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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 5d522f36ca33e7d6ee1b75dca348586c16f95138 / . / 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>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]190 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]191 </ol>
192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]194
195<div class="doc_author">
196 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
197 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]198</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]200<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201<div class="doc_section"> <a name="abstract">Abstract </a></div>
202<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]204<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205<p>This document is a reference manual for the LLVM assembly language.
206LLVM is an SSA based representation that provides type safety,
207low-level operations, flexibility, and the capability of representing
208'all' high-level languages cleanly. It is the common code
209representation used throughout all phases of the LLVM compilation
210strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]211</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214<div class="doc_section"> <a name="introduction">Introduction</a> </div>
215<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]217<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219<p>The LLVM code representation is designed to be used in three
220different forms: as an in-memory compiler IR, as an on-disk bytecode
221representation (suitable for fast loading by a Just-In-Time compiler),
222and as a human readable assembly language representation. This allows
223LLVM to provide a powerful intermediate representation for efficient
224compiler transformations and analysis, while providing a natural means
225to debug and visualize the transformations. The three different forms
226of LLVM are all equivalent. This document describes the human readable
227representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]228
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]229<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]230while being expressive, typed, and extensible at the same time. It
231aims to be a "universal IR" of sorts, by being at a low enough level
232that high-level ideas may be cleanly mapped to it (similar to how
233microprocessors are "universal IR's", allowing many source languages to
234be mapped to them). By providing type information, LLVM can be used as
235the target of optimizations: for example, through pointer analysis, it
236can be proven that a C automatic variable is never accessed outside of
237the current function... allowing it to be promoted to a simple SSA
238value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]240</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]242<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]243<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]245<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]246
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]247<p>It is important to note that this document describes 'well formed'
248LLVM assembly language. There is a difference between what the parser
249accepts and what is considered 'well formed'. For example, the
250following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]251
252<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]253 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254</pre>
255
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256<p>...because the definition of <tt>%x</tt> does not dominate all of
257its uses. The LLVM infrastructure provides a verification pass that may
258be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]259automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]260the optimizer before it outputs bytecode. The violations pointed out
261by the verifier pass indicate bugs in transformation passes or input to
262the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]263
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]264<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]266<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]267<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]268<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]270<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]271
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]272<p>LLVM uses three different forms of identifiers, for different
273purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]275<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]276 <li>Named values are represented as a string of characters with a '%' prefix.
277 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
278 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
279 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]280 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]281 in a name.</li>
282
283 <li>Unnamed values are represented as an unsigned numeric value with a '%'
284 prefix. For example, %12, %2, %44.</li>
285
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]286 <li>Constants, which are described in a <a href="#constants">section about
287 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]288</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]289
290<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
291don't need to worry about name clashes with reserved words, and the set of
292reserved words may be expanded in the future without penalty. Additionally,
293unnamed identifiers allow a compiler to quickly come up with a temporary
294variable without having to avoid symbol table conflicts.</p>
295
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]297languages. There are keywords for different opcodes
298('<tt><a href="#i_add">add</a></tt>',
299 '<tt><a href="#i_bitcast">bitcast</a></tt>',
300 '<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]301href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]302and others. These reserved words cannot conflict with variable names, because
303none of them start with a '%' character.</p>
304
305<p>Here is an example of LLVM code to multiply the integer variable
306'<tt>%X</tt>' by 8:</p>
307
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]308<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]309
310<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]311 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]312</pre>
313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
316<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]317 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]318</pre>
319
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
322<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]323 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
324 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
325 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]326</pre>
327
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]328<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
329important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]330
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]331<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]332
333 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
334 line.</li>
335
336 <li>Unnamed temporaries are created when the result of a computation is not
337 assigned to a named value.</li>
338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]343<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344demonstrating instructions, we will follow an instruction with a comment that
345defines the type and name of value produced. Comments are shown in italic
346text.</p>
347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]348</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]349
350<!-- *********************************************************************** -->
351<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
352<!-- *********************************************************************** -->
353
354<!-- ======================================================================= -->
355<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
356</div>
357
358<div class="doc_text">
359
360<p>LLVM programs are composed of "Module"s, each of which is a
361translation unit of the input programs. Each module consists of
362functions, global variables, and symbol table entries. Modules may be
363combined together with the LLVM linker, which merges function (and
364global variable) definitions, resolves forward declarations, and merges
365symbol table entries. Here is an example of the "hello world" module:</p>
366
367<pre><i>; Declare the string constant as a global constant...</i>
368<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]369 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]370
371<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]372<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]373
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]374<i>; Global variable / Function body section separator</i>
375implementation
376
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]377<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]378define i32 %main() { <i>; i32()* </i>
379 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]380 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]381 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]382
383 <i>; Call puts function to write out the string to stdout...</i>
384 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]387 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]388
389<p>This example is made up of a <a href="#globalvars">global variable</a>
390named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
391function, and a <a href="#functionstructure">function definition</a>
392for "<tt>main</tt>".</p>
393
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394<p>In general, a module is made up of a list of global values,
395where both functions and global variables are global values. Global values are
396represented by a pointer to a memory location (in this case, a pointer to an
397array of char, and a pointer to a function), and have one of the following <a
398href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]399
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]400<p>Due to a limitation in the current LLVM assembly parser (it is limited by
401one-token lookahead), modules are split into two pieces by the "implementation"
402keyword. Global variable prototypes and definitions must occur before the
403keyword, and function definitions must occur after it. Function prototypes may
404occur either before or after it. In the future, the implementation keyword may
405become a noop, if the parser gets smarter.</p>
406
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407</div>
408
409<!-- ======================================================================= -->
410<div class="doc_subsection">
411 <a name="linkage">Linkage Types</a>
412</div>
413
414<div class="doc_text">
415
416<p>
417All Global Variables and Functions have one of the following types of linkage:
418</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]419
420<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]422 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
424 <dd>Global values with internal linkage are only directly accessible by
425 objects in the current module. In particular, linking code into a module with
426 an internal global value may cause the internal to be renamed as necessary to
427 avoid collisions. Because the symbol is internal to the module, all
428 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]429 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]432 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]434 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
435 the same name when linkage occurs. This is typically used to implement
436 inline functions, templates, or other code which must be generated in each
437 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
438 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]439 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]441 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
443 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
444 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]445 used for globals that may be emitted in multiple translation units, but that
446 are not guaranteed to be emitted into every translation unit that uses them.
447 One example of this are common globals in C, such as "<tt>int X;</tt>" at
448 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]449 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]451 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
453 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
454 pointer to array type. When two global variables with appending linkage are
455 linked together, the two global arrays are appended together. This is the
456 LLVM, typesafe, equivalent of having the system linker append together
457 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]458 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]460 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
461 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
462 until linked, if not linked, the symbol becomes null instead of being an
463 undefined reference.
464 </dd>
465</dl>
466
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]467 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
469 <dd>If none of the above identifiers are used, the global is externally
470 visible, meaning that it participates in linkage and can be used to resolve
471 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]472 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]473
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]474 <p>
475 The next two types of linkage are targeted for Microsoft Windows platform
476 only. They are designed to support importing (exporting) symbols from (to)
477 DLLs.
478 </p>
479
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]480 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]481 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
482
483 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
484 or variable via a global pointer to a pointer that is set up by the DLL
485 exporting the symbol. On Microsoft Windows targets, the pointer name is
486 formed by combining <code>_imp__</code> and the function or variable name.
487 </dd>
488
489 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
490
491 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
492 pointer to a pointer in a DLL, so that it can be referenced with the
493 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
494 name is formed by combining <code>_imp__</code> and the function or variable
495 name.
496 </dd>
497
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498</dl>
499
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]500<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
502variable and was linked with this one, one of the two would be renamed,
503preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
504external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]505outside of the current module.</p>
506<p>It is illegal for a function <i>declaration</i>
507to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]508or <tt>extern_weak</tt>.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]509
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510</div>
511
512<!-- ======================================================================= -->
513<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]514 <a name="callingconv">Calling Conventions</a>
515</div>
516
517<div class="doc_text">
518
519<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
520and <a href="#i_invoke">invokes</a> can all have an optional calling convention
521specified for the call. The calling convention of any pair of dynamic
522caller/callee must match, or the behavior of the program is undefined. The
523following calling conventions are supported by LLVM, and more may be added in
524the future:</p>
525
526<dl>
527 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
528
529 <dd>This calling convention (the default if no other calling convention is
530 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]531 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]532 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]533 </dd>
534
535 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
536
537 <dd>This calling convention attempts to make calls as fast as possible
538 (e.g. by passing things in registers). This calling convention allows the
539 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]540 without having to conform to an externally specified ABI. Implementations of
541 this convention should allow arbitrary tail call optimization to be supported.
542 This calling convention does not support varargs and requires the prototype of
543 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]544 </dd>
545
546 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
547
548 <dd>This calling convention attempts to make code in the caller as efficient
549 as possible under the assumption that the call is not commonly executed. As
550 such, these calls often preserve all registers so that the call does not break
551 any live ranges in the caller side. This calling convention does not support
552 varargs and requires the prototype of all callees to exactly match the
553 prototype of the function definition.
554 </dd>
555
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]556 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]557
558 <dd>Any calling convention may be specified by number, allowing
559 target-specific calling conventions to be used. Target specific calling
560 conventions start at 64.
561 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]562</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]563
564<p>More calling conventions can be added/defined on an as-needed basis, to
565support pascal conventions or any other well-known target-independent
566convention.</p>
567
568</div>
569
570<!-- ======================================================================= -->
571<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]572 <a name="visibility">Visibility Styles</a>
573</div>
574
575<div class="doc_text">
576
577<p>
578All Global Variables and Functions have one of the following visibility styles:
579</p>
580
581<dl>
582 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
583
584 <dd>On ELF, default visibility means that the declaration is visible to other
585 modules and, in shared libraries, means that the declared entity may be
586 overridden. On Darwin, default visibility means that the declaration is
587 visible to other modules. Default visibility corresponds to "external
588 linkage" in the language.
589 </dd>
590
591 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
592
593 <dd>Two declarations of an object with hidden visibility refer to the same
594 object if they are in the same shared object. Usually, hidden visibility
595 indicates that the symbol will not be placed into the dynamic symbol table,
596 so no other module (executable or shared library) can reference it
597 directly.
598 </dd>
599
600</dl>
601
602</div>
603
604<!-- ======================================================================= -->
605<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]606 <a name="globalvars">Global Variables</a>
607</div>
608
609<div class="doc_text">
610
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]611<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]612instead of run-time. Global variables may optionally be initialized, may have
613an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]614have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]615variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]616contents of the variable will <b>never</b> be modified (enabling better
617optimization, allowing the global data to be placed in the read-only section of
618an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]619cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]620
621<p>
622LLVM explicitly allows <em>declarations</em> of global variables to be marked
623constant, even if the final definition of the global is not. This capability
624can be used to enable slightly better optimization of the program, but requires
625the language definition to guarantee that optimizations based on the
626'constantness' are valid for the translation units that do not include the
627definition.
