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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / de151948393534b6f3ed9c2540d80256605a4103 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame^]29 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]30 </ol>
31 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]32 <li><a href="#typesystem">Type System</a>
33 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]34 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]37 </ol>
38 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]39 <li><a href="#t_derived">Derived Types</a>
40 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]42 <li><a href="#t_function">Function Type</a></li>
43 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]44 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]45 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]46 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]47 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]48 </ol>
49 </li>
50 </ol>
51 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]52 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]53 <ol>
54 <li><a href="#simpleconstants">Simple Constants</a>
55 <li><a href="#aggregateconstants">Aggregate Constants</a>
56 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
57 <li><a href="#undefvalues">Undefined Values</a>
58 <li><a href="#constantexprs">Constant Expressions</a>
59 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]60 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]61 <li><a href="#othervalues">Other Values</a>
62 <ol>
63 <li><a href="#inlineasm">Inline Assembler Expressions</a>
64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#instref">Instruction Reference</a>
67 <ol>
68 <li><a href="#terminators">Terminator Instructions</a>
69 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]70 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
71 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]72 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
73 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]74 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]75 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 </ol>
77 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]78 <li><a href="#binaryops">Binary Operations</a>
79 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
81 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
82 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]83 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
84 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
85 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]86 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
87 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
88 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]89 </ol>
90 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]91 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
92 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]93 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
94 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
95 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]96 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]98 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </ol>
100 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]101 <li><a href="#vectorops">Vector Operations</a>
102 <ol>
103 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
104 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
105 <li><a href="#i_shufflevector">'<tt>shufflevector</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>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]118 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]119 <ol>
120 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
121 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]125 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
126 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
127 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]129 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
130 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]131 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]132 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]133 <li><a href="#otherops">Other Operations</a>
134 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]135 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
136 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]138 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]140 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]143 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]145 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
148 <ol>
149 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
151 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
152 </ol>
153 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]154 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
155 <ol>
156 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
158 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
159 </ol>
160 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]161 <li><a href="#int_codegen">Code Generator Intrinsics</a>
162 <ol>
163 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
164 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]165 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
166 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]167 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]168 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]169 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]170 </ol>
171 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]172 <li><a href="#int_libc">Standard C Library Intrinsics</a>
173 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]174 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
176 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]177 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]178 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]179 </ol>
180 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]181 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]182 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]183 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]184 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]187 </ol>
188 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]189 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]193
194<div class="doc_author">
195 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
196 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]197</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]200<div class="doc_section"> <a name="abstract">Abstract </a></div>
201<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]202
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]203<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]204<p>This document is a reference manual for the LLVM assembly language.
205LLVM is an SSA based representation that provides type safety,
206low-level operations, flexibility, and the capability of representing
207'all' high-level languages cleanly. It is the common code
208representation used throughout all phases of the LLVM compilation
209strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]210</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]212<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213<div class="doc_section"> <a name="introduction">Introduction</a> </div>
214<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]216<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]218<p>The LLVM code representation is designed to be used in three
219different forms: as an in-memory compiler IR, as an on-disk bytecode
220representation (suitable for fast loading by a Just-In-Time compiler),
221and as a human readable assembly language representation. This allows
222LLVM to provide a powerful intermediate representation for efficient
223compiler transformations and analysis, while providing a natural means
224to debug and visualize the transformations. The three different forms
225of LLVM are all equivalent. This document describes the human readable
226representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]227
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]228<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]229while being expressive, typed, and extensible at the same time. It
230aims to be a "universal IR" of sorts, by being at a low enough level
231that high-level ideas may be cleanly mapped to it (similar to how
232microprocessors are "universal IR's", allowing many source languages to
233be mapped to them). By providing type information, LLVM can be used as
234the target of optimizations: for example, through pointer analysis, it
235can be proven that a C automatic variable is never accessed outside of
236the current function... allowing it to be promoted to a simple SSA
237value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]239</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]241<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]242<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]246<p>It is important to note that this document describes 'well formed'
247LLVM assembly language. There is a difference between what the parser
248accepts and what is considered 'well formed'. For example, the
249following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]250
251<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]252 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]253</pre>
254
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]255<p>...because the definition of <tt>%x</tt> does not dominate all of
256its uses. The LLVM infrastructure provides a verification pass that may
257be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]258automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]259the optimizer before it outputs bytecode. The violations pointed out
260by the verifier pass indicate bugs in transformation passes or input to
261the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]263<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]264
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]265<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]266<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]267<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]268
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]269<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]270
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]271<p>LLVM uses three different forms of identifiers, for different
272purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]273
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]274<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]275 <li>Named values are represented as a string of characters with a '%' prefix.
276 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
277 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
278 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]279 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]280 in a name.</li>
281
282 <li>Unnamed values are represented as an unsigned numeric value with a '%'
283 prefix. For example, %12, %2, %44.</li>
284
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]285 <li>Constants, which are described in a <a href="#constants">section about
286 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]287</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]288
289<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
290don't need to worry about name clashes with reserved words, and the set of
291reserved words may be expanded in the future without penalty. Additionally,
292unnamed identifiers allow a compiler to quickly come up with a temporary
293variable without having to avoid symbol table conflicts.</p>
294
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]295<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]296languages. There are keywords for different opcodes
297('<tt><a href="#i_add">add</a></tt>',
298 '<tt><a href="#i_bitcast">bitcast</a></tt>',
299 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]300href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]301and others. These reserved words cannot conflict with variable names, because
302none of them start with a '%' character.</p>
303
304<p>Here is an example of LLVM code to multiply the integer variable
305'<tt>%X</tt>' by 8:</p>
306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]307<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]308
309<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]310 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]311</pre>
312
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]313<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]314
315<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]316 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]317</pre>
318
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]319<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]320
321<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]322 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
323 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
324 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]325</pre>
326
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]327<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
328important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]329
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]330<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]331
332 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
333 line.</li>
334
335 <li>Unnamed temporaries are created when the result of a computation is not
336 assigned to a named value.</li>
337
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]338 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]339
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]340</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]341
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]342<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]343demonstrating instructions, we will follow an instruction with a comment that
344defines the type and name of value produced. Comments are shown in italic
345text.</p>
346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]348
349<!-- *********************************************************************** -->
350<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
351<!-- *********************************************************************** -->
352
353<!-- ======================================================================= -->
354<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
355</div>
356
357<div class="doc_text">
358
359<p>LLVM programs are composed of "Module"s, each of which is a
360translation unit of the input programs. Each module consists of
361functions, global variables, and symbol table entries. Modules may be
362combined together with the LLVM linker, which merges function (and
363global variable) definitions, resolves forward declarations, and merges
364symbol table entries. Here is an example of the "hello world" module:</p>
365
366<pre><i>; Declare the string constant as a global constant...</i>
367<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]368 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]369
370<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]371<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]372
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]373<i>; Global variable / Function body section separator</i>
374implementation
375
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]376<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]377define i32 %main() { <i>; i32()* </i>
378 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]379 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]380 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]381
382 <i>; Call puts function to write out the string to stdout...</i>
383 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]384 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]385 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]386 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]387
388<p>This example is made up of a <a href="#globalvars">global variable</a>
389named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
390function, and a <a href="#functionstructure">function definition</a>
391for "<tt>main</tt>".</p>
392
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]393<p>In general, a module is made up of a list of global values,
394where both functions and global variables are global values. Global values are
395represented by a pointer to a memory location (in this case, a pointer to an
396array of char, and a pointer to a function), and have one of the following <a
397href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]398
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]399<p>Due to a limitation in the current LLVM assembly parser (it is limited by
400one-token lookahead), modules are split into two pieces by the "implementation"
401keyword. Global variable prototypes and definitions must occur before the
402keyword, and function definitions must occur after it. Function prototypes may
403occur either before or after it. In the future, the implementation keyword may
404become a noop, if the parser gets smarter.</p>
405
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]406</div>
407
408<!-- ======================================================================= -->
409<div class="doc_subsection">
410 <a name="linkage">Linkage Types</a>
411</div>
412
413<div class="doc_text">
414
415<p>
416All Global Variables and Functions have one of the following types of linkage:
417</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]418
419<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]420
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]421 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]422
423 <dd>Global values with internal linkage are only directly accessible by
424 objects in the current module. In particular, linking code into a module with
425 an internal global value may cause the internal to be renamed as necessary to
426 avoid collisions. Because the symbol is internal to the module, all
427 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]428 '<tt>static</tt>' keyword in C.
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_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]433 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
434 the same name when linkage occurs. This is typically used to implement
435 inline functions, templates, or other code which must be generated in each
436 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
437 allowed to be discarded.
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_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]441
442 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
443 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]444 used for globals that may be emitted in multiple translation units, but that
445 are not guaranteed to be emitted into every translation unit that uses them.
446 One example of this are common globals in C, such as "<tt>int X;</tt>" at
447 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]448 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]450 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
452 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
453 pointer to array type. When two global variables with appending linkage are
454 linked together, the two global arrays are appended together. This is the
455 LLVM, typesafe, equivalent of having the system linker append together
456 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]457 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]459 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
460 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
461 until linked, if not linked, the symbol becomes null instead of being an
462 undefined reference.
463 </dd>
464</dl>
465
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]466 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
468 <dd>If none of the above identifiers are used, the global is externally
469 visible, meaning that it participates in linkage and can be used to resolve
470 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]471 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]472
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]473 <p>
474 The next two types of linkage are targeted for Microsoft Windows platform
475 only. They are designed to support importing (exporting) symbols from (to)
476 DLLs.
477 </p>
478
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]479 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]480 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
481
482 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
483 or variable via a global pointer to a pointer that is set up by the DLL
484 exporting the symbol. On Microsoft Windows targets, the pointer name is
485 formed by combining <code>_imp__</code> and the function or variable name.
486 </dd>
487
488 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
489
490 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
491 pointer to a pointer in a DLL, so that it can be referenced with the
492 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
493 name is formed by combining <code>_imp__</code> and the function or variable
494 name.
495 </dd>
496
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]497</dl>
498
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]499<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
501variable and was linked with this one, one of the two would be renamed,
502preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
503external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]504outside of the current module.</p>
505<p>It is illegal for a function <i>declaration</i>
506to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]507or <tt>extern_weak</tt>.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]508
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]513 <a name="callingconv">Calling Conventions</a>
514</div>
515
516<div class="doc_text">
517
518<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
519and <a href="#i_invoke">invokes</a> can all have an optional calling convention
520specified for the call. The calling convention of any pair of dynamic
521caller/callee must match, or the behavior of the program is undefined. The
522following calling conventions are supported by LLVM, and more may be added in
523the future:</p>
524
525<dl>
526 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
527
528 <dd>This calling convention (the default if no other calling convention is
529 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]530 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]531 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]532 </dd>
533
534 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
535
536 <dd>This calling convention attempts to make calls as fast as possible
537 (e.g. by passing things in registers). This calling convention allows the
538 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]539 without having to conform to an externally specified ABI. Implementations of
540 this convention should allow arbitrary tail call optimization to be supported.
541 This calling convention does not support varargs and requires the prototype of
542 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]543 </dd>
544
545 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
546
547 <dd>This calling convention attempts to make code in the caller as efficient
548 as possible under the assumption that the call is not commonly executed. As
549 such, these calls often preserve all registers so that the call does not break
550 any live ranges in the caller side. This calling convention does not support
551 varargs and requires the prototype of all callees to exactly match the
552 prototype of the function definition.
553 </dd>
554
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]555 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]556
557 <dd>Any calling convention may be specified by number, allowing
558 target-specific calling conventions to be used. Target specific calling
559 conventions start at 64.
560 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]561</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]562
563<p>More calling conventions can be added/defined on an as-needed basis, to
564support pascal conventions or any other well-known target-independent
565convention.</p>
566
567</div>
568
569<!-- ======================================================================= -->
570<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]571 <a name="visibility">Visibility Styles</a>
572</div>
573
574<div class="doc_text">
575
576<p>
577All Global Variables and Functions have one of the following visibility styles:
578</p>
579
580<dl>
581 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
582
583 <dd>On ELF, default visibility means that the declaration is visible to other
584 modules and, in shared libraries, means that the declared entity may be
585 overridden. On Darwin, default visibility means that the declaration is
586 visible to other modules. Default visibility corresponds to "external
587 linkage" in the language.
