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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0a783f783ca05c961234385f5b269d4cf03dbbdb / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
27 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]28 </ol>
29 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]30 <li><a href="#typesystem">Type System</a>
31 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]32 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]33 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]34 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 </ol>
36 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]37 <li><a href="#t_derived">Derived Types</a>
38 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]39 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]40 <li><a href="#t_function">Function Type</a></li>
41 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]43 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]44 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]45 </ol>
46 </li>
47 </ol>
48 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]49 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]50 <ol>
51 <li><a href="#simpleconstants">Simple Constants</a>
52 <li><a href="#aggregateconstants">Aggregate Constants</a>
53 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
54 <li><a href="#undefvalues">Undefined Values</a>
55 <li><a href="#constantexprs">Constant Expressions</a>
56 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]57 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]58 <li><a href="#othervalues">Other Values</a>
59 <ol>
60 <li><a href="#inlineasm">Inline Assembler Expressions</a>
61 </ol>
62 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]63 <li><a href="#instref">Instruction Reference</a>
64 <ol>
65 <li><a href="#terminators">Terminator Instructions</a>
66 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
68 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
70 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]72 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]73 </ol>
74 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]75 <li><a href="#binaryops">Binary Operations</a>
76 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
78 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
79 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]80 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
81 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
82 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]83 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
84 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
85 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]86 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]89 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
90 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]91 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]92 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]93 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]96 </ol>
97 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]98 <li><a href="#vectorops">Vector Operations</a>
99 <ol>
100 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
101 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
102 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]103 <li><a href="#i_vsetint">'<tt>vsetint</tt>' Instruction</a></li>
104 <li><a href="#i_vsetfp">'<tt>vsetfp</tt>' Instruction</a></li>
105 <li><a href="#i_vselect">'<tt>vselect</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]106 </ol>
107 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]108 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
111 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
112 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]113 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
114 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
115 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#otherops">Other Operations</a>
119 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]121 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]122 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]123 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]124 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]125 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]127 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]128 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]129 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]130 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
132 <ol>
133 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
134 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
135 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
136 </ol>
137 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]138 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
139 <ol>
140 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
141 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
142 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
143 </ol>
144 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]145 <li><a href="#int_codegen">Code Generator Intrinsics</a>
146 <ol>
147 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
148 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]149 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
150 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]151 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]152 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]153 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]156 <li><a href="#int_libc">Standard C Library Intrinsics</a>
157 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]158 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
159 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
160 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]161 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
162 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]163 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]164 </ol>
165 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]166 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]167 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]168 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]169 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
170 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
171 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]172 </ol>
173 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]174 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]177</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]178
179<div class="doc_author">
180 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
181 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]182</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]183
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]184<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]185<div class="doc_section"> <a name="abstract">Abstract </a></div>
186<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]187
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]188<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]189<p>This document is a reference manual for the LLVM assembly language.
190LLVM is an SSA based representation that provides type safety,
191low-level operations, flexibility, and the capability of representing
192'all' high-level languages cleanly. It is the common code
193representation used throughout all phases of the LLVM compilation
194strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]195</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]196
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]197<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]198<div class="doc_section"> <a name="introduction">Introduction</a> </div>
199<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]200
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]201<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]203<p>The LLVM code representation is designed to be used in three
204different forms: as an in-memory compiler IR, as an on-disk bytecode
205representation (suitable for fast loading by a Just-In-Time compiler),
206and as a human readable assembly language representation. This allows
207LLVM to provide a powerful intermediate representation for efficient
208compiler transformations and analysis, while providing a natural means
209to debug and visualize the transformations. The three different forms
210of LLVM are all equivalent. This document describes the human readable
211representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]213<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214while being expressive, typed, and extensible at the same time. It
215aims to be a "universal IR" of sorts, by being at a low enough level
216that high-level ideas may be cleanly mapped to it (similar to how
217microprocessors are "universal IR's", allowing many source languages to
218be mapped to them). By providing type information, LLVM can be used as
219the target of optimizations: for example, through pointer analysis, it
220can be proven that a C automatic variable is never accessed outside of
221the current function... allowing it to be promoted to a simple SSA
222value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]223
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]224</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]225
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]226<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]227<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]228
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]229<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]230
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]231<p>It is important to note that this document describes 'well formed'
232LLVM assembly language. There is a difference between what the parser
233accepts and what is considered 'well formed'. For example, the
234following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]235
236<pre>
237 %x = <a href="#i_add">add</a> int 1, %x
238</pre>
239
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]240<p>...because the definition of <tt>%x</tt> does not dominate all of
241its uses. The LLVM infrastructure provides a verification pass that may
242be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]243automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]244the optimizer before it outputs bytecode. The violations pointed out
245by the verifier pass indicate bugs in transformation passes or input to
246the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]247
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]248<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]250<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]251<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]252<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]254<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]255
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256<p>LLVM uses three different forms of identifiers, for different
257purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]258
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]259<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]260 <li>Named values are represented as a string of characters with a '%' prefix.
261 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
262 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
263 Identifiers which require other characters in their names can be surrounded
264 with quotes. In this way, anything except a <tt>"</tt> character can be used
265 in a name.</li>
266
267 <li>Unnamed values are represented as an unsigned numeric value with a '%'
268 prefix. For example, %12, %2, %44.</li>
269
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]270 <li>Constants, which are described in a <a href="#constants">section about
271 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]272</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]273
274<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
275don't need to worry about name clashes with reserved words, and the set of
276reserved words may be expanded in the future without penalty. Additionally,
277unnamed identifiers allow a compiler to quickly come up with a temporary
278variable without having to avoid symbol table conflicts.</p>
279
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]280<p>Reserved words in LLVM are very similar to reserved words in other
281languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]282href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
283href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
284href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
285and others. These reserved words cannot conflict with variable names, because
286none of them start with a '%' character.</p>
287
288<p>Here is an example of LLVM code to multiply the integer variable
289'<tt>%X</tt>' by 8:</p>
290
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]291<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]292
293<pre>
294 %result = <a href="#i_mul">mul</a> uint %X, 8
295</pre>
296
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]297<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]298
299<pre>
300 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
301</pre>
302
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]303<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]304
305<pre>
306 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
307 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
308 %result = <a href="#i_add">add</a> uint %1, %1
309</pre>
310
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]311<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
312important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]313
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]314<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
316 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
317 line.</li>
318
319 <li>Unnamed temporaries are created when the result of a computation is not
320 assigned to a named value.</li>
321
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]322 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]323
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]324</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]326<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]327demonstrating instructions, we will follow an instruction with a comment that
328defines the type and name of value produced. Comments are shown in italic
329text.</p>
330
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]331</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]332
333<!-- *********************************************************************** -->
334<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
335<!-- *********************************************************************** -->
336
337<!-- ======================================================================= -->
338<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
339</div>
340
341<div class="doc_text">
342
343<p>LLVM programs are composed of "Module"s, each of which is a
344translation unit of the input programs. Each module consists of
345functions, global variables, and symbol table entries. Modules may be
346combined together with the LLVM linker, which merges function (and
347global variable) definitions, resolves forward declarations, and merges
348symbol table entries. Here is an example of the "hello world" module:</p>
349
350<pre><i>; Declare the string constant as a global constant...</i>
351<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
352 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
353
354<i>; External declaration of the puts function</i>
355<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
356
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]357<i>; Global variable / Function body section separator</i>
358implementation
359
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]360<i>; Definition of main function</i>
361int %main() { <i>; int()* </i>
362 <i>; Convert [13x sbyte]* to sbyte *...</i>
363 %cast210 = <a
364 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
365
366 <i>; Call puts function to write out the string to stdout...</i>
367 <a
368 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
369 <a
370 href="#i_ret">ret</a> int 0<br>}<br></pre>
371
372<p>This example is made up of a <a href="#globalvars">global variable</a>
373named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
374function, and a <a href="#functionstructure">function definition</a>
375for "<tt>main</tt>".</p>
376
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]377<p>In general, a module is made up of a list of global values,
378where both functions and global variables are global values. Global values are
379represented by a pointer to a memory location (in this case, a pointer to an
380array of char, and a pointer to a function), and have one of the following <a
381href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]382
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]383<p>Due to a limitation in the current LLVM assembly parser (it is limited by
384one-token lookahead), modules are split into two pieces by the "implementation"
385keyword. Global variable prototypes and definitions must occur before the
386keyword, and function definitions must occur after it. Function prototypes may
387occur either before or after it. In the future, the implementation keyword may
388become a noop, if the parser gets smarter.</p>
389
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]390</div>
391
392<!-- ======================================================================= -->
393<div class="doc_subsection">
394 <a name="linkage">Linkage Types</a>
395</div>
396
397<div class="doc_text">
398
399<p>
400All Global Variables and Functions have one of the following types of linkage:
401</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]402
403<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]404
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]405 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]406
407 <dd>Global values with internal linkage are only directly accessible by
408 objects in the current module. In particular, linking code into a module with
409 an internal global value may cause the internal to be renamed as necessary to
410 avoid collisions. Because the symbol is internal to the module, all
411 references can be updated. This corresponds to the notion of the
412 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]413 </dd>
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_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]416
417 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
418 the twist that linking together two modules defining the same
419 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
420 is typically used to implement inline functions. Unreferenced
421 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]422 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]424 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]425
426 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
427 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
428 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]429 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
434 pointer to array type. When two global variables with appending linkage are
435 linked together, the two global arrays are appended together. This is the
436 LLVM, typesafe, equivalent of having the system linker append together
437 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]438 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]440 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
442 <dd>If none of the above identifiers are used, the global is externally
443 visible, meaning that it participates in linkage and can be used to resolve
444 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]445 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]446
447 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
448
449 <dd>"<tt>extern_weak</tt>" TBD
450 </dd>
451
452 <p>
453 The next two types of linkage are targeted for Microsoft Windows platform
454 only. They are designed to support importing (exporting) symbols from (to)
455 DLLs.
456 </p>
457
458 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
459
460 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
461 or variable via a global pointer to a pointer that is set up by the DLL
462 exporting the symbol. On Microsoft Windows targets, the pointer name is
463 formed by combining <code>_imp__</code> and the function or variable name.
464 </dd>
465
466 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
467
468 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
469 pointer to a pointer in a DLL, so that it can be referenced with the
470 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
471 name is formed by combining <code>_imp__</code> and the function or variable
472 name.
473 </dd>
474
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]475</dl>
476
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
478variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
479variable and was linked with this one, one of the two would be renamed,
480preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
481external (i.e., lacking any linkage declarations), they are accessible
482outside of the current module. It is illegal for a function <i>declaration</i>
483to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]484
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]489 <a name="callingconv">Calling Conventions</a>
490</div>
491
492<div class="doc_text">
493
494<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
495and <a href="#i_invoke">invokes</a> can all have an optional calling convention
496specified for the call. The calling convention of any pair of dynamic
497caller/callee must match, or the behavior of the program is undefined. The
498following calling conventions are supported by LLVM, and more may be added in
499the future:</p>
500
501<dl>
502 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
503
504 <dd>This calling convention (the default if no other calling convention is
505 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]506 supports varargs function calls and tolerates some mismatch in the declared
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]507 prototype and implemented declaration of the function (as does normal C).
508 </dd>
509
Chris Lattner5710ce92006-05-19 21:15:36 +0000[diff] [blame]510 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
511
512 <dd>This calling convention matches the target C calling conventions, except
513 that functions with this convention are required to take a pointer as their
514 first argument, and the return type of the function must be void. This is
515 used for C functions that return aggregates by-value. In this case, the
516 function has been transformed to take a pointer to the struct as the first
517 argument to the function. For targets where the ABI specifies specific
518 behavior for structure-return calls, the calling convention can be used to
519 distinguish between struct return functions and other functions that take a
520 pointer to a struct as the first argument.
521 </dd>
522
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]523 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
524
525 <dd>This calling convention attempts to make calls as fast as possible
526 (e.g. by passing things in registers). This calling convention allows the
527 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]528 without having to conform to an externally specified ABI. Implementations of
529 this convention should allow arbitrary tail call optimization to be supported.