628</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]629
630<p>As SSA values, global variables define pointer values that are in
631scope (i.e. they dominate) all basic blocks in the program. Global
632variables always define a pointer to their "content" type because they
633describe a region of memory, and all memory objects in LLVM are
634accessed through pointers.</p>
635
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]636<p>LLVM allows an explicit section to be specified for globals. If the target
637supports it, it will emit globals to the section specified.</p>
638
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]639<p>An explicit alignment may be specified for a global. If not present, or if
640the alignment is set to zero, the alignment of the global is set by the target
641to whatever it feels convenient. If an explicit alignment is specified, the
642global is forced to have at least that much alignment. All alignments must be
643a power of 2.</p>
644
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]645<p>For example, the following defines a global with an initializer, section,
646 and alignment:</p>
647
648<pre>
649 %G = constant float 1.0, section "foo", align 4
650</pre>
651
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]652</div>
653
654
655<!-- ======================================================================= -->
656<div class="doc_subsection">
657 <a name="functionstructure">Functions</a>
658</div>
659
660<div class="doc_text">
661
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]662<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
663an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]664<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]665<a href="#callingconv">calling convention</a>, a return type, an optional
666<a href="#paramattrs">parameter attribute</a> for the return type, a function
667name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]668<a href="#paramattrs">parameter attributes</a>), an optional section, an
669optional alignment, an opening curly brace, a list of basic blocks, and a
670closing curly brace.
671
672LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
673optional <a href="#linkage">linkage type</a>, an optional
674<a href="#visibility">visibility style</a>, an optional
675<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]676<a href="#paramattrs">parameter attribute</a> for the return type, a function
677name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]678
679<p>A function definition contains a list of basic blocks, forming the CFG for
680the function. Each basic block may optionally start with a label (giving the
681basic block a symbol table entry), contains a list of instructions, and ends
682with a <a href="#terminators">terminator</a> instruction (such as a branch or
683function return).</p>
684
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]685<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]686executed on entrance to the function, and it is not allowed to have predecessor
687basic blocks (i.e. there can not be any branches to the entry block of a
688function). Because the block can have no predecessors, it also cannot have any
689<a href="#i_phi">PHI nodes</a>.</p>
690
691<p>LLVM functions are identified by their name and type signature. Hence, two
692functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]693considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]694appropriately.</p>
695
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]696<p>LLVM allows an explicit section to be specified for functions. If the target
697supports it, it will emit functions to the section specified.</p>
698
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]699<p>An explicit alignment may be specified for a function. If not present, or if
700the alignment is set to zero, the alignment of the function is set by the target
701to whatever it feels convenient. If an explicit alignment is specified, the
702function is forced to have at least that much alignment. All alignments must be
703a power of 2.</p>
704
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]705</div>
706
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]707<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]708<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
709<div class="doc_text">
710 <p>The return type and each parameter of a function type may have a set of
711 <i>parameter attributes</i> associated with them. Parameter attributes are
712 used to communicate additional information about the result or parameters of
713 a function. Parameter attributes are considered to be part of the function
714 type so two functions types that differ only by the parameter attributes
715 are different function types.</p>
716
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]717 <p>Parameter attributes are simple keywords that follow the type specified. If
718 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]719 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]720 %someFunc = i16 (i8 sext %someParam) zext
721 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]722 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]723 a different attribute (sext in the first one, zext in the second). Also note
724 that the attribute for the function result (zext) comes immediately after the
725 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]726
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]727 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]728 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]729 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]730 <dd>This indicates that the parameter should be zero extended just before
731 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]732 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]733 <dd>This indicates that the parameter should be sign extended just before
734 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]735 <dt><tt>inreg</tt></dt>
736 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]737 possible) during assembling function call. Support for this attribute is
738 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]739 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]740 <dd>This indicates that the parameter specifies the address of a structure
741 that is the return value of the function in the source program.
742 </dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]743 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]744
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]745</div>
746
747<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]748<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]749 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]750</div>
751
752<div class="doc_text">
753<p>
754Modules may contain "module-level inline asm" blocks, which corresponds to the
755GCC "file scope inline asm" blocks. These blocks are internally concatenated by
756LLVM and treated as a single unit, but may be separated in the .ll file if
757desired. The syntax is very simple:
758</p>
759
760<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]761 module asm "inline asm code goes here"
762 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]763</pre></div>
764
765<p>The strings can contain any character by escaping non-printable characters.
766 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
767 for the number.
768</p>
769
770<p>
771 The inline asm code is simply printed to the machine code .s file when
772 assembly code is generated.
773</p>
774</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]775
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]776<!-- ======================================================================= -->
777<div class="doc_subsection">
778 <a name="datalayout">Data Layout</a>
779</div>
780
781<div class="doc_text">
782<p>A module may specify a target specific data layout string that specifies how
783data is to be laid out in memory. The syntax for the data layout is simply:<br/>
784<pre> target datalayout = "<i>layout specification</i>"
785</pre>
786The <i>layout specification</i> consists of a list of specifications separated
787by the minus sign character ('-'). Each specification starts with a letter
788and may include other information after the letter to define some aspect of the
789data layout. The specifications accepted are as follows: </p>
790<dl>
791 <dt><tt>E</tt></dt>
792 <dd>Specifies that the target lays out data in big-endian form. That is, the
793 bits with the most significance have the lowest address location.</dd>
794 <dt><tt>e</tt></dt>
795 <dd>Specifies that hte target lays out data in little-endian form. That is,
796 the bits with the least significance have the lowest address location.</dd>
797 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
798 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
799 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
800 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
801 too.</dd>
802 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
803 <dd>This specifies the alignment for an integer type of a given bit
804 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
805 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
806 <dd>This specifies the alignment for a vector type of a given bit
807 <i>size</i>.</dd>
808 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
809 <dd>This specifies the alignment for a floating point type of a given bit
810 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
811 (double).</dd>
812 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
813 <dd>This specifies the alignment for an aggregate type of a given bit
814 <i>size</i>.</dd>
815</dl>
816<p>When constructing the data layout for a given target, LLVM starts with a
817default set of specifications which are then (possibly) overriden by the
818specifications in the <tt>datalayout</tt> keyword. The default specifications
819are given in this list:</p>
820<ul>
821 <li><tt>E</tt> - big endian</li>
822 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
823 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
824 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
825 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
826 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
827 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
828 alignment of 64-bits</li>
829 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
830 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
831 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
832 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
833 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
834</ul>
835<p>When llvm is determining the alignment for a given type, it uses the
836following rules:
837<ol>
838 <li>If the type sought is an exact match for one of the specifications, that
839 specification is used.</li>
840 <li>If no match is found, and the type sought is an integer type, then the
841 smallest integer type that is larger than the bitwidth of the sought type is
842 used. If none of the specifications are larger than the bitwidth then the the
843 largest integer type is used. For example, given the default specifications
844 above, the i7 type will use the alignment of i8 (next largest) while both
845 i65 and i256 will use the alignment of i64 (largest specified).</li>
846 <li>If no match is found, and the type sought is a vector type, then the
847 largest vector type that is smaller than the sought vector type will be used
848 as a fall back. This happens because <128 x double> can be implemented in
849 terms of 64 <2 x double>, for example.</li>
850</ol>
851</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]853<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]854<div class="doc_section"> <a name="typesystem">Type System</a> </div>
855<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]856
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]857<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]858
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]859<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]860intermediate representation. Being typed enables a number of
861optimizations to be performed on the IR directly, without having to do
862extra analyses on the side before the transformation. A strong type
863system makes it easier to read the generated code and enables novel
864analyses and transformations that are not feasible to perform on normal
865three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]866
867</div>
868
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]869<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]870<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]871<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]872<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]873system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]874
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]875<table class="layout">
876 <tr class="layout">
877 <td class="left">
878 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]879 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]880 <tr><th>Type</th><th>Description</th></tr>
881 <tr><td><tt>void</tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]882 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
883 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]884 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]885 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]886 </tbody>
887 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]888 </td>
889 <td class="right">
890 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]891 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]892 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]893 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]894 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
895 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]896 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]897 </tbody>
898 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]899 </td>
900 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]901</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]902</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]903
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]904<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]905<div class="doc_subsubsection"> <a name="t_classifications">Type
906Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]907<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908<p>These different primitive types fall into a few useful
909classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]910
911<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]912 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]913 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]914 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]915 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]916 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]917 </tr>
918 <tr>
919 <td><a name="t_floating">floating point</a></td>
920 <td><tt>float, double</tt></td>
921 </tr>
922 <tr>
923 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]924 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]925 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]926 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]927 </tr>
928 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]929</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]930
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]931<p>The <a href="#t_firstclass">first class</a> types are perhaps the
932most important. Values of these types are the only ones which can be
933produced by instructions, passed as arguments, or used as operands to
934instructions. This means that all structures and arrays must be
935manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]936</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]937
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]938<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]939<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]940
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]941<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]942
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]943<p>The real power in LLVM comes from the derived types in the system.
944This is what allows a programmer to represent arrays, functions,
945pointers, and other useful types. Note that these derived types may be
946recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]947
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]948</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]949
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]950<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]951<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]952
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]953<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]954
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]955<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]956
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]957<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]958sequentially in memory. The array type requires a size (number of
959elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]960
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]961<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]962
963<pre>
964 [&lt;# elements&gt; x &lt;elementtype&gt;]
965</pre>
966
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]967<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]968be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]969
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]970<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]971<table class="layout">
972 <tr class="layout">
973 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]974 <tt>[40 x i32 ]</tt><br/>
975 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]976 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]977 </td>
978 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]979 Array of 40 32-bit integer values.<br/>
980 Array of 41 32-bit integer values.<br/>
981 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]982 </td>
983 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]984</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]985<p>Here are some examples of multidimensional arrays:</p>
986<table class="layout">
987 <tr class="layout">
988 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]989 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]990 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]991 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]992 </td>
993 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]994 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]995 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]996 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]997 </td>
998 </tr>
999</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1000
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1001<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1002length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1003LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1004As a special case, however, zero length arrays are recognized to be variable
1005length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1006type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1007
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1008</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1009
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1010<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1011<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1012<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1013<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1014<p>The function type can be thought of as a function signature. It
1015consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1016Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017(which are structures of pointers to functions), for indirect function
1018calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1019<p>
1020The return type of a function type cannot be an aggregate type.
1021</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1022<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1023<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1024<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]1025specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1026which indicates that the function takes a variable number of arguments.
1027Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1028 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1029<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1030<table class="layout">
1031 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1032 <td class="left"><tt>i32 (i32)</tt></td>
1033 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1034 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1035 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1036 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1037 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1038 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1039 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1040 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1041 <tt>float</tt>.
