3026<a href="#t_floating">floating point</a> type to a larger
3027<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3028used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3029<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]3030
3031<h5>Example:</h5>
3032<pre>
3033 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3034 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3035</pre>
3036</div>
3037
3038<!-- _______________________________________________________________________ -->
3039<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]3040 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3041</div>
3042<div class="doc_text">
3043
3044<h5>Syntax:</h5>
3045<pre>
3046 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3047</pre>
3048
3049<h5>Overview:</h5>
3050<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3051unsigned integer equivalent of type <tt>ty2</tt>.
3052</p>
3053
3054<h5>Arguments:</h5>
3055<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3056<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3057must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3058
3059<h5>Semantics:</h5>
3060<p> The '<tt>fp2uint</tt>' instruction converts its
3061<a href="#t_floating">floating point</a> operand into the nearest (rounding
3062towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3063the results are undefined.</p>
3064
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3065<p>When converting to i1, the conversion is done as a comparison against
3066zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3067If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3068
3069<h5>Example:</h5>
3070<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3071 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3072 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3073 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074</pre>
3075</div>
3076
3077<!-- _______________________________________________________________________ -->
3078<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3079 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3080</div>
3081<div class="doc_text">
3082
3083<h5>Syntax:</h5>
3084<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3085 &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]3086</pre>
3087
3088<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3089<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3090<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]3091</p>
3092
3093
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3094<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3095<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3096<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3097must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3098
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3099<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3100<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3101<a href="#t_floating">floating point</a> operand into the nearest (rounding
3102towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3103the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3104
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3105<p>When converting to i1, the conversion is done as a comparison against
3106zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3107If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3108
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3109<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3110<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3111 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3112 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3113 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3114</pre>
3115</div>
3116
3117<!-- _______________________________________________________________________ -->
3118<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3119 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3120</div>
3121<div class="doc_text">
3122
3123<h5>Syntax:</h5>
3124<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3125 &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]3126</pre>
3127
3128<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3129<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3130integer and converts that value to the <tt>ty2</tt> type.</p>
3131
3132
3133<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3134<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3135<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3136be a <a href="#t_floating">floating point</a> type.</p>
3137
3138<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3139<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3140integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3141the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3142
3143
3144<h5>Example:</h5>
3145<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3146 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3147 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3148</pre>
3149</div>
3150
3151<!-- _______________________________________________________________________ -->
3152<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3153 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3154</div>
3155<div class="doc_text">
3156
3157<h5>Syntax:</h5>
3158<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3159 &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]3160</pre>
3161
3162<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3163<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3164integer and converts that value to the <tt>ty2</tt> type.</p>
3165
3166<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3167<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3168<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3169a <a href="#t_floating">floating point</a> type.</p>
3170
3171<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3172<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3173integer quantity and converts it to the corresponding floating point value. If
Jeff Cohencb757312007-04-22 14:56:37 +0000[diff] [blame]3174the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3175
3176<h5>Example:</h5>
3177<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3178 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3179 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3180</pre>
3181</div>
3182
3183<!-- _______________________________________________________________________ -->
3184<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3185 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3186</div>
3187<div class="doc_text">
3188
3189<h5>Syntax:</h5>
3190<pre>
3191 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3192</pre>
3193
3194<h5>Overview:</h5>
3195<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3196the integer type <tt>ty2</tt>.</p>
3197
3198<h5>Arguments:</h5>
3199<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3200must 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]3201<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3202
3203<h5>Semantics:</h5>
3204<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3205<tt>ty2</tt> by interpreting the pointer value as an integer and either
3206truncating or zero extending that value to the size of the integer type. If
3207<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3208<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]3209are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3210change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3211
3212<h5>Example:</h5>
3213<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3214 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3215 %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]3216</pre>
3217</div>
3218
3219<!-- _______________________________________________________________________ -->
3220<div class="doc_subsubsection">
3221 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3222</div>
3223<div class="doc_text">
3224
3225<h5>Syntax:</h5>
3226<pre>
3227 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3228</pre>
3229
3230<h5>Overview:</h5>
3231<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3232a pointer type, <tt>ty2</tt>.</p>
3233
3234<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3235<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3236value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3237<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3238
3239<h5>Semantics:</h5>
3240<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3241<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3242the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3243size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3244the size of a pointer then a zero extension is done. If they are the same size,
3245nothing is done (<i>no-op cast</i>).</p>
3246
3247<h5>Example:</h5>
3248<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3249 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3250 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3251 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3252</pre>
3253</div>
3254
3255<!-- _______________________________________________________________________ -->
3256<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3257 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3258</div>
3259<div class="doc_text">
3260
3261<h5>Syntax:</h5>
3262<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3263 &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]3264</pre>
3265
3266<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3267<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3268<tt>ty2</tt> without changing any bits.</p>
3269
3270<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3271<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3272a first class value, and a type to cast it to, which must also be a <a
3273 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3274and the destination type, <tt>ty2</tt>, must be identical. If the source
3275type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3276
3277<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3278<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3279<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3280this conversion. The conversion is done as if the <tt>value</tt> had been
3281stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3282converted to other pointer types with this instruction. To convert pointers to