588 </dd>
589
590 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
591
592 <dd>Two declarations of an object with hidden visibility refer to the same
593 object if they are in the same shared object. Usually, hidden visibility
594 indicates that the symbol will not be placed into the dynamic symbol table,
595 so no other module (executable or shared library) can reference it
596 directly.
597 </dd>
598
599</dl>
600
601</div>
602
603<!-- ======================================================================= -->
604<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]605 <a name="globalvars">Global Variables</a>
606</div>
607
608<div class="doc_text">
609
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]610<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]611instead of run-time. Global variables may optionally be initialized, may have
612an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]613have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]614variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]615contents of the variable will <b>never</b> be modified (enabling better
616optimization, allowing the global data to be placed in the read-only section of
617an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]618cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]619
620<p>
621LLVM explicitly allows <em>declarations</em> of global variables to be marked
622constant, even if the final definition of the global is not. This capability
623can be used to enable slightly better optimization of the program, but requires
624the language definition to guarantee that optimizations based on the
625'constantness' are valid for the translation units that do not include the
626definition.
627</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]628
629<p>As SSA values, global variables define pointer values that are in
630scope (i.e. they dominate) all basic blocks in the program. Global
631variables always define a pointer to their "content" type because they
632describe a region of memory, and all memory objects in LLVM are
633accessed through pointers.</p>
634
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]635<p>LLVM allows an explicit section to be specified for globals. If the target
636supports it, it will emit globals 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 global. If not present, or if
639the alignment is set to zero, the alignment of the global is set by the target
640to whatever it feels convenient. If an explicit alignment is specified, the
641global is forced to have at least that much alignment. All alignments must be
642a power of 2.</p>
643
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]644<p>For example, the following defines a global with an initializer, section,
645 and alignment:</p>
646
647<pre>
648 %G = constant float 1.0, section "foo", align 4
649</pre>
650
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]651</div>
652
653
654<!-- ======================================================================= -->
655<div class="doc_subsection">
656 <a name="functionstructure">Functions</a>
657</div>
658
659<div class="doc_text">
660
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]661<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
662an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]663<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]664<a href="#callingconv">calling convention</a>, a return type, an optional
665<a href="#paramattrs">parameter attribute</a> for the return type, a function
666name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]667<a href="#paramattrs">parameter attributes</a>), an optional section, an
668optional alignment, an opening curly brace, a list of basic blocks, and a
669closing curly brace.
670
671LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
672optional <a href="#linkage">linkage type</a>, an optional
673<a href="#visibility">visibility style</a>, an optional
674<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]675<a href="#paramattrs">parameter attribute</a> for the return type, a function
676name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]677
678<p>A function definition contains a list of basic blocks, forming the CFG for
679the function. Each basic block may optionally start with a label (giving the
680basic block a symbol table entry), contains a list of instructions, and ends
681with a <a href="#terminators">terminator</a> instruction (such as a branch or
682function return).</p>
683
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]684<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]685executed on entrance to the function, and it is not allowed to have predecessor
686basic blocks (i.e. there can not be any branches to the entry block of a
687function). Because the block can have no predecessors, it also cannot have any
688<a href="#i_phi">PHI nodes</a>.</p>
689
690<p>LLVM functions are identified by their name and type signature. Hence, two
691functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]692considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]693appropriately.</p>
694
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]695<p>LLVM allows an explicit section to be specified for functions. If the target
696supports it, it will emit functions to the section specified.</p>
697
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]698<p>An explicit alignment may be specified for a function. If not present, or if
699the alignment is set to zero, the alignment of the function is set by the target
700to whatever it feels convenient. If an explicit alignment is specified, the
701function is forced to have at least that much alignment. All alignments must be
702a power of 2.</p>
703
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]704</div>
705
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]706<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]707<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
708<div class="doc_text">
709 <p>The return type and each parameter of a function type may have a set of
710 <i>parameter attributes</i> associated with them. Parameter attributes are
711 used to communicate additional information about the result or parameters of
712 a function. Parameter attributes are considered to be part of the function
713 type so two functions types that differ only by the parameter attributes
714 are different function types.</p>
715
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]716 <p>Parameter attributes are simple keywords that follow the type specified. If
717 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]718 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]719 %someFunc = i16 (i8 sext %someParam) zext
720 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]721 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]722 a different attribute (sext in the first one, zext in the second). Also note
723 that the attribute for the function result (zext) comes immediately after the
724 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]725
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]726 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]727 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]728 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]729 <dd>This indicates that the parameter should be zero extended just before
730 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]731 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]732 <dd>This indicates that the parameter should be sign extended just before
733 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]734 <dt><tt>inreg</tt></dt>
735 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]736 possible) during assembling function call. Support for this attribute is
737 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]738 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]739 <dd>This indicates that the parameter specifies the address of a structure
740 that is the return value of the function in the source program.
741 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]742 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]743
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]744</div>
745
746<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]747<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]748 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]749</div>
750
751<div class="doc_text">
752<p>
753Modules may contain "module-level inline asm" blocks, which corresponds to the
754GCC "file scope inline asm" blocks. These blocks are internally concatenated by
755LLVM and treated as a single unit, but may be separated in the .ll file if
756desired. The syntax is very simple:
757</p>
758
759<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]760 module asm "inline asm code goes here"
761 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]762</pre></div>
763
764<p>The strings can contain any character by escaping non-printable characters.
765 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
766 for the number.
767</p>
768
769<p>
770 The inline asm code is simply printed to the machine code .s file when
771 assembly code is generated.
772</p>
773</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]774
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame^]775<!-- ======================================================================= -->
776<div class="doc_subsection">
777 <a name="datalayout">Data Layout</a>
778</div>
779
780<div class="doc_text">
781<p>A module may specify a target specific data layout string that specifies how
782data is to be laid out in memory. The syntax for the data layout is simply:<br/>
783<pre> target datalayout = "<i>layout specification</i>"
784</pre>
785The <i>layout specification</i> consists of a list of specifications separated
786by the minus sign character ('-'). Each specification starts with a letter
787and may include other information after the letter to define some aspect of the
788data layout. The specifications accepted are as follows: </p>
789<dl>
790 <dt><tt>E</tt></dt>
791 <dd>Specifies that the target lays out data in big-endian form. That is, the
792 bits with the most significance have the lowest address location.</dd>
793 <dt><tt>e</tt></dt>
794 <dd>Specifies that hte target lays out data in little-endian form. That is,
795 the bits with the least significance have the lowest address location.</dd>
796 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
797 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
798 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
799 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
800 too.</dd>
801 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
802 <dd>This specifies the alignment for an integer type of a given bit
803 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
804 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
805 <dd>This specifies the alignment for a vector type of a given bit
806 <i>size</i>.</dd>
807 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
808 <dd>This specifies the alignment for a floating point type of a given bit
809 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
810 (double).</dd>
811 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
812 <dd>This specifies the alignment for an aggregate type of a given bit
813 <i>size</i>.</dd>
814</dl>
815<p>When constructing the data layout for a given target, LLVM starts with a
816default set of specifications which are then (possibly) overriden by the
817specifications in the <tt>datalayout</tt> keyword. The default specifications
818are given in this list:</p>
819<ul>
820 <li><tt>E</tt> - big endian</li>
821 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
822 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
823 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
824 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
825 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
826 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
827 alignment of 64-bits</li>
828 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
829 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
830 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
831 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
832 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
833</ul>
834<p>When llvm is determining the alignment for a given type, it uses the
835following rules:
836<ol>
837 <li>If the type sought is an exact match for one of the specifications, that
838 specification is used.</li>
839 <li>If no match is found, and the type sought is an integer type, then the
840 smallest integer type that is larger than the bitwidth of the sought type is
841 used. If none of the specifications are larger than the bitwidth then the the
842 largest integer type is used. For example, given the default specifications
843 above, the i7 type will use the alignment of i8 (next largest) while both
844 i65 and i256 will use the alignment of i64 (largest specified).</li>
845 <li>If no match is found, and the type sought is a vector type, then the
846 largest vector type that is smaller than the sought vector type will be used
847 as a fall back. This happens because <128 x double> can be implemented in
848 terms of 64 <2 x double>, for example.</li>
849</ol>
850</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]851
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]852<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]853<div class="doc_section"> <a name="typesystem">Type System</a> </div>
854<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]855
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]856<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]857
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]858<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]859intermediate representation. Being typed enables a number of
860optimizations to be performed on the IR directly, without having to do
861extra analyses on the side before the transformation. A strong type
862system makes it easier to read the generated code and enables novel
863analyses and transformations that are not feasible to perform on normal
864three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]865
866</div>
867
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]868<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]869<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]870<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]871<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]872system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]873
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]874<table class="layout">
875 <tr class="layout">
876 <td class="left">
877 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]878 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]879 <tr><th>Type</th><th>Description</th></tr>
880 <tr><td><tt>void</tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]881 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
882 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]883 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]884 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]885 </tbody>
886 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]887 </td>
888 <td class="right">
889 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]890 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]891 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]892 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]893 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
894 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]895 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]896 </tbody>
897 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]898 </td>
899 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]900</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]901</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]902
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]903<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]904<div class="doc_subsubsection"> <a name="t_classifications">Type
905Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]906<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]907<p>These different primitive types fall into a few useful
908classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]909
910<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]911 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]912 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]913 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]914 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]915 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]916 </tr>
917 <tr>
918 <td><a name="t_floating">floating point</a></td>
919 <td><tt>float, double</tt></td>
920 </tr>
921 <tr>
922 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]923 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]924 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]925 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]926 </tr>
927 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]928</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]929
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]930<p>The <a href="#t_firstclass">first class</a> types are perhaps the
931most important. Values of these types are the only ones which can be
932produced by instructions, passed as arguments, or used as operands to
933instructions. This means that all structures and arrays must be
934manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]935</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]936
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]937<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]938<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]939
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]940<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]941
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]942<p>The real power in LLVM comes from the derived types in the system.
943This is what allows a programmer to represent arrays, functions,
944pointers, and other useful types. Note that these derived types may be
945recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]946
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]947</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]948
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]949<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]950<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]951
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]952<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]953
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]954<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]955
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]956<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]957sequentially in memory. The array type requires a size (number of
958elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]959
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]960<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]961
962<pre>
963 [&lt;# elements&gt; x &lt;elementtype&gt;]
964</pre>
965
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]966<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]967be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]968
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]969<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]970<table class="layout">
971 <tr class="layout">
972 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]973 <tt>[40 x i32 ]</tt><br/>
974 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]975 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]976 </td>
977 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]978 Array of 40 32-bit integer values.<br/>
979 Array of 41 32-bit integer values.<br/>
980 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]981 </td>
982 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]983</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]984<p>Here are some examples of multidimensional arrays:</p>
985<table class="layout">
986 <tr class="layout">
987 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]988 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]989 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]990 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]991 </td>
992 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]993 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]994 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]995 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]996 </td>
997 </tr>
998</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]999
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1000<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1001length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1002LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1003As a special case, however, zero length arrays are recognized to be variable
1004length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1005type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1006
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1007</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1008
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1009<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1010<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1011<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1012<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1013<p>The function type can be thought of as a function signature. It
1014consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1015Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1016(which are structures of pointers to functions), for indirect function
1017calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1018<p>
1019The return type of a function type cannot be an aggregate type.
1020</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1021<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1022<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1023<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]1024specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1025which indicates that the function takes a variable number of arguments.
1026Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1027 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1028<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1029<table class="layout">
1030 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1031 <td class="left"><tt>i32 (i32)</tt></td>
1032 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1033 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1034 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1035 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1036 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1037 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1038 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1039 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1040 <tt>float</tt>.