1042 </td>
1043 </tr><tr class="layout">
1044 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1045 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1046 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1047 which returns an integer. This is the signature for <tt>printf</tt> in
1048 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1049 </td>
1050 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1051</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1052
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1053</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1054<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1055<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1056<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1057<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1058<p>The structure type is used to represent a collection of data members
1059together in memory. The packing of the field types is defined to match
1060the ABI of the underlying processor. The elements of a structure may
1061be any type that has a size.</p>
1062<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1063and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1064field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1065instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1066<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1067<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1068<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1069<table class="layout">
1070 <tr class="layout">
1071 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1072 <tt>{ i32, i32, i32 }</tt><br/>
1073 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1074 </td>
1075 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1076 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1077 A pair, where the first element is a <tt>float</tt> and the second element
1078 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]1079 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1080 </td>
1081 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1082</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1083</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1084
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1085<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1086<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1087</div>
1088<div class="doc_text">
1089<h5>Overview:</h5>
1090<p>The packed structure type is used to represent a collection of data members
1091together in memory. There is no padding between fields. Further, the alignment
1092of a packed structure is 1 byte. The elements of a packed structure may
1093be any type that has a size.</p>
1094<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1095and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1096field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1097instruction.</p>
1098<h5>Syntax:</h5>
1099<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1100<h5>Examples:</h5>
1101<table class="layout">
1102 <tr class="layout">
1103 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1104 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1105 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1106 </td>
1107 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1108 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1109 A pair, where the first element is a <tt>float</tt> and the second element
1110 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]1111 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1112 </td>
1113 </tr>
1114</table>
1115</div>
1116
1117<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1118<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1119<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1120<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1121<p>As in many languages, the pointer type represents a pointer or
1122reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1123<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1124<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1125<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1126<table class="layout">
1127 <tr class="layout">
1128 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1129 <tt>[4x i32]*</tt><br/>
1130 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1131 </td>
1132 <td class="left">
1133 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]1134 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1135 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1136 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1137 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1138 </td>
1139 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1140</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1141</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1142
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1143<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1144<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1145<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1146
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1147<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1148
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1149<p>A vector type is a simple derived type that represents a vector
1150of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1151are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1152A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1153elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1154of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1155considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1156
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1157<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1158
1159<pre>
1160 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1161</pre>
1162
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1163<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1164be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1165
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1166<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1167
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1168<table class="layout">
1169 <tr class="layout">
1170 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1171 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1172 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1173 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1174 </td>
1175 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1176 Vector of 4 32-bit integer values.<br/>
1177 Vector of 8 floating-point values.<br/>
1178 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1179 </td>
1180 </tr>
1181</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1182</div>
1183
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1184<!-- _______________________________________________________________________ -->
1185<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1186<div class="doc_text">
1187
1188<h5>Overview:</h5>
1189
1190<p>Opaque types are used to represent unknown types in the system. This
1191corresponds (for example) to the C notion of a foward declared structure type.
1192In LLVM, opaque types can eventually be resolved to any type (not just a
1193structure type).</p>
1194
1195<h5>Syntax:</h5>
1196
1197<pre>
1198 opaque
1199</pre>
1200
1201<h5>Examples:</h5>
1202
1203<table class="layout">
1204 <tr class="layout">
1205 <td class="left">
1206 <tt>opaque</tt>
1207 </td>
1208 <td class="left">
1209 An opaque type.<br/>
1210 </td>
1211 </tr>
1212</table>
1213</div>
1214
1215
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1216<!-- *********************************************************************** -->
1217<div class="doc_section"> <a name="constants">Constants</a> </div>
1218<!-- *********************************************************************** -->
1219
1220<div class="doc_text">
1221
1222<p>LLVM has several different basic types of constants. This section describes
1223them all and their syntax.</p>
1224
1225</div>
1226
1227<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1228<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1229
1230<div class="doc_text">
1231
1232<dl>
1233 <dt><b>Boolean constants</b></dt>
1234
1235 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1236 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1237 </dd>
1238
1239 <dt><b>Integer constants</b></dt>
1240
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1241 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1242 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1243 integer types.
1244 </dd>
1245
1246 <dt><b>Floating point constants</b></dt>
1247
1248 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1249 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1250 notation (see below). Floating point constants must have a <a
1251 href="#t_floating">floating point</a> type. </dd>
1252
1253 <dt><b>Null pointer constants</b></dt>
1254
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1255 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1256 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1257
1258</dl>
1259
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1260<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1261of floating point constants. For example, the form '<tt>double
12620x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12634.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1264(and the only time that they are generated by the disassembler) is when a
1265floating point constant must be emitted but it cannot be represented as a
1266decimal floating point number. For example, NaN's, infinities, and other
1267special values are represented in their IEEE hexadecimal format so that
1268assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1269
1270</div>
1271
1272<!-- ======================================================================= -->
1273<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1274</div>
1275
1276<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1277<p>Aggregate constants arise from aggregation of simple constants
1278and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1279
1280<dl>
1281 <dt><b>Structure constants</b></dt>
1282
1283 <dd>Structure constants are represented with notation similar to structure
1284 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1285 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1286 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]1287 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1288 types of elements must match those specified by the type.
1289 </dd>
1290
1291 <dt><b>Array constants</b></dt>
1292
1293 <dd>Array constants are represented with notation similar to array type
1294 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1295 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1296 constants must have <a href="#t_array">array type</a>, and the number and
1297 types of elements must match those specified by the type.
1298 </dd>
1299
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1300 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1301
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1302 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1303 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1304 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]1305 i32 11, i32 74, i32 100 &gt;</tt>". VEctor constants must have <a
1306 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1307 match those specified by the type.
1308 </dd>
1309
1310 <dt><b>Zero initialization</b></dt>
1311
1312 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1313 value to zero of <em>any</em> type, including scalar and aggregate types.
1314 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]1315 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1316 initializers.
1317 </dd>
1318</dl>
1319
1320</div>
1321
1322<!-- ======================================================================= -->
1323<div class="doc_subsection">
1324 <a name="globalconstants">Global Variable and Function Addresses</a>
1325</div>
1326
1327<div class="doc_text">
1328
1329<p>The addresses of <a href="#globalvars">global variables</a> and <a
1330href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1331constants. These constants are explicitly referenced when the <a
1332href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1333href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1334file:</p>
1335
1336<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1337 %X = global i32 17
1338 %Y = global i32 42
1339 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1340</pre>
1341
1342</div>
1343
1344<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1345<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1346<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1347 <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]1348 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1349 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1350
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1351 <p>Undefined values indicate to the compiler that the program is well defined
1352 no matter what value is used, giving the compiler more freedom to optimize.
1353 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1354</div>
1355
1356<!-- ======================================================================= -->
1357<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1358</div>
1359
1360<div class="doc_text">
1361
1362<p>Constant expressions are used to allow expressions involving other constants
1363to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1364href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1365that does not have side effects (e.g. load and call are not supported). The
1366following is the syntax for constant expressions:</p>
1367
1368<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1369 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1370 <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]1371 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1373 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1374 <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]1375 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]1376
1377 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1378 <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]1379 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]1380
1381 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1382 <dd>Truncate a floating point constant to another floating point type. The
1383 size of CST must be larger than the size of TYPE. Both types must be
1384 floating point.</dd>
1385
1386 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1387 <dd>Floating point extend a constant to another type. The size of CST must be
1388 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1389
1390 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1391 <dd>Convert a floating point constant to the corresponding unsigned integer
1392 constant. TYPE must be an integer type. CST must be floating point. If the
1393 value won't fit in the integer type, the results are undefined.</dd>
1394
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1395 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1396 <dd>Convert a floating point constant to the corresponding signed integer
1397 constant. TYPE must be an integer type. CST must be floating point. If the
1398 value won't fit in the integer type, the results are undefined.</dd>
1399
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1400 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1401 <dd>Convert an unsigned integer constant to the corresponding floating point
1402 constant. TYPE must be floating point. CST must be of integer type. If the
1403 value won't fit in the floating point type, the results are undefined.</dd>
1404
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1405 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1406 <dd>Convert a signed integer constant to the corresponding floating point
1407 constant. TYPE must be floating point. CST must be of integer type. If the
1408 value won't fit in the floating point type, the results are undefined.</dd>
1409
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1410 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1411 <dd>Convert a pointer typed constant to the corresponding integer constant
1412 TYPE must be an integer type. CST must be of pointer type. The CST value is
1413 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1414
1415 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1416 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1417 pointer type. CST must be of integer type. The CST value is zero extended,
1418 truncated, or unchanged to make it fit in a pointer size. This one is
1419 <i>really</i> dangerous!</dd>
1420
1421 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1422 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1423 identical (same number of bits). The conversion is done as if the CST value
1424 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]1425 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1426 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]1427 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1428 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1429
1430 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1431
1432 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1433 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1434 instruction, the index list may have zero or more indexes, which are required
1435 to make sense for the type of "CSTPTR".</dd>
1436
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1437 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1438
1439 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1440 constants.</dd>
1441
1442 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1443 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1444
1445 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1446 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1447
1448 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1449
1450 <dd>Perform the <a href="#i_extractelement">extractelement
1451 operation</a> on constants.
1452
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1453 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1454
1455 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1456 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1457
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1458
1459 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1460
1461 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1462 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1463
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1464 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1465
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1466 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1467 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1468 binary</a> operations. The constraints on operands are the same as those for
1469 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1470 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1471</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1472</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1473
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1474<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1475<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1476<!-- *********************************************************************** -->
1477
1478<!-- ======================================================================= -->
1479<div class="doc_subsection">
1480<a name="inlineasm">Inline Assembler Expressions</a>
1481</div>
1482
1483<div class="doc_text">
1484
1485<p>
1486LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1487Module-Level Inline Assembly</a>) through the use of a special value. This
1488value represents the inline assembler as a string (containing the instructions
1489to emit), a list of operand constraints (stored as a string), and a flag that
1490indicates whether or not the inline asm expression has side effects. An example
1491inline assembler expression is:
1492</p>
1493
1494<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1495 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1496</pre>
1497
1498<p>
1499Inline assembler expressions may <b>only</b> be used as the callee operand of
1500a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1501</p>
1502
1503<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1504 %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]1505</pre>
1506
1507<p>
1508Inline asms with side effects not visible in the constraint list must be marked
1509as having side effects. This is done through the use of the
1510'<tt>sideeffect</tt>' keyword, like so:
1511</p>
1512
1513<pre>
1514 call void asm sideeffect "eieio", ""()
1515</pre>
1516
1517<p>TODO: The format of the asm and constraints string still need to be
1518documented here. Constraints on what can be done (e.g. duplication, moving, etc
1519need to be documented).
1520</p>
1521
1522</div>
1523
1524<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1525<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1526<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1527
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1528<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1529
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1530<p>The LLVM instruction set consists of several different
1531classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1532instructions</a>, <a href="#binaryops">binary instructions</a>,
1533<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1534 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1535instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1537</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1539<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1540<div class="doc_subsection"> <a name="terminators">Terminator
1541Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1543<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1544
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1545<p>As mentioned <a href="#functionstructure">previously</a>, every
1546basic block in a program ends with a "Terminator" instruction, which
1547indicates which block should be executed after the current block is
1548finished. These terminator instructions typically yield a '<tt>void</tt>'
1549value: they produce control flow, not values (the one exception being
1550the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1551<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1552 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1553instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1554the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1555 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1556 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1557
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1558</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1559
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1560<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1561<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1562Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1563<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1564<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1565<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]1566 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1567</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1568<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1569<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1570value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1571<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1572returns a value and then causes control flow, and one that just causes
1573control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1574<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1575<p>The '<tt>ret</tt>' instruction may return any '<a
1576 href="#t_firstclass">first class</a>' type. Notice that a function is
1577not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1578instruction inside of the function that returns a value that does not
1579match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1580<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1581<p>When the '<tt>ret</tt>' instruction is executed, control flow
1582returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1583 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1584the instruction after the call. If the caller was an "<a
1585 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1586at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1587returns a value, that value shall set the call or invoke instruction's
1588return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1590<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1591 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1593</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1594<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1595<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1596<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1598<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]1599</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1600<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1601<p>The '<tt>br</tt>' instruction is used to cause control flow to
1602transfer to a different basic block in the current function. There are
1603two forms of this instruction, corresponding to a conditional branch
1604and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1605<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1606<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1607single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1608unconditional form of the '<tt>br</tt>' instruction takes a single
1609'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1610<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1611<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1612argument is evaluated. If the value is <tt>true</tt>, control flows
1613to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1614control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1615<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1616<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]1617 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]1618</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1619<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1620<div class="doc_subsubsection">
1621 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1622</div>
1623
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1624<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1626
1627<pre>
1628 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1629</pre>
1630
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1631<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1632
1633<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1634several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1635instruction, allowing a branch to occur to one of many possible
1636destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1637
1638
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1639<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1640
1641<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1642comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1643an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1644table is not allowed to contain duplicate constant entries.</p>
1645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1646<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1647
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1648<p>The <tt>switch</tt> instruction specifies a table of values and
1649destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1650table is searched for the given value. If the value is found, control flow is
1651transfered to the corresponding destination; otherwise, control flow is
1652transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1653
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1654<h5>Implementation:</h5>
1655
1656<p>Depending on properties of the target machine and the particular
1657<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1658ways. For example, it could be generated as a series of chained conditional
1659branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1660
1661<h5>Example:</h5>
1662
1663<pre>
1664 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1665 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1666 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1667
1668 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1669 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1670
1671 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1672 switch i32 %val, label %otherwise [ i32 0, label %onzero
1673 i32 1, label %onone
1674 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1675</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1676</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1677
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1679<div class="doc_subsubsection">
1680 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1681</div>
1682
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1686
1687<pre>
1688 &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]1689 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1690</pre>
1691
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1692<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1693
1694<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1695function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1696'<tt>normal</tt>' label or the
1697'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1698"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1699"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1700href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1701continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1702
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1704
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1705<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1706
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1707<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1708 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1709 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1710 convention</a> the call should use. If none is specified, the call defaults
1711 to using C calling conventions.