3283other types, use the <a href="#i_inttoptr">inttoptr</a> or
3284<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3285
3286<h5>Example:</h5>
3287<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3288 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3289 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3290 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3291</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3292</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3293
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3294<!-- ======================================================================= -->
3295<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3296<div class="doc_text">
3297<p>The instructions in this category are the "miscellaneous"
3298instructions, which defy better classification.</p>
3299</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3300
3301<!-- _______________________________________________________________________ -->
3302<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3303</div>
3304<div class="doc_text">
3305<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3306<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]3307</pre>
3308<h5>Overview:</h5>
3309<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3310of its two integer operands.</p>
3311<h5>Arguments:</h5>
3312<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3313the condition code indicating the kind of comparison to perform. It is not
3314a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3315<ol>
3316 <li><tt>eq</tt>: equal</li>
3317 <li><tt>ne</tt>: not equal </li>
3318 <li><tt>ugt</tt>: unsigned greater than</li>
3319 <li><tt>uge</tt>: unsigned greater or equal</li>
3320 <li><tt>ult</tt>: unsigned less than</li>
3321 <li><tt>ule</tt>: unsigned less or equal</li>
3322 <li><tt>sgt</tt>: signed greater than</li>
3323 <li><tt>sge</tt>: signed greater or equal</li>
3324 <li><tt>slt</tt>: signed less than</li>
3325 <li><tt>sle</tt>: signed less or equal</li>
3326</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3327<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3328<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3329<h5>Semantics:</h5>
3330<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3331the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3332yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3333<ol>
3334 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3335 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3336 </li>
3337 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3338 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3339 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3340 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3341 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3342 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3343 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3344 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3345 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3346 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3347 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3348 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3349 <li><tt>sge</tt>: interprets the operands as signed values and yields
3350 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3351 <li><tt>slt</tt>: interprets the operands as signed values and yields
3352 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3353 <li><tt>sle</tt>: interprets the operands as signed values and yields
3354 <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]3355</ol>
3356<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3357values are compared as if they were integers.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3358
3359<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3360<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3361 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3362 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3363 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3364 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3365 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3366</pre>
3367</div>
3368
3369<!-- _______________________________________________________________________ -->
3370<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3371</div>
3372<div class="doc_text">
3373<h5>Syntax:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3374<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]3375</pre>
3376<h5>Overview:</h5>
3377<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3378of its floating point operands.</p>
3379<h5>Arguments:</h5>
3380<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3381the condition code indicating the kind of comparison to perform. It is not
3382a value, just a keyword. The possible condition code are:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3383<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3384 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3385 <li><tt>oeq</tt>: ordered and equal</li>
3386 <li><tt>ogt</tt>: ordered and greater than </li>
3387 <li><tt>oge</tt>: ordered and greater than or equal</li>
3388 <li><tt>olt</tt>: ordered and less than </li>
3389 <li><tt>ole</tt>: ordered and less than or equal</li>
3390 <li><tt>one</tt>: ordered and not equal</li>
3391 <li><tt>ord</tt>: ordered (no nans)</li>
3392 <li><tt>ueq</tt>: unordered or equal</li>
3393 <li><tt>ugt</tt>: unordered or greater than </li>
3394 <li><tt>uge</tt>: unordered or greater than or equal</li>
3395 <li><tt>ult</tt>: unordered or less than </li>
3396 <li><tt>ule</tt>: unordered or less than or equal</li>
3397 <li><tt>une</tt>: unordered or not equal</li>
3398 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3399 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3400</ol>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3401<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3402<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3403<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3404<a href="#t_floating">floating point</a> typed. They must have identical
3405types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3406<h5>Semantics:</h5>
3407<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3408the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3409yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3410<ol>
3411 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3412 <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]3413 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3414 <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]3415 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3416 <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]3417 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3418 <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]3419 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3420 <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]3421 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3422 <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]3423 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3424 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3425 <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]3426 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3427 <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]3428 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3429 <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]3430 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3431 <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]3432 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3433 <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]3434 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3435 <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]3436 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3437 <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]3438 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3439</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3440
3441<h5>Example:</h5>
3442<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3443 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3444 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3445 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3446</pre>
3447</div>
3448
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3449<!-- _______________________________________________________________________ -->
3450<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3451Instruction</a> </div>
3452<div class="doc_text">
3453<h5>Syntax:</h5>
3454<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3455<h5>Overview:</h5>
3456<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3457the SSA graph representing the function.</p>
3458<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3459<p>The type of the incoming values is specified with the first type
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3460field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3461as arguments, with one pair for each predecessor basic block of the
3462current block. Only values of <a href="#t_firstclass">first class</a>
3463type may be used as the value arguments to the PHI node. Only labels
3464may be used as the label arguments.</p>
3465<p>There must be no non-phi instructions between the start of a basic
3466block and the PHI instructions: i.e. PHI instructions must be first in
3467a basic block.</p>
3468<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3469<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3470specified by the pair corresponding to the predecessor basic block that executed
3471just prior to the current block.</p>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3472<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3473<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]3474</div>
3475
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3476<!-- _______________________________________________________________________ -->
3477<div class="doc_subsubsection">
3478 <a name="i_select">'<tt>select</tt>' Instruction</a>
3479</div>
3480
3481<div class="doc_text">
3482
3483<h5>Syntax:</h5>
3484
3485<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3486 &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]3487</pre>
3488
3489<h5>Overview:</h5>
3490
3491<p>
3492The '<tt>select</tt>' instruction is used to choose one value based on a
3493condition, without branching.