1041 </td>
1042 </tr><tr class="layout">
1043 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1044 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1045 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1046 which returns an integer. This is the signature for <tt>printf</tt> in
1047 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1048 </td>
1049 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1050</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1051
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1052</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1053<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1054<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1055<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1056<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1057<p>The structure type is used to represent a collection of data members
1058together in memory. The packing of the field types is defined to match
1059the ABI of the underlying processor. The elements of a structure may
1060be any type that has a size.</p>
1061<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1062and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1063field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1064instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1065<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1066<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1067<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1068<table class="layout">
1069 <tr class="layout">
1070 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1071 <tt>{ i32, i32, i32 }</tt><br/>
1072 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1073 </td>
1074 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1075 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1076 A pair, where the first element is a <tt>float</tt> and the second element
1077 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1078 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1079 </td>
1080 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1081</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1082</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1083
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1084<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1085<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1086</div>
1087<div class="doc_text">
1088<h5>Overview:</h5>
1089<p>The packed structure type is used to represent a collection of data members
1090together in memory. There is no padding between fields. Further, the alignment
1091of a packed structure is 1 byte. The elements of a packed structure may
1092be any type that has a size.</p>
1093<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1094and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1095field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1096instruction.</p>
1097<h5>Syntax:</h5>
1098<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1099<h5>Examples:</h5>
1100<table class="layout">
1101 <tr class="layout">
1102 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1103 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1104 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1105 </td>
1106 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1107 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1108 A pair, where the first element is a <tt>float</tt> and the second element
1109 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1110 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1111 </td>
1112 </tr>
1113</table>
1114</div>
1115
1116<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1117<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1118<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1119<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1120<p>As in many languages, the pointer type represents a pointer or
1121reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1122<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1123<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1124<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1125<table class="layout">
1126 <tr class="layout">
1127 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1128 <tt>[4x i32]*</tt><br/>
1129 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1130 </td>
1131 <td class="left">
1132 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1133 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1134 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1135 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1136 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1137 </td>
1138 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1139</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1140</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1141
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1142<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1143<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1144<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1145
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1146<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1147
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1148<p>A vector type is a simple derived type that represents a vector
1149of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1150are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1151A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1152elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1153of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1154considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1155
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1156<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1157
1158<pre>
1159 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1160</pre>
1161
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1162<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1163be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1164
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1165<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1166
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1167<table class="layout">
1168 <tr class="layout">
1169 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1170 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1171 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1172 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1173 </td>
1174 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1175 Vector of 4 32-bit integer values.<br/>
1176 Vector of 8 floating-point values.<br/>
1177 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1178 </td>
1179 </tr>
1180</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1181</div>
1182
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1183<!-- _______________________________________________________________________ -->
1184<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1185<div class="doc_text">
1186
1187<h5>Overview:</h5>
1188
1189<p>Opaque types are used to represent unknown types in the system. This
1190corresponds (for example) to the C notion of a foward declared structure type.
1191In LLVM, opaque types can eventually be resolved to any type (not just a
1192structure type).</p>
1193
1194<h5>Syntax:</h5>
1195
1196<pre>
1197 opaque
1198</pre>
1199
1200<h5>Examples:</h5>
1201
1202<table class="layout">
1203 <tr class="layout">
1204 <td class="left">
1205 <tt>opaque</tt>
1206 </td>
1207 <td class="left">
1208 An opaque type.<br/>
1209 </td>
1210 </tr>
1211</table>
1212</div>
1213
1214
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1215<!-- *********************************************************************** -->
1216<div class="doc_section"> <a name="constants">Constants</a> </div>
1217<!-- *********************************************************************** -->
1218
1219<div class="doc_text">
1220
1221<p>LLVM has several different basic types of constants. This section describes
1222them all and their syntax.</p>
1223
1224</div>
1225
1226<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1227<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1228
1229<div class="doc_text">
1230
1231<dl>
1232 <dt><b>Boolean constants</b></dt>
1233
1234 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1235 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1236 </dd>
1237
1238 <dt><b>Integer constants</b></dt>
1239
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1240 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1241 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1242 integer types.
1243 </dd>
1244
1245 <dt><b>Floating point constants</b></dt>
1246
1247 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1248 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1249 notation (see below). Floating point constants must have a <a
1250 href="#t_floating">floating point</a> type. </dd>
1251
1252 <dt><b>Null pointer constants</b></dt>
1253
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1254 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1255 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1256
1257</dl>
1258
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1259<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1260of floating point constants. For example, the form '<tt>double
12610x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12624.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1263(and the only time that they are generated by the disassembler) is when a
1264floating point constant must be emitted but it cannot be represented as a
1265decimal floating point number. For example, NaN's, infinities, and other
1266special values are represented in their IEEE hexadecimal format so that
1267assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1268
1269</div>
1270
1271<!-- ======================================================================= -->
1272<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1273</div>
1274
1275<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1276<p>Aggregate constants arise from aggregation of simple constants
1277and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1278
1279<dl>
1280 <dt><b>Structure constants</b></dt>
1281
1282 <dd>Structure constants are represented with notation similar to structure
1283 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1284 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1285 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1286 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1287 types of elements must match those specified by the type.
1288 </dd>
1289
1290 <dt><b>Array constants</b></dt>
1291
1292 <dd>Array constants are represented with notation similar to array type
1293 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1294 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1295 constants must have <a href="#t_array">array type</a>, and the number and
1296 types of elements must match those specified by the type.
1297 </dd>
1298
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1299 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1300
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1301 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1302 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1303 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1304 i32 11, i32 74, i32 100 &gt;</tt>". VEctor constants must have <a
1305 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1306 match those specified by the type.
1307 </dd>
1308
1309 <dt><b>Zero initialization</b></dt>
1310
1311 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1312 value to zero of <em>any</em> type, including scalar and aggregate types.
1313 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]1314 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1315 initializers.
1316 </dd>
1317</dl>
1318
1319</div>
1320
1321<!-- ======================================================================= -->
1322<div class="doc_subsection">
1323 <a name="globalconstants">Global Variable and Function Addresses</a>
1324</div>
1325
1326<div class="doc_text">
1327
1328<p>The addresses of <a href="#globalvars">global variables</a> and <a
1329href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1330constants. These constants are explicitly referenced when the <a
1331href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1332href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1333file:</p>
1334
1335<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1336 %X = global i32 17
1337 %Y = global i32 42
1338 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1339</pre>
1340
1341</div>
1342
1343<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1344<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1345<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1346 <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]1347 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1348 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1349
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1350 <p>Undefined values indicate to the compiler that the program is well defined
1351 no matter what value is used, giving the compiler more freedom to optimize.
1352 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1353</div>
1354
1355<!-- ======================================================================= -->
1356<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1357</div>
1358
1359<div class="doc_text">
1360
1361<p>Constant expressions are used to allow expressions involving other constants
1362to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1363href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1364that does not have side effects (e.g. load and call are not supported). The
1365following is the syntax for constant expressions:</p>
1366
1367<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1368 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1369 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1370 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1371
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1372 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1373 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1374 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1375
1376 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1377 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1378 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1379
1380 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1381 <dd>Truncate a floating point constant to another floating point type. The
1382 size of CST must be larger than the size of TYPE. Both types must be
1383 floating point.</dd>
1384
1385 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1386 <dd>Floating point extend a constant to another type. The size of CST must be
1387 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1388
1389 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1390 <dd>Convert a floating point constant to the corresponding unsigned integer
1391 constant. TYPE must be an integer type. CST must be floating point. If the
1392 value won't fit in the integer type, the results are undefined.</dd>
1393
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1394 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1395 <dd>Convert a floating point constant to the corresponding signed integer
1396 constant. TYPE must be an integer type. CST must be floating point. If the
1397 value won't fit in the integer type, the results are undefined.</dd>
1398
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1399 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1400 <dd>Convert an unsigned integer constant to the corresponding floating point
1401 constant. TYPE must be floating point. CST must be of integer type. If the
1402 value won't fit in the floating point type, the results are undefined.</dd>
1403
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1404 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1405 <dd>Convert a signed integer constant to the corresponding floating point
1406 constant. TYPE must be floating point. CST must be of integer type. If the
1407 value won't fit in the floating point type, the results are undefined.</dd>
1408
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1409 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1410 <dd>Convert a pointer typed constant to the corresponding integer constant
1411 TYPE must be an integer type. CST must be of pointer type. The CST value is
1412 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1413
1414 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1415 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1416 pointer type. CST must be of integer type. The CST value is zero extended,
1417 truncated, or unchanged to make it fit in a pointer size. This one is
1418 <i>really</i> dangerous!</dd>
1419
1420 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1421 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1422 identical (same number of bits). The conversion is done as if the CST value
1423 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1424 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1425 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1426 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1427 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1428
1429 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1430
1431 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1432 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1433 instruction, the index list may have zero or more indexes, which are required
1434 to make sense for the type of "CSTPTR".</dd>
1435
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1436 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1437
1438 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1439 constants.</dd>
1440
1441 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1442 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1443
1444 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1445 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1446
1447 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1448
1449 <dd>Perform the <a href="#i_extractelement">extractelement
1450 operation</a> on constants.
1451
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1452 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1453
1454 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1455 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1456
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1457
1458 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1459
1460 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1461 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1462
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1463 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1464
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1465 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1466 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467 binary</a> operations. The constraints on operands are the same as those for
1468 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1469 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1470</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1471</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1472
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1473<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1474<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1475<!-- *********************************************************************** -->
1476
1477<!-- ======================================================================= -->
1478<div class="doc_subsection">
1479<a name="inlineasm">Inline Assembler Expressions</a>
1480</div>
1481
1482<div class="doc_text">
1483
1484<p>
1485LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1486Module-Level Inline Assembly</a>) through the use of a special value. This
1487value represents the inline assembler as a string (containing the instructions
1488to emit), a list of operand constraints (stored as a string), and a flag that
1489indicates whether or not the inline asm expression has side effects. An example
1490inline assembler expression is:
1491</p>
1492
1493<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1494 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1495</pre>
1496
1497<p>
1498Inline assembler expressions may <b>only</b> be used as the callee operand of
1499a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1500</p>
1501
1502<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1503 %X = call i32 asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1504</pre>
1505
1506<p>
1507Inline asms with side effects not visible in the constraint list must be marked
1508as having side effects. This is done through the use of the
1509'<tt>sideeffect</tt>' keyword, like so:
1510</p>
1511
1512<pre>
1513 call void asm sideeffect "eieio", ""()
1514</pre>
1515
1516<p>TODO: The format of the asm and constraints string still need to be
1517documented here. Constraints on what can be done (e.g. duplication, moving, etc
1518need to be documented).
1519</p>
1520
1521</div>
1522
1523<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1524<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1525<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1526
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1527<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1528
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1529<p>The LLVM instruction set consists of several different
1530classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1531instructions</a>, <a href="#binaryops">binary instructions</a>,
1532<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1533 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1534instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1536</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1537
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1538<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1539<div class="doc_subsection"> <a name="terminators">Terminator
1540Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1541
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1542<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1544<p>As mentioned <a href="#functionstructure">previously</a>, every
1545basic block in a program ends with a "Terminator" instruction, which
1546indicates which block should be executed after the current block is
1547finished. These terminator instructions typically yield a '<tt>void</tt>'
1548value: they produce control flow, not values (the one exception being
1549the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1550<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1551 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1552instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1553the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1554 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1555 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1556
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1557</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1558
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1559<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1560<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1561Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1562<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1563<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1564<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]1565 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1566</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1567<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1568<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1569value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1570<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1571returns a value and then causes control flow, and one that just causes
1572control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1573<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1574<p>The '<tt>ret</tt>' instruction may return any '<a
1575 href="#t_firstclass">first class</a>' type. Notice that a function is
1576not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1577instruction inside of the function that returns a value that does not
1578match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1579<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1580<p>When the '<tt>ret</tt>' instruction is executed, control flow
1581returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1582 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1583the instruction after the call. If the caller was an "<a
1584 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1585at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1586returns a value, that value shall set the call or invoke instruction's
1587return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1588<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1589<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1590 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1591</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1592</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1593<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1594<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1595<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1596<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1597<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1598</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1599<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1600<p>The '<tt>br</tt>' instruction is used to cause control flow to
1601transfer to a different basic block in the current function. There are
1602two forms of this instruction, corresponding to a conditional branch
1603and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1605<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1606single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame^]1607unconditional form of the '<tt>br</tt>' instruction takes a single
1608'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1609<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1610<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1611argument is evaluated. If the value is <tt>true</tt>, control flows
1612to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1613control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1614<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1615<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1616 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1617</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1619<div class="doc_subsubsection">
1620 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1621</div>
1622
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1623<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1624<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1625
1626<pre>
1627 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1628</pre>
1629
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1630<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1631
1632<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1633several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1634instruction, allowing a branch to occur to one of many possible
1635destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1636
1637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1638<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1639
1640<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1641comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1642an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1643table is not allowed to contain duplicate constant entries.</p>
1644
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1646
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1647<p>The <tt>switch</tt> instruction specifies a table of values and
1648destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1649table is searched for the given value. If the value is found, control flow is
1650transfered to the corresponding destination; otherwise, control flow is
1651transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1652
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1653<h5>Implementation:</h5>
1654
1655<p>Depending on properties of the target machine and the particular
1656<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1657ways. For example, it could be generated as a series of chained conditional
1658branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1659
1660<h5>Example:</h5>
1661
1662<pre>
1663 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1664 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1665 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1666
1667 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1668 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1669
1670 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1671 switch i32 %val, label %otherwise [ i32 0, label %onzero
1672 i32 1, label %onone
1673 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1674</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1675</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1677<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1678<div class="doc_subsubsection">
1679 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1680</div>
1681
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1682<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1683
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1684<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1685
1686<pre>
1687 &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]1688 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1689</pre>
1690
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1691<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1692
1693<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1694function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1695'<tt>normal</tt>' label or the
1696'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1697"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1698"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1699href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1700continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1701
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1702<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1703
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1704<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1706<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1707 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1708 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1709 convention</a> the call should use. If none is specified, the call defaults
1710 to using C calling conventions.