1712 </li>
1713 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1714 function value being invoked. In most cases, this is a direct function
1715 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1716 an arbitrary pointer to function value.
1717 </li>
1718
1719 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1720 function to be invoked. </li>
1721
1722 <li>'<tt>function args</tt>': argument list whose types match the function
1723 signature argument types. If the function signature indicates the function
1724 accepts a variable number of arguments, the extra arguments can be
1725 specified. </li>
1726
1727 <li>'<tt>normal label</tt>': the label reached when the called function
1728 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1729
1730 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1731 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1732
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1733</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1734
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1736
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1737<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1738href="#i_call">call</a></tt>' instruction in most regards. The primary
1739difference is that it establishes an association with a label, which is used by
1740the runtime library to unwind the stack.</p>
1741
1742<p>This instruction is used in languages with destructors to ensure that proper
1743cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1744exception. Additionally, this is important for implementation of
1745'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1746
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1747<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1748<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1749 %retval = invoke i32 %Test(i32 15) to label %Continue
1750 unwind label %TestCleanup <i>; {i32}:retval set</i>
1751 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1752 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1754</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1755
1756
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1757<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1758
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1759<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1760Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1762<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1763
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1764<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1765<pre>
1766 unwind
1767</pre>
1768
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1769<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1770
1771<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1772at the first callee in the dynamic call stack which used an <a
1773href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1774primarily used to implement exception handling.</p>
1775
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1776<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1777
1778<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1779immediately halt. The dynamic call stack is then searched for the first <a
1780href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1781execution continues at the "exceptional" destination block specified by the
1782<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1783dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1784</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1785
1786<!-- _______________________________________________________________________ -->
1787
1788<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1789Instruction</a> </div>
1790
1791<div class="doc_text">
1792
1793<h5>Syntax:</h5>
1794<pre>
1795 unreachable
1796</pre>
1797
1798<h5>Overview:</h5>
1799
1800<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1801instruction is used to inform the optimizer that a particular portion of the
1802code is not reachable. This can be used to indicate that the code after a
1803no-return function cannot be reached, and other facts.</p>
1804
1805<h5>Semantics:</h5>
1806
1807<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1808</div>
1809
1810
1811
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1812<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1813<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1814<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1815<p>Binary operators are used to do most of the computation in a
1816program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1817produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1818multiple 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]1819The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1820necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1821<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1822</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1823<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1824<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1825Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1826<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1827<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1828<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]1829</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1830<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1831<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1832<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1833<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1834 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1835 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]1836Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1838<p>The value produced is the integer or floating point sum of the two
1839operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1840<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1841<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]1842</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1843</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1845<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1846Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1847<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1848<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1849<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]1850</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1851<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1852<p>The '<tt>sub</tt>' instruction returns the difference of its two
1853operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1854<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1855instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1856<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1857<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1858 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1859values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1860This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1861Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1862<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1863<p>The value produced is the integer or floating point difference of
1864the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1866<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1867 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1868</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1869</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1870<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1871<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1872Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1873<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1874<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1875<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]1876</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<p>The '<tt>mul</tt>' instruction returns the product of its two
1879operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1881<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1882 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1883values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1884This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1885Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1886<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1887<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1888two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1889<p>Because the operands are the same width, the result of an integer
1890multiplication is the same whether the operands should be deemed unsigned or
1891signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1893<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]1894</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1895</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1896<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1897<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1898</a></div>
1899<div class="doc_text">
1900<h5>Syntax:</h5>
1901<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1902</pre>
1903<h5>Overview:</h5>
1904<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1905operands.</p>
1906<h5>Arguments:</h5>
1907<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1908<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1909types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1910of the values in which case the elements must be integers.</p>
1911<h5>Semantics:</h5>
1912<p>The value produced is the unsigned integer quotient of the two operands. This
1913instruction always performs an unsigned division operation, regardless of
1914whether the arguments are unsigned or not.</p>
1915<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1916<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]1917</pre>
1918</div>
1919<!-- _______________________________________________________________________ -->
1920<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1921</a> </div>
1922<div class="doc_text">
1923<h5>Syntax:</h5>
1924<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1925</pre>
1926<h5>Overview:</h5>
1927<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1928operands.</p>
1929<h5>Arguments:</h5>
1930<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1931<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1932types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1933of the values in which case the elements must be integers.</p>
1934<h5>Semantics:</h5>
1935<p>The value produced is the signed integer quotient of the two operands. This
1936instruction always performs a signed division operation, regardless of whether
1937the arguments are signed or not.</p>
1938<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1939<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]1940</pre>
1941</div>
1942<!-- _______________________________________________________________________ -->
1943<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1944Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1946<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1947<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]1948</pre>
1949<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1950<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1951operands.</p>
1952<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1953<p>The two arguments to the '<tt>div</tt>' instruction must be
1954<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1955identical types. This instruction can also take <a href="#t_vector">vector</a>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1956versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1957<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1958<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1959<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1960<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]1961</pre>
1962</div>
1963<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1964<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1965</div>
1966<div class="doc_text">
1967<h5>Syntax:</h5>
1968<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1969</pre>
1970<h5>Overview:</h5>
1971<p>The '<tt>urem</tt>' instruction returns the remainder from the
1972unsigned division of its two arguments.</p>
1973<h5>Arguments:</h5>
1974<p>The two arguments to the '<tt>urem</tt>' instruction must be
1975<a href="#t_integer">integer</a> values. Both arguments must have identical
1976types.</p>
1977<h5>Semantics:</h5>
1978<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1979This instruction always performs an unsigned division to get the remainder,
1980regardless of whether the arguments are unsigned or not.</p>
1981<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1982<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]1983</pre>
1984
1985</div>
1986<!-- _______________________________________________________________________ -->
1987<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1988Instruction</a> </div>
1989<div class="doc_text">
1990<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1991<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]1992</pre>
1993<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1994<p>The '<tt>srem</tt>' instruction returns the remainder from the
1995signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1996<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1997<p>The two arguments to the '<tt>srem</tt>' instruction must be
1998<a href="#t_integer">integer</a> values. Both arguments must have identical
1999types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2000<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2001<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2002has the same sign as the divisor), not the <i>modulus</i> (where the
2003result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2004information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2005 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2006Math Forum</a>.</p>
2007<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2008<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]2009</pre>
2010
2011</div>
2012<!-- _______________________________________________________________________ -->
2013<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2014Instruction</a> </div>
2015<div class="doc_text">
2016<h5>Syntax:</h5>
2017<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2018</pre>
2019<h5>Overview:</h5>
2020<p>The '<tt>frem</tt>' instruction returns the remainder from the
2021division of its two operands.</p>
2022<h5>Arguments:</h5>
2023<p>The two arguments to the '<tt>frem</tt>' instruction must be
2024<a href="#t_floating">floating point</a> values. Both arguments must have
2025identical types.</p>
2026<h5>Semantics:</h5>
2027<p>This instruction returns the <i>remainder</i> of a division.</p>
2028<h5>Example:</h5>
2029<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]2030</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2031</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2032
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2033<!-- ======================================================================= -->
2034<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2035Operations</a> </div>
2036<div class="doc_text">
2037<p>Bitwise binary operators are used to do various forms of
2038bit-twiddling in a program. They are generally very efficient
2039instructions and can commonly be strength reduced from other
2040instructions. They require two operands, execute an operation on them,
2041and produce a single value. The resulting value of the bitwise binary
2042operators is always the same type as its first operand.</p>
2043</div>
2044
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2045<!-- _______________________________________________________________________ -->
2046<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2047Instruction</a> </div>
2048<div class="doc_text">
2049<h5>Syntax:</h5>
2050<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2051</pre>
2052<h5>Overview:</h5>
2053<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2054the left a specified number of bits.</p>
2055<h5>Arguments:</h5>
2056<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2057 href="#t_integer">integer</a> type.</p>
2058<h5>Semantics:</h5>
2059<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2060<h5>Example:</h5><pre>
2061 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2062 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2063 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2064</pre>
2065</div>
2066<!-- _______________________________________________________________________ -->
2067<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2068Instruction</a> </div>
2069<div class="doc_text">
2070<h5>Syntax:</h5>
2071<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2072</pre>
2073
2074<h5>Overview:</h5>
2075<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2076operand shifted to the right a specified number of bits.</p>
2077
2078<h5>Arguments:</h5>
2079<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2080<a href="#t_integer">integer</a> type.</p>
2081
2082<h5>Semantics:</h5>
2083<p>This instruction always performs a logical shift right operation. The most
2084significant bits of the result will be filled with zero bits after the
2085shift.</p>
2086
2087<h5>Example:</h5>
2088<pre>
2089 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2090 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2091 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2092 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2093</pre>
2094</div>
2095
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2096<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2097<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2098Instruction</a> </div>
2099<div class="doc_text">
2100
2101<h5>Syntax:</h5>
2102<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2103</pre>
2104
2105<h5>Overview:</h5>
2106<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2107operand shifted to the right a specified number of bits.</p>
2108
2109<h5>Arguments:</h5>
2110<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2111<a href="#t_integer">integer</a> type.</p>
2112
2113<h5>Semantics:</h5>
2114<p>This instruction always performs an arithmetic shift right operation,
2115The most significant bits of the result will be filled with the sign bit
2116of <tt>var1</tt>.</p>
2117
2118<h5>Example:</h5>
2119<pre>
2120 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2121 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2122 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2123 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2124</pre>
2125</div>
2126
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2127<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2128<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2129Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2130<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2131<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2132<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]2133</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2134<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2135<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2136its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2138<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2139 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2140identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2141<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2142<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2143<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2144<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2145<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2146 <tbody>
2147 <tr>
2148 <td>In0</td>
2149 <td>In1</td>
2150 <td>Out</td>
2151 </tr>
2152 <tr>
2153 <td>0</td>
2154 <td>0</td>
2155 <td>0</td>
2156 </tr>
2157 <tr>
2158 <td>0</td>
2159 <td>1</td>
2160 <td>0</td>
2161 </tr>
2162 <tr>
2163 <td>1</td>
2164 <td>0</td>
2165 <td>0</td>
2166 </tr>
2167 <tr>
2168 <td>1</td>
2169 <td>1</td>
2170 <td>1</td>
2171 </tr>
2172 </tbody>
2173</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2174</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2175<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2176<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2177 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2178 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2179</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2180</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2181<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2182<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2183<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2184<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2185<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]2186</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2187<h5>Overview:</h5>
2188<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2189or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2190<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2191<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2192 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2193identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2194<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2195<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2196<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2197<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2198<table border="1" cellspacing="0" cellpadding="4">
2199 <tbody>
2200 <tr>
2201 <td>In0</td>
2202 <td>In1</td>
2203 <td>Out</td>
2204 </tr>
2205 <tr>
2206 <td>0</td>
2207 <td>0</td>
2208 <td>0</td>
2209 </tr>
2210 <tr>
2211 <td>0</td>
2212 <td>1</td>
2213 <td>1</td>
2214 </tr>
2215 <tr>
2216 <td>1</td>
2217 <td>0</td>
2218 <td>1</td>
2219 </tr>
2220 <tr>
2221 <td>1</td>
2222 <td>1</td>
2223 <td>1</td>
2224 </tr>
2225 </tbody>
2226</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2227</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2228<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2229<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2230 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2231 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2232</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2233</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2234<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2235<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2236Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2237<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2238<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2239<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]2240</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2241<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2242<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2243or of its two operands. The <tt>xor</tt> is used to implement the
2244"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2245<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2246<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2247 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2248identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2249<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2250<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2251<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2252<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2253<table border="1" cellspacing="0" cellpadding="4">
2254 <tbody>
2255 <tr>
2256 <td>In0</td>
2257 <td>In1</td>
2258 <td>Out</td>
2259 </tr>
2260 <tr>
2261 <td>0</td>
2262 <td>0</td>
2263 <td>0</td>
2264 </tr>
2265 <tr>
2266 <td>0</td>
2267 <td>1</td>
2268 <td>1</td>
2269 </tr>
2270 <tr>
2271 <td>1</td>
2272 <td>0</td>
2273 <td>1</td>
2274 </tr>
2275 <tr>
2276 <td>1</td>
2277 <td>1</td>
2278 <td>0</td>
2279 </tr>
2280 </tbody>
2281</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2282</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2283<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2284<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2285<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2286 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2287 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2288 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2289</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2290</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2291
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2292<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2293<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2294 <a name="vectorops">Vector Operations</a>
2295</div>
2296
2297<div class="doc_text">
2298
2299<p>LLVM supports several instructions to represent vector operations in a
2300target-independent manner. This instructions cover the element-access and
2301vector-specific operations needed to process vectors effectively. While LLVM
2302does directly support these vector operations, many sophisticated algorithms
2303will want to use target-specific intrinsics to take full advantage of a specific
2304target.</p>
2305
2306</div>
2307
2308<!-- _______________________________________________________________________ -->
2309<div class="doc_subsubsection">
2310 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2311</div>
2312
2313<div class="doc_text">
2314
2315<h5>Syntax:</h5>
2316
2317<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2318 &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]2319</pre>
2320
2321<h5>Overview:</h5>
2322
2323<p>
2324The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2325element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2326</p>
2327
2328
2329<h5>Arguments:</h5>
2330
2331<p>
2332The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2333value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2334an index indicating the position from which to extract the element.