3494</p>
3495
3496
3497<h5>Arguments:</h5>
3498
3499<p>
3500The '<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.
3501</p>
3502
3503<h5>Semantics:</h5>
3504
3505<p>
3506If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3507value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3508</p>
3509
3510<h5>Example:</h5>
3511
3512<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3513 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3514</pre>
3515</div>
3516
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3517
3518<!-- _______________________________________________________________________ -->
3519<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3520 <a name="i_call">'<tt>call</tt>' Instruction</a>
3521</div>
3522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3523<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3526<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3527 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3528</pre>
3529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3530<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3532<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3534<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3536<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3537
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3538<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3539 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3540 <p>The optional "tail" marker indicates whether the callee function accesses
3541 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3542 function call is eligible for tail call optimization. Note that calls may
3543 be marked "tail" even if they do not occur before a <a
3544 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3545 </li>
3546 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]3547 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3548 convention</a> the call should use. If none is specified, the call defaults
3549 to using C calling conventions.
3550 </li>
3551 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3552 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3553 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3554 signature. This type can be omitted if the function is not varargs and
3555 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3556 </li>
3557 <li>
3558 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3559 be invoked. In most cases, this is a direct function invocation, but
3560 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3561 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3562 </li>
3563 <li>
3564 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3565 function signature argument types. All arguments must be of
3566 <a href="#t_firstclass">first class</a> type. If the function signature
3567 indicates the function accepts a variable number of arguments, the extra
3568 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3569 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3570</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3572<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3573
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3574<p>The '<tt>call</tt>' instruction is used to cause control flow to
3575transfer to a specified function, with its incoming arguments bound to
3576the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3577instruction in the called function, control flow continues with the
3578instruction after the function call, and the return value of the
3579function is bound to the result argument. This is a simpler case of
3580the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3581
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3583
3584<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3585 %retval = call i32 %test(i32 %argc)
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3586 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3587 %X = tail call i32 %foo()
3588 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3589</pre>
3590
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3591</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3592
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3593<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3594<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3595 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3596</div>
3597
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3598<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3599
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3600<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3601
3602<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3603 &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]3604</pre>
3605
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3606<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3607
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3608<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3609the "variable argument" area of a function call. It is used to implement the
3610<tt>va_arg</tt> macro in C.</p>
3611
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3612<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3613
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3614<p>This instruction takes a <tt>va_list*</tt> value and the type of
3615the argument. It returns a value of the specified argument type and
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3616increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3617actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3618
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3619<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3620
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3621<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3622type from the specified <tt>va_list</tt> and causes the
3623<tt>va_list</tt> to point to the next argument. For more information,
3624see the variable argument handling <a href="#int_varargs">Intrinsic
3625Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3626
3627<p>It is legal for this instruction to be called in a function which does not
3628take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3629function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3630
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3631<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3632href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3633argument.</p>
3634
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3635<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3636
3637<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3638
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3639</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3640
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3641<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3642<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3643<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3644
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3646
3647<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3648well known names and semantics and are required to follow certain restrictions.