1711 </li>
1712 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1713 function value being invoked. In most cases, this is a direct function
1714 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1715 an arbitrary pointer to function value.
1716 </li>
1717
1718 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1719 function to be invoked. </li>
1720
1721 <li>'<tt>function args</tt>': argument list whose types match the function
1722 signature argument types. If the function signature indicates the function
1723 accepts a variable number of arguments, the extra arguments can be
1724 specified. </li>
1725
1726 <li>'<tt>normal label</tt>': the label reached when the called function
1727 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1728
1729 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1730 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1731
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1732</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1733
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1735
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1736<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1737href="#i_call">call</a></tt>' instruction in most regards. The primary
1738difference is that it establishes an association with a label, which is used by
1739the runtime library to unwind the stack.</p>
1740
1741<p>This instruction is used in languages with destructors to ensure that proper
1742cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1743exception. Additionally, this is important for implementation of
1744'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1745
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1747<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1748 %retval = invoke i32 %Test(i32 15) to label %Continue
1749 unwind label %TestCleanup <i>; {i32}:retval set</i>
1750 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1751 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1754
1755
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1756<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1757
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1758<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1759Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1760
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1762
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1763<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1764<pre>
1765 unwind
1766</pre>
1767
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1768<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1769
1770<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1771at the first callee in the dynamic call stack which used an <a
1772href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1773primarily used to implement exception handling.</p>
1774
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1775<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1776
1777<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1778immediately halt. The dynamic call stack is then searched for the first <a
1779href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1780execution continues at the "exceptional" destination block specified by the
1781<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1782dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1783</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1784
1785<!-- _______________________________________________________________________ -->
1786
1787<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1788Instruction</a> </div>
1789
1790<div class="doc_text">
1791
1792<h5>Syntax:</h5>
1793<pre>
1794 unreachable
1795</pre>
1796
1797<h5>Overview:</h5>
1798
1799<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1800instruction is used to inform the optimizer that a particular portion of the
1801code is not reachable. This can be used to indicate that the code after a
1802no-return function cannot be reached, and other facts.</p>
1803
1804<h5>Semantics:</h5>
1805
1806<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1807</div>
1808
1809
1810
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1811<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1812<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1813<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1814<p>Binary operators are used to do most of the computation in a
1815program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1816produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1817multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1818The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1819necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1820<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1821</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1824Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1825<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827<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]1828</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1830<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1831<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1832<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1833 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1834 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1835Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1836<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1837<p>The value produced is the integer or floating point sum of the two
1838operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1840<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1841</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1842</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1843<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1844<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1845Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1846<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1847<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1848<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]1849</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1850<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1851<p>The '<tt>sub</tt>' instruction returns the difference of its two
1852operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1853<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1854instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1856<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1857 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1858values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1859This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1860Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1861<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1862<p>The value produced is the integer or floating point difference of
1863the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1864<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1865<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1866 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1867</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1868</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1869<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1870<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1871Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1872<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1873<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<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]1875</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1876<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1877<p>The '<tt>mul</tt>' instruction returns the product of its two
1878operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1879<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1880<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1882values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1883This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1884Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1885<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1886<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1887two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1888<p>Because the operands are the same width, the result of an integer
1889multiplication is the same whether the operands should be deemed unsigned or
1890signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1891<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1892<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1894</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1896<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1897</a></div>
1898<div class="doc_text">
1899<h5>Syntax:</h5>
1900<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1901</pre>
1902<h5>Overview:</h5>
1903<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1904operands.</p>
1905<h5>Arguments:</h5>
1906<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1907<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1908types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1909of the values in which case the elements must be integers.</p>
1910<h5>Semantics:</h5>
1911<p>The value produced is the unsigned integer quotient of the two operands. This
1912instruction always performs an unsigned division operation, regardless of
1913whether the arguments are unsigned or not.</p>
1914<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1915<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1916</pre>
1917</div>
1918<!-- _______________________________________________________________________ -->
1919<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1920</a> </div>
1921<div class="doc_text">
1922<h5>Syntax:</h5>
1923<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1924</pre>
1925<h5>Overview:</h5>
1926<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1927operands.</p>
1928<h5>Arguments:</h5>
1929<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1930<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1931types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1932of the values in which case the elements must be integers.</p>
1933<h5>Semantics:</h5>
1934<p>The value produced is the signed integer quotient of the two operands. This
1935instruction always performs a signed division operation, regardless of whether
1936the arguments are signed or not.</p>
1937<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1938<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1939</pre>
1940</div>
1941<!-- _______________________________________________________________________ -->
1942<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1943Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1944<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1945<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1946<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]1947</pre>
1948<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1949<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1950operands.</p>
1951<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1952<p>The two arguments to the '<tt>div</tt>' instruction must be
1953<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1954identical types. This instruction can also take <a href="#t_vector">vector</a>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1955versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1956<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1957<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1958<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1959<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]1960</pre>
1961</div>
1962<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1963<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1964</div>
1965<div class="doc_text">
1966<h5>Syntax:</h5>
1967<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1968</pre>
1969<h5>Overview:</h5>
1970<p>The '<tt>urem</tt>' instruction returns the remainder from the
1971unsigned division of its two arguments.</p>
1972<h5>Arguments:</h5>
1973<p>The two arguments to the '<tt>urem</tt>' instruction must be
1974<a href="#t_integer">integer</a> values. Both arguments must have identical
1975types.</p>
1976<h5>Semantics:</h5>
1977<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1978This instruction always performs an unsigned division to get the remainder,
1979regardless of whether the arguments are unsigned or not.</p>
1980<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1981<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1982</pre>
1983
1984</div>
1985<!-- _______________________________________________________________________ -->
1986<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1987Instruction</a> </div>
1988<div class="doc_text">
1989<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1990<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]1991</pre>
1992<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1993<p>The '<tt>srem</tt>' instruction returns the remainder from the
1994signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1996<p>The two arguments to the '<tt>srem</tt>' instruction must be
1997<a href="#t_integer">integer</a> values. Both arguments must have identical
1998types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1999<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2000<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2001has the same sign as the divisor), not the <i>modulus</i> (where the
2002result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2003information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2004 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2005Math Forum</a>.</p>
2006<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2007<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2008</pre>
2009
2010</div>
2011<!-- _______________________________________________________________________ -->
2012<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2013Instruction</a> </div>
2014<div class="doc_text">
2015<h5>Syntax:</h5>
2016<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2017</pre>
2018<h5>Overview:</h5>
2019<p>The '<tt>frem</tt>' instruction returns the remainder from the
2020division of its two operands.</p>
2021<h5>Arguments:</h5>
2022<p>The two arguments to the '<tt>frem</tt>' instruction must be
2023<a href="#t_floating">floating point</a> values. Both arguments must have
2024identical types.</p>
2025<h5>Semantics:</h5>
2026<p>This instruction returns the <i>remainder</i> of a division.</p>
2027<h5>Example:</h5>
2028<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]2029</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2030</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2031
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2032<!-- ======================================================================= -->
2033<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2034Operations</a> </div>
2035<div class="doc_text">
2036<p>Bitwise binary operators are used to do various forms of
2037bit-twiddling in a program. They are generally very efficient
2038instructions and can commonly be strength reduced from other
2039instructions. They require two operands, execute an operation on them,
2040and produce a single value. The resulting value of the bitwise binary
2041operators is always the same type as its first operand.</p>
2042</div>
2043
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2044<!-- _______________________________________________________________________ -->
2045<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2046Instruction</a> </div>
2047<div class="doc_text">
2048<h5>Syntax:</h5>
2049<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2050</pre>
2051<h5>Overview:</h5>
2052<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2053the left a specified number of bits.</p>
2054<h5>Arguments:</h5>
2055<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2056 href="#t_integer">integer</a> type.</p>
2057<h5>Semantics:</h5>
2058<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2059<h5>Example:</h5><pre>
2060 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2061 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2062 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2063</pre>
2064</div>
2065<!-- _______________________________________________________________________ -->
2066<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2067Instruction</a> </div>
2068<div class="doc_text">
2069<h5>Syntax:</h5>
2070<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2071</pre>
2072
2073<h5>Overview:</h5>
2074<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2075operand shifted to the right a specified number of bits.</p>
2076
2077<h5>Arguments:</h5>
2078<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2079<a href="#t_integer">integer</a> type.</p>
2080
2081<h5>Semantics:</h5>
2082<p>This instruction always performs a logical shift right operation. The most
2083significant bits of the result will be filled with zero bits after the
2084shift.</p>
2085
2086<h5>Example:</h5>
2087<pre>
2088 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2089 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2090 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2091 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2092</pre>
2093</div>
2094
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2095<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2096<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2097Instruction</a> </div>
2098<div class="doc_text">
2099
2100<h5>Syntax:</h5>
2101<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2102</pre>
2103
2104<h5>Overview:</h5>
2105<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2106operand shifted to the right a specified number of bits.</p>
2107
2108<h5>Arguments:</h5>
2109<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2110<a href="#t_integer">integer</a> type.</p>
2111
2112<h5>Semantics:</h5>
2113<p>This instruction always performs an arithmetic shift right operation,
2114The most significant bits of the result will be filled with the sign bit
2115of <tt>var1</tt>.</p>
2116
2117<h5>Example:</h5>
2118<pre>
2119 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2120 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2121 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2122 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2123</pre>
2124</div>
2125
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2126<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2127<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2128Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2129<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2130<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2131<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]2132</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2133<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2134<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2135its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2136<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2137<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2138 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2139identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2140<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2141<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2142<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2143<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2144<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2145 <tbody>
2146 <tr>
2147 <td>In0</td>
2148 <td>In1</td>
2149 <td>Out</td>
2150 </tr>
2151 <tr>
2152 <td>0</td>
2153 <td>0</td>
2154 <td>0</td>
2155 </tr>
2156 <tr>
2157 <td>0</td>
2158 <td>1</td>
2159 <td>0</td>
2160 </tr>
2161 <tr>
2162 <td>1</td>
2163 <td>0</td>
2164 <td>0</td>
2165 </tr>
2166 <tr>
2167 <td>1</td>
2168 <td>1</td>
2169 <td>1</td>
2170 </tr>
2171 </tbody>
2172</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2173</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2174<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2175<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2176 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2177 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2178</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2179</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2180<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2181<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2182<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2183<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2184<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]2185</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2186<h5>Overview:</h5>
2187<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2188or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2189<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2190<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2191 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2192identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2193<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2194<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2195<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2196<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2197<table border="1" cellspacing="0" cellpadding="4">
2198 <tbody>
2199 <tr>
2200 <td>In0</td>
2201 <td>In1</td>
2202 <td>Out</td>
2203 </tr>
2204 <tr>
2205 <td>0</td>
2206 <td>0</td>
2207 <td>0</td>
2208 </tr>
2209 <tr>
2210 <td>0</td>
2211 <td>1</td>
2212 <td>1</td>
2213 </tr>
2214 <tr>
2215 <td>1</td>
2216 <td>0</td>
2217 <td>1</td>
2218 </tr>
2219 <tr>
2220 <td>1</td>
2221 <td>1</td>
2222 <td>1</td>
2223 </tr>
2224 </tbody>
2225</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2226</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2227<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2228<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2229 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2230 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2231</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2232</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2233<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2234<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2235Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2236<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2237<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2238<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]2239</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2240<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2241<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2242or of its two operands. The <tt>xor</tt> is used to implement the
2243"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2244<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2245<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2246 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2247identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2248<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2249<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2250<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2251<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2252<table border="1" cellspacing="0" cellpadding="4">
2253 <tbody>
2254 <tr>
2255 <td>In0</td>
2256 <td>In1</td>
2257 <td>Out</td>
2258 </tr>
2259 <tr>
2260 <td>0</td>
2261 <td>0</td>
2262 <td>0</td>
2263 </tr>
2264 <tr>
2265 <td>0</td>
2266 <td>1</td>
2267 <td>1</td>
2268 </tr>
2269 <tr>
2270 <td>1</td>
2271 <td>0</td>
2272 <td>1</td>
2273 </tr>
2274 <tr>
2275 <td>1</td>
2276 <td>1</td>
2277 <td>0</td>
2278 </tr>
2279 </tbody>
2280</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2281</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2282<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2283<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2284<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2285 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2286 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2287 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2288</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2289</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2290
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2291<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2292<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2293 <a name="vectorops">Vector Operations</a>
2294</div>
2295
2296<div class="doc_text">
2297
2298<p>LLVM supports several instructions to represent vector operations in a
2299target-independent manner. This instructions cover the element-access and
2300vector-specific operations needed to process vectors effectively. While LLVM
2301does directly support these vector operations, many sophisticated algorithms
2302will want to use target-specific intrinsics to take full advantage of a specific
2303target.</p>
2304
2305</div>
2306
2307<!-- _______________________________________________________________________ -->
2308<div class="doc_subsubsection">
2309 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2310</div>
2311
2312<div class="doc_text">
2313
2314<h5>Syntax:</h5>
2315
2316<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2317 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2318</pre>
2319
2320<h5>Overview:</h5>
2321
2322<p>
2323The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2324element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2325</p>
2326
2327
2328<h5>Arguments:</h5>
2329
2330<p>
2331The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2332value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2333an index indicating the position from which to extract the element.