530 This calling convention does not support varargs and requires the prototype of
531 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]532 </dd>
533
534 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
535
536 <dd>This calling convention attempts to make code in the caller as efficient
537 as possible under the assumption that the call is not commonly executed. As
538 such, these calls often preserve all registers so that the call does not break
539 any live ranges in the caller side. This calling convention does not support
540 varargs and requires the prototype of all callees to exactly match the
541 prototype of the function definition.
542 </dd>
543
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]544 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]545
546 <dd>Any calling convention may be specified by number, allowing
547 target-specific calling conventions to be used. Target specific calling
548 conventions start at 64.
549 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]550</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]551
552<p>More calling conventions can be added/defined on an as-needed basis, to
553support pascal conventions or any other well-known target-independent
554convention.</p>
555
556</div>
557
558<!-- ======================================================================= -->
559<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]560 <a name="globalvars">Global Variables</a>
561</div>
562
563<div class="doc_text">
564
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]565<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]566instead of run-time. Global variables may optionally be initialized, may have
567an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]568have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]569variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]570contents of the variable will <b>never</b> be modified (enabling better
571optimization, allowing the global data to be placed in the read-only section of
572an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]573cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]574
575<p>
576LLVM explicitly allows <em>declarations</em> of global variables to be marked
577constant, even if the final definition of the global is not. This capability
578can be used to enable slightly better optimization of the program, but requires
579the language definition to guarantee that optimizations based on the
580'constantness' are valid for the translation units that do not include the
581definition.
582</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]583
584<p>As SSA values, global variables define pointer values that are in
585scope (i.e. they dominate) all basic blocks in the program. Global
586variables always define a pointer to their "content" type because they
587describe a region of memory, and all memory objects in LLVM are
588accessed through pointers.</p>
589
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]590<p>LLVM allows an explicit section to be specified for globals. If the target
591supports it, it will emit globals to the section specified.</p>
592
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]593<p>An explicit alignment may be specified for a global. If not present, or if
594the alignment is set to zero, the alignment of the global is set by the target
595to whatever it feels convenient. If an explicit alignment is specified, the
596global is forced to have at least that much alignment. All alignments must be
597a power of 2.</p>
598
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]599</div>
600
601
602<!-- ======================================================================= -->
603<div class="doc_subsection">
604 <a name="functionstructure">Functions</a>
605</div>
606
607<div class="doc_text">
608
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]609<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
610type</a>, an optional <a href="#callingconv">calling convention</a>, a return
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]611type, a function name, a (possibly empty) argument list, an optional section,
612an optional alignment, an opening curly brace,
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]613a list of basic blocks, and a closing curly brace. LLVM function declarations
614are defined with the "<tt>declare</tt>" keyword, an optional <a
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]615href="#callingconv">calling convention</a>, a return type, a function name,
616a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]617
618<p>A function definition contains a list of basic blocks, forming the CFG for
619the function. Each basic block may optionally start with a label (giving the
620basic block a symbol table entry), contains a list of instructions, and ends
621with a <a href="#terminators">terminator</a> instruction (such as a branch or
622function return).</p>
623
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]624<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]625executed on entrance to the function, and it is not allowed to have predecessor
626basic blocks (i.e. there can not be any branches to the entry block of a
627function). Because the block can have no predecessors, it also cannot have any
628<a href="#i_phi">PHI nodes</a>.</p>
629
630<p>LLVM functions are identified by their name and type signature. Hence, two
631functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]632considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]633appropriately.</p>
634
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]635<p>LLVM allows an explicit section to be specified for functions. If the target
636supports it, it will emit functions to the section specified.</p>
637
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]638<p>An explicit alignment may be specified for a function. If not present, or if
639the alignment is set to zero, the alignment of the function is set by the target
640to whatever it feels convenient. If an explicit alignment is specified, the
641function is forced to have at least that much alignment. All alignments must be
642a power of 2.</p>
643
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]644</div>
645
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]646<!-- ======================================================================= -->
647<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]648 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]649</div>
650
651<div class="doc_text">
652<p>
653Modules may contain "module-level inline asm" blocks, which corresponds to the
654GCC "file scope inline asm" blocks. These blocks are internally concatenated by
655LLVM and treated as a single unit, but may be separated in the .ll file if
656desired. The syntax is very simple:
657</p>
658
659<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]660 module asm "inline asm code goes here"
661 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]662</pre></div>
663
664<p>The strings can contain any character by escaping non-printable characters.
665 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
666 for the number.
667</p>
668
669<p>
670 The inline asm code is simply printed to the machine code .s file when
671 assembly code is generated.
672</p>
673</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]674
675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]676<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]677<div class="doc_section"> <a name="typesystem">Type System</a> </div>
678<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]679
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]680<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]681
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]682<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]683intermediate representation. Being typed enables a number of
684optimizations to be performed on the IR directly, without having to do
685extra analyses on the side before the transformation. A strong type
686system makes it easier to read the generated code and enables novel
687analyses and transformations that are not feasible to perform on normal
688three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]689
690</div>
691
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]692<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]693<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]694<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]695<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]696system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]697
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]698<table class="layout">
699 <tr class="layout">
700 <td class="left">
701 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]702 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]703 <tr><th>Type</th><th>Description</th></tr>
704 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]705 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
706 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
707 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
708 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
709 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]710 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]711 </tbody>
712 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]713 </td>
714 <td class="right">
715 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]716 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]717 <tr><th>Type</th><th>Description</th></tr>
718 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]719 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
720 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
721 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
722 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
723 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]724 </tbody>
725 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]726 </td>
727 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]728</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]729</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]730
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]731<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]732<div class="doc_subsubsection"> <a name="t_classifications">Type
733Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]734<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]735<p>These different primitive types fall into a few useful
736classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]737
738<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]739 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]740 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]741 <tr>
742 <td><a name="t_signed">signed</a></td>
743 <td><tt>sbyte, short, int, long, float, double</tt></td>
744 </tr>
745 <tr>
746 <td><a name="t_unsigned">unsigned</a></td>
747 <td><tt>ubyte, ushort, uint, ulong</tt></td>
748 </tr>
749 <tr>
750 <td><a name="t_integer">integer</a></td>
751 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
752 </tr>
753 <tr>
754 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]755 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
756 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]757 </tr>
758 <tr>
759 <td><a name="t_floating">floating point</a></td>
760 <td><tt>float, double</tt></td>
761 </tr>
762 <tr>
763 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]764 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
765 float, double, <a href="#t_pointer">pointer</a>,
766 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]767 </tr>
768 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]769</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]770
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]771<p>The <a href="#t_firstclass">first class</a> types are perhaps the
772most important. Values of these types are the only ones which can be
773produced by instructions, passed as arguments, or used as operands to
774instructions. This means that all structures and arrays must be
775manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]776</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]777
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]778<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]779<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]780
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]781<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]782
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]783<p>The real power in LLVM comes from the derived types in the system.
784This is what allows a programmer to represent arrays, functions,
785pointers, and other useful types. Note that these derived types may be
786recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]787
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]788</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]789
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]790<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]791<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]792
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]793<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]794
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]795<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]796
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]797<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798sequentially in memory. The array type requires a size (number of
799elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]800
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]801<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]802
803<pre>
804 [&lt;# elements&gt; x &lt;elementtype&gt;]
805</pre>
806
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]807<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]808be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]809
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]810<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]811<table class="layout">
812 <tr class="layout">
813 <td class="left">
814 <tt>[40 x int ]</tt><br/>
815 <tt>[41 x int ]</tt><br/>
816 <tt>[40 x uint]</tt><br/>
817 </td>
818 <td class="left">
819 Array of 40 integer values.<br/>
820 Array of 41 integer values.<br/>
821 Array of 40 unsigned integer values.<br/>
822 </td>
823 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]824</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]825<p>Here are some examples of multidimensional arrays:</p>
826<table class="layout">
827 <tr class="layout">
828 <td class="left">
829 <tt>[3 x [4 x int]]</tt><br/>
830 <tt>[12 x [10 x float]]</tt><br/>
831 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
832 </td>
833 <td class="left">
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]834 3x4 array of integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]835 12x10 array of single precision floating point values.<br/>
836 2x3x4 array of unsigned integer values.<br/>
837 </td>
838 </tr>
839</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]840
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]841<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
842length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]843LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
844As a special case, however, zero length arrays are recognized to be variable
845length. This allows implementation of 'pascal style arrays' with the LLVM
846type "{ int, [0 x float]}", for example.</p>
847
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]848</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]849
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]850<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]851<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]852<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]853<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]854<p>The function type can be thought of as a function signature. It
855consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]856Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]857(which are structures of pointers to functions), for indirect function
858calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]859<p>
860The return type of a function type cannot be an aggregate type.
861</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]862<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]863<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]864<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]865specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]866which indicates that the function takes a variable number of arguments.
867Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]868 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]869<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]870<table class="layout">
871 <tr class="layout">
872 <td class="left">
873 <tt>int (int)</tt> <br/>
874 <tt>float (int, int *) *</tt><br/>
875 <tt>int (sbyte *, ...)</tt><br/>
876 </td>
877 <td class="left">
878 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
879 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]880 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]881 returning <tt>float</tt>.<br/>
882 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
883 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
884 the signature for <tt>printf</tt> in LLVM.<br/>
885 </td>
886 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]887</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]888
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]889</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]890<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]891<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]892<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]893<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]894<p>The structure type is used to represent a collection of data members
895together in memory. The packing of the field types is defined to match
896the ABI of the underlying processor. The elements of a structure may
897be any type that has a size.</p>
898<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
899and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
900field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
901instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]902<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]903<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]904<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]905<table class="layout">
906 <tr class="layout">
907 <td class="left">
908 <tt>{ int, int, int }</tt><br/>
909 <tt>{ float, int (int) * }</tt><br/>
910 </td>
911 <td class="left">
912 a triple of three <tt>int</tt> values<br/>
913 A pair, where the first element is a <tt>float</tt> and the second element
914 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
915 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
916 </td>
917 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]918</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]919</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]921<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]922<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]923<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]924<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]925<p>As in many languages, the pointer type represents a pointer or
926reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]927<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]928<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]929<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]930<table class="layout">
931 <tr class="layout">
932 <td class="left">
933 <tt>[4x int]*</tt><br/>
934 <tt>int (int *) *</tt><br/>
935 </td>
936 <td class="left">
937 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
938 four <tt>int</tt> values<br/>
939 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]940 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]941 <tt>int</tt>.<br/>
942 </td>
943 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]944</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]945</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]946
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]947<!-- _______________________________________________________________________ -->
948<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]949<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]950
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]951<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]952
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]953<p>A packed type is a simple derived type that represents a vector
954of elements. Packed types are used when multiple primitive data
955are operated in parallel using a single instruction (SIMD).
956A packed type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]957elements) and an underlying primitive data type. Vectors must have a power
958of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]959considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]960
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]961<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]962
963<pre>
964 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
965</pre>
966
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]967<p>The number of elements is a constant integer value; elementtype may
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]968be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]969
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]970<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]971
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]972<table class="layout">
973 <tr class="layout">
974 <td class="left">
975 <tt>&lt;4 x int&gt;</tt><br/>
976 <tt>&lt;8 x float&gt;</tt><br/>
977 <tt>&lt;2 x uint&gt;</tt><br/>
978 </td>
979 <td class="left">
980 Packed vector of 4 integer values.<br/>
981 Packed vector of 8 floating-point values.<br/>
982 Packed vector of 2 unsigned integer values.<br/>
983 </td>
984 </tr>
985</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]986</div>
987
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]988<!-- _______________________________________________________________________ -->
989<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
990<div class="doc_text">
991
992<h5>Overview:</h5>
993
994<p>Opaque types are used to represent unknown types in the system. This
995corresponds (for example) to the C notion of a foward declared structure type.