3649Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3650language that does not require changing all of the transformations in LLVM when
3651adding to the language (or the bytecode reader/writer, the parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3652
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3653<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3654prefix is reserved in LLVM for intrinsic names; thus, function names may not
3655begin with this prefix. Intrinsic functions must always be external functions:
3656you cannot define the body of intrinsic functions. Intrinsic functions may
3657only be used in call or invoke instructions: it is illegal to take the address
3658of an intrinsic function. Additionally, because intrinsic functions are part
3659of the LLVM language, it is required if any are added that they be documented
3660here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3661
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3662<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3663a family of functions that perform the same operation but on different data
3664types. This is most frequent with the integer types. Since LLVM can represent
3665over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3666that can be overloaded based on its arguments. Such an intrinsic will have the
3667names of its argument types encoded into its function name, each
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3668preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3669integer of any width. This leads to a family of functions such as
3670<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3671</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3672
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]3673
3674<p>To learn how to add an intrinsic function, please see the
3675<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3676</p>
3677
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3678</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3679
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3680<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3681<div class="doc_subsection">
3682 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3683</div>
3684
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3685<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3686
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3687<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3688 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3689intrinsic functions. These functions are related to the similarly
3690named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3691
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3692<p>All of these functions operate on arguments that use a
3693target-specific value type "<tt>va_list</tt>". The LLVM assembly
3694language reference manual does not define what this type is, so all
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3695transformations should be prepared to handle these functions regardless of
3696the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3697
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3698<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]3699instruction and the variable argument handling intrinsic functions are
3700used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3701
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3702<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3703define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3704 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3705 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3706 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3707 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3708
3709 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3710 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3711
3712 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3713 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3714 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3715 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3716 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3717
3718 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3719 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3720 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3721}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3722
3723declare void @llvm.va_start(i8*)
3724declare void @llvm.va_copy(i8*, i8*)
3725declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3726</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3727</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3728
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3729<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3730<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3731 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3732</div>
3733
3734
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3735<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3736<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3737<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3738<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3739<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3740<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3741href="#i_va_arg">va_arg</a></tt>.</p>
3742
3743<h5>Arguments:</h5>
3744
3745<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3746
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3747<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3748
3749<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3750macro available in C. In a target-dependent way, it initializes the
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3751<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]3752<tt>va_arg</tt> will produce the first variable argument passed to the function.
3753Unlike 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]3754last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3755
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3756</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3757
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3758<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3759<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3760 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3761</div>
3762
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3763<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3764<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3765<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3766<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3767
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3768<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3769which 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]3770or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3771
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3772<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3773
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3774<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]3775
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3776<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3777
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3778<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]3779macro available in C. In a target-dependent way, it destroys the
3780<tt>va_list</tt> element to which the argument points. Calls to <a
3781href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3782<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3783<tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3784
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3785</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3786
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3787<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3788<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3789 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3790</div>
3791
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3792<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3793
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3794<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3795
3796<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3797 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3798</pre>
3799
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3800<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3801
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3802<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3803from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3804
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3805<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3806
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3807<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]3808The 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]3809
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3810
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3811<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3812
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]3813<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3814macro available in C. In a target-dependent way, it copies the source
3815<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3816intrinsic is necessary because the <tt><a href="#int_va_start">
3817llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3818example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3819
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3820</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3821
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3822<!-- ======================================================================= -->
3823<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3824 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3825</div>
3826
3827<div class="doc_text">
3828
3829<p>
3830LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3831Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3832These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3833stack</a>, as well as garbage collector implementations that require <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3834href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3835Front-ends for type-safe garbage collected languages should generate these
3836intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3837href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3838</p>
3839</div>
3840
3841<!-- _______________________________________________________________________ -->
3842<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3843 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3844</div>
3845
3846<div class="doc_text">
3847
3848<h5>Syntax:</h5>
3849
3850<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3851 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3852</pre>
3853
3854<h5>Overview:</h5>
3855
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3856<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]3857the code generator, and allows some metadata to be associated with it.</p>
3858
3859<h5>Arguments:</h5>
3860
3861<p>The first argument specifies the address of a stack object that contains the
3862root pointer. The second pointer (which must be either a constant or a global
3863value address) contains the meta-data to be associated with the root.</p>
3864
3865<h5>Semantics:</h5>
3866
3867<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3868location. At compile-time, the code generator generates information to allow
3869the runtime to find the pointer at GC safe points.