2335The index may be a variable.</p>
2336
2337<h5>Semantics:</h5>
2338
2339<p>
2340The result is a scalar of the same type as the element type of
2341<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2342<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2343results are undefined.
2344</p>
2345
2346<h5>Example:</h5>
2347
2348<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2349 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2350</pre>
2351</div>
2352
2353
2354<!-- _______________________________________________________________________ -->
2355<div class="doc_subsubsection">
2356 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2357</div>
2358
2359<div class="doc_text">
2360
2361<h5>Syntax:</h5>
2362
2363<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2364 &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]2365</pre>
2366
2367<h5>Overview:</h5>
2368
2369<p>
2370The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2371element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2372</p>
2373
2374
2375<h5>Arguments:</h5>
2376
2377<p>
2378The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2379value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2380scalar value whose type must equal the element type of the first
2381operand. The third operand is an index indicating the position at
2382which to insert the value. The index may be a variable.</p>
2383
2384<h5>Semantics:</h5>
2385
2386<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2387The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2388element values are those of <tt>val</tt> except at position
2389<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2390exceeds the length of <tt>val</tt>, the results are undefined.
2391</p>
2392
2393<h5>Example:</h5>
2394
2395<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2396 %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]2397</pre>
2398</div>
2399
2400<!-- _______________________________________________________________________ -->
2401<div class="doc_subsubsection">
2402 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2403</div>
2404
2405<div class="doc_text">
2406
2407<h5>Syntax:</h5>
2408
2409<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2410 &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]2411</pre>
2412
2413<h5>Overview:</h5>
2414
2415<p>
2416The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2417from two input vectors, returning a vector of the same type.
2418</p>
2419
2420<h5>Arguments:</h5>
2421
2422<p>
2423The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2424with types that match each other and types that match the result of the
2425instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2426of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2427</p>
2428
2429<p>
2430The shuffle mask operand is required to be a constant vector with either
2431constant integer or undef values.
2432</p>
2433
2434<h5>Semantics:</h5>
2435
2436<p>
2437The elements of the two input vectors are numbered from left to right across
2438both of the vectors. The shuffle mask operand specifies, for each element of
2439the result vector, which element of the two input registers the result element
2440gets. The element selector may be undef (meaning "don't care") and the second
2441operand may be undef if performing a shuffle from only one vector.
2442</p>
2443
2444<h5>Example:</h5>
2445
2446<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2447 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2448 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2449 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2450 &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]2451</pre>
2452</div>
2453
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2454
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2455<!-- ======================================================================= -->
2456<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2457 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2458</div>
2459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2460<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2461
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2462<p>A key design point of an SSA-based representation is how it
2463represents memory. In LLVM, no memory locations are in SSA form, which
2464makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2465allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2466
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2467</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2468
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2469<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470<div class="doc_subsubsection">
2471 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2472</div>
2473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2474<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2475
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2476<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2477
2478<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2479 &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]2480</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2481
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2483
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2484<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2485heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2486
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2487<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2488
2489<p>The '<tt>malloc</tt>' instruction allocates
2490<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2491bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2492appropriate type to the program. If "NumElements" is specified, it is the
2493number of elements allocated. If an alignment is specified, the value result
2494of the allocation is guaranteed to be aligned to at least that boundary. If
2495not specified, or if zero, the target can choose to align the allocation on any
2496convenient boundary.</p>
2497
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2498<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2499
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2500<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2501
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2502<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2503a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2504
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2505<h5>Example:</h5>
2506
2507<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2508 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2509
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2510 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2511 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2512 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2513 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2514 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2515</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2516</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2517
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2518<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2519<div class="doc_subsubsection">
2520 <a name="i_free">'<tt>free</tt>' Instruction</a>
2521</div>
2522
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2523<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2524
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2525<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2526
2527<pre>
2528 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2529</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2531<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2532
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2533<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2534memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2535
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2536<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2537
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2538<p>'<tt>value</tt>' shall be a pointer value that points to a value
2539that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2540instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2542<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2543
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2544<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2545after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2546
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2547<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2548
2549<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2550 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2551 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2552</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2553</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2554
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2555<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2556<div class="doc_subsubsection">
2557 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2558</div>
2559
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2560<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2561
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2562<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2563
2564<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2565 &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]2566</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2567
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2568<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2569
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2570<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2571stack frame of the procedure that is live until the current function
2572returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2574<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2575
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2576<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2577bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2578appropriate type to the program. If "NumElements" is specified, it is the
2579number of elements allocated. If an alignment is specified, the value result
2580of the allocation is guaranteed to be aligned to at least that boundary. If
2581not specified, or if zero, the target can choose to align the allocation on any
2582convenient boundary.</p>
2583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2584<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2585
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2586<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2587
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2588<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2589memory is automatically released when the function returns. The '<tt>alloca</tt>'
2590instruction is commonly used to represent automatic variables that must
2591have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2592 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]2593instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2595<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596
2597<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2598 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2599 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2600 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2601 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2602</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2603</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2606<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2607Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2608<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2609<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2610<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]2611<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2612<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2613<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2614<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2615address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2616 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2617marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2618the number or order of execution of this <tt>load</tt> with other
2619volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2620instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2621<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2622<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2623<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2624<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2625 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2626 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2627 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2628</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2629</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2630<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2631<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2632Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2633<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2634<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2635<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]2636 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]2637</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2638<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2639<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2640<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2641<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2642to 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]2643operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2644operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2645optimizer is not allowed to modify the number or order of execution of
2646this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2647 href="#i_store">store</a></tt> instructions.</p>
2648<h5>Semantics:</h5>
2649<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2650at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2651<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2652<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2653 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2654 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2655 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2656</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2657</div>
2658
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2659<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2660<div class="doc_subsubsection">
2661 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2662</div>
2663
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2664<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2665<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2666<pre>
2667 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2668</pre>
2669
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2670<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2671
2672<p>
2673The '<tt>getelementptr</tt>' instruction is used to get the address of a
2674subelement of an aggregate data structure.</p>
2675
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2676<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2677
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2678<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2679elements of the aggregate object to index to. The actual types of the arguments
2680provided depend on the type of the first pointer argument. The
2681'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2682levels 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]2683structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2684into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2685be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2686
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2687<p>For example, let's consider a C code fragment and how it gets
2688compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2689
2690<pre>
2691 struct RT {
2692 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2693 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2694 char C;
2695 };
2696 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2697 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2698 double Y;
2699 struct RT Z;
2700 };
2701
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2702 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2703 return &amp;s[1].Z.B[5][13];
2704 }
2705</pre>
2706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2707<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2708
2709<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2710 %RT = type { i8 , [10 x [20 x i32]], i8 }
2711 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2712
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2713 implementation
2714
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2715 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2716 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2717 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2718 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2719 }
2720</pre>
2721
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2722<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2723
2724<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2725on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2726and <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]2727<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]2728to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2729<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2730
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2731<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]2732type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2733}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2734the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2735i8 }</tt>' type, another structure. The third index indexes into the second
2736element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2737array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2738'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2739to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2740
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2741<p>Note that it is perfectly legal to index partially through a
2742structure, returning a pointer to an inner element. Because of this,
2743the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2744
2745<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2746 define i32* %foo(%ST* %s) {
2747 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2748 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2749 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2750 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2751 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2752 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2753 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2754</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2755
2756<p>Note that it is undefined to access an array out of bounds: array and
2757pointer indexes must always be within the defined bounds of the array type.