996In LLVM, opaque types can eventually be resolved to any type (not just a
997structure type).</p>
998
999<h5>Syntax:</h5>
1000
1001<pre>
1002 opaque
1003</pre>
1004
1005<h5>Examples:</h5>
1006
1007<table class="layout">
1008 <tr class="layout">
1009 <td class="left">
1010 <tt>opaque</tt>
1011 </td>
1012 <td class="left">
1013 An opaque type.<br/>
1014 </td>
1015 </tr>
1016</table>
1017</div>
1018
1019
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1020<!-- *********************************************************************** -->
1021<div class="doc_section"> <a name="constants">Constants</a> </div>
1022<!-- *********************************************************************** -->
1023
1024<div class="doc_text">
1025
1026<p>LLVM has several different basic types of constants. This section describes
1027them all and their syntax.</p>
1028
1029</div>
1030
1031<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1032<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1033
1034<div class="doc_text">
1035
1036<dl>
1037 <dt><b>Boolean constants</b></dt>
1038
1039 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1040 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1041 </dd>
1042
1043 <dt><b>Integer constants</b></dt>
1044
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1045 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1046 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1047 integer types.
1048 </dd>
1049
1050 <dt><b>Floating point constants</b></dt>
1051
1052 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1053 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1054 notation (see below). Floating point constants must have a <a
1055 href="#t_floating">floating point</a> type. </dd>
1056
1057 <dt><b>Null pointer constants</b></dt>
1058
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1059 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1060 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1061
1062</dl>
1063
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1064<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1065of floating point constants. For example, the form '<tt>double
10660x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
10674.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1068(and the only time that they are generated by the disassembler) is when a
1069floating point constant must be emitted but it cannot be represented as a
1070decimal floating point number. For example, NaN's, infinities, and other
1071special values are represented in their IEEE hexadecimal format so that
1072assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1073
1074</div>
1075
1076<!-- ======================================================================= -->
1077<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1078</div>
1079
1080<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1081<p>Aggregate constants arise from aggregation of simple constants
1082and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1083
1084<dl>
1085 <dt><b>Structure constants</b></dt>
1086
1087 <dd>Structure constants are represented with notation similar to structure
1088 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1089 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
1090 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
1091 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1092 types of elements must match those specified by the type.
1093 </dd>
1094
1095 <dt><b>Array constants</b></dt>
1096
1097 <dd>Array constants are represented with notation similar to array type
1098 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1099 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1100 constants must have <a href="#t_array">array type</a>, and the number and
1101 types of elements must match those specified by the type.
1102 </dd>
1103
1104 <dt><b>Packed constants</b></dt>
1105
1106 <dd>Packed constants are represented with notation similar to packed type
1107 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1108 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1109 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
1110 href="#t_packed">packed type</a>, and the number and types of elements must
1111 match those specified by the type.
1112 </dd>
1113
1114 <dt><b>Zero initialization</b></dt>
1115
1116 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1117 value to zero of <em>any</em> type, including scalar and aggregate types.
1118 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]1119 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1120 initializers.
1121 </dd>
1122</dl>
1123
1124</div>
1125
1126<!-- ======================================================================= -->
1127<div class="doc_subsection">
1128 <a name="globalconstants">Global Variable and Function Addresses</a>
1129</div>
1130
1131<div class="doc_text">
1132
1133<p>The addresses of <a href="#globalvars">global variables</a> and <a
1134href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1135constants. These constants are explicitly referenced when the <a
1136href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1137href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1138file:</p>
1139
1140<pre>
1141 %X = global int 17
1142 %Y = global int 42
1143 %Z = global [2 x int*] [ int* %X, int* %Y ]
1144</pre>
1145
1146</div>
1147
1148<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1149<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1150<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1151 <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]1152 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1153 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1154
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1155 <p>Undefined values indicate to the compiler that the program is well defined
1156 no matter what value is used, giving the compiler more freedom to optimize.
1157 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1158</div>
1159
1160<!-- ======================================================================= -->
1161<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1162</div>
1163
1164<div class="doc_text">
1165
1166<p>Constant expressions are used to allow expressions involving other constants
1167to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1168href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1169that does not have side effects (e.g. load and call are not supported). The
1170following is the syntax for constant expressions:</p>
1171
1172<dl>
1173 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1174
1175 <dd>Cast a constant to another type.</dd>
1176
1177 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1178
1179 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1180 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1181 instruction, the index list may have zero or more indexes, which are required
1182 to make sense for the type of "CSTPTR".</dd>
1183
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1184 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1185
1186 <dd>Perform the <a href="#i_select">select operation</a> on
1187 constants.
1188
1189 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1190
1191 <dd>Perform the <a href="#i_extractelement">extractelement
1192 operation</a> on constants.
1193
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1194 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1195
1196 <dd>Perform the <a href="#i_insertelement">insertelement
1197 operation</a> on constants.
1198
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1199
1200 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1201
1202 <dd>Perform the <a href="#i_shufflevector">shufflevector
1203 operation</a> on constants.
1204
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1205 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1206
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1207 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1208 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1209 binary</a> operations. The constraints on operands are the same as those for
1210 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1211 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1212</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1213</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1215<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1216<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1217<!-- *********************************************************************** -->
1218
1219<!-- ======================================================================= -->
1220<div class="doc_subsection">
1221<a name="inlineasm">Inline Assembler Expressions</a>
1222</div>
1223
1224<div class="doc_text">
1225
1226<p>
1227LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1228Module-Level Inline Assembly</a>) through the use of a special value. This
1229value represents the inline assembler as a string (containing the instructions
1230to emit), a list of operand constraints (stored as a string), and a flag that
1231indicates whether or not the inline asm expression has side effects. An example
1232inline assembler expression is:
1233</p>
1234
1235<pre>
1236 int(int) asm "bswap $0", "=r,r"
1237</pre>
1238
1239<p>
1240Inline assembler expressions may <b>only</b> be used as the callee operand of
1241a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1242</p>
1243
1244<pre>
1245 %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y)
1246</pre>
1247
1248<p>
1249Inline asms with side effects not visible in the constraint list must be marked
1250as having side effects. This is done through the use of the
1251'<tt>sideeffect</tt>' keyword, like so:
1252</p>
1253
1254<pre>
1255 call void asm sideeffect "eieio", ""()
1256</pre>
1257
1258<p>TODO: The format of the asm and constraints string still need to be
1259documented here. Constraints on what can be done (e.g. duplication, moving, etc
1260need to be documented).
1261</p>
1262
1263</div>
1264
1265<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1266<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1267<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1269<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1270
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1271<p>The LLVM instruction set consists of several different
1272classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1273instructions</a>, <a href="#binaryops">binary instructions</a>,
1274<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1275 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1276instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1277
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1278</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1279
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1280<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1281<div class="doc_subsection"> <a name="terminators">Terminator
1282Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1283
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1284<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1285
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1286<p>As mentioned <a href="#functionstructure">previously</a>, every
1287basic block in a program ends with a "Terminator" instruction, which
1288indicates which block should be executed after the current block is
1289finished. These terminator instructions typically yield a '<tt>void</tt>'
1290value: they produce control flow, not values (the one exception being
1291the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1292<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1293 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1294instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1295the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1296 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1297 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1299</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1301<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1302<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1303Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1304<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1305<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1306<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]1307 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1308</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1309<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1310<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1311value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1312<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1313returns a value and then causes control flow, and one that just causes
1314control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1315<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1316<p>The '<tt>ret</tt>' instruction may return any '<a
1317 href="#t_firstclass">first class</a>' type. Notice that a function is
1318not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1319instruction inside of the function that returns a value that does not
1320match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1321<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1322<p>When the '<tt>ret</tt>' instruction is executed, control flow
1323returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1324 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1325the instruction after the call. If the caller was an "<a
1326 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1327at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1328returns a value, that value shall set the call or invoke instruction's
1329return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1330<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1331<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1332 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1333</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1334</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1335<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1336<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1337<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1338<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1339<pre> br bool &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]1340</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1341<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1342<p>The '<tt>br</tt>' instruction is used to cause control flow to
1343transfer to a different basic block in the current function. There are
1344two forms of this instruction, corresponding to a conditional branch
1345and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1346<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1347<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1348single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1349unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1350value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1351<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1352<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1353argument is evaluated. If the value is <tt>true</tt>, control flows
1354to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1355control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1356<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1357<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1358 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1359</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1360<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1361<div class="doc_subsubsection">
1362 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1363</div>
1364
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1365<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1366<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1367
1368<pre>
1369 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1370</pre>
1371
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1372<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1373
1374<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1375several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1376instruction, allowing a branch to occur to one of many possible
1377destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1378
1379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1380<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1381
1382<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1383comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1384an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1385table is not allowed to contain duplicate constant entries.</p>
1386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1387<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1388
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1389<p>The <tt>switch</tt> instruction specifies a table of values and
1390destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1391table is searched for the given value. If the value is found, control flow is
1392transfered to the corresponding destination; otherwise, control flow is
1393transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1394
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1395<h5>Implementation:</h5>
1396
1397<p>Depending on properties of the target machine and the particular
1398<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1399ways. For example, it could be generated as a series of chained conditional
1400branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1401
1402<h5>Example:</h5>
1403
1404<pre>
1405 <i>; Emulate a conditional br instruction</i>
1406 %Val = <a href="#i_cast">cast</a> bool %value to int
1407 switch int %Val, label %truedest [int 0, label %falsedest ]
1408
1409 <i>; Emulate an unconditional br instruction</i>
1410 switch uint 0, label %dest [ ]
1411
1412 <i>; Implement a jump table:</i>
1413 switch uint %val, label %otherwise [ uint 0, label %onzero
1414 uint 1, label %onone
1415 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1416</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1417</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1418
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1419<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1420<div class="doc_subsubsection">
1421 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1422</div>
1423
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1424<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1425
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1426<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1427
1428<pre>
1429 &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]1430 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1431</pre>
1432
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1433<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1434
1435<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1436function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1437'<tt>normal</tt>' label or the
1438'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1439"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1440"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1441href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1442continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1443
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1444<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1445
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1446<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1447
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1448<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1449 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1450 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1451 convention</a> the call should use. If none is specified, the call defaults
1452 to using C calling conventions.
1453 </li>
1454 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1455 function value being invoked. In most cases, this is a direct function
1456 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1457 an arbitrary pointer to function value.
1458 </li>
1459
1460 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1461 function to be invoked. </li>
1462
1463 <li>'<tt>function args</tt>': argument list whose types match the function
1464 signature argument types. If the function signature indicates the function
1465 accepts a variable number of arguments, the extra arguments can be
1466 specified. </li>
1467
1468 <li>'<tt>normal label</tt>': the label reached when the called function
1469 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1470
1471 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1472 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1474</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1476<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1477
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1478<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1479href="#i_call">call</a></tt>' instruction in most regards. The primary
1480difference is that it establishes an association with a label, which is used by
1481the runtime library to unwind the stack.</p>
1482
1483<p>This instruction is used in languages with destructors to ensure that proper
1484cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1485exception. Additionally, this is important for implementation of
1486'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1487
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1488<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1489<pre>
1490 %retval = invoke int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1491 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1492 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]1493 unwind label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1494</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1495</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1496
1497
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1498<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1499
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1500<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1501Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1502
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1503<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1504
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1505<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1506<pre>
1507 unwind
1508</pre>
1509
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1510<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1511
1512<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1513at the first callee in the dynamic call stack which used an <a
1514href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1515primarily used to implement exception handling.</p>
1516
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1517<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1518
1519<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1520immediately halt. The dynamic call stack is then searched for the first <a
1521href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1522execution continues at the "exceptional" destination block specified by the
1523<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1524dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1525</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1526
1527<!-- _______________________________________________________________________ -->
1528
1529<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1530Instruction</a> </div>
1531
1532<div class="doc_text">
1533
1534<h5>Syntax:</h5>
1535<pre>
1536 unreachable
1537</pre>
1538
1539<h5>Overview:</h5>
1540
1541<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1542instruction is used to inform the optimizer that a particular portion of the
1543code is not reachable. This can be used to indicate that the code after a
1544no-return function cannot be reached, and other facts.</p>
1545
1546<h5>Semantics:</h5>
1547
1548<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1549</div>
1550
1551
1552
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1553<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1554<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1555<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1556<p>Binary operators are used to do most of the computation in a
1557program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1558produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1559multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1560The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1561necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1562<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1563</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1564<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1565<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1566Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1567<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1568<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1569<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]1570</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1572<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1573<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1574<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1575 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1576 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1577Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1578<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1579<p>The value produced is the integer or floating point sum of the two
1580operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1581<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1582<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1583</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1584</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1585<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1586<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1587Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1588<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590<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]1591</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1593<p>The '<tt>sub</tt>' instruction returns the difference of its two
1594operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1595<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1596instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1598<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1599 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1600values.