3870</p>
3871
3872</div>
3873
3874
3875<!-- _______________________________________________________________________ -->
3876<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3877 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3878</div>
3879
3880<div class="doc_text">
3881
3882<h5>Syntax:</h5>
3883
3884<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3885 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3886</pre>
3887
3888<h5>Overview:</h5>
3889
3890<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3891locations, allowing garbage collector implementations that require read
3892barriers.</p>
3893
3894<h5>Arguments:</h5>
3895
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3896<p>The second argument is the address to read from, which should be an address
3897allocated from the garbage collector. The first object is a pointer to the
3898start of the referenced object, if needed by the language runtime (otherwise
3899null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3900
3901<h5>Semantics:</h5>
3902
3903<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3904instruction, but may be replaced with substantially more complex code by the
3905garbage collector runtime, as needed.</p>
3906
3907</div>
3908
3909
3910<!-- _______________________________________________________________________ -->
3911<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3912 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3913</div>
3914
3915<div class="doc_text">
3916
3917<h5>Syntax:</h5>
3918
3919<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3920 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3921</pre>
3922
3923<h5>Overview:</h5>
3924
3925<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3926locations, allowing garbage collector implementations that require write
3927barriers (such as generational or reference counting collectors).</p>
3928
3929<h5>Arguments:</h5>
3930
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3931<p>The first argument is the reference to store, the second is the start of the
3932object to store it to, and the third is the address of the field of Obj to
3933store to. If the runtime does not require a pointer to the object, Obj may be
3934null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3935
3936<h5>Semantics:</h5>
3937
3938<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3939instruction, but may be replaced with substantially more complex code by the
3940garbage collector runtime, as needed.</p>
3941
3942</div>
3943
3944
3945
3946<!-- ======================================================================= -->
3947<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3948 <a name="int_codegen">Code Generator Intrinsics</a>
3949</div>
3950
3951<div class="doc_text">
3952<p>
3953These intrinsics are provided by LLVM to expose special features that may only
3954be implemented with code generator support.
3955</p>
3956
3957</div>
3958
3959<!-- _______________________________________________________________________ -->
3960<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]3961 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3962</div>
3963
3964<div class="doc_text">
3965
3966<h5>Syntax:</h5>
3967<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3968 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3969</pre>
3970
3971<h5>Overview:</h5>
3972
3973<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3974The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3975target-specific value indicating the return address of the current function
3976or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3977</p>
3978
3979<h5>Arguments:</h5>
3980
3981<p>
3982The argument to this intrinsic indicates which function to return the address
3983for. Zero indicates the calling function, one indicates its caller, etc. The
3984argument is <b>required</b> to be a constant integer value.
3985</p>
3986
3987<h5>Semantics:</h5>
3988
3989<p>
3990The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3991the return address of the specified call frame, or zero if it cannot be
3992identified. The value returned by this intrinsic is likely to be incorrect or 0
3993for arguments other than zero, so it should only be used for debugging purposes.
3994</p>
3995
3996<p>
3997Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3998aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3999source-language caller.
4000</p>
4001</div>
4002
4003
4004<!-- _______________________________________________________________________ -->
4005<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4006 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4007</div>
4008
4009<div class="doc_text">
4010
4011<h5>Syntax:</h5>
4012<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4013 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4014</pre>
4015
4016<h5>Overview:</h5>
4017
4018<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]4019The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4020target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4021</p>
4022
4023<h5>Arguments:</h5>
4024
4025<p>
4026The argument to this intrinsic indicates which function to return the frame
4027pointer for. Zero indicates the calling function, one indicates its caller,
4028etc. The argument is <b>required</b> to be a constant integer value.
4029</p>
4030
4031<h5>Semantics:</h5>
4032
4033<p>
4034The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4035the frame address of the specified call frame, or zero if it cannot be
4036identified. The value returned by this intrinsic is likely to be incorrect or 0
4037for arguments other than zero, so it should only be used for debugging purposes.
4038</p>
4039
4040<p>
4041Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]4042aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4043source-language caller.
4044</p>
4045</div>
4046
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4047<!-- _______________________________________________________________________ -->
4048<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4049 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4050</div>
4051
4052<div class="doc_text">
4053
4054<h5>Syntax:</h5>
4055<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4056 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4057</pre>
4058
4059<h5>Overview:</h5>
4060
4061<p>
4062The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4063the function stack, for use with <a href="#int_stackrestore">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4064<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4065features like scoped automatic variable sized arrays in C99.
4066</p>
4067
4068<h5>Semantics:</h5>
4069
4070<p>
4071This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4072href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4073<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4074<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4075state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4076practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4077that were allocated after the <tt>llvm.stacksave</tt> was executed.
4078</p>
4079
4080</div>
4081
4082<!-- _______________________________________________________________________ -->
4083<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4084 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4085</div>
4086
4087<div class="doc_text">
4088
4089<h5>Syntax:</h5>
4090<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4091 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4092</pre>
4093
4094<h5>Overview:</h5>
4095
4096<p>
4097The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4098the function stack to the state it was in when the corresponding <a
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4099href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4100useful for implementing language features like scoped automatic variable sized
4101arrays in C99.