2758The one exception for this rules is zero length arrays. These arrays are
2759defined to be accessible as variable length arrays, which requires access
2760beyond the zero'th element.</p>
2761
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2762<p>The getelementptr instruction is often confusing. For some more insight
2763into how it works, see <a href="GetElementPtr.html">the getelementptr
2764FAQ</a>.</p>
2765
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2766<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2767
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2768<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2769 <i>; yields [12 x i8]*:aptr</i>
2770 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2772</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2773
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2774<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2775<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2776</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2777<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2778<p>The instructions in this category are the conversion instructions (casting)
2779which all take a single operand and a type. They perform various bit conversions
2780on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2781</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2782
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2783<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2784<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2785 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2786</div>
2787<div class="doc_text">
2788
2789<h5>Syntax:</h5>
2790<pre>
2791 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2792</pre>
2793
2794<h5>Overview:</h5>
2795<p>
2796The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2797</p>
2798
2799<h5>Arguments:</h5>
2800<p>
2801The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2802be 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]2803and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2804type. The bit size of <tt>value</tt> must be larger than the bit size of
2805<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2806
2807<h5>Semantics:</h5>
2808<p>
2809The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2810and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2811larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2812It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2813
2814<h5>Example:</h5>
2815<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2816 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2817 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2818 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2819</pre>
2820</div>
2821
2822<!-- _______________________________________________________________________ -->
2823<div class="doc_subsubsection">
2824 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2825</div>
2826<div class="doc_text">
2827
2828<h5>Syntax:</h5>
2829<pre>
2830 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2831</pre>
2832
2833<h5>Overview:</h5>
2834<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2835<tt>ty2</tt>.</p>
2836
2837
2838<h5>Arguments:</h5>
2839<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]2840<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2841also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2842<tt>value</tt> must be smaller than the bit size of the destination type,
2843<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2844
2845<h5>Semantics:</h5>
2846<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2847bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2848the operand and the type are the same size, no bit filling is done and the
2849cast is considered a <i>no-op cast</i> because no bits change (only the type
2850changes).</p>
2851
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2852<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]2853
2854<h5>Example:</h5>
2855<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2856 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2857 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2858</pre>
2859</div>
2860
2861<!-- _______________________________________________________________________ -->
2862<div class="doc_subsubsection">
2863 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2864</div>
2865<div class="doc_text">
2866
2867<h5>Syntax:</h5>
2868<pre>
2869 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2870</pre>
2871
2872<h5>Overview:</h5>
2873<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2874
2875<h5>Arguments:</h5>
2876<p>
2877The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2878<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2879also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2880<tt>value</tt> must be smaller than the bit size of the destination type,
2881<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2882
2883<h5>Semantics:</h5>
2884<p>
2885The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2886bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2887the type <tt>ty2</tt>. When the the operand and the type are the same size,
2888no bit filling is done and the cast is considered a <i>no-op cast</i> because
2889no bits change (only the type changes).</p>
2890
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2891<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]2892
2893<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2894<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2895 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2896 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2897</pre>
2898</div>
2899
2900<!-- _______________________________________________________________________ -->
2901<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2902 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2903</div>
2904
2905<div class="doc_text">
2906
2907<h5>Syntax:</h5>
2908
2909<pre>
2910 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2911</pre>
2912
2913<h5>Overview:</h5>
2914<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2915<tt>ty2</tt>.</p>
2916
2917
2918<h5>Arguments:</h5>
2919<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2920 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2921cast it to. The size of <tt>value</tt> must be larger than the size of
2922<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2923<i>no-op cast</i>.</p>
2924
2925<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2926<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2927<a href="#t_floating">floating point</a> type to a smaller
2928<a href="#t_floating">floating point</a> type. If the value cannot fit within
2929the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2930
2931<h5>Example:</h5>
2932<pre>
2933 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2934 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2935</pre>
2936</div>
2937
2938<!-- _______________________________________________________________________ -->
2939<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2940 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2941</div>
2942<div class="doc_text">
2943
2944<h5>Syntax:</h5>
2945<pre>
2946 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2947</pre>
2948
2949<h5>Overview:</h5>
2950<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2951floating point value.</p>
2952
2953<h5>Arguments:</h5>
2954<p>The '<tt>fpext</tt>' instruction takes a
2955<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2956and a <a href="#t_floating">floating point</a> type to cast it to. The source
2957type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2958
2959<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2960<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2961<a href="t_floating">floating point</a> type to a larger
2962<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2963used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2964<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]2965
2966<h5>Example:</h5>
2967<pre>
2968 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2969 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2970</pre>
2971</div>
2972
2973<!-- _______________________________________________________________________ -->
2974<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]2975 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2976</div>
2977<div class="doc_text">
2978
2979<h5>Syntax:</h5>
2980<pre>
2981 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2982</pre>
2983
2984<h5>Overview:</h5>
2985<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2986unsigned integer equivalent of type <tt>ty2</tt>.
2987</p>
2988
2989<h5>Arguments:</h5>
2990<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2991<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]2992must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2993
2994<h5>Semantics:</h5>
2995<p> The '<tt>fp2uint</tt>' instruction converts its
2996<a href="#t_floating">floating point</a> operand into the nearest (rounding
2997towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2998the results are undefined.</p>
2999
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3000<p>When converting to i1, the conversion is done as a comparison against
3001zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3002If 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]3003
3004<h5>Example:</h5>
3005<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3006 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3007 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3008 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3009</pre>
3010</div>
3011
3012<!-- _______________________________________________________________________ -->
3013<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3014 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3015</div>
3016<div class="doc_text">
3017
3018<h5>Syntax:</h5>
3019<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3020 &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]3021</pre>
3022
3023<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3024<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3025<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]3026</p>
3027
3028
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3029<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3030<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]3031<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]3032must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3033
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3034<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3035<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3036<a href="#t_floating">floating point</a> operand into the nearest (rounding
3037towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3038the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3039
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3040<p>When converting to i1, the conversion is done as a comparison against
3041zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3042If 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]3043
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3044<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3045<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3046 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3047 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3048 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3049</pre>
3050</div>
3051
3052<!-- _______________________________________________________________________ -->
3053<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3054 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3055</div>
3056<div class="doc_text">
3057
3058<h5>Syntax:</h5>
3059<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3060 &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]3061</pre>
3062
3063<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3064<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3065integer and converts that value to the <tt>ty2</tt> type.</p>
3066
3067
3068<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3069<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]3070<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]3071be a <a href="#t_floating">floating point</a> type.</p>
3072
3073<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3074<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3075integer quantity and converts it to the corresponding floating point value. If
3076the value cannot fit in the floating point value, the results are undefined.</p>
3077
3078
3079<h5>Example:</h5>
3080<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3081 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3082 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3083</pre>
3084</div>
3085
3086<!-- _______________________________________________________________________ -->
3087<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3088 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3089</div>
3090<div class="doc_text">
3091
3092<h5>Syntax:</h5>
3093<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3094 &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]3095</pre>
3096
3097<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3098<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3099integer and converts that value to the <tt>ty2</tt> type.</p>
3100
3101<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3102<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]3103<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]3104a <a href="#t_floating">floating point</a> type.</p>
3105
3106<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3107<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3108integer quantity and converts it to the corresponding floating point value. If
3109the value cannot fit in the floating point value, the results are undefined.</p>
3110
3111<h5>Example:</h5>
3112<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3113 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3114 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3115</pre>
3116</div>
3117
3118<!-- _______________________________________________________________________ -->
3119<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3120 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3121</div>
3122<div class="doc_text">
3123
3124<h5>Syntax:</h5>
3125<pre>
3126 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3127</pre>
3128
3129<h5>Overview:</h5>
3130<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3131the integer type <tt>ty2</tt>.</p>
3132
3133<h5>Arguments:</h5>
3134<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3135must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3136<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3137
3138<h5>Semantics:</h5>
3139<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3140<tt>ty2</tt> by interpreting the pointer value as an integer and either
3141truncating or zero extending that value to the size of the integer type. If
3142<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3143<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3144are the same size, then nothing is done (<i>no-op cast</i>).</p>
3145
3146<h5>Example:</h5>
3147<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3148 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3149 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3150</pre>
3151</div>
3152
3153<!-- _______________________________________________________________________ -->
3154<div class="doc_subsubsection">
3155 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3156</div>
3157<div class="doc_text">
3158
3159<h5>Syntax:</h5>
3160<pre>
3161 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3162</pre>
3163
3164<h5>Overview:</h5>
3165<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3166a pointer type, <tt>ty2</tt>.</p>
3167
3168<h5>Arguments:</h5>
3169<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3170value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3171<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3172
3173<h5>Semantics:</h5>
3174<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3175<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3176the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3177size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3178the size of a pointer then a zero extension is done. If they are the same size,
3179nothing is done (<i>no-op cast</i>).</p>
3180
3181<h5>Example:</h5>
3182<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3183 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3184 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3185 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3186</pre>
3187</div>
3188
3189<!-- _______________________________________________________________________ -->
3190<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3191 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3192</div>
3193<div class="doc_text">
3194
3195<h5>Syntax:</h5>
3196<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3197 &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]3198</pre>
3199
3200<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3201<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3202<tt>ty2</tt> without changing any bits.</p>
3203
3204<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3205<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3206a first class value, and a type to cast it to, which must also be a <a
3207 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3208and the destination type, <tt>ty2</tt>, must be identical. If the source
3209type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3210
3211<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3212<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3213<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3214this conversion. The conversion is done as if the <tt>value</tt> had been
3215stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3216converted to other pointer types with this instruction. To convert pointers to
3217other types, use the <a href="#i_inttoptr">inttoptr</a> or
3218<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3219
3220<h5>Example:</h5>
3221<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3222 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3223 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3224 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3225</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3226</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3227
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3228<!-- ======================================================================= -->
3229<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3230<div class="doc_text">
3231<p>The instructions in this category are the "miscellaneous"
3232instructions, which defy better classification.</p>
3233</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3234
3235<!-- _______________________________________________________________________ -->
3236<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3237</div>
3238<div class="doc_text">
3239<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3240<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3241<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3242</pre>
3243<h5>Overview:</h5>
3244<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3245of its two integer operands.</p>
3246<h5>Arguments:</h5>
3247<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3248the condition code which indicates the kind of comparison to perform. It is not
3249a value, just a keyword. The possibilities for the condition code are:
3250<ol>
3251 <li><tt>eq</tt>: equal</li>
3252 <li><tt>ne</tt>: not equal </li>
3253 <li><tt>ugt</tt>: unsigned greater than</li>
3254 <li><tt>uge</tt>: unsigned greater or equal</li>
3255 <li><tt>ult</tt>: unsigned less than</li>
3256 <li><tt>ule</tt>: unsigned less or equal</li>
3257 <li><tt>sgt</tt>: signed greater than</li>
3258 <li><tt>sge</tt>: signed greater or equal</li>
3259 <li><tt>slt</tt>: signed less than</li>
3260 <li><tt>sle</tt>: signed less or equal</li>
3261</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3262<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3263<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3264<h5>Semantics:</h5>
3265<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3266the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3267yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3268<ol>
3269 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3270 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3271 </li>
3272 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3273 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3274 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3275 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3276 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3277 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3278 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3279 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3280 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3281 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3282 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3283 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3284 <li><tt>sge</tt>: interprets the operands as signed values and yields
3285 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3286 <li><tt>slt</tt>: interprets the operands as signed values and yields
3287 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3288 <li><tt>sle</tt>: interprets the operands as signed values and yields
3289 <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]3290</ol>
3291<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3292values are treated as integers and then compared.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3293
3294<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3295<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3296 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3297 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3298 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3299 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3300 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3301</pre>
3302</div>
3303
3304<!-- _______________________________________________________________________ -->
3305<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3306</div>
3307<div class="doc_text">
3308<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3309<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3310<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3311</pre>
3312<h5>Overview:</h5>
3313<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3314of its floating point operands.</p>
3315<h5>Arguments:</h5>
3316<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3317the condition code which indicates the kind of comparison to perform. It is not
3318a value, just a keyword. The possibilities for the condition code are:
3319<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3320 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3321 <li><tt>oeq</tt>: ordered and equal</li>
3322 <li><tt>ogt</tt>: ordered and greater than </li>
3323 <li><tt>oge</tt>: ordered and greater than or equal</li>
3324 <li><tt>olt</tt>: ordered and less than </li>
3325 <li><tt>ole</tt>: ordered and less than or equal</li>
3326 <li><tt>one</tt>: ordered and not equal</li>
3327 <li><tt>ord</tt>: ordered (no nans)</li>
3328 <li><tt>ueq</tt>: unordered or equal</li>
3329 <li><tt>ugt</tt>: unordered or greater than </li>
3330 <li><tt>uge</tt>: unordered or greater than or equal</li>
3331 <li><tt>ult</tt>: unordered or less than </li>
3332 <li><tt>ule</tt>: unordered or less than or equal</li>
3333 <li><tt>une</tt>: unordered or not equal</li>
3334 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3335 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3336</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3337<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3338<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3339<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3340<a href="#t_floating">floating point</a> typed. They must have identical
3341types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3342<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3343<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3344<h5>Semantics:</h5>
3345<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3346the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3347yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3348<ol>
3349 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3350 <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]3351 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3352 <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]3353 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3354 <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]3355 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3356 <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]3357 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3358 <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]3359 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3360 <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]3361 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3362 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3363 <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]3364 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3365 <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]3366 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3367 <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]3368 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3369 <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]3370 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3371 <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]3372 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3373 <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]3374 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3375 <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]3376 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3377</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3378
3379<h5>Example:</h5>
3380<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3381 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3382 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3383 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3384</pre>
3385</div>
3386
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3387<!-- _______________________________________________________________________ -->
3388<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3389Instruction</a> </div>
3390<div class="doc_text">
3391<h5>Syntax:</h5>
3392<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3393<h5>Overview:</h5>
3394<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3395the SSA graph representing the function.</p>
3396<h5>Arguments:</h5>
3397<p>The type of the incoming values are specified with the first type
3398field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3399as arguments, with one pair for each predecessor basic block of the
3400current block. Only values of <a href="#t_firstclass">first class</a>
3401type may be used as the value arguments to the PHI node. Only labels
3402may be used as the label arguments.</p>
3403<p>There must be no non-phi instructions between the start of a basic
3404block and the PHI instructions: i.e. PHI instructions must be first in
3405a basic block.</p>
3406<h5>Semantics:</h5>
3407<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3408value specified by the parameter, depending on which basic block we
3409came from in the last <a href="#terminators">terminator</a> instruction.</p>
3410<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3411<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]3412</div>
3413
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3414<!-- _______________________________________________________________________ -->
3415<div class="doc_subsubsection">
3416 <a name="i_select">'<tt>select</tt>' Instruction</a>
3417</div>
3418
3419<div class="doc_text">
3420
3421<h5>Syntax:</h5>
3422
3423<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3424 &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]3425</pre>
3426
3427<h5>Overview:</h5>
3428
3429<p>
3430The '<tt>select</tt>' instruction is used to choose one value based on a
3431condition, without branching.