1601This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1602Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1603<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1604<p>The value produced is the integer or floating point difference of
1605the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1606<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1607<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1608 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1609</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1610</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1611<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1612<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1613Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1614<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1615<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1616<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]1617</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1619<p>The '<tt>mul</tt>' instruction returns the product of its two
1620operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1621<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1622<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1623 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1624values.
1625This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1626Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1627<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1628<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1629two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1630<p>There is no signed vs unsigned multiplication. The appropriate
1631action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1632<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1633<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1634</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1635</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1636<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1637<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1638</a></div>
1639<div class="doc_text">
1640<h5>Syntax:</h5>
1641<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1642</pre>
1643<h5>Overview:</h5>
1644<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1645operands.</p>
1646<h5>Arguments:</h5>
1647<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1648<a href="#t_integer">integer</a> values. Both arguments must have identical
1649types. This instruction can also take <a href="#t_packed">packed</a> versions
1650of the values in which case the elements must be integers.</p>
1651<h5>Semantics:</h5>
1652<p>The value produced is the unsigned integer quotient of the two operands. This
1653instruction always performs an unsigned division operation, regardless of
1654whether the arguments are unsigned or not.</p>
1655<h5>Example:</h5>
1656<pre> &lt;result&gt; = udiv uint 4, %var <i>; yields {uint}:result = 4 / %var</i>
1657</pre>
1658</div>
1659<!-- _______________________________________________________________________ -->
1660<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1661</a> </div>
1662<div class="doc_text">
1663<h5>Syntax:</h5>
1664<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1665</pre>
1666<h5>Overview:</h5>
1667<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1668operands.</p>
1669<h5>Arguments:</h5>
1670<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1671<a href="#t_integer">integer</a> values. Both arguments must have identical
1672types. This instruction can also take <a href="#t_packed">packed</a> versions
1673of the values in which case the elements must be integers.</p>
1674<h5>Semantics:</h5>
1675<p>The value produced is the signed integer quotient of the two operands. This
1676instruction always performs a signed division operation, regardless of whether
1677the arguments are signed or not.</p>
1678<h5>Example:</h5>
1679<pre> &lt;result&gt; = sdiv int 4, %var <i>; yields {int}:result = 4 / %var</i>
1680</pre>
1681</div>
1682<!-- _______________________________________________________________________ -->
1683<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1684Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1685<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1686<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1687<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]1688</pre>
1689<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1690<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1691operands.</p>
1692<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1693<p>The two arguments to the '<tt>div</tt>' instruction must be
1694<a href="#t_floating">floating point</a> values. Both arguments must have
1695identical types. This instruction can also take <a href="#t_packed">packed</a>
1696versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1697<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1698<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1699<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1700<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]1701</pre>
1702</div>
1703<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1704<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1705</div>
1706<div class="doc_text">
1707<h5>Syntax:</h5>
1708<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1709</pre>
1710<h5>Overview:</h5>
1711<p>The '<tt>urem</tt>' instruction returns the remainder from the
1712unsigned division of its two arguments.</p>
1713<h5>Arguments:</h5>
1714<p>The two arguments to the '<tt>urem</tt>' instruction must be
1715<a href="#t_integer">integer</a> values. Both arguments must have identical
1716types.</p>
1717<h5>Semantics:</h5>
1718<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1719This instruction always performs an unsigned division to get the remainder,
1720regardless of whether the arguments are unsigned or not.</p>
1721<h5>Example:</h5>
1722<pre> &lt;result&gt; = urem uint 4, %var <i>; yields {uint}:result = 4 % %var</i>
1723</pre>
1724
1725</div>
1726<!-- _______________________________________________________________________ -->
1727<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1728Instruction</a> </div>
1729<div class="doc_text">
1730<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1731<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]1732</pre>
1733<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1734<p>The '<tt>srem</tt>' instruction returns the remainder from the
1735signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1737<p>The two arguments to the '<tt>srem</tt>' instruction must be
1738<a href="#t_integer">integer</a> values. Both arguments must have identical
1739types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1740<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1741<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1742has the same sign as the divisor), not the <i>modulus</i> (where the
1743result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1744information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1745 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1746Math Forum</a>.</p>
1747<h5>Example:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame^]1748<pre> &lt;result&gt; = srem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1749</pre>
1750
1751</div>
1752<!-- _______________________________________________________________________ -->
1753<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1754Instruction</a> </div>
1755<div class="doc_text">
1756<h5>Syntax:</h5>
1757<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1758</pre>
1759<h5>Overview:</h5>
1760<p>The '<tt>frem</tt>' instruction returns the remainder from the
1761division of its two operands.</p>
1762<h5>Arguments:</h5>
1763<p>The two arguments to the '<tt>frem</tt>' instruction must be
1764<a href="#t_floating">floating point</a> values. Both arguments must have
1765identical types.</p>
1766<h5>Semantics:</h5>
1767<p>This instruction returns the <i>remainder</i> of a division.</p>
1768<h5>Example:</h5>
1769<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]1770</pre>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1771
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1772</div>
1773<!-- _______________________________________________________________________ -->
1774<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1775Instructions</a> </div>
1776<div class="doc_text">
1777<h5>Syntax:</h5>
1778<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1779 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1780 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1781 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1782 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1783 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1784</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1785<h5>Overview:</h5>
1786<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1787value based on a comparison of their two operands.</p>
1788<h5>Arguments:</h5>
1789<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1790be of <a href="#t_firstclass">first class</a> type (it is not possible
1791to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1792or '<tt>void</tt>' values, etc...). Both arguments must have identical
1793types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1796value if both operands are equal.<br>
1797The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1798value if both operands are unequal.<br>
1799The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1800value if the first operand is less than the second operand.<br>
1801The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1802value if the first operand is greater than the second operand.<br>
1803The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1804value if the first operand is less than or equal to the second operand.<br>
1805The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1806value if the first operand is greater than or equal to the second
1807operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1809<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1810 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1811 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1812 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1813 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1814 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1815</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1816</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]1817
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1818<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1819<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1820Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1821<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1822<p>Bitwise binary operators are used to do various forms of
1823bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1824instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1825instructions. They require two operands, execute an operation on them,
1826and produce a single value. The resulting value of the bitwise binary
1827operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1828</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1830<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1831Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1832<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1833<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1834<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]1835</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1836<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1837<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1838its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1840<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1841 href="#t_integral">integral</a> values. Both arguments must have
1842identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1843<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1844<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1845<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1846<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1847<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1848 <tbody>
1849 <tr>
1850 <td>In0</td>
1851 <td>In1</td>
1852 <td>Out</td>
1853 </tr>
1854 <tr>
1855 <td>0</td>
1856 <td>0</td>
1857 <td>0</td>
1858 </tr>
1859 <tr>
1860 <td>0</td>
1861 <td>1</td>
1862 <td>0</td>
1863 </tr>
1864 <tr>
1865 <td>1</td>
1866 <td>0</td>
1867 <td>0</td>
1868 </tr>
1869 <tr>
1870 <td>1</td>
1871 <td>1</td>
1872 <td>1</td>
1873 </tr>
1874 </tbody>
1875</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1876</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1879 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1880 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1881</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1882</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1884<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1885<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1887<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]1888</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1889<h5>Overview:</h5>
1890<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1891or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1893<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1894 href="#t_integral">integral</a> values. Both arguments must have
1895identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1896<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1897<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1898<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1899<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1900<table border="1" cellspacing="0" cellpadding="4">
1901 <tbody>
1902 <tr>
1903 <td>In0</td>
1904 <td>In1</td>
1905 <td>Out</td>
1906 </tr>
1907 <tr>
1908 <td>0</td>
1909 <td>0</td>
1910 <td>0</td>
1911 </tr>
1912 <tr>
1913 <td>0</td>
1914 <td>1</td>
1915 <td>1</td>
1916 </tr>
1917 <tr>
1918 <td>1</td>
1919 <td>0</td>
1920 <td>1</td>
1921 </tr>
1922 <tr>
1923 <td>1</td>
1924 <td>1</td>
1925 <td>1</td>
1926 </tr>
1927 </tbody>
1928</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1929</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1931<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1932 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1933 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1934</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1935</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1936<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1937<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1938Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1939<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1940<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1941<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]1942</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1943<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1944<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1945or of its two operands. The <tt>xor</tt> is used to implement the
1946"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1947<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1948<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1949 href="#t_integral">integral</a> values. Both arguments must have
1950identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1953<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1954<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1955<table border="1" cellspacing="0" cellpadding="4">
1956 <tbody>
1957 <tr>
1958 <td>In0</td>
1959 <td>In1</td>
1960 <td>Out</td>
1961 </tr>
1962 <tr>
1963 <td>0</td>
1964 <td>0</td>
1965 <td>0</td>
1966 </tr>
1967 <tr>
1968 <td>0</td>
1969 <td>1</td>
1970 <td>1</td>
1971 </tr>
1972 <tr>
1973 <td>1</td>
1974 <td>0</td>
1975 <td>1</td>
1976 </tr>
1977 <tr>
1978 <td>1</td>
1979 <td>1</td>
1980 <td>0</td>
1981 </tr>
1982 </tbody>
1983</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1984</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1985<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1986<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1987<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1988 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1989 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1990 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1991</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1992</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1993<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1994<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1995Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1996<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1998<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2002the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2003<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2005 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
2006type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2007<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2008<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2009<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2010<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2011 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
2012 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
2013</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2014</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2015<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
2017Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2018<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2019<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2020<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2021</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2022<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2023<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
2024the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2025<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2026<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2027 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
2028type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2029<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2030<p>If the first argument is a <a href="#t_signed">signed</a> type, the
2031most significant bit is duplicated in the newly free'd bit positions.
2032If the first argument is unsigned, zero bits shall fill the empty
2033positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2035<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]2036 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2037 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]2038 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
2039 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2040</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2042
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2043<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2044<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2045 <a name="vectorops">Vector Operations</a>
2046</div>
2047
2048<div class="doc_text">
2049
2050<p>LLVM supports several instructions to represent vector operations in a
2051target-independent manner. This instructions cover the element-access and
2052vector-specific operations needed to process vectors effectively. While LLVM
2053does directly support these vector operations, many sophisticated algorithms
2054will want to use target-specific intrinsics to take full advantage of a specific
2055target.</p>
2056
2057</div>
2058
2059<!-- _______________________________________________________________________ -->
2060<div class="doc_subsubsection">
2061 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2062</div>
2063
2064<div class="doc_text">
2065
2066<h5>Syntax:</h5>
2067
2068<pre>
2069 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, uint &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2070</pre>
2071
2072<h5>Overview:</h5>
2073
2074<p>
2075The '<tt>extractelement</tt>' instruction extracts a single scalar
2076element from a packed vector at a specified index.
2077</p>
2078
2079
2080<h5>Arguments:</h5>
2081
2082<p>
2083The first operand of an '<tt>extractelement</tt>' instruction is a
2084value of <a href="#t_packed">packed</a> type. The second operand is
2085an index indicating the position from which to extract the element.
2086The index may be a variable.</p>
2087
2088<h5>Semantics:</h5>
2089
2090<p>
2091The result is a scalar of the same type as the element type of
2092<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2093<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2094results are undefined.
2095</p>
2096
2097<h5>Example:</h5>
2098
2099<pre>
2100 %result = extractelement &lt;4 x int&gt; %vec, uint 0 <i>; yields int</i>
2101</pre>
2102</div>
2103
2104
2105<!-- _______________________________________________________________________ -->
2106<div class="doc_subsubsection">
2107 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2108</div>
2109
2110<div class="doc_text">
2111
2112<h5>Syntax:</h5>
2113
2114<pre>
2115 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, uint &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2116</pre>
2117
2118<h5>Overview:</h5>
2119
2120<p>
2121The '<tt>insertelement</tt>' instruction inserts a scalar
2122element into a packed vector at a specified index.