2334The index may be a variable.</p>
2335
2336<h5>Semantics:</h5>
2337
2338<p>
2339The result is a scalar of the same type as the element type of
2340<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2341<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2342results are undefined.
2343</p>
2344
2345<h5>Example:</h5>
2346
2347<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2348 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2349</pre>
2350</div>
2351
2352
2353<!-- _______________________________________________________________________ -->
2354<div class="doc_subsubsection">
2355 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2356</div>
2357
2358<div class="doc_text">
2359
2360<h5>Syntax:</h5>
2361
2362<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2363 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2364</pre>
2365
2366<h5>Overview:</h5>
2367
2368<p>
2369The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2370element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2371</p>
2372
2373
2374<h5>Arguments:</h5>
2375
2376<p>
2377The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2378value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2379scalar value whose type must equal the element type of the first
2380operand. The third operand is an index indicating the position at
2381which to insert the value. The index may be a variable.</p>
2382
2383<h5>Semantics:</h5>
2384
2385<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2386The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2387element values are those of <tt>val</tt> except at position
2388<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2389exceeds the length of <tt>val</tt>, the results are undefined.
2390</p>
2391
2392<h5>Example:</h5>
2393
2394<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2395 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2396</pre>
2397</div>
2398
2399<!-- _______________________________________________________________________ -->
2400<div class="doc_subsubsection">
2401 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2402</div>
2403
2404<div class="doc_text">
2405
2406<h5>Syntax:</h5>
2407
2408<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2409 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2410</pre>
2411
2412<h5>Overview:</h5>
2413
2414<p>
2415The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2416from two input vectors, returning a vector of the same type.
2417</p>
2418
2419<h5>Arguments:</h5>
2420
2421<p>
2422The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2423with types that match each other and types that match the result of the
2424instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2425of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2426</p>
2427
2428<p>
2429The shuffle mask operand is required to be a constant vector with either
2430constant integer or undef values.
2431</p>
2432
2433<h5>Semantics:</h5>
2434
2435<p>
2436The elements of the two input vectors are numbered from left to right across
2437both of the vectors. The shuffle mask operand specifies, for each element of
2438the result vector, which element of the two input registers the result element
2439gets. The element selector may be undef (meaning "don't care") and the second
2440operand may be undef if performing a shuffle from only one vector.
2441</p>
2442
2443<h5>Example:</h5>
2444
2445<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2446 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2447 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2448 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2449 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2450</pre>
2451</div>
2452
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2453
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2454<!-- ======================================================================= -->
2455<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2456 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2457</div>
2458
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2459<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2460
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2461<p>A key design point of an SSA-based representation is how it
2462represents memory. In LLVM, no memory locations are in SSA form, which
2463makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2464allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2465
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2466</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2467
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2468<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2469<div class="doc_subsubsection">
2470 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2471</div>
2472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2473<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2475<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2476
2477<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2478 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2481<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2482
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2483<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2484heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2485
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2486<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2487
2488<p>The '<tt>malloc</tt>' instruction allocates
2489<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2490bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2491appropriate type to the program. If "NumElements" is specified, it is the
2492number of elements allocated. If an alignment is specified, the value result
2493of the allocation is guaranteed to be aligned to at least that boundary. If
2494not specified, or if zero, the target can choose to align the allocation on any
2495convenient boundary.</p>
2496
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2497<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2498
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2499<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2500
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2501<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2502a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2503
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2504<h5>Example:</h5>
2505
2506<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2507 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2508
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2509 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2510 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2511 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2512 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2513 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2514</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2515</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2516
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2517<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2518<div class="doc_subsubsection">
2519 <a name="i_free">'<tt>free</tt>' Instruction</a>
2520</div>
2521
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2522<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2523
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2525
2526<pre>
2527 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2528</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2529
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2530<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2531
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2532<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2533memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2534
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2535<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2536
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2537<p>'<tt>value</tt>' shall be a pointer value that points to a value
2538that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2539instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2540
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2541<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2542
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2543<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2544after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2546<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2547
2548<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2549 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2550 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2551</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2552</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2553
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2554<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2555<div class="doc_subsubsection">
2556 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2557</div>
2558
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2559<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2560
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2561<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2562
2563<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2564 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2565</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2568
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2569<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2570stack frame of the procedure that is live until the current function
2571returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2572
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2573<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2574
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2575<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2576bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2577appropriate type to the program. If "NumElements" is specified, it is the
2578number of elements allocated. If an alignment is specified, the value result
2579of the allocation is guaranteed to be aligned to at least that boundary. If
2580not specified, or if zero, the target can choose to align the allocation on any
2581convenient boundary.</p>
2582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2583<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2584
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2585<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2586
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2587<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2588memory is automatically released when the function returns. The '<tt>alloca</tt>'
2589instruction is commonly used to represent automatic variables that must
2590have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2591 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]2592instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2594<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2595
2596<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2597 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2598 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2599 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2600 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2601</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2602</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2604<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2605<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2606Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2607<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2608<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2609<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]2610<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2611<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2612<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2613<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2614address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2615 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2616marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2617the number or order of execution of this <tt>load</tt> with other
2618volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2619instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2620<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2621<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2622<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2623<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2624 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2625 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2626 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2627</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2628</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2629<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2630<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2631Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2632<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2633<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2634<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]2635 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]2636</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2637<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2638<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2639<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2640<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2641to 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]2642operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2643operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2644optimizer is not allowed to modify the number or order of execution of
2645this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2646 href="#i_store">store</a></tt> instructions.</p>
2647<h5>Semantics:</h5>
2648<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2649at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2650<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2651<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2652 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2653 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2654 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2655</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2656</div>
2657
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2658<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2659<div class="doc_subsubsection">
2660 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2661</div>
2662
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2663<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2664<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2665<pre>
2666 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2667</pre>
2668
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2669<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2670
2671<p>
2672The '<tt>getelementptr</tt>' instruction is used to get the address of a
2673subelement of an aggregate data structure.</p>
2674
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2675<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2676
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2677<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2678elements of the aggregate object to index to. The actual types of the arguments
2679provided depend on the type of the first pointer argument. The
2680'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2681levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2682structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2683into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2684be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2685
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2686<p>For example, let's consider a C code fragment and how it gets
2687compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2688
2689<pre>
2690 struct RT {
2691 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2692 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2693 char C;
2694 };
2695 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2696 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2697 double Y;
2698 struct RT Z;
2699 };
2700
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2701 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2702 return &amp;s[1].Z.B[5][13];
2703 }
2704</pre>
2705
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2706<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2707
2708<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2709 %RT = type { i8 , [10 x [20 x i32]], i8 }
2710 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2711
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2712 implementation
2713
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2714 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2715 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2716 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2717 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2718 }
2719</pre>
2720
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2721<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2722
2723<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2724on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2725and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2726<a href="#t_integer">integer</a> type but the value will always be sign extended
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2727to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2728<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2729
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2730<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2731type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2732}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2733the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2734i8 }</tt>' type, another structure. The third index indexes into the second
2735element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2736array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2737'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2738to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2739
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2740<p>Note that it is perfectly legal to index partially through a
2741structure, returning a pointer to an inner element. Because of this,
2742the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2743
2744<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2745 define i32* %foo(%ST* %s) {
2746 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2747 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2748 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2749 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2750 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2751 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2752 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2753</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2754
2755<p>Note that it is undefined to access an array out of bounds: array and
2756pointer indexes must always be within the defined bounds of the array type.