4102</p>
4103
4104<h5>Semantics:</h5>
4105
4106<p>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4107See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4108</p>
4109
4110</div>
4111
4112
4113<!-- _______________________________________________________________________ -->
4114<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4115 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4116</div>
4117
4118<div class="doc_text">
4119
4120<h5>Syntax:</h5>
4121<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4122 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4123 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4124</pre>
4125
4126<h5>Overview:</h5>
4127
4128
4129<p>
4130The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4131a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4132no
4133effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4134characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4135</p>
4136
4137<h5>Arguments:</h5>
4138
4139<p>
4140<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4141determining if the fetch should be for a read (0) or write (1), and
4142<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4143locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4144<tt>locality</tt> arguments must be constant integers.
4145</p>
4146
4147<h5>Semantics:</h5>
4148
4149<p>
4150This intrinsic does not modify the behavior of the program. In particular,
4151prefetches cannot trap and do not produce a value. On targets that support this
4152intrinsic, the prefetch can provide hints to the processor cache for better
4153performance.
4154</p>
4155
4156</div>
4157
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4158<!-- _______________________________________________________________________ -->
4159<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4160 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4161</div>
4162
4163<div class="doc_text">
4164
4165<h5>Syntax:</h5>
4166<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4167 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4168</pre>
4169
4170<h5>Overview:</h5>
4171
4172
4173<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4174The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4175(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4176code to simulators and other tools. The method is target specific, but it is
4177expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4178The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4179after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4180optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4181correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4182</p>
4183
4184<h5>Arguments:</h5>
4185
4186<p>
4187<tt>id</tt> is a numerical id identifying the marker.
4188</p>
4189
4190<h5>Semantics:</h5>
4191
4192<p>
4193This intrinsic does not modify the behavior of the program. Backends that do not
4194support this intrinisic may ignore it.
4195</p>
4196
4197</div>
4198
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4199<!-- _______________________________________________________________________ -->
4200<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4201 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4202</div>
4203
4204<div class="doc_text">
4205
4206<h5>Syntax:</h5>
4207<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4208 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4209</pre>
4210
4211<h5>Overview:</h5>
4212
4213
4214<p>
4215The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4216counter register (or similar low latency, high accuracy clocks) on those targets
4217that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4218As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4219should only be used for small timings.
4220</p>
4221
4222<h5>Semantics:</h5>
4223
4224<p>
4225When directly supported, reading the cycle counter should not modify any memory.
4226Implementations are allowed to either return a application specific value or a
4227system wide value. On backends without support, this is lowered to a constant 0.
4228</p>
4229
4230</div>
4231
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4232<!-- ======================================================================= -->
4233<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4234 <a name="int_libc">Standard C Library Intrinsics</a>
4235</div>
4236
4237<div class="doc_text">
4238<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4239LLVM provides intrinsics for a few important standard C library functions.
4240These intrinsics allow source-language front-ends to pass information about the
4241alignment of the pointer arguments to the code generator, providing opportunity
4242for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4243</p>
4244
4245</div>
4246
4247<!-- _______________________________________________________________________ -->
4248<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4249 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4250</div>
4251
4252<div class="doc_text">
4253
4254<h5>Syntax:</h5>
4255<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4256 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4257 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4258 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4259 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4260</pre>
4261
4262<h5>Overview:</h5>
4263
4264<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4265The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4266location to the destination location.
4267</p>
4268
4269<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4270Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4271intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4272</p>
4273
4274<h5>Arguments:</h5>
4275
4276<p>
4277The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4278the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4279specifying the number of bytes to copy, and the fourth argument is the alignment
4280of the source and destination locations.
4281</p>
4282
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4283<p>
4284If 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]4285the caller guarantees that both the source and destination pointers are aligned
4286to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4287</p>
4288
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4289<h5>Semantics:</h5>
4290
4291<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4292The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4293location to the destination location, which are not allowed to overlap. It
4294copies "len" bytes of memory over. If the argument is known to be aligned to
4295some boundary, this can be specified as the fourth argument, otherwise it should
4296be set to 0 or 1.
4297</p>
4298</div>
4299
4300
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4301<!-- _______________________________________________________________________ -->
4302<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4303 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4304</div>
4305
4306<div class="doc_text">
4307
4308<h5>Syntax:</h5>
4309<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4310 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4311 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4312 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4313 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4314</pre>
4315
4316<h5>Overview:</h5>
4317
4318<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4319The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4320location to the destination location. It is similar to the
4321'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4322</p>
4323
4324<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4325Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4326intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4327</p>
4328
4329<h5>Arguments:</h5>
4330
4331<p>
4332The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4333the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4334specifying the number of bytes to copy, and the fourth argument is the alignment
4335of the source and destination locations.
4336</p>
4337
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4338<p>
4339If 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]4340the caller guarantees that the source and destination pointers are aligned to
4341that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4342</p>
4343
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4344<h5>Semantics:</h5>
4345
4346<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4347The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4348location to the destination location, which may overlap. It
4349copies "len" bytes of memory over. If the argument is known to be aligned to
4350some boundary, this can be specified as the fourth argument, otherwise it should
4351be set to 0 or 1.