2123</p>
2124
2125
2126<h5>Arguments:</h5>
2127
2128<p>
2129The first operand of an '<tt>insertelement</tt>' instruction is a
2130value of <a href="#t_packed">packed</a> type. The second operand is a
2131scalar value whose type must equal the element type of the first
2132operand. The third operand is an index indicating the position at
2133which to insert the value. The index may be a variable.</p>
2134
2135<h5>Semantics:</h5>
2136
2137<p>
2138The result is a packed vector of the same type as <tt>val</tt>. Its
2139element values are those of <tt>val</tt> except at position
2140<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2141exceeds the length of <tt>val</tt>, the results are undefined.
2142</p>
2143
2144<h5>Example:</h5>
2145
2146<pre>
2147 %result = insertelement &lt;4 x int&gt; %vec, int 1, uint 0 <i>; yields &lt;4 x int&gt;</i>
2148</pre>
2149</div>
2150
2151<!-- _______________________________________________________________________ -->
2152<div class="doc_subsubsection">
2153 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2154</div>
2155
2156<div class="doc_text">
2157
2158<h5>Syntax:</h5>
2159
2160<pre>
2161 &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 uint&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2162</pre>
2163
2164<h5>Overview:</h5>
2165
2166<p>
2167The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2168from two input vectors, returning a vector of the same type.
2169</p>
2170
2171<h5>Arguments:</h5>
2172
2173<p>
2174The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2175with types that match each other and types that match the result of the
2176instruction. The third argument is a shuffle mask, which has the same number
2177of elements as the other vector type, but whose element type is always 'uint'.
2178</p>
2179
2180<p>
2181The shuffle mask operand is required to be a constant vector with either
2182constant integer or undef values.
2183</p>
2184
2185<h5>Semantics:</h5>
2186
2187<p>
2188The elements of the two input vectors are numbered from left to right across
2189both of the vectors. The shuffle mask operand specifies, for each element of
2190the result vector, which element of the two input registers the result element
2191gets. The element selector may be undef (meaning "don't care") and the second
2192operand may be undef if performing a shuffle from only one vector.
2193</p>
2194
2195<h5>Example:</h5>
2196
2197<pre>
2198 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; %v2,
2199 &lt;4 x uint&gt; &lt;uint 0, uint 4, uint 1, uint 5&gt; <i>; yields &lt;4 x int&gt;</i>
2200 %result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; undef,
2201 &lt;4 x uint&gt; &lt;uint 0, uint 1, uint 2, uint 3&gt; <i>; yields &lt;4 x int&gt;</i> - Identity shuffle.
2202</pre>
2203</div>
2204
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2205
2206<!-- _______________________________________________________________________ -->
2207<div class="doc_subsubsection"> <a name="i_vsetint">'<tt>vsetint</tt>'
2208Instruction</a> </div>
2209<div class="doc_text">
2210<h5>Syntax:</h5>
2211<pre>&lt;result&gt; = vsetint &lt;op&gt;, &lt;n x &lt;ty&gt;&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields &lt;n x bool&gt;</i>
2212</pre>
2213
2214<h5>Overview:</h5>
2215
2216<p>The '<tt>vsetint</tt>' instruction takes two integer vectors and
2217returns a vector of boolean values representing, at each position, the
2218result of the comparison between the values at that position in the
2219two operands.</p>
2220
2221<h5>Arguments:</h5>
2222
2223<p>The arguments to a '<tt>vsetint</tt>' instruction are a comparison
2224operation and two value arguments. The value arguments must be of <a
2225href="#t_integral">integral</a> <a href="#t_packed">packed</a> type,
2226and they must have identical types. The operation argument must be
2227one of <tt>eq</tt>, <tt>ne</tt>, <tt>slt</tt>, <tt>sgt</tt>,
2228<tt>sle</tt>, <tt>sge</tt>, <tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>,
2229<tt>uge</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a
2230packed <tt>bool</tt> value with the same length as each operand.</p>
2231
2232<h5>Semantics:</h5>
2233
2234<p>The following table shows the semantics of '<tt>vsetint</tt>'. For
2235each position of the result, the comparison is done on the
2236corresponding positions of the two value arguments. Note that the
2237signedness of the comparison depends on the comparison opcode and
2238<i>not</i> on the signedness of the value operands. E.g., <tt>vsetint
2239slt <4 x unsigned> %x, %y</tt> does an elementwise <i>signed</i>
2240comparison of <tt>%x</tt> and <tt>%y</tt>.</p>
2241
2242<table border="1" cellspacing="0" cellpadding="4">
2243 <tbody>
2244 <tr><th>Operation</th><th>Result is true iff</th><th>Comparison is</th></tr>
2245 <tr><td><tt>eq</tt></td><td>var1 == var2</td><td>--</td></tr>
2246 <tr><td><tt>ne</tt></td><td>var1 != var2</td><td>--</td></tr>
2247 <tr><td><tt>slt</tt></td><td>var1 &lt; var2</td><td>signed</td></tr>
2248 <tr><td><tt>sgt</tt></td><td>var1 &gt; var2</td><td>signed</td></tr>
2249 <tr><td><tt>sle</tt></td><td>var1 &lt;= var2</td><td>signed</td></tr>
2250 <tr><td><tt>sge</tt></td><td>var1 &gt;= var2</td><td>signed</td></tr>
2251 <tr><td><tt>ult</tt></td><td>var1 &lt; var2</td><td>unsigned</td></tr>
2252 <tr><td><tt>ugt</tt></td><td>var1 &gt; var2</td><td>unsigned</td></tr>
2253 <tr><td><tt>ule</tt></td><td>var1 &lt;= var2</td><td>unsigned</td></tr>
2254 <tr><td><tt>uge</tt></td><td>var1 &gt;= var2</td><td>unsigned</td></tr>
2255 <tr><td><tt>true</tt></td><td>always</td><td>--</td></tr>
2256 <tr><td><tt>false</tt></td><td>never</td><td>--</td></tr>
2257 </tbody>
2258</table>
2259
2260<h5>Example:</h5>
2261<pre> &lt;result&gt; = vsetint eq &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, false</i>
2262 &lt;result&gt; = vsetint ne &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, true</i>
2263 &lt;result&gt; = vsetint slt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2264 &lt;result&gt; = vsetint sgt &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2265 &lt;result&gt; = vsetint sle &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2266 &lt;result&gt; = vsetint sge &lt;2 x int&gt; &lt;int 0, int 1&gt;, &lt;int 1, int 0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2267</pre>
2268</div>
2269
2270<!-- _______________________________________________________________________ -->
2271<div class="doc_subsubsection"> <a name="i_vsetfp">'<tt>vsetfp</tt>'
2272Instruction</a> </div>
2273<div class="doc_text">
2274<h5>Syntax:</h5>
2275<pre>&lt;result&gt; = vsetfp &lt;op&gt;, &lt;n x &lt;ty&gt;&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields &lt;n x bool&gt;</i>
2276</pre>
2277
2278<h5>Overview:</h5>
2279
2280<p>The '<tt>vsetfp</tt>' instruction takes two floating point vector
2281arguments and returns a vector of boolean values representing, at each
2282position, the result of the comparison between the values at that
2283position in the two operands.</p>
2284
2285<h5>Arguments:</h5>
2286
2287<p>The arguments to a '<tt>vsetfp</tt>' instruction are a comparison
2288operation and two value arguments. The value arguments must be of <a
2289href="t_floating">floating point</a> <a href="#t_packed">packed</a>
2290type, and they must have identical types. The operation argument must
2291be one of <tt>eq</tt>, <tt>ne</tt>, <tt>lt</tt>, <tt>gt</tt>,
2292<tt>le</tt>, <tt>ge</tt>, <tt>oeq</tt>, <tt>one</tt>, <tt>olt</tt>,
2293<tt>ogt</tt>, <tt>ole</tt>, <tt>oge</tt>, <tt>ueq</tt>, <tt>une</tt>,
2294<tt>ult</tt>, <tt>ugt</tt>, <tt>ule</tt>, <tt>uge</tt>, <tt>o</tt>,
2295<tt>u</tt>, <tt>true</tt>, and <tt>false</tt>. The result is a packed
2296<tt>bool</tt> value with the same length as each operand.</p>
2297
2298<h5>Semantics:</h5>
2299
2300<p>The following table shows the semantics of '<tt>vsetfp</tt>' for
2301floating point types. If either operand is a floating point Not a
2302Number (NaN) value, the operation is unordered, and the value in the
2303first column below is produced at that position. Otherwise, the
2304operation is ordered, and the value in the second column is
2305produced.</p>
2306
2307<table border="1" cellspacing="0" cellpadding="4">
2308 <tbody>
2309 <tr><th>Operation</th><th>If unordered<th>Otherwise true iff</th></tr>
2310 <tr><td><tt>eq</tt></td><td>undefined</td><td>var1 == var2</td></tr>
2311 <tr><td><tt>ne</tt></td><td>undefined</td><td>var1 != var2</td></tr>
2312 <tr><td><tt>lt</tt></td><td>undefined</td><td>var1 &lt; var2</td></tr>
2313 <tr><td><tt>gt</tt></td><td>undefined</td><td>var1 &gt; var2</td></tr>
2314 <tr><td><tt>le</tt></td><td>undefined</td><td>var1 &lt;= var2</td></tr>
2315 <tr><td><tt>ge</tt></td><td>undefined</td><td>var1 &gt;= var2</td></tr>
2316 <tr><td><tt>oeq</tt></td><td>false</td><td>var1 == var2</td></tr>
2317 <tr><td><tt>one</tt></td><td>false</td><td>var1 != var2</td></tr>
2318 <tr><td><tt>olt</tt></td><td>false</td><td>var1 &lt; var2</td></tr>
2319 <tr><td><tt>ogt</tt></td><td>false</td><td>var1 &gt; var2</td></tr>
2320 <tr><td><tt>ole</tt></td><td>false</td><td>var1 &lt;= var2</td></tr>
2321 <tr><td><tt>oge</tt></td><td>false</td><td>var1 &gt;= var2</td></tr>
2322 <tr><td><tt>ueq</tt></td><td>true</td><td>var1 == var2</td></tr>
2323 <tr><td><tt>une</tt></td><td>true</td><td>var1 != var2</td></tr>
2324 <tr><td><tt>ult</tt></td><td>true</td><td>var1 &lt; var2</td></tr>
2325 <tr><td><tt>ugt</tt></td><td>true</td><td>var1 &gt; var2</td></tr>
2326 <tr><td><tt>ule</tt></td><td>true</td><td>var1 &lt;= var2</td></tr>
2327 <tr><td><tt>uge</tt></td><td>true</td><td>var1 &gt;= var2</td></tr>
2328 <tr><td><tt>o</tt></td><td>false</td><td>always</td></tr>
2329 <tr><td><tt>u</tt></td><td>true</td><td>never</td></tr>
2330 <tr><td><tt>true</tt></td><td>true</td><td>always</td></tr>
2331 <tr><td><tt>false</tt></td><td>false</td><td>never</td></tr>
2332 </tbody>
2333</table>
2334
2335<h5>Example:</h5>
2336<pre> &lt;result&gt; = vsetfp eq &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, false</i>
2337 &lt;result&gt; = vsetfp ne &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, true</i>
2338 &lt;result&gt; = vsetfp lt &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2339 &lt;result&gt; = vsetfp gt &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2340 &lt;result&gt; = vsetfp le &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = true, false</i>
2341 &lt;result&gt; = vsetfp ge &lt;2 x float&gt; &lt;float 0.0, float 1.0&gt;, &lt;float 1.0, float 0.0&gt; <i>; yields {&lt;2 x bool&gt;}:result = false, true</i>
2342</pre>
2343</div>
2344
2345<!-- _______________________________________________________________________ -->
2346<div class="doc_subsubsection">
2347 <a name="i_vselect">'<tt>vselect</tt>' Instruction</a>
2348</div>
2349
2350<div class="doc_text">
2351
2352<h5>Syntax:</h5>
2353
2354<pre>
2355 &lt;result&gt; = vselect &lt;n x bool&gt; &lt;cond&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;val2&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2356</pre>
2357
2358<h5>Overview:</h5>
2359
2360<p>
2361The '<tt>vselect</tt>' instruction chooses one value at each position
2362of a vector based on a condition.