2757The one exception for this rules is zero length arrays. These arrays are
2758defined to be accessible as variable length arrays, which requires access
2759beyond the zero'th element.</p>
2760
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2761<p>The getelementptr instruction is often confusing. For some more insight
2762into how it works, see <a href="GetElementPtr.html">the getelementptr
2763FAQ</a>.</p>
2764
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2765<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2766
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2767<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2768 <i>; yields [12 x i8]*:aptr</i>
2769 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2770</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2773<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2774<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2775</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2776<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2777<p>The instructions in this category are the conversion instructions (casting)
2778which all take a single operand and a type. They perform various bit conversions
2779on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2780</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2781
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2782<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2783<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2784 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2785</div>
2786<div class="doc_text">
2787
2788<h5>Syntax:</h5>
2789<pre>
2790 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2791</pre>
2792
2793<h5>Overview:</h5>
2794<p>
2795The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2796</p>
2797
2798<h5>Arguments:</h5>
2799<p>
2800The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2801be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2802and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2803type. The bit size of <tt>value</tt> must be larger than the bit size of
2804<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2805
2806<h5>Semantics:</h5>
2807<p>
2808The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2809and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2810larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2811It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2812
2813<h5>Example:</h5>
2814<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2815 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2816 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2817 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2818</pre>
2819</div>
2820
2821<!-- _______________________________________________________________________ -->
2822<div class="doc_subsubsection">
2823 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2824</div>
2825<div class="doc_text">
2826
2827<h5>Syntax:</h5>
2828<pre>
2829 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2830</pre>
2831
2832<h5>Overview:</h5>
2833<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2834<tt>ty2</tt>.</p>
2835
2836
2837<h5>Arguments:</h5>
2838<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2839<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2840also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2841<tt>value</tt> must be smaller than the bit size of the destination type,
2842<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2843
2844<h5>Semantics:</h5>
2845<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2846bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2847the operand and the type are the same size, no bit filling is done and the
2848cast is considered a <i>no-op cast</i> because no bits change (only the type
2849changes).</p>
2850
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2851<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2852
2853<h5>Example:</h5>
2854<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2855 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2856 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2857</pre>
2858</div>
2859
2860<!-- _______________________________________________________________________ -->
2861<div class="doc_subsubsection">
2862 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2863</div>
2864<div class="doc_text">
2865
2866<h5>Syntax:</h5>
2867<pre>
2868 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2869</pre>
2870
2871<h5>Overview:</h5>
2872<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2873
2874<h5>Arguments:</h5>
2875<p>
2876The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2877<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2878also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2879<tt>value</tt> must be smaller than the bit size of the destination type,
2880<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2881
2882<h5>Semantics:</h5>
2883<p>
2884The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2885bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2886the type <tt>ty2</tt>. When the the operand and the type are the same size,
2887no bit filling is done and the cast is considered a <i>no-op cast</i> because
2888no bits change (only the type changes).</p>
2889
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2890<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2891
2892<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2893<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2894 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2895 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2896</pre>
2897</div>
2898
2899<!-- _______________________________________________________________________ -->
2900<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2901 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2902</div>
2903
2904<div class="doc_text">
2905
2906<h5>Syntax:</h5>
2907
2908<pre>
2909 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2910</pre>
2911
2912<h5>Overview:</h5>
2913<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2914<tt>ty2</tt>.</p>
2915
2916
2917<h5>Arguments:</h5>
2918<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2919 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2920cast it to. The size of <tt>value</tt> must be larger than the size of
2921<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2922<i>no-op cast</i>.</p>
2923
2924<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2925<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2926<a href="#t_floating">floating point</a> type to a smaller
2927<a href="#t_floating">floating point</a> type. If the value cannot fit within
2928the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2929
2930<h5>Example:</h5>
2931<pre>
2932 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2933 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2934</pre>
2935</div>
2936
2937<!-- _______________________________________________________________________ -->
2938<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2939 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2940</div>
2941<div class="doc_text">
2942
2943<h5>Syntax:</h5>
2944<pre>
2945 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2946</pre>
2947
2948<h5>Overview:</h5>
2949<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2950floating point value.</p>
2951
2952<h5>Arguments:</h5>
2953<p>The '<tt>fpext</tt>' instruction takes a
2954<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2955and a <a href="#t_floating">floating point</a> type to cast it to. The source
2956type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2957
2958<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2959<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2960<a href="t_floating">floating point</a> type to a larger
2961<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2962used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2963<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2964
2965<h5>Example:</h5>
2966<pre>
2967 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2968 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2969</pre>
2970</div>
2971
2972<!-- _______________________________________________________________________ -->
2973<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]2974 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2975</div>
2976<div class="doc_text">
2977
2978<h5>Syntax:</h5>
2979<pre>
2980 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2981</pre>
2982
2983<h5>Overview:</h5>
2984<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2985unsigned integer equivalent of type <tt>ty2</tt>.
2986</p>
2987
2988<h5>Arguments:</h5>
2989<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2990<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2991must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2992
2993<h5>Semantics:</h5>
2994<p> The '<tt>fp2uint</tt>' instruction converts its
2995<a href="#t_floating">floating point</a> operand into the nearest (rounding
2996towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2997the results are undefined.</p>
2998
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2999<p>When converting to i1, the conversion is done as a comparison against
3000zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3001If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3002
3003<h5>Example:</h5>
3004<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3005 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3006 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3007 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3008</pre>
3009</div>
3010
3011<!-- _______________________________________________________________________ -->
3012<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3013 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3014</div>
3015<div class="doc_text">
3016
3017<h5>Syntax:</h5>
3018<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3019 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3020</pre>
3021
3022<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3023<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3024<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3025</p>
3026
3027
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3028<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3029<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3030<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3031must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3032
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3033<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3034<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3035<a href="#t_floating">floating point</a> operand into the nearest (rounding
3036towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3037the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3038
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3039<p>When converting to i1, the conversion is done as a comparison against
3040zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3041If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3042
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3043<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3044<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3045 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3046 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3047 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3048</pre>
3049</div>
3050
3051<!-- _______________________________________________________________________ -->
3052<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3053 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3054</div>
3055<div class="doc_text">
3056
3057<h5>Syntax:</h5>
3058<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3059 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3060</pre>
3061
3062<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3063<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3064integer and converts that value to the <tt>ty2</tt> type.</p>
3065
3066
3067<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3068<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3069<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3070be a <a href="#t_floating">floating point</a> type.</p>
3071
3072<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3073<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3074integer quantity and converts it to the corresponding floating point value. If
3075the value cannot fit in the floating point value, the results are undefined.</p>
3076
3077
3078<h5>Example:</h5>
3079<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3080 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3081 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3082</pre>
3083</div>
3084
3085<!-- _______________________________________________________________________ -->
3086<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3087 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3088</div>
3089<div class="doc_text">
3090
3091<h5>Syntax:</h5>
3092<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3093 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3094</pre>
3095
3096<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3097<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3098integer and converts that value to the <tt>ty2</tt> type.</p>
3099
3100<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3101<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3102<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3103a <a href="#t_floating">floating point</a> type.</p>
3104
3105<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3106<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3107integer quantity and converts it to the corresponding floating point value. If
3108the value cannot fit in the floating point value, the results are undefined.</p>
3109
3110<h5>Example:</h5>
3111<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3112 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3113 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3114</pre>
3115</div>
3116
3117<!-- _______________________________________________________________________ -->
3118<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3119 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3120</div>
3121<div class="doc_text">
3122
3123<h5>Syntax:</h5>
3124<pre>
3125 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3126</pre>
3127
3128<h5>Overview:</h5>
3129<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3130the integer type <tt>ty2</tt>.</p>
3131
3132<h5>Arguments:</h5>
3133<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3134must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3135<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3136
3137<h5>Semantics:</h5>
3138<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3139<tt>ty2</tt> by interpreting the pointer value as an integer and either
3140truncating or zero extending that value to the size of the integer type. If
3141<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3142<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3143are the same size, then nothing is done (<i>no-op cast</i>).</p>
3144
3145<h5>Example:</h5>
3146<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3147 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3148 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3149</pre>
3150</div>
3151
3152<!-- _______________________________________________________________________ -->
3153<div class="doc_subsubsection">
3154 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3155</div>
3156<div class="doc_text">
3157
3158<h5>Syntax:</h5>
3159<pre>
3160 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3161</pre>
3162
3163<h5>Overview:</h5>
3164<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3165a pointer type, <tt>ty2</tt>.</p>
3166
3167<h5>Arguments:</h5>
3168<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3169value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3170<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3171
3172<h5>Semantics:</h5>
3173<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3174<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3175the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3176size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3177the size of a pointer then a zero extension is done. If they are the same size,
3178nothing is done (<i>no-op cast</i>).</p>
3179
3180<h5>Example:</h5>
3181<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3182 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3183 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3184 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3185</pre>
3186</div>
3187
3188<!-- _______________________________________________________________________ -->
3189<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3190 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3191</div>
3192<div class="doc_text">
3193
3194<h5>Syntax:</h5>
3195<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3196 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3197</pre>
3198
3199<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3200<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3201<tt>ty2</tt> without changing any bits.</p>
3202
3203<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3204<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3205a first class value, and a type to cast it to, which must also be a <a
3206 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3207and the destination type, <tt>ty2</tt>, must be identical. If the source
3208type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3209
3210<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3211<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3212<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3213this conversion. The conversion is done as if the <tt>value</tt> had been
3214stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3215converted to other pointer types with this instruction. To convert pointers to
3216other types, use the <a href="#i_inttoptr">inttoptr</a> or
3217<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3218
3219<h5>Example:</h5>
3220<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3221 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3222 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3223 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3224</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3225</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3226
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3227<!-- ======================================================================= -->
3228<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3229<div class="doc_text">
3230<p>The instructions in this category are the "miscellaneous"
3231instructions, which defy better classification.</p>
3232</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3233
3234<!-- _______________________________________________________________________ -->
3235<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3236</div>
3237<div class="doc_text">
3238<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3239<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3240<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3241</pre>
3242<h5>Overview:</h5>
3243<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3244of its two integer operands.</p>
3245<h5>Arguments:</h5>
3246<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3247the condition code which indicates the kind of comparison to perform. It is not
3248a value, just a keyword. The possibilities for the condition code are:
3249<ol>
3250 <li><tt>eq</tt>: equal</li>
3251 <li><tt>ne</tt>: not equal </li>
3252 <li><tt>ugt</tt>: unsigned greater than</li>
3253 <li><tt>uge</tt>: unsigned greater or equal</li>
3254 <li><tt>ult</tt>: unsigned less than</li>
3255 <li><tt>ule</tt>: unsigned less or equal</li>
3256 <li><tt>sgt</tt>: signed greater than</li>
3257 <li><tt>sge</tt>: signed greater or equal</li>
3258 <li><tt>slt</tt>: signed less than</li>
3259 <li><tt>sle</tt>: signed less or equal</li>
3260</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3261<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3262<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3263<h5>Semantics:</h5>
3264<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3265the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3266yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3267<ol>
3268 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3269 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3270 </li>
3271 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3272 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3273 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3274 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3275 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3276 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3277 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3278 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3279 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3280 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3281 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3282 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3283 <li><tt>sge</tt>: interprets the operands as signed values and yields
3284 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3285 <li><tt>slt</tt>: interprets the operands as signed values and yields
3286 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3287 <li><tt>sle</tt>: interprets the operands as signed values and yields
3288 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3289</ol>
3290<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3291values are treated as integers and then compared.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3292
3293<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3294<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3295 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3296 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3297 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3298 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3299 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3300</pre>
3301</div>
3302
3303<!-- _______________________________________________________________________ -->
3304<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3305</div>
3306<div class="doc_text">
3307<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3308<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3309<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3310</pre>
3311<h5>Overview:</h5>
3312<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3313of its floating point operands.</p>
3314<h5>Arguments:</h5>
3315<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3316the condition code which indicates the kind of comparison to perform. It is not
3317a value, just a keyword. The possibilities for the condition code are:
3318<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3319 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3320 <li><tt>oeq</tt>: ordered and equal</li>
3321 <li><tt>ogt</tt>: ordered and greater than </li>
3322 <li><tt>oge</tt>: ordered and greater than or equal</li>
3323 <li><tt>olt</tt>: ordered and less than </li>
3324 <li><tt>ole</tt>: ordered and less than or equal</li>
3325 <li><tt>one</tt>: ordered and not equal</li>
3326 <li><tt>ord</tt>: ordered (no nans)</li>
3327 <li><tt>ueq</tt>: unordered or equal</li>
3328 <li><tt>ugt</tt>: unordered or greater than </li>
3329 <li><tt>uge</tt>: unordered or greater than or equal</li>
3330 <li><tt>ult</tt>: unordered or less than </li>
3331 <li><tt>ule</tt>: unordered or less than or equal</li>
3332 <li><tt>une</tt>: unordered or not equal</li>
3333 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3334 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3335</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3336<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3337<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3338<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3339<a href="#t_floating">floating point</a> typed. They must have identical
3340types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3341<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3342<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3343<h5>Semantics:</h5>
3344<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3345the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3346yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3347<ol>
3348 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3349 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3350 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3351 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3352 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3353 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3354 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3355 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3356 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3357 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3358 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3359 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3360 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3361 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3362 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3363 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3364 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3365 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3366 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3367 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3368 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3369 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3370 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3371 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3372 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3373 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3374 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3375 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3376</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3377
3378<h5>Example:</h5>
3379<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3380 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3381 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3382 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3383</pre>
3384</div>
3385
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
3387<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3388Instruction</a> </div>
3389<div class="doc_text">
3390<h5>Syntax:</h5>
3391<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3392<h5>Overview:</h5>
3393<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3394the SSA graph representing the function.</p>
3395<h5>Arguments:</h5>
3396<p>The type of the incoming values are specified with the first type
3397field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3398as arguments, with one pair for each predecessor basic block of the
3399current block. Only values of <a href="#t_firstclass">first class</a>
3400type may be used as the value arguments to the PHI node. Only labels
3401may be used as the label arguments.</p>
3402<p>There must be no non-phi instructions between the start of a basic
3403block and the PHI instructions: i.e. PHI instructions must be first in
3404a basic block.</p>
3405<h5>Semantics:</h5>
3406<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3407value specified by the parameter, depending on which basic block we
3408came from in the last <a href="#terminators">terminator</a> instruction.</p>
3409<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3410<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3411</div>
3412
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection">
3415 <a name="i_select">'<tt>select</tt>' Instruction</a>
3416</div>
3417
3418<div class="doc_text">
3419
3420<h5>Syntax:</h5>
3421
3422<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3423 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3424</pre>
3425
3426<h5>Overview:</h5>
3427
3428<p>
3429The '<tt>select</tt>' instruction is used to choose one value based on a
3430condition, without branching.