3432</p>
3433
3434
3435<h5>Arguments:</h5>
3436
3437<p>
3438The '<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.
3439</p>
3440
3441<h5>Semantics:</h5>
3442
3443<p>
3444If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3445value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3446</p>
3447
3448<h5>Example:</h5>
3449
3450<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3451 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3452</pre>
3453</div>
3454
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3455
3456<!-- _______________________________________________________________________ -->
3457<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3458 <a name="i_call">'<tt>call</tt>' Instruction</a>
3459</div>
3460
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3461<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3462
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3463<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3464<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3465 &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]3466</pre>
3467
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3468<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3469
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3470<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3471
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3472<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3473
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3474<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3475
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3476<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3477 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3478 <p>The optional "tail" marker indicates whether the callee function accesses
3479 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3480 function call is eligible for tail call optimization. Note that calls may
3481 be marked "tail" even if they do not occur before a <a
3482 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3483 </li>
3484 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3485 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3486 convention</a> the call should use. If none is specified, the call defaults
3487 to using C calling conventions.
3488 </li>
3489 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3490 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3491 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3492 signature. This type can be omitted if the function is not varargs and
3493 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3494 </li>
3495 <li>
3496 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3497 be invoked. In most cases, this is a direct function invocation, but
3498 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3499 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3500 </li>
3501 <li>
3502 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3503 function signature argument types. All arguments must be of
3504 <a href="#t_firstclass">first class</a> type. If the function signature
3505 indicates the function accepts a variable number of arguments, the extra
3506 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3507 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3508</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3509
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3510<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3511
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3512<p>The '<tt>call</tt>' instruction is used to cause control flow to
3513transfer to a specified function, with its incoming arguments bound to
3514the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3515instruction in the called function, control flow continues with the
3516instruction after the function call, and the return value of the
3517function is bound to the result argument. This is a simpler case of
3518the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3519
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3520<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3521
3522<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3523 %retval = call i32 %test(i32 %argc)
3524 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3525 %X = tail call i32 %foo()
3526 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3527</pre>
3528
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3529</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3530
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3531<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3532<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3533 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3534</div>
3535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3536<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3537
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3538<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3539
3540<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3541 &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]3542</pre>
3543
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3544<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3545
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3546<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3547the "variable argument" area of a function call. It is used to implement the
3548<tt>va_arg</tt> macro in C.</p>
3549
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3550<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3551
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3552<p>This instruction takes a <tt>va_list*</tt> value and the type of
3553the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3554increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3555actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3556
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3557<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3558
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3559<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3560type from the specified <tt>va_list</tt> and causes the
3561<tt>va_list</tt> to point to the next argument. For more information,
3562see the variable argument handling <a href="#int_varargs">Intrinsic
3563Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3564
3565<p>It is legal for this instruction to be called in a function which does not
3566take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3567function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3568
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3569<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3570href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3571argument.</p>
3572
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3573<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3574
3575<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3576
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3577</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3578
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3579<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3580<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3581<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3582
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3583<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3584
3585<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3586well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3587restrictions. Overall, these instructions represent an extension mechanism for
3588the LLVM language that does not require changing all of the transformations in
3589LLVM to add to the language (or the bytecode reader/writer, the parser,
3590etc...).</p>
3591
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3592<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3593prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3594this. Intrinsic functions must always be external functions: you cannot define
3595the body of intrinsic functions. Intrinsic functions may only be used in call
3596or invoke instructions: it is illegal to take the address of an intrinsic
3597function. Additionally, because intrinsic functions are part of the LLVM
3598language, it is required that they all be documented here if any are added.</p>
3599
3600
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3601<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3602href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3603</p>
3604
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3605</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3606
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3607<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3608<div class="doc_subsection">
3609 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3610</div>
3611
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3612<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3613
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3614<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3615 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3616intrinsic functions. These functions are related to the similarly
3617named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3618
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3619<p>All of these functions operate on arguments that use a
3620target-specific value type "<tt>va_list</tt>". The LLVM assembly
3621language reference manual does not define what this type is, so all
3622transformations should be prepared to handle intrinsics with any type
3623used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3624
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3625<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]3626instruction and the variable argument handling intrinsic functions are
3627used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3628
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3629<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame^]3630define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3631 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3632 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3633 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame^]3634 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3635
3636 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3637 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3638
3639 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3640 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3641 %aq2 = bitcast i8** %aq to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame^]3642 call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
3643 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3644
3645 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame^]3646 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3647 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3648}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame^]3649
3650declare void @llvm.va_start(i8*)
3651declare void @llvm.va_copy(i8*, i8*)
3652declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3653</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3654</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3655
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3656<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3657<div class="doc_subsubsection">
3658 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3659</div>
3660
3661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3662<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3663<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3664<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3665<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3666<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3667<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3668href="#i_va_arg">va_arg</a></tt>.</p>
3669
3670<h5>Arguments:</h5>
3671
3672<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3673
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3674<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3675
3676<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3677macro available in C. In a target-dependent way, it initializes the
3678<tt>va_list</tt> element the argument points to, so that the next call to
3679<tt>va_arg</tt> will produce the first variable argument passed to the function.
3680Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3681last argument of the function, the compiler can figure that out.</p>
3682
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3683</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3684
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3685<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3686<div class="doc_subsubsection">
3687 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3688</div>
3689
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3690<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3691<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3692<pre> declare void %llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3693<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3694
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3695<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3696which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3697or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3698
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3699<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3700
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3701<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3702
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3703<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3704
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3705<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]3706macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3707Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3708 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3709with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3710
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3711</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3712
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3713<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3714<div class="doc_subsubsection">
3715 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3716</div>
3717
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3718<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3719
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3720<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3721
3722<pre>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3723 declare void %llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3724</pre>
3725
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3726<h5>Overview:</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 '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3729the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3730
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3731<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3732
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3733<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]3734The 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]3735
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3736
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3737<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3738
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3739<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3740available in C. In a target-dependent way, it copies the source
3741<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3742because 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]3743arbitrarily complex and require memory allocation, for example.</p>
3744
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3745</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3746
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3747<!-- ======================================================================= -->
3748<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3749 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3750</div>
3751
3752<div class="doc_text">
3753
3754<p>
3755LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3756Collection</a> requires the implementation and generation of these intrinsics.
3757These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3758stack</a>, as well as garbage collector implementations that require <a
3759href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3760Front-ends for type-safe garbage collected languages should generate these
3761intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3762href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3763</p>
3764</div>
3765
3766<!-- _______________________________________________________________________ -->
3767<div class="doc_subsubsection">
3768 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3769</div>
3770
3771<div class="doc_text">
3772
3773<h5>Syntax:</h5>
3774
3775<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3776 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3777</pre>
3778
3779<h5>Overview:</h5>
3780
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3781<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]3782the code generator, and allows some metadata to be associated with it.</p>
3783
3784<h5>Arguments:</h5>
3785
3786<p>The first argument specifies the address of a stack object that contains the
3787root pointer. The second pointer (which must be either a constant or a global
3788value address) contains the meta-data to be associated with the root.</p>
3789
3790<h5>Semantics:</h5>
3791
3792<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3793location. At compile-time, the code generator generates information to allow
3794the runtime to find the pointer at GC safe points.
3795</p>
3796
3797</div>
3798
3799
3800<!-- _______________________________________________________________________ -->
3801<div class="doc_subsubsection">
3802 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3803</div>
3804
3805<div class="doc_text">
3806
3807<h5>Syntax:</h5>
3808
3809<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3810 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3811</pre>
3812
3813<h5>Overview:</h5>
3814
3815<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3816locations, allowing garbage collector implementations that require read
3817barriers.</p>
3818
3819<h5>Arguments:</h5>
3820
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3821<p>The second argument is the address to read from, which should be an address
3822allocated from the garbage collector. The first object is a pointer to the
3823start of the referenced object, if needed by the language runtime (otherwise
3824null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3825
3826<h5>Semantics:</h5>
3827
3828<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3829instruction, but may be replaced with substantially more complex code by the
3830garbage collector runtime, as needed.</p>
3831
3832</div>
3833
3834
3835<!-- _______________________________________________________________________ -->
3836<div class="doc_subsubsection">
3837 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3838</div>
3839
3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
3843
3844<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3845 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3846</pre>
3847
3848<h5>Overview:</h5>
3849
3850<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3851locations, allowing garbage collector implementations that require write
3852barriers (such as generational or reference counting collectors).</p>
3853
3854<h5>Arguments:</h5>
3855
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3856<p>The first argument is the reference to store, the second is the start of the
3857object to store it to, and the third is the address of the field of Obj to
3858store to. If the runtime does not require a pointer to the object, Obj may be
3859null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3860
3861<h5>Semantics:</h5>
3862
3863<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3864instruction, but may be replaced with substantially more complex code by the
3865garbage collector runtime, as needed.</p>
3866
3867</div>
3868
3869
3870
3871<!-- ======================================================================= -->
3872<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3873 <a name="int_codegen">Code Generator Intrinsics</a>
3874</div>
3875
3876<div class="doc_text">
3877<p>
3878These intrinsics are provided by LLVM to expose special features that may only
3879be implemented with code generator support.