4352</p>
4353</div>
4354
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4355
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4356<!-- _______________________________________________________________________ -->
4357<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4358 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4359</div>
4360
4361<div class="doc_text">
4362
4363<h5>Syntax:</h5>
4364<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4365 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4366 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4367 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4368 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4369</pre>
4370
4371<h5>Overview:</h5>
4372
4373<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4374The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4375byte value.
4376</p>
4377
4378<p>
4379Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4380does not return a value, and takes an extra alignment argument.
4381</p>
4382
4383<h5>Arguments:</h5>
4384
4385<p>
4386The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4387byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4388argument specifying the number of bytes to fill, and the fourth argument is the
4389known alignment of destination location.
4390</p>
4391
4392<p>
4393If 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]4394the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4395</p>
4396
4397<h5>Semantics:</h5>
4398
4399<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4400The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4401the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4402destination location. If the argument is known to be aligned to some boundary,
4403this can be specified as the fourth argument, otherwise it should be set to 0 or
44041.
4405</p>
4406</div>
4407
4408
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4409<!-- _______________________________________________________________________ -->
4410<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4411 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4412</div>
4413
4414<div class="doc_text">
4415
4416<h5>Syntax:</h5>
4417<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4418 declare float @llvm.sqrt.f32(float %Val)
4419 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4420</pre>
4421
4422<h5>Overview:</h5>
4423
4424<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4425The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4426returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4427<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4428negative numbers (which allows for better optimization).
4429</p>
4430
4431<h5>Arguments:</h5>
4432
4433<p>
4434The argument and return value are floating point numbers of the same type.
4435</p>
4436
4437<h5>Semantics:</h5>
4438
4439<p>
4440This function returns the sqrt of the specified operand if it is a positive
4441floating point number.
4442</p>
4443</div>
4444
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4447 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4448</div>
4449
4450<div class="doc_text">
4451
4452<h5>Syntax:</h5>
4453<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4454 declare float @llvm.powi.f32(float %Val, i32 %power)
4455 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4456</pre>
4457
4458<h5>Overview:</h5>
4459
4460<p>
4461The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4462specified (positive or negative) power. The order of evaluation of
4463multiplications is not defined.
4464</p>
4465
4466<h5>Arguments:</h5>
4467
4468<p>
4469The second argument is an integer power, and the first is a value to raise to
4470that power.
4471</p>
4472
4473<h5>Semantics:</h5>
4474
4475<p>
4476This function returns the first value raised to the second power with an
4477unspecified sequence of rounding operations.</p>
4478</div>
4479
4480
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4481<!-- ======================================================================= -->
4482<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4483 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4484</div>
4485
4486<div class="doc_text">
4487<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4488LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4489These allow efficient code generation for some algorithms.
4490</p>
4491
4492</div>
4493
4494<!-- _______________________________________________________________________ -->
4495<div class="doc_subsubsection">
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4496 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4497</div>
4498
4499<div class="doc_text">
4500
4501<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4502<p>This is an overloaded intrinsic function. You can use bswap on any integer
4503type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4504that includes the type for the result and the operand.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4505<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4506 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4507 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer543ab1d2007-04-02 00:19:52 +0000[diff] [blame]4508 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4509</pre>
4510
4511<h5>Overview:</h5>
4512
4513<p>
Reid Spencer338ea092007-04-02 02:25:19 +0000[diff] [blame]4514The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4515values with an even number of bytes (positive multiple of 16 bits). These are
4516useful for performing operations on data that is not in the target's native
4517byte order.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4518</p>
4519
4520<h5>Semantics:</h5>
4521
4522<p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4523The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4524and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4525intrinsic returns an i32 value that has the four bytes of the input i32
4526swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4527i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4528<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4529additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4530</p>
4531
4532</div>
4533
4534<!-- _______________________________________________________________________ -->
4535<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4536 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4537</div>
4538
4539<div class="doc_text">
4540
4541<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4542<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4543width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4544<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4545 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4546 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4547 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4548 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4549 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4550</pre>
4551
4552<h5>Overview:</h5>
4553
4554<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4555The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4556value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4557</p>
4558
4559<h5>Arguments:</h5>
4560
4561<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4562The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4563integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4564</p>
4565
4566<h5>Semantics:</h5>
4567
4568<p>
4569The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4570</p>
4571</div>
4572
4573<!-- _______________________________________________________________________ -->
4574<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4575 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4576</div>
4577
4578<div class="doc_text">
4579
4580<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4581<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4582integer bit width. Not all targets support all bit widths however.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4583<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4584 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4585 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4586 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4587 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4588 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4589</pre>
4590
4591<h5>Overview:</h5>
4592
4593<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4594The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4595leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4596</p>
4597
4598<h5>Arguments:</h5>
4599
4600<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4601The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4602integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4603</p>
4604
4605<h5>Semantics:</h5>
4606
4607<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4608The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4609in 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]4610of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4611</p>
4612</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4613
4614
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4615
4616<!-- _______________________________________________________________________ -->
4617<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4618 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4619</div>
4620
4621<div class="doc_text">
4622
4623<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4624<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4625integer bit width. Not all targets support all bit widths however.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4626<pre>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4627 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4628 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4629 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]4630 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4631 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4632</pre>
4633
4634<h5>Overview:</h5>
4635
4636<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4637The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4638trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4639</p>
4640
4641<h5>Arguments:</h5>
4642
4643<p>
4644The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4645integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4646</p>
4647
4648<h5>Semantics:</h5>
4649
4650<p>
4651The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4652in a variable. If the src == 0 then the result is the size in bits of the type
4653of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4654</p>
4655</div>
4656
Reid Spencer497d93e2007-04-01 08:27:01 +0000[diff] [blame]4657<!-- _______________________________________________________________________ -->
4658<div class="doc_subsubsection">
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4659 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4660</div>
4661
4662<div class="doc_text">
4663
4664<h5>Syntax:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4665<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4666on any integer bit width.