2363</p>
2364
2365
2366<h5>Arguments:</h5>
2367
2368<p>
2369The '<tt>vselect</tt>' instruction requires a <a
2370href="#t_packed">packed</a> <tt>bool</tt> value indicating the
2371condition at each vector position, and two values of the same packed
2372type. All three operands must have the same length. The type of the
2373result is the same as the type of the two value operands.</p>
2374
2375<h5>Semantics:</h5>
2376
2377<p>
2378At each position where the <tt>bool</tt> vector is true, that position
2379of the result gets its value from the first value argument; otherwise,
2380it gets its value from the second value argument.
2381</p>
2382
2383<h5>Example:</h5>
2384
2385<pre>
2386 %X = vselect bool &lt;2 x bool&gt; &lt;bool true, bool false&gt;, &lt;2 x ubyte&gt; &lt;ubyte 17, ubyte 17&gt;,
2387 &lt;2 x ubyte&gt; &lt;ubyte 42, ubyte 42&gt; <i>; yields &lt;2 x ubyte&gt;:17, 42</i>
2388</pre>
2389</div>
2390
2391
2392
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2393<!-- ======================================================================= -->
2394<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2395 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2396</div>
2397
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2398<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2399
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2400<p>A key design point of an SSA-based representation is how it
2401represents memory. In LLVM, no memory locations are in SSA form, which
2402makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2403allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2404
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2405</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2406
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2407<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2408<div class="doc_subsubsection">
2409 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2410</div>
2411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2412<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2414<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2415
2416<pre>
2417 &lt;result&gt; = malloc &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2418</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2420<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2421
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2422<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2423heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2424
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2425<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2426
2427<p>The '<tt>malloc</tt>' instruction allocates
2428<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2429bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2430appropriate type to the program. If "NumElements" is specified, it is the
2431number of elements allocated. If an alignment is specified, the value result
2432of the allocation is guaranteed to be aligned to at least that boundary. If
2433not specified, or if zero, the target can choose to align the allocation on any
2434convenient boundary.</p>
2435
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2436<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2437
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2438<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2439
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2440<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2441a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2442
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2443<h5>Example:</h5>
2444
2445<pre>
2446 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
2447
2448 %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2449 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
2450 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2451 %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i>
2452 %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2453</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2454</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2455
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2456<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2457<div class="doc_subsubsection">
2458 <a name="i_free">'<tt>free</tt>' Instruction</a>
2459</div>
2460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2461<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2462
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2463<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2464
2465<pre>
2466 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2467</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2468
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2471<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2472memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2474<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2475
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2476<p>'<tt>value</tt>' shall be a pointer value that points to a value
2477that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2478instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2479
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2480<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2481
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2482<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2483after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2485<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2486
2487<pre>
2488 %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2489 free [4 x ubyte]* %array
2490</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2491</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2492
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2493<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2494<div class="doc_subsubsection">
2495 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2496</div>
2497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2498<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2500<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2501
2502<pre>
2503 &lt;result&gt; = alloca &lt;type&gt;[, uint &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2504</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2505
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2506<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2507
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2508<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2509stack frame of the procedure that is live until the current function
2510returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2511
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2512<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2513
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2514<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2515bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2516appropriate type to the program. If "NumElements" is specified, it is the
2517number of elements allocated. If an alignment is specified, the value result
2518of the allocation is guaranteed to be aligned to at least that boundary. If
2519not specified, or if zero, the target can choose to align the allocation on any
2520convenient boundary.</p>
2521
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2525
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2526<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2527memory is automatically released when the function returns. The '<tt>alloca</tt>'
2528instruction is commonly used to represent automatic variables that must
2529have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2530 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]2531instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2532
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2533<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2534
2535<pre>
2536 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2537 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2538 %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i>
2539 %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2540</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2541</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2542
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2543<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2544<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2545Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2546<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2547<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2548<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2549<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2550<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2551<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2552<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2553address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2554 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2555marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2556the number or order of execution of this <tt>load</tt> with other
2557volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2558instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2559<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2560<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2561<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2562<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2563 <a
2564 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2565 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2566</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2567</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2568<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2569<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2570Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2571<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2572<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattnerf0651072003-09-08 18:27:49 +0000[diff] [blame]2573 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2574</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2575<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2576<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2577<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2578<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2579to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2580operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2581operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2582optimizer is not allowed to modify the number or order of execution of
2583this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2584 href="#i_store">store</a></tt> instructions.</p>
2585<h5>Semantics:</h5>
2586<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2587at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2588<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2589<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
2590 <a
2591 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2592 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
2593</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2594<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2595<div class="doc_subsubsection">
2596 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2597</div>
2598
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2599<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2600<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2601<pre>
2602 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2603</pre>
2604
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2605<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2606
2607<p>
2608The '<tt>getelementptr</tt>' instruction is used to get the address of a
2609subelement of an aggregate data structure.</p>
2610
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2611<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2612
2613<p>This instruction takes a list of integer constants that indicate what
2614elements of the aggregate object to index to. The actual types of the arguments
2615provided depend on the type of the first pointer argument. The
2616'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2617levels of a structure or to a specific index in an array. When indexing into a
2618structure, only <tt>uint</tt>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2619integer constants are allowed. When indexing into an array or pointer,
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2620<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
2621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2622<p>For example, let's consider a C code fragment and how it gets
2623compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2624
2625<pre>
2626 struct RT {
2627 char A;
2628 int B[10][20];
2629 char C;
2630 };
2631 struct ST {
2632 int X;
2633 double Y;
2634 struct RT Z;
2635 };
2636
2637 int *foo(struct ST *s) {
2638 return &amp;s[1].Z.B[5][13];
2639 }
2640</pre>
2641
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2642<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2643
2644<pre>
2645 %RT = type { sbyte, [10 x [20 x int]], sbyte }
2646 %ST = type { int, double, %RT }
2647
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2648 implementation
2649
2650 int* %foo(%ST* %s) {
2651 entry:
2652 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2653 ret int* %reg
2654 }
2655</pre>
2656
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2657<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2658
2659<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2660on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2661and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
2662<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2663types require <tt>uint</tt> <b>constants</b>.</p>
2664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2665<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2666type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
2667}</tt>' type, a structure. The second index indexes into the third element of
2668the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
2669sbyte }</tt>' type, another structure. The third index indexes into the second
2670element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
2671array. The two dimensions of the array are subscripted into, yielding an
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2672'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2673to this element, thus computing a value of '<tt>int*</tt>' type.</p>
2674
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2675<p>Note that it is perfectly legal to index partially through a
2676structure, returning a pointer to an inner element. Because of this,
2677the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2678
2679<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]2680 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2681 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
2682 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
2683 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
2684 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
2685 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
2686 ret int* %t5
2687 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2688</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2689
2690<p>Note that it is undefined to access an array out of bounds: array and
2691pointer indexes must always be within the defined bounds of the array type.
2692The one exception for this rules is zero length arrays. These arrays are
2693defined to be accessible as variable length arrays, which requires access
2694beyond the zero'th element.</p>
2695
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2696<p>The getelementptr instruction is often confusing. For some more insight
2697into how it works, see <a href="GetElementPtr.html">the getelementptr
2698FAQ</a>.</p>
2699
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2700<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2701
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2702<pre>
2703 <i>; yields [12 x ubyte]*:aptr</i>
2704 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
2705</pre>
2706
2707</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2708<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2709<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2710<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2711<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2712instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2713</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2714<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2715<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2716Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2717<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2718<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2719<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2720<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2721<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2722the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2723<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2724<p>The type of the incoming values are specified with the first type
2725field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2726as arguments, with one pair for each predecessor basic block of the
2727current block. Only values of <a href="#t_firstclass">first class</a>
2728type may be used as the value arguments to the PHI node. Only labels
2729may be used as the label arguments.</p>
2730<p>There must be no non-phi instructions between the start of a basic
2731block and the PHI instructions: i.e. PHI instructions must be first in
2732a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2733<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2734<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2735value specified by the parameter, depending on which basic block we
2736came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2737<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2738<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2739</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2740
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2741<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2742<div class="doc_subsubsection">
2743 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2744</div>
2745
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2746<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2747
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2748<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2749
2750<pre>
2751 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2752</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2753
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2754<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2755
2756<p>
2757The '<tt>cast</tt>' instruction is used as the primitive means to convert
2758integers to floating point, change data type sizes, and break type safety (by
2759casting pointers).
2760</p>
2761
2762
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2763<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2764
2765<p>
2766The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2767class value, and a type to cast it to, which must also be a <a
2768href="#t_firstclass">first class</a> type.
2769</p>
2770
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2771<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2772
2773<p>
2774This instruction follows the C rules for explicit casts when determining how the
2775data being cast must change to fit in its new container.
2776</p>
2777
2778<p>
2779When casting to bool, any value that would be considered true in the context of
2780a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2781all else are '<tt>false</tt>'.
2782</p>
2783
2784<p>
2785When extending an integral value from a type of one signness to another (for
2786example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2787<b>source</b> value is signed, and zero-extended if the source value is
2788unsigned. <tt>bool</tt> values are always zero extended into either zero or
2789one.
2790</p>
2791
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2792<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2793
2794<pre>
2795 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2796 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2797</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2798</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2799
2800<!-- _______________________________________________________________________ -->
2801<div class="doc_subsubsection">
2802 <a name="i_select">'<tt>select</tt>' Instruction</a>
2803</div>
2804
2805<div class="doc_text">
2806
2807<h5>Syntax:</h5>
2808
2809<pre>
2810 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2811</pre>
2812
2813<h5>Overview:</h5>
2814
2815<p>
2816The '<tt>select</tt>' instruction is used to choose one value based on a
2817condition, without branching.
2818</p>
2819
2820
2821<h5>Arguments:</h5>
2822
2823<p>
2824The '<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.
2825</p>
2826
2827<h5>Semantics:</h5>
2828
2829<p>
2830If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2831value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2832</p>
2833
2834<h5>Example:</h5>
2835
2836<pre>
2837 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2838</pre>
2839</div>
2840
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]2841
2842<!-- _______________________________________________________________________ -->
2843<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2844 <a name="i_call">'<tt>call</tt>' Instruction</a>
2845</div>
2846
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2847<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2848
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2849<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2850<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2851 &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]2852</pre>
2853
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2854<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2856<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2857
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2858<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2860<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2861
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2862<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2863 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2864 <p>The optional "tail" marker indicates whether the callee function accesses
2865 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2866 function call is eligible for tail call optimization. Note that calls may
2867 be marked "tail" even if they do not occur before a <a
2868 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2869 </li>
2870 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2871 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2872 convention</a> the call should use. If none is specified, the call defaults
2873 to using C calling conventions.