3431</p>
3432
3433
3434<h5>Arguments:</h5>
3435
3436<p>
3437The '<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.
3438</p>
3439
3440<h5>Semantics:</h5>
3441
3442<p>
3443If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3444value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3445</p>
3446
3447<h5>Example:</h5>
3448
3449<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3450 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3451</pre>
3452</div>
3453
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3454
3455<!-- _______________________________________________________________________ -->
3456<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3457 <a name="i_call">'<tt>call</tt>' Instruction</a>
3458</div>
3459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3460<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3461
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3462<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3463<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3464 &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]3465</pre>
3466
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3467<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3469<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3471<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3473<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3474
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3475<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3476 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3477 <p>The optional "tail" marker indicates whether the callee function accesses
3478 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3479 function call is eligible for tail call optimization. Note that calls may
3480 be marked "tail" even if they do not occur before a <a
3481 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3482 </li>
3483 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3484 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3485 convention</a> the call should use. If none is specified, the call defaults
3486 to using C calling conventions.
3487 </li>
3488 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3489 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3490 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3491 signature. This type can be omitted if the function is not varargs and
3492 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3493 </li>
3494 <li>
3495 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3496 be invoked. In most cases, this is a direct function invocation, but
3497 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3498 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3499 </li>
3500 <li>
3501 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3502 function signature argument types. All arguments must be of
3503 <a href="#t_firstclass">first class</a> type. If the function signature
3504 indicates the function accepts a variable number of arguments, the extra
3505 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3506 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3507</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3508
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3509<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3511<p>The '<tt>call</tt>' instruction is used to cause control flow to
3512transfer to a specified function, with its incoming arguments bound to
3513the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3514instruction in the called function, control flow continues with the
3515instruction after the function call, and the return value of the
3516function is bound to the result argument. This is a simpler case of
3517the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3518
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3519<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3520
3521<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3522 %retval = call i32 %test(i32 %argc)
3523 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3524 %X = tail call i32 %foo()
3525 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3526</pre>
3527
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3528</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3529
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3530<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3531<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3532 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3533</div>
3534
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3535<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3536
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3537<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3538
3539<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3540 &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]3541</pre>
3542
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3543<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3544
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3545<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3546the "variable argument" area of a function call. It is used to implement the
3547<tt>va_arg</tt> macro in C.</p>
3548
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3549<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3550
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3551<p>This instruction takes a <tt>va_list*</tt> value and the type of
3552the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3553increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3554actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3555
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3556<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3557
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3558<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3559type from the specified <tt>va_list</tt> and causes the
3560<tt>va_list</tt> to point to the next argument. For more information,
3561see the variable argument handling <a href="#int_varargs">Intrinsic
3562Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3563
3564<p>It is legal for this instruction to be called in a function which does not
3565take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3566function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3567
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3568<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3569href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3570argument.</p>
3571
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3572<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3573
3574<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3575
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3576</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3577
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3578<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3579<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3580<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3581
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3582<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3583
3584<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3585well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3586restrictions. Overall, these instructions represent an extension mechanism for
3587the LLVM language that does not require changing all of the transformations in
3588LLVM to add to the language (or the bytecode reader/writer, the parser,
3589etc...).</p>
3590
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3591<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3592prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3593this. Intrinsic functions must always be external functions: you cannot define
3594the body of intrinsic functions. Intrinsic functions may only be used in call
3595or invoke instructions: it is illegal to take the address of an intrinsic
3596function. Additionally, because intrinsic functions are part of the LLVM
3597language, it is required that they all be documented here if any are added.</p>
3598
3599
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3600<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3601href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3602</p>
3603
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3604</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3605
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3606<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3607<div class="doc_subsection">
3608 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3609</div>
3610
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3611<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3612
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3613<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3614 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3615intrinsic functions. These functions are related to the similarly
3616named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3617
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3618<p>All of these functions operate on arguments that use a
3619target-specific value type "<tt>va_list</tt>". The LLVM assembly
3620language reference manual does not define what this type is, so all
3621transformations should be prepared to handle intrinsics with any type
3622used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3623
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3624<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]3625instruction and the variable argument handling intrinsic functions are
3626used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3627
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3628<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3629define i32 %test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3630 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3631 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3632 %ap2 = bitcast i8** %ap to i8*
3633 call void %<a href="#i_va_start">llvm.va_start</a>(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3634
3635 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3636 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3637
3638 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3639 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3640 %aq2 = bitcast i8** %aq to i8*
3641 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 *%aq2, i8* %ap2)
3642 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3643
3644 ; Stop processing of arguments.
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3645 call void %<a href="#i_va_end">llvm.va_end</a>(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3646 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3647}
3648</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3649</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3650
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3651<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3652<div class="doc_subsubsection">
3653 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3654</div>
3655
3656
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3657<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3658<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3659<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3660<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3661<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3662<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3663href="#i_va_arg">va_arg</a></tt>.</p>
3664
3665<h5>Arguments:</h5>
3666
3667<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3668
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3669<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3670
3671<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3672macro available in C. In a target-dependent way, it initializes the
3673<tt>va_list</tt> element the argument points to, so that the next call to
3674<tt>va_arg</tt> will produce the first variable argument passed to the function.
3675Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3676last argument of the function, the compiler can figure that out.</p>
3677
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3678</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3679
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3680<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3681<div class="doc_subsubsection">
3682 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3683</div>
3684
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3685<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3686<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3687<pre> declare void %llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3688<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3689
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3690<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3691which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3692or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3693
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3694<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3695
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3696<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3697
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3698<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3699
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3700<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]3701macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3702Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3703 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3704with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3705
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3706</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3707
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3708<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3709<div class="doc_subsubsection">
3710 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3711</div>
3712
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3713<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3714
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3715<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3716
3717<pre>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3718 declare void %llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3719</pre>
3720
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3721<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3722
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3723<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3724the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3725
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3726<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3727
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3728<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]3729The 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]3730
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3731
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3732<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3733
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3734<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3735available in C. In a target-dependent way, it copies the source
3736<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3737because 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]3738arbitrarily complex and require memory allocation, for example.</p>
3739
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3740</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3741
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3742<!-- ======================================================================= -->
3743<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3744 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3745</div>
3746
3747<div class="doc_text">
3748
3749<p>
3750LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3751Collection</a> requires the implementation and generation of these intrinsics.
3752These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3753stack</a>, as well as garbage collector implementations that require <a
3754href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3755Front-ends for type-safe garbage collected languages should generate these
3756intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3757href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3758</p>
3759</div>
3760
3761<!-- _______________________________________________________________________ -->
3762<div class="doc_subsubsection">
3763 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3764</div>
3765
3766<div class="doc_text">
3767
3768<h5>Syntax:</h5>
3769
3770<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3771 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3772</pre>
3773
3774<h5>Overview:</h5>
3775
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3776<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]3777the code generator, and allows some metadata to be associated with it.</p>
3778
3779<h5>Arguments:</h5>
3780
3781<p>The first argument specifies the address of a stack object that contains the
3782root pointer. The second pointer (which must be either a constant or a global
3783value address) contains the meta-data to be associated with the root.</p>
3784
3785<h5>Semantics:</h5>
3786
3787<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3788location. At compile-time, the code generator generates information to allow
3789the runtime to find the pointer at GC safe points.
3790</p>
3791
3792</div>
3793
3794
3795<!-- _______________________________________________________________________ -->
3796<div class="doc_subsubsection">
3797 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3798</div>
3799
3800<div class="doc_text">
3801
3802<h5>Syntax:</h5>
3803
3804<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3805 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3806</pre>
3807
3808<h5>Overview:</h5>
3809
3810<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3811locations, allowing garbage collector implementations that require read
3812barriers.</p>
3813
3814<h5>Arguments:</h5>
3815
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3816<p>The second argument is the address to read from, which should be an address
3817allocated from the garbage collector. The first object is a pointer to the
3818start of the referenced object, if needed by the language runtime (otherwise
3819null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3820
3821<h5>Semantics:</h5>
3822
3823<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3824instruction, but may be replaced with substantially more complex code by the
3825garbage collector runtime, as needed.</p>
3826
3827</div>
3828
3829
3830<!-- _______________________________________________________________________ -->
3831<div class="doc_subsubsection">
3832 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3833</div>
3834
3835<div class="doc_text">
3836
3837<h5>Syntax:</h5>
3838
3839<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3840 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3841</pre>
3842
3843<h5>Overview:</h5>
3844
3845<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3846locations, allowing garbage collector implementations that require write
3847barriers (such as generational or reference counting collectors).</p>
3848
3849<h5>Arguments:</h5>
3850
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3851<p>The first argument is the reference to store, the second is the start of the
3852object to store it to, and the third is the address of the field of Obj to
3853store to. If the runtime does not require a pointer to the object, Obj may be
3854null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3855
3856<h5>Semantics:</h5>
3857
3858<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3859instruction, but may be replaced with substantially more complex code by the
3860garbage collector runtime, as needed.</p>
3861
3862</div>
3863
3864
3865
3866<!-- ======================================================================= -->
3867<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3868 <a name="int_codegen">Code Generator Intrinsics</a>
3869</div>
3870
3871<div class="doc_text">
3872<p>
3873These intrinsics are provided by LLVM to expose special features that may only
3874be implemented with code generator support.
3875</p>
3876
3877</div>
3878
3879<!-- _______________________________________________________________________ -->
3880<div class="doc_subsubsection">
3881 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3882</div>
3883
3884<div class="doc_text">
3885
3886<h5>Syntax:</h5>
3887<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3888 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3889</pre>
3890
3891<h5>Overview:</h5>
3892
3893<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3894The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3895target-specific value indicating the return address of the current function
3896or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3897</p>
3898
3899<h5>Arguments:</h5>
3900
3901<p>
3902The argument to this intrinsic indicates which function to return the address
3903for. Zero indicates the calling function, one indicates its caller, etc. The
3904argument is <b>required</b> to be a constant integer value.
3905</p>
3906
3907<h5>Semantics:</h5>
3908
3909<p>
3910The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3911the return address of the specified call frame, or zero if it cannot be
3912identified. The value returned by this intrinsic is likely to be incorrect or 0
3913for arguments other than zero, so it should only be used for debugging purposes.
3914</p>
3915
3916<p>
3917Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3918aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3919source-language caller.
3920</p>
3921</div>
3922
3923
3924<!-- _______________________________________________________________________ -->
3925<div class="doc_subsubsection">
3926 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3927</div>
3928
3929<div class="doc_text">
3930
3931<h5>Syntax:</h5>
3932<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3933 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3934</pre>
3935
3936<h5>Overview:</h5>
3937
3938<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3939The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3940target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3941</p>
3942
3943<h5>Arguments:</h5>
3944
3945<p>
3946The argument to this intrinsic indicates which function to return the frame
3947pointer for. Zero indicates the calling function, one indicates its caller,
3948etc. The argument is <b>required</b> to be a constant integer value.
3949</p>
3950
3951<h5>Semantics:</h5>
3952
3953<p>
3954The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3955the frame address of the specified call frame, or zero if it cannot be
3956identified. The value returned by this intrinsic is likely to be incorrect or 0
3957for arguments other than zero, so it should only be used for debugging purposes.
3958</p>
3959
3960<p>
3961Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3962aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3963source-language caller.