4667<pre>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4668 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4669 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4670</pre>
4671
4672<h5>Overview:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4673<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4674range of bits from an integer value and returns them in the same bit width as
4675the original value.</p>
4676
4677<h5>Arguments:</h5>
4678<p>The first argument, <tt>%val</tt> and the result may be integer types of
4679any bit width but they must have the same bit width. The second and third
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4680arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4681
4682<h5>Semantics:</h5>
Reid Spencerbeacf662007-04-10 02:51:31 +0000[diff] [blame]4683<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]4684of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4685<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4686operates in forward mode.</p>
4687<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4688right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4689only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4690<ol>
4691 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4692 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4693 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4694 to determine the number of bits to retain.</li>
4695 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4696 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4697</ol>
Reid Spencerd6a85b52007-05-14 16:14:57 +0000[diff] [blame]4698<p>In reverse mode, a similar computation is made except that the bits are
4699returned in the reverse order. So, for example, if <tt>X</tt> has the value
4700<tt>i16 0x0ACF (101011001111)</tt> and we apply
4701<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4702<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencera13ba7d2007-04-01 19:00:37 +0000[diff] [blame]4703</div>
4704
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4705<div class="doc_subsubsection">
4706 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4707</div>
4708
4709<div class="doc_text">
4710
4711<h5>Syntax:</h5>
4712<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4713on any integer bit width.
4714<pre>
4715 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4716 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4717</pre>
4718
4719<h5>Overview:</h5>
4720<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4721of bits in an integer value with another integer value. It returns the integer
4722with the replaced bits.</p>
4723
4724<h5>Arguments:</h5>
4725<p>The first argument, <tt>%val</tt> and the result may be integer types of
4726any bit width but they must have the same bit width. <tt>%val</tt> is the value
4727whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4728integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4729type since they specify only a bit index.</p>
4730
4731<h5>Semantics:</h5>
4732<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4733of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4734<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4735operates in forward mode.</p>
4736<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4737truncating it down to the size of the replacement area or zero extending it
4738up to that size.</p>
4739<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4740are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4741in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4742to the <tt>%hi</tt>th bit.
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4743<p>In reverse mode, a similar computation is made except that the bits are
4744reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4745<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]4746<h5>Examples:</h5>
4747<pre>
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4748 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencerc6749c42007-05-14 16:50:20 +0000[diff] [blame]4749 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4750 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4751 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerf0dbf642007-04-12 01:03:03 +0000[diff] [blame]4752 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]4753</pre>
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]4754</div>
4755
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4756<!-- ======================================================================= -->
4757<div class="doc_subsection">
4758 <a name="int_debugger">Debugger Intrinsics</a>
4759</div>
4760
4761<div class="doc_text">
4762<p>
4763The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4764are described in the <a
4765href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4766Debugging</a> document.
4767</p>
4768</div>
4769
4770
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4771<!-- ======================================================================= -->
4772<div class="doc_subsection">
4773 <a name="int_eh">Exception Handling Intrinsics</a>
4774</div>
4775
4776<div class="doc_text">
4777<p> The LLVM exception handling intrinsics (which all start with
4778<tt>llvm.eh.</tt> prefix), are described in the <a
4779href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4780Handling</a> document. </p>
4781</div>
4782
4783
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4784<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4785<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4786<address>
4787 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4788 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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4790 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4791
4792 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4793 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4794 Last modified: $Date$
4795</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4796</body>
4797</html>