2874 </li>
2875 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2876 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2877 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2878 signature. This type can be omitted if the function is not varargs and
2879 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2880 </li>
2881 <li>
2882 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2883 be invoked. In most cases, this is a direct function invocation, but
2884 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2885 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2886 </li>
2887 <li>
2888 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2889 function signature argument types. All arguments must be of
2890 <a href="#t_firstclass">first class</a> type. If the function signature
2891 indicates the function accepts a variable number of arguments, the extra
2892 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2893 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2894</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2895
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2897
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2898<p>The '<tt>call</tt>' instruction is used to cause control flow to
2899transfer to a specified function, with its incoming arguments bound to
2900the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2901instruction in the called function, control flow continues with the
2902instruction after the function call, and the return value of the
2903function is bound to the result argument. This is a simpler case of
2904the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2905
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2906<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2907
2908<pre>
2909 %retval = call int %test(int %argc)
2910 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2911 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2912 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2913</pre>
2914
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2915</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2916
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2918<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]2919 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2920</div>
2921
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2922<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2923
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2924<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2925
2926<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2927 &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]2928</pre>
2929
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2930<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2931
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2932<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2933the "variable argument" area of a function call. It is used to implement the
2934<tt>va_arg</tt> macro in C.</p>
2935
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2936<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2937
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2938<p>This instruction takes a <tt>va_list*</tt> value and the type of
2939the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]2940increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2941actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2942
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2943<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2944
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2945<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
2946type from the specified <tt>va_list</tt> and causes the
2947<tt>va_list</tt> to point to the next argument. For more information,
2948see the variable argument handling <a href="#int_varargs">Intrinsic
2949Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2950
2951<p>It is legal for this instruction to be called in a function which does not
2952take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2953function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2954
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]2955<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2956href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2957argument.</p>
2958
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2959<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2960
2961<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2962
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2963</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2964
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2965<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2966<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2967<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2968
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2969<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2970
2971<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2972well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2973restrictions. Overall, these instructions represent an extension mechanism for
2974the LLVM language that does not require changing all of the transformations in
2975LLVM to add to the language (or the bytecode reader/writer, the parser,
2976etc...).</p>
2977
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2978<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
2979prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2980this. Intrinsic functions must always be external functions: you cannot define
2981the body of intrinsic functions. Intrinsic functions may only be used in call
2982or invoke instructions: it is illegal to take the address of an intrinsic
2983function. Additionally, because intrinsic functions are part of the LLVM
2984language, it is required that they all be documented here if any are added.</p>
2985
2986
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2987<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]2988href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2989</p>
2990
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2991</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2992
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2993<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2994<div class="doc_subsection">
2995 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2996</div>
2997
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2998<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2999
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3000<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3001 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3002intrinsic functions. These functions are related to the similarly
3003named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3004
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3005<p>All of these functions operate on arguments that use a
3006target-specific value type "<tt>va_list</tt>". The LLVM assembly
3007language reference manual does not define what this type is, so all
3008transformations should be prepared to handle intrinsics with any type
3009used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3010
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3011<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]3012instruction and the variable argument handling intrinsic functions are
3013used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3014
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3015<pre>
3016int %test(int %X, ...) {
3017 ; Initialize variable argument processing
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3018 %ap = alloca sbyte*
3019 call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3020
3021 ; Read a single integer argument
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3022 %tmp = va_arg sbyte** %ap, int
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3023
3024 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3025 %aq = alloca sbyte*
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3026 call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap)
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3027 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3028
3029 ; Stop processing of arguments.
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3030 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3031 ret int %tmp
3032}
3033</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3034</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3035
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3036<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3037<div class="doc_subsubsection">
3038 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3039</div>
3040
3041
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3042<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3043<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3044<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3045<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3046<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3047<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3048href="#i_va_arg">va_arg</a></tt>.</p>
3049
3050<h5>Arguments:</h5>
3051
3052<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3053
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3054<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3055
3056<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3057macro available in C. In a target-dependent way, it initializes the
3058<tt>va_list</tt> element the argument points to, so that the next call to
3059<tt>va_arg</tt> will produce the first variable argument passed to the function.
3060Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3061last argument of the function, the compiler can figure that out.</p>
3062
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3063</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3064
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3065<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3066<div class="doc_subsubsection">
3067 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3068</div>
3069
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3070<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3071<h5>Syntax:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3072<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3073<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3074<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3075which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3076or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3077<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3078<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3079<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3080<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3081macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3082Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3083 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3084with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3085</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3086
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3087<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3088<div class="doc_subsubsection">
3089 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3090</div>
3091
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3092<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3093
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3094<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3095
3096<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3097 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharthd0a4c622005-06-22 20:38:11 +0000[diff] [blame]3098 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3099</pre>
3100
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3101<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3102
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3103<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3104the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3105
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3106<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3107
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3108<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]3109The 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]3110
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3111
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3112<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3113
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3114<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3115available in C. In a target-dependent way, it copies the source
3116<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3117because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3118arbitrarily complex and require memory allocation, for example.</p>
3119
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3120</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3121
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3122<!-- ======================================================================= -->
3123<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3124 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3125</div>
3126
3127<div class="doc_text">
3128
3129<p>
3130LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3131Collection</a> requires the implementation and generation of these intrinsics.
3132These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3133stack</a>, as well as garbage collector implementations that require <a
3134href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3135Front-ends for type-safe garbage collected languages should generate these
3136intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3137href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3138</p>
3139</div>
3140
3141<!-- _______________________________________________________________________ -->
3142<div class="doc_subsubsection">
3143 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3144</div>
3145
3146<div class="doc_text">
3147
3148<h5>Syntax:</h5>
3149
3150<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3151 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3152</pre>
3153
3154<h5>Overview:</h5>
3155
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3156<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]3157the code generator, and allows some metadata to be associated with it.</p>
3158
3159<h5>Arguments:</h5>
3160
3161<p>The first argument specifies the address of a stack object that contains the
3162root pointer. The second pointer (which must be either a constant or a global
3163value address) contains the meta-data to be associated with the root.</p>
3164
3165<h5>Semantics:</h5>
3166
3167<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3168location. At compile-time, the code generator generates information to allow
3169the runtime to find the pointer at GC safe points.
3170</p>
3171
3172</div>
3173
3174
3175<!-- _______________________________________________________________________ -->
3176<div class="doc_subsubsection">
3177 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3178</div>
3179
3180<div class="doc_text">
3181
3182<h5>Syntax:</h5>
3183
3184<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3185 declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3186</pre>
3187
3188<h5>Overview:</h5>
3189
3190<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3191locations, allowing garbage collector implementations that require read
3192barriers.</p>
3193
3194<h5>Arguments:</h5>
3195
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3196<p>The second argument is the address to read from, which should be an address
3197allocated from the garbage collector. The first object is a pointer to the
3198start of the referenced object, if needed by the language runtime (otherwise
3199null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3200
3201<h5>Semantics:</h5>
3202
3203<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3204instruction, but may be replaced with substantially more complex code by the
3205garbage collector runtime, as needed.</p>
3206
3207</div>
3208
3209
3210<!-- _______________________________________________________________________ -->
3211<div class="doc_subsubsection">
3212 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3213</div>
3214
3215<div class="doc_text">
3216
3217<h5>Syntax:</h5>
3218
3219<pre>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3220 declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3221</pre>
3222
3223<h5>Overview:</h5>
3224
3225<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3226locations, allowing garbage collector implementations that require write
3227barriers (such as generational or reference counting collectors).</p>
3228
3229<h5>Arguments:</h5>
3230
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3231<p>The first argument is the reference to store, the second is the start of the
3232object to store it to, and the third is the address of the field of Obj to
3233store to. If the runtime does not require a pointer to the object, Obj may be
3234null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3235
3236<h5>Semantics:</h5>
3237
3238<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3239instruction, but may be replaced with substantially more complex code by the
3240garbage collector runtime, as needed.</p>
3241
3242</div>
3243
3244
3245
3246<!-- ======================================================================= -->
3247<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3248 <a name="int_codegen">Code Generator Intrinsics</a>
3249</div>
3250
3251<div class="doc_text">
3252<p>
3253These intrinsics are provided by LLVM to expose special features that may only
3254be implemented with code generator support.
3255</p>
3256
3257</div>
3258
3259<!-- _______________________________________________________________________ -->
3260<div class="doc_subsubsection">
3261 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3262</div>
3263
3264<div class="doc_text">
3265
3266<h5>Syntax:</h5>
3267<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3268 declare sbyte *%llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3269</pre>
3270
3271<h5>Overview:</h5>
3272
3273<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3274The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3275target-specific value indicating the return address of the current function
3276or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3277</p>
3278
3279<h5>Arguments:</h5>
3280
3281<p>
3282The argument to this intrinsic indicates which function to return the address
3283for. Zero indicates the calling function, one indicates its caller, etc. The
3284argument is <b>required</b> to be a constant integer value.
3285</p>
3286
3287<h5>Semantics:</h5>
3288
3289<p>
3290The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3291the return address of the specified call frame, or zero if it cannot be
3292identified. The value returned by this intrinsic is likely to be incorrect or 0
3293for arguments other than zero, so it should only be used for debugging purposes.
3294</p>
3295
3296<p>
3297Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3298aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3299source-language caller.
3300</p>
3301</div>
3302
3303
3304<!-- _______________________________________________________________________ -->
3305<div class="doc_subsubsection">
3306 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3307</div>
3308
3309<div class="doc_text">
3310
3311<h5>Syntax:</h5>
3312<pre>
Chris Lattnerfcf39d42006-01-13 01:20:27 +0000[diff] [blame]3313 declare sbyte *%llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3314</pre>
3315
3316<h5>Overview:</h5>
3317
3318<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3319The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3320target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3321</p>
3322
3323<h5>Arguments:</h5>
3324
3325<p>
3326The argument to this intrinsic indicates which function to return the frame
3327pointer for. Zero indicates the calling function, one indicates its caller,
3328etc. The argument is <b>required</b> to be a constant integer value.
3329</p>
3330
3331<h5>Semantics:</h5>
3332
3333<p>
3334The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3335the frame address of the specified call frame, or zero if it cannot be
3336identified. The value returned by this intrinsic is likely to be incorrect or 0
3337for arguments other than zero, so it should only be used for debugging purposes.
3338</p>
3339
3340<p>
3341Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3342aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3343source-language caller.
3344</p>
3345</div>
3346
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3347<!-- _______________________________________________________________________ -->
3348<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3349 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3350</div>
3351
3352<div class="doc_text">
3353
3354<h5>Syntax:</h5>
3355<pre>
3356 declare sbyte *%llvm.stacksave()
3357</pre>
3358
3359<h5>Overview:</h5>
3360
3361<p>
3362The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3363the function stack, for use with <a href="#i_stackrestore">
3364<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3365features like scoped automatic variable sized arrays in C99.
3366</p>
3367
3368<h5>Semantics:</h5>
3369
3370<p>
3371This intrinsic returns a opaque pointer value that can be passed to <a
3372href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3373<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3374<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3375state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3376practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3377that were allocated after the <tt>llvm.stacksave</tt> was executed.
3378</p>
3379
3380</div>
3381
3382<!-- _______________________________________________________________________ -->
3383<div class="doc_subsubsection">
3384 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3385</div>
3386
3387<div class="doc_text">
3388
3389<h5>Syntax:</h5>
3390<pre>
3391 declare void %llvm.stackrestore(sbyte* %ptr)
3392</pre>
3393
3394<h5>Overview:</h5>
3395
3396<p>
3397The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3398the function stack to the state it was in when the corresponding <a
3399href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3400useful for implementing language features like scoped automatic variable sized
3401arrays in C99.
3402</p>
3403
3404<h5>Semantics:</h5>
3405
3406<p>
3407See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3408</p>
3409
3410</div>
3411
3412
3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3415 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3416</div>
3417
3418<div class="doc_text">
3419
3420<h5>Syntax:</h5>
3421<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3422 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
3423 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3424</pre>
3425
3426<h5>Overview:</h5>
3427
3428
3429<p>
3430The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3431a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3432no
3433effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]3434characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3435</p>
3436
3437<h5>Arguments:</h5>
3438
3439<p>
3440<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3441determining if the fetch should be for a read (0) or write (1), and
3442<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]3443locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3444<tt>locality</tt> arguments must be constant integers.
3445</p>
3446
3447<h5>Semantics:</h5>
3448
3449<p>
3450This intrinsic does not modify the behavior of the program. In particular,
3451prefetches cannot trap and do not produce a value. On targets that support this
3452intrinsic, the prefetch can provide hints to the processor cache for better
3453performance.
3454</p>
3455
3456</div>
3457
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3458<!-- _______________________________________________________________________ -->
3459<div class="doc_subsubsection">
3460 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3461</div>
3462
3463<div class="doc_text">
3464
3465<h5>Syntax:</h5>
3466<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3467 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3468</pre>
3469
3470<h5>Overview:</h5>
3471
3472
3473<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3474The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3475(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3476code to simulators and other tools. The method is target specific, but it is
3477expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3478The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]3479after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]3480optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3481correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]3482</p>
3483
3484<h5>Arguments:</h5>
3485
3486<p>
3487<tt>id</tt> is a numerical id identifying the marker.