3964</p>
3965</div>
3966
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3967<!-- _______________________________________________________________________ -->
3968<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3969 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3970</div>
3971
3972<div class="doc_text">
3973
3974<h5>Syntax:</h5>
3975<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3976 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3977</pre>
3978
3979<h5>Overview:</h5>
3980
3981<p>
3982The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3983the function stack, for use with <a href="#i_stackrestore">
3984<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3985features like scoped automatic variable sized arrays in C99.
3986</p>
3987
3988<h5>Semantics:</h5>
3989
3990<p>
3991This intrinsic returns a opaque pointer value that can be passed to <a
3992href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3993<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3994<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3995state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3996practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3997that were allocated after the <tt>llvm.stacksave</tt> was executed.
3998</p>
3999
4000</div>
4001
4002<!-- _______________________________________________________________________ -->
4003<div class="doc_subsubsection">
4004 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4005</div>
4006
4007<div class="doc_text">
4008
4009<h5>Syntax:</h5>
4010<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4011 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4012</pre>
4013
4014<h5>Overview:</h5>
4015
4016<p>
4017The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4018the function stack to the state it was in when the corresponding <a
4019href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4020useful for implementing language features like scoped automatic variable sized
4021arrays in C99.
4022</p>
4023
4024<h5>Semantics:</h5>
4025
4026<p>
4027See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
4028</p>
4029
4030</div>
4031
4032
4033<!-- _______________________________________________________________________ -->
4034<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4035 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4036</div>
4037
4038<div class="doc_text">
4039
4040<h5>Syntax:</h5>
4041<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4042 declare void %llvm.prefetch(i8 * &lt;address&gt;,
4043 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4044</pre>
4045
4046<h5>Overview:</h5>
4047
4048
4049<p>
4050The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4051a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4052no
4053effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4054characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4055</p>
4056
4057<h5>Arguments:</h5>
4058
4059<p>
4060<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4061determining if the fetch should be for a read (0) or write (1), and
4062<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4063locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4064<tt>locality</tt> arguments must be constant integers.
4065</p>
4066
4067<h5>Semantics:</h5>
4068
4069<p>
4070This intrinsic does not modify the behavior of the program. In particular,
4071prefetches cannot trap and do not produce a value. On targets that support this
4072intrinsic, the prefetch can provide hints to the processor cache for better
4073performance.
4074</p>
4075
4076</div>
4077
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4081</div>
4082
4083<div class="doc_text">
4084
4085<h5>Syntax:</h5>
4086<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4087 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4088</pre>
4089
4090<h5>Overview:</h5>
4091
4092
4093<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4094The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4095(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4096code to simulators and other tools. The method is target specific, but it is
4097expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4098The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4099after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4100optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4101correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4102</p>
4103
4104<h5>Arguments:</h5>
4105
4106<p>
4107<tt>id</tt> is a numerical id identifying the marker.
4108</p>
4109
4110<h5>Semantics:</h5>
4111
4112<p>
4113This intrinsic does not modify the behavior of the program. Backends that do not
4114support this intrinisic may ignore it.
4115</p>
4116
4117</div>
4118
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4119<!-- _______________________________________________________________________ -->
4120<div class="doc_subsubsection">
4121 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4122</div>
4123
4124<div class="doc_text">
4125
4126<h5>Syntax:</h5>
4127<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4128 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4129</pre>
4130
4131<h5>Overview:</h5>
4132
4133
4134<p>
4135The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4136counter register (or similar low latency, high accuracy clocks) on those targets
4137that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4138As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4139should only be used for small timings.
4140</p>
4141
4142<h5>Semantics:</h5>
4143
4144<p>
4145When directly supported, reading the cycle counter should not modify any memory.
4146Implementations are allowed to either return a application specific value or a
4147system wide value. On backends without support, this is lowered to a constant 0.
4148</p>
4149
4150</div>
4151
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4152<!-- ======================================================================= -->
4153<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4154 <a name="int_libc">Standard C Library Intrinsics</a>
4155</div>
4156
4157<div class="doc_text">
4158<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4159LLVM provides intrinsics for a few important standard C library functions.
4160These intrinsics allow source-language front-ends to pass information about the
4161alignment of the pointer arguments to the code generator, providing opportunity
4162for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4163</p>
4164
4165</div>
4166
4167<!-- _______________________________________________________________________ -->
4168<div class="doc_subsubsection">
4169 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4170</div>
4171
4172<div class="doc_text">
4173
4174<h5>Syntax:</h5>
4175<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4176 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4177 i32 &lt;len&gt;, i32 &lt;align&gt;)
4178 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4179 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4180</pre>
4181
4182<h5>Overview:</h5>
4183
4184<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4185The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4186location to the destination location.
4187</p>
4188
4189<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4190Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4191intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4192</p>
4193
4194<h5>Arguments:</h5>
4195
4196<p>
4197The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4198the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4199specifying the number of bytes to copy, and the fourth argument is the alignment
4200of the source and destination locations.
4201</p>
4202
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4203<p>
4204If 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]4205the caller guarantees that both the source and destination pointers are aligned
4206to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4207</p>
4208
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4209<h5>Semantics:</h5>
4210
4211<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4212The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4213location to the destination location, which are not allowed to overlap. It
4214copies "len" bytes of memory over. If the argument is known to be aligned to
4215some boundary, this can be specified as the fourth argument, otherwise it should
4216be set to 0 or 1.
4217</p>
4218</div>
4219
4220
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4221<!-- _______________________________________________________________________ -->
4222<div class="doc_subsubsection">
4223 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4224</div>
4225
4226<div class="doc_text">
4227
4228<h5>Syntax:</h5>
4229<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4230 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4231 i32 &lt;len&gt;, i32 &lt;align&gt;)
4232 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4233 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4234</pre>
4235
4236<h5>Overview:</h5>
4237
4238<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4239The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4240location to the destination location. It is similar to the
4241'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4242</p>
4243
4244<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4245Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4246intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4247</p>
4248
4249<h5>Arguments:</h5>
4250
4251<p>
4252The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4253the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4254specifying the number of bytes to copy, and the fourth argument is the alignment
4255of the source and destination locations.
4256</p>
4257
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4258<p>
4259If 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]4260the caller guarantees that the source and destination pointers are aligned to
4261that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4262</p>
4263
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4264<h5>Semantics:</h5>
4265
4266<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4267The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4268location to the destination location, which may overlap. It
4269copies "len" bytes of memory over. If the argument is known to be aligned to
4270some boundary, this can be specified as the fourth argument, otherwise it should
4271be set to 0 or 1.
4272</p>
4273</div>
4274
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4275
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4276<!-- _______________________________________________________________________ -->
4277<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4278 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4279</div>
4280
4281<div class="doc_text">
4282
4283<h5>Syntax:</h5>
4284<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4285 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4286 i32 &lt;len&gt;, i32 &lt;align&gt;)
4287 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4288 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4289</pre>
4290
4291<h5>Overview:</h5>
4292
4293<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4294The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4295byte value.
4296</p>
4297
4298<p>
4299Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4300does not return a value, and takes an extra alignment argument.
4301</p>
4302
4303<h5>Arguments:</h5>
4304
4305<p>
4306The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4307byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4308argument specifying the number of bytes to fill, and the fourth argument is the
4309known alignment of destination location.
4310</p>
4311
4312<p>
4313If 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]4314the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4315</p>
4316
4317<h5>Semantics:</h5>
4318
4319<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4320The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4321the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4322destination location. If the argument is known to be aligned to some boundary,
4323this can be specified as the fourth argument, otherwise it should be set to 0 or
43241.
4325</p>
4326</div>
4327
4328
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4329<!-- _______________________________________________________________________ -->
4330<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4331 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4332</div>
4333
4334<div class="doc_text">
4335
4336<h5>Syntax:</h5>
4337<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4338 declare float %llvm.sqrt.f32(float %Val)
4339 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4340</pre>
4341
4342<h5>Overview:</h5>
4343
4344<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4345The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4346returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4347<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4348negative numbers (which allows for better optimization).
4349</p>
4350
4351<h5>Arguments:</h5>
4352
4353<p>
4354The argument and return value are floating point numbers of the same type.
4355</p>
4356
4357<h5>Semantics:</h5>
4358
4359<p>
4360This function returns the sqrt of the specified operand if it is a positive
4361floating point number.
4362</p>
4363</div>
4364
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4365<!-- _______________________________________________________________________ -->
4366<div class="doc_subsubsection">
4367 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4368</div>
4369
4370<div class="doc_text">
4371
4372<h5>Syntax:</h5>
4373<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4374 declare float %llvm.powi.f32(float %Val, i32 %power)
4375 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4376</pre>
4377
4378<h5>Overview:</h5>
4379
4380<p>
4381The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4382specified (positive or negative) power. The order of evaluation of
4383multiplications is not defined.
4384</p>
4385
4386<h5>Arguments:</h5>
4387
4388<p>
4389The second argument is an integer power, and the first is a value to raise to
4390that power.
4391</p>
4392
4393<h5>Semantics:</h5>
4394
4395<p>
4396This function returns the first value raised to the second power with an
4397unspecified sequence of rounding operations.</p>
4398</div>
4399
4400
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4401<!-- ======================================================================= -->
4402<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4403 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4404</div>
4405
4406<div class="doc_text">
4407<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4408LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4409These allow efficient code generation for some algorithms.
4410</p>
4411
4412</div>
4413
4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4416 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4417</div>
4418
4419<div class="doc_text">
4420
4421<h5>Syntax:</h5>
4422<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4423 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4424 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4425 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4426</pre>
4427
4428<h5>Overview:</h5>
4429
4430<p>
4431The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
443264 bit quantity. These are useful for performing operations on data that is not
4433in the target's native byte order.
4434</p>
4435
4436<h5>Semantics:</h5>
4437
4438<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4439The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4440and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4441intrinsic returns an i32 value that has the four bytes of the input i32
4442swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4443i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4444intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4445</p>
4446
4447</div>
4448
4449<!-- _______________________________________________________________________ -->
4450<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4451 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4452</div>
4453
4454<div class="doc_text">
4455
4456<h5>Syntax:</h5>
4457<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4458 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4459 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4460 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4461 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4462</pre>
4463
4464<h5>Overview:</h5>
4465
4466<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4467The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4468value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4469</p>
4470
4471<h5>Arguments:</h5>
4472
4473<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4474The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4475integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4476</p>
4477
4478<h5>Semantics:</h5>
4479
4480<p>
4481The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4482</p>
4483</div>
4484
4485<!-- _______________________________________________________________________ -->
4486<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4487 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4488</div>
4489
4490<div class="doc_text">
4491
4492<h5>Syntax:</h5>
4493<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4494 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4495 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4496 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4497 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4498</pre>
4499
4500<h5>Overview:</h5>
4501
4502<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4503The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4504leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4505</p>
4506
4507<h5>Arguments:</h5>
4508
4509<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4510The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4511integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4512</p>
4513
4514<h5>Semantics:</h5>
4515
4516<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4517The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4518in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4519of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4520</p>
4521</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4522
4523
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4524
4525<!-- _______________________________________________________________________ -->
4526<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4527 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4528</div>
4529
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4534 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4535 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4536 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4537 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4538</pre>
4539
4540<h5>Overview:</h5>
4541
4542<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4543The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4544trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4545</p>
4546
4547<h5>Arguments:</h5>
4548
4549<p>
4550The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4551integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4552</p>
4553
4554<h5>Semantics:</h5>
4555
4556<p>
4557The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4558in a variable. If the src == 0 then the result is the size in bits of the type
4559of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4560</p>
4561</div>
4562
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4563<!-- ======================================================================= -->
4564<div class="doc_subsection">
4565 <a name="int_debugger">Debugger Intrinsics</a>
4566</div>
4567
4568<div class="doc_text">
4569<p>
4570The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4571are described in the <a
4572href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4573Debugging</a> document.
4574</p>
4575</div>
4576
4577
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4578<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4579<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4580<address>
4581 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4582 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4583 <a href="http://validator.w3.org/check/referer"><img
4584 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4585
4586 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4587 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4588 Last modified: $Date$
4589</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4590</body>
4591</html>