3488</p>
3489
3490<h5>Semantics:</h5>
3491
3492<p>
3493This intrinsic does not modify the behavior of the program. Backends that do not
3494support this intrinisic may ignore it.
3495</p>
3496
3497</div>
3498
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]3499<!-- _______________________________________________________________________ -->
3500<div class="doc_subsubsection">
3501 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
3502</div>
3503
3504<div class="doc_text">
3505
3506<h5>Syntax:</h5>
3507<pre>
3508 declare ulong %llvm.readcyclecounter( )
3509</pre>
3510
3511<h5>Overview:</h5>
3512
3513
3514<p>
3515The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
3516counter register (or similar low latency, high accuracy clocks) on those targets
3517that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
3518As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
3519should only be used for small timings.
3520</p>
3521
3522<h5>Semantics:</h5>
3523
3524<p>
3525When directly supported, reading the cycle counter should not modify any memory.
3526Implementations are allowed to either return a application specific value or a
3527system wide value. On backends without support, this is lowered to a constant 0.
3528</p>
3529
3530</div>
3531
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3532<!-- ======================================================================= -->
3533<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3534 <a name="int_libc">Standard C Library Intrinsics</a>
3535</div>
3536
3537<div class="doc_text">
3538<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3539LLVM provides intrinsics for a few important standard C library functions.
3540These intrinsics allow source-language front-ends to pass information about the
3541alignment of the pointer arguments to the code generator, providing opportunity
3542for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3543</p>
3544
3545</div>
3546
3547<!-- _______________________________________________________________________ -->
3548<div class="doc_subsubsection">
3549 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
3550</div>
3551
3552<div class="doc_text">
3553
3554<h5>Syntax:</h5>
3555<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3556 declare void %llvm.memcpy.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3557 uint &lt;len&gt;, uint &lt;align&gt;)
3558 declare void %llvm.memcpy.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3559 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3560</pre>
3561
3562<h5>Overview:</h5>
3563
3564<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3565The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3566location to the destination location.
3567</p>
3568
3569<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3570Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
3571intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3572</p>
3573
3574<h5>Arguments:</h5>
3575
3576<p>
3577The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3578the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3579specifying the number of bytes to copy, and the fourth argument is the alignment
3580of the source and destination locations.
3581</p>
3582
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3583<p>
3584If 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]3585the caller guarantees that both the source and destination pointers are aligned
3586to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3587</p>
3588
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3589<h5>Semantics:</h5>
3590
3591<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3592The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3593location to the destination location, which are not allowed to overlap. It
3594copies "len" bytes of memory over. If the argument is known to be aligned to
3595some boundary, this can be specified as the fourth argument, otherwise it should
3596be set to 0 or 1.
3597</p>
3598</div>
3599
3600
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3601<!-- _______________________________________________________________________ -->
3602<div class="doc_subsubsection">
3603 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3604</div>
3605
3606<div class="doc_text">
3607
3608<h5>Syntax:</h5>
3609<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3610 declare void %llvm.memmove.i32(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3611 uint &lt;len&gt;, uint &lt;align&gt;)
3612 declare void %llvm.memmove.i64(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3613 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3614</pre>
3615
3616<h5>Overview:</h5>
3617
3618<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3619The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
3620location to the destination location. It is similar to the
3621'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3622</p>
3623
3624<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3625Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
3626intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3627</p>
3628
3629<h5>Arguments:</h5>
3630
3631<p>
3632The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3633the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3634specifying the number of bytes to copy, and the fourth argument is the alignment
3635of the source and destination locations.
3636</p>
3637
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3638<p>
3639If 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]3640the caller guarantees that the source and destination pointers are aligned to
3641that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3642</p>
3643
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3644<h5>Semantics:</h5>
3645
3646<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3647The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3648location to the destination location, which may overlap. It
3649copies "len" bytes of memory over. If the argument is known to be aligned to
3650some boundary, this can be specified as the fourth argument, otherwise it should
3651be set to 0 or 1.
3652</p>
3653</div>
3654
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3655
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3656<!-- _______________________________________________________________________ -->
3657<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3658 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3659</div>
3660
3661<div class="doc_text">
3662
3663<h5>Syntax:</h5>
3664<pre>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3665 declare void %llvm.memset.i32(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3666 uint &lt;len&gt;, uint &lt;align&gt;)
3667 declare void %llvm.memset.i64(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3668 ulong &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3669</pre>
3670
3671<h5>Overview:</h5>
3672
3673<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3674The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3675byte value.
3676</p>
3677
3678<p>
3679Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3680does not return a value, and takes an extra alignment argument.
3681</p>
3682
3683<h5>Arguments:</h5>
3684
3685<p>
3686The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3687byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3688argument specifying the number of bytes to fill, and the fourth argument is the
3689known alignment of destination location.
3690</p>
3691
3692<p>
3693If 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]3694the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3695</p>
3696
3697<h5>Semantics:</h5>
3698
3699<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]3700The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
3701the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3702destination location. If the argument is known to be aligned to some boundary,
3703this can be specified as the fourth argument, otherwise it should be set to 0 or
37041.
3705</p>
3706</div>
3707
3708
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3709<!-- _______________________________________________________________________ -->
3710<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3711 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3712</div>
3713
3714<div class="doc_text">
3715
3716<h5>Syntax:</h5>
3717<pre>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3718 declare bool %llvm.isunordered.f32(float Val1, float Val2)
3719 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3720</pre>
3721
3722<h5>Overview:</h5>
3723
3724<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3725The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3726specified floating point values is a NAN.
3727</p>
3728
3729<h5>Arguments:</h5>
3730
3731<p>
3732The arguments are floating point numbers of the same type.
3733</p>
3734
3735<h5>Semantics:</h5>
3736
3737<p>
3738If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3739false.
3740</p>
3741</div>
3742
3743
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3744<!-- _______________________________________________________________________ -->
3745<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3746 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3747</div>
3748
3749<div class="doc_text">
3750
3751<h5>Syntax:</h5>
3752<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]3753 declare float %llvm.sqrt.f32(float %Val)
3754 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3755</pre>
3756
3757<h5>Overview:</h5>
3758
3759<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3760The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]3761returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
3762<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
3763negative numbers (which allows for better optimization).
3764</p>
3765
3766<h5>Arguments:</h5>
3767
3768<p>
3769The argument and return value are floating point numbers of the same type.
3770</p>
3771
3772<h5>Semantics:</h5>
3773
3774<p>
3775This function returns the sqrt of the specified operand if it is a positive
3776floating point number.
3777</p>
3778</div>
3779
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]3780<!-- _______________________________________________________________________ -->
3781<div class="doc_subsubsection">
3782 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
3783</div>
3784
3785<div class="doc_text">
3786
3787<h5>Syntax:</h5>
3788<pre>
3789 declare float %llvm.powi.f32(float %Val, int %power)
3790 declare double %llvm.powi.f64(double %Val, int %power)
3791</pre>
3792
3793<h5>Overview:</h5>
3794
3795<p>
3796The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
3797specified (positive or negative) power. The order of evaluation of
3798multiplications is not defined.
3799</p>
3800
3801<h5>Arguments:</h5>
3802
3803<p>
3804The second argument is an integer power, and the first is a value to raise to
3805that power.
3806</p>
3807
3808<h5>Semantics:</h5>
3809
3810<p>
3811This function returns the first value raised to the second power with an
3812unspecified sequence of rounding operations.</p>
3813</div>
3814
3815
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3816<!-- ======================================================================= -->
3817<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3818 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3819</div>
3820
3821<div class="doc_text">
3822<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3823LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3824These allow efficient code generation for some algorithms.
3825</p>
3826
3827</div>
3828
3829<!-- _______________________________________________________________________ -->
3830<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3831 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
3832</div>
3833
3834<div class="doc_text">
3835
3836<h5>Syntax:</h5>
3837<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3838 declare ushort %llvm.bswap.i16(ushort &lt;id&gt;)
3839 declare uint %llvm.bswap.i32(uint &lt;id&gt;)
3840 declare ulong %llvm.bswap.i64(ulong &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3841</pre>
3842
3843<h5>Overview:</h5>
3844
3845<p>
3846The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
384764 bit quantity. These are useful for performing operations on data that is not
3848in the target's native byte order.
3849</p>
3850
3851<h5>Semantics:</h5>
3852
3853<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3854The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low
3855byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3856returns a uint value that has the four bytes of the input uint swapped, so that
3857if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3858bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]3859to 64 bits.
3860</p>
3861
3862</div>
3863
3864<!-- _______________________________________________________________________ -->
3865<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3866 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3867</div>
3868
3869<div class="doc_text">
3870
3871<h5>Syntax:</h5>
3872<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3873 declare ubyte %llvm.ctpop.i8 (ubyte &lt;src&gt;)
3874 declare ushort %llvm.ctpop.i16(ushort &lt;src&gt;)
3875 declare uint %llvm.ctpop.i32(uint &lt;src&gt;)
3876 declare ulong %llvm.ctpop.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3877</pre>
3878
3879<h5>Overview:</h5>
3880
3881<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3882The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
3883value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3884</p>
3885
3886<h5>Arguments:</h5>
3887
3888<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3889The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3890unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3891</p>
3892
3893<h5>Semantics:</h5>
3894
3895<p>
3896The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3897</p>
3898</div>
3899
3900<!-- _______________________________________________________________________ -->
3901<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3902 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3903</div>
3904
3905<div class="doc_text">
3906
3907<h5>Syntax:</h5>
3908<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3909 declare ubyte %llvm.ctlz.i8 (ubyte &lt;src&gt;)
3910 declare ushort %llvm.ctlz.i16(ushort &lt;src&gt;)
3911 declare uint %llvm.ctlz.i32(uint &lt;src&gt;)
3912 declare ulong %llvm.ctlz.i64(ulong &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3913</pre>
3914
3915<h5>Overview:</h5>
3916
3917<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3918The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
3919leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3920</p>
3921
3922<h5>Arguments:</h5>
3923
3924<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]3925The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3926unsigned integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3927</p>
3928
3929<h5>Semantics:</h5>
3930
3931<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3932The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
3933in a variable. If the src == 0 then the result is the size in bits of the type
Chris Lattner99d3c272006-04-21 21:37:40 +0000[diff] [blame]3934of src. For example, <tt>llvm.ctlz(int 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3935</p>
3936</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3937
3938
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3939
3940<!-- _______________________________________________________________________ -->
3941<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]3942 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3943</div>
3944
3945<div class="doc_text">
3946
3947<h5>Syntax:</h5>
3948<pre>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3949 declare ubyte %llvm.cttz.i8 (ubyte &lt;src&gt;)
3950 declare ushort %llvm.cttz.i16(ushort &lt;src&gt;)
3951 declare uint %llvm.cttz.i32(uint &lt;src&gt;)
3952 declare ulong %llvm.cttz.i64(ulong &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3953</pre>
3954
3955<h5>Overview:</h5>
3956
3957<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]3958The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
3959trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3960</p>
3961
3962<h5>Arguments:</h5>
3963
3964<p>
3965The only argument is the value to be counted. The argument may be of any
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]3966unsigned integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]3967</p>
3968
3969<h5>Semantics:</h5>
3970
3971<p>
3972The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
3973in a variable. If the src == 0 then the result is the size in bits of the type
3974of src. For example, <tt>llvm.cttz(2) = 1</tt>.
3975</p>
3976</div>
3977
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3978<!-- ======================================================================= -->
3979<div class="doc_subsection">
3980 <a name="int_debugger">Debugger Intrinsics</a>
3981</div>
3982
3983<div class="doc_text">
3984<p>
3985The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3986are described in the <a
3987href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3988Debugging</a> document.
3989</p>
3990</div>
3991
3992
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3993<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3994<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3995<address>
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3999 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4000
4001 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4002 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4003 Last modified: $Date$
4004</address>
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