3880</p>
3881
3882</div>
3883
3884<!-- _______________________________________________________________________ -->
3885<div class="doc_subsubsection">
3886 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3887</div>
3888
3889<div class="doc_text">
3890
3891<h5>Syntax:</h5>
3892<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3893 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3894</pre>
3895
3896<h5>Overview:</h5>
3897
3898<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3899The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3900target-specific value indicating the return address of the current function
3901or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3902</p>
3903
3904<h5>Arguments:</h5>
3905
3906<p>
3907The argument to this intrinsic indicates which function to return the address
3908for. Zero indicates the calling function, one indicates its caller, etc. The
3909argument is <b>required</b> to be a constant integer value.
3910</p>
3911
3912<h5>Semantics:</h5>
3913
3914<p>
3915The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3916the return address of the specified call frame, or zero if it cannot be
3917identified. The value returned by this intrinsic is likely to be incorrect or 0
3918for arguments other than zero, so it should only be used for debugging purposes.
3919</p>
3920
3921<p>
3922Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3923aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3924source-language caller.
3925</p>
3926</div>
3927
3928
3929<!-- _______________________________________________________________________ -->
3930<div class="doc_subsubsection">
3931 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3932</div>
3933
3934<div class="doc_text">
3935
3936<h5>Syntax:</h5>
3937<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3938 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3939</pre>
3940
3941<h5>Overview:</h5>
3942
3943<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3944The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3945target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3946</p>
3947
3948<h5>Arguments:</h5>
3949
3950<p>
3951The argument to this intrinsic indicates which function to return the frame
3952pointer for. Zero indicates the calling function, one indicates its caller,
3953etc. The argument is <b>required</b> to be a constant integer value.
3954</p>
3955
3956<h5>Semantics:</h5>
3957
3958<p>
3959The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3960the frame address of the specified call frame, or zero if it cannot be
3961identified. The value returned by this intrinsic is likely to be incorrect or 0
3962for arguments other than zero, so it should only be used for debugging purposes.
3963</p>
3964
3965<p>
3966Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3967aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3968source-language caller.
3969</p>
3970</div>
3971
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3972<!-- _______________________________________________________________________ -->
3973<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3974 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3975</div>
3976
3977<div class="doc_text">
3978
3979<h5>Syntax:</h5>
3980<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3981 declare i8 *%llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3982</pre>
3983
3984<h5>Overview:</h5>
3985
3986<p>
3987The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3988the function stack, for use with <a href="#i_stackrestore">
3989<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3990features like scoped automatic variable sized arrays in C99.
3991</p>
3992
3993<h5>Semantics:</h5>
3994
3995<p>
3996This intrinsic returns a opaque pointer value that can be passed to <a
3997href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3998<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3999<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4000state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4001practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4002that were allocated after the <tt>llvm.stacksave</tt> was executed.
4003</p>
4004
4005</div>
4006
4007<!-- _______________________________________________________________________ -->
4008<div class="doc_subsubsection">
4009 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4010</div>
4011
4012<div class="doc_text">
4013
4014<h5>Syntax:</h5>
4015<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4016 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4017</pre>
4018
4019<h5>Overview:</h5>
4020
4021<p>
4022The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4023the function stack to the state it was in when the corresponding <a
4024href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4025useful for implementing language features like scoped automatic variable sized
4026arrays in C99.
4027</p>
4028
4029<h5>Semantics:</h5>
4030
4031<p>
4032See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
4033</p>
4034
4035</div>
4036
4037
4038<!-- _______________________________________________________________________ -->
4039<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4040 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4041</div>
4042
4043<div class="doc_text">
4044
4045<h5>Syntax:</h5>
4046<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4047 declare void %llvm.prefetch(i8 * &lt;address&gt;,
4048 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4049</pre>
4050
4051<h5>Overview:</h5>
4052
4053
4054<p>
4055The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4056a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4057no
4058effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4059characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4060</p>
4061
4062<h5>Arguments:</h5>
4063
4064<p>
4065<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4066determining if the fetch should be for a read (0) or write (1), and
4067<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4068locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4069<tt>locality</tt> arguments must be constant integers.
4070</p>
4071
4072<h5>Semantics:</h5>
4073
4074<p>
4075This intrinsic does not modify the behavior of the program. In particular,
4076prefetches cannot trap and do not produce a value. On targets that support this
4077intrinsic, the prefetch can provide hints to the processor cache for better
4078performance.
4079</p>
4080
4081</div>
4082
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4083<!-- _______________________________________________________________________ -->
4084<div class="doc_subsubsection">
4085 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4086</div>
4087
4088<div class="doc_text">
4089
4090<h5>Syntax:</h5>
4091<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4092 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4093</pre>
4094
4095<h5>Overview:</h5>
4096
4097
4098<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4099The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4100(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4101code to simulators and other tools. The method is target specific, but it is
4102expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4103The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4104after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4105optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4106correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4107</p>
4108
4109<h5>Arguments:</h5>
4110
4111<p>
4112<tt>id</tt> is a numerical id identifying the marker.
4113</p>
4114
4115<h5>Semantics:</h5>
4116
4117<p>
4118This intrinsic does not modify the behavior of the program. Backends that do not
4119support this intrinisic may ignore it.
4120</p>
4121
4122</div>
4123
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4124<!-- _______________________________________________________________________ -->
4125<div class="doc_subsubsection">
4126 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4127</div>
4128
4129<div class="doc_text">
4130
4131<h5>Syntax:</h5>
4132<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4133 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4134</pre>
4135
4136<h5>Overview:</h5>
4137
4138
4139<p>
4140The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4141counter register (or similar low latency, high accuracy clocks) on those targets
4142that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4143As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4144should only be used for small timings.
4145</p>
4146
4147<h5>Semantics:</h5>
4148
4149<p>
4150When directly supported, reading the cycle counter should not modify any memory.
4151Implementations are allowed to either return a application specific value or a
4152system wide value. On backends without support, this is lowered to a constant 0.
4153</p>
4154
4155</div>
4156
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4157<!-- ======================================================================= -->
4158<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4159 <a name="int_libc">Standard C Library Intrinsics</a>
4160</div>
4161
4162<div class="doc_text">
4163<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4164LLVM provides intrinsics for a few important standard C library functions.
4165These intrinsics allow source-language front-ends to pass information about the
4166alignment of the pointer arguments to the code generator, providing opportunity
4167for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4168</p>
4169
4170</div>
4171
4172<!-- _______________________________________________________________________ -->
4173<div class="doc_subsubsection">
4174 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4175</div>
4176
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
4180<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4181 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4182 i32 &lt;len&gt;, i32 &lt;align&gt;)
4183 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4184 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4185</pre>
4186
4187<h5>Overview:</h5>
4188
4189<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4190The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4191location to the destination location.
4192</p>
4193
4194<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4195Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4196intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4197</p>
4198
4199<h5>Arguments:</h5>
4200
4201<p>
4202The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4203the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4204specifying the number of bytes to copy, and the fourth argument is the alignment
4205of the source and destination locations.
4206</p>
4207
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4208<p>
4209If 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]4210the caller guarantees that both the source and destination pointers are aligned
4211to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4212</p>
4213
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4214<h5>Semantics:</h5>
4215
4216<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4217The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4218location to the destination location, which are not allowed to overlap. It
4219copies "len" bytes of memory over. If the argument is known to be aligned to
4220some boundary, this can be specified as the fourth argument, otherwise it should
4221be set to 0 or 1.
4222</p>
4223</div>
4224
4225
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4226<!-- _______________________________________________________________________ -->
4227<div class="doc_subsubsection">
4228 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4229</div>
4230
4231<div class="doc_text">
4232
4233<h5>Syntax:</h5>
4234<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4235 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4236 i32 &lt;len&gt;, i32 &lt;align&gt;)
4237 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4238 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4239</pre>
4240
4241<h5>Overview:</h5>
4242
4243<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4244The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4245location to the destination location. It is similar to the
4246'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4247</p>
4248
4249<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4250Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4251intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4252</p>
4253
4254<h5>Arguments:</h5>
4255
4256<p>
4257The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4258the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4259specifying the number of bytes to copy, and the fourth argument is the alignment
4260of the source and destination locations.
4261</p>
4262
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4263<p>
4264If 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]4265the caller guarantees that the source and destination pointers are aligned to
4266that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4267</p>
4268
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4269<h5>Semantics:</h5>
4270
4271<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4272The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4273location to the destination location, which may overlap. It
4274copies "len" bytes of memory over. If the argument is known to be aligned to
4275some boundary, this can be specified as the fourth argument, otherwise it should
4276be set to 0 or 1.
4277</p>
4278</div>
4279
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4280
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4281<!-- _______________________________________________________________________ -->
4282<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4283 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4284</div>
4285
4286<div class="doc_text">
4287
4288<h5>Syntax:</h5>
4289<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4290 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4291 i32 &lt;len&gt;, i32 &lt;align&gt;)
4292 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4293 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4294</pre>
4295
4296<h5>Overview:</h5>
4297
4298<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4299The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4300byte value.
4301</p>
4302
4303<p>
4304Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4305does not return a value, and takes an extra alignment argument.
4306</p>
4307
4308<h5>Arguments:</h5>
4309
4310<p>
4311The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4312byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4313argument specifying the number of bytes to fill, and the fourth argument is the
4314known alignment of destination location.
4315</p>
4316
4317<p>
4318If 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]4319the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4320</p>
4321
4322<h5>Semantics:</h5>
4323
4324<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4325The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4326the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4327destination location. If the argument is known to be aligned to some boundary,
4328this can be specified as the fourth argument, otherwise it should be set to 0 or
43291.
4330</p>
4331</div>
4332
4333
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4334<!-- _______________________________________________________________________ -->
4335<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4336 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4337</div>
4338
4339<div class="doc_text">
4340
4341<h5>Syntax:</h5>
4342<pre>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4343 declare float %llvm.sqrt.f32(float %Val)
4344 declare double %llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4345</pre>
4346
4347<h5>Overview:</h5>
4348
4349<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4350The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4351returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4352<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4353negative numbers (which allows for better optimization).
4354</p>
4355
4356<h5>Arguments:</h5>
4357
4358<p>
4359The argument and return value are floating point numbers of the same type.
4360</p>
4361
4362<h5>Semantics:</h5>
4363
4364<p>
4365This function returns the sqrt of the specified operand if it is a positive
4366floating point number.
4367</p>
4368</div>
4369
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4370<!-- _______________________________________________________________________ -->
4371<div class="doc_subsubsection">
4372 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4373</div>
4374
4375<div class="doc_text">
4376
4377<h5>Syntax:</h5>
4378<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4379 declare float %llvm.powi.f32(float %Val, i32 %power)
4380 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
4386The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4387specified (positive or negative) power. The order of evaluation of
4388multiplications is not defined.
4389</p>
4390
4391<h5>Arguments:</h5>
4392
4393<p>
4394The second argument is an integer power, and the first is a value to raise to
4395that power.
4396</p>
4397
4398<h5>Semantics:</h5>
4399
4400<p>
4401This function returns the first value raised to the second power with an
4402unspecified sequence of rounding operations.</p>
4403</div>
4404
4405
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4406<!-- ======================================================================= -->
4407<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4408 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4409</div>
4410
4411<div class="doc_text">
4412<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4413LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4414These allow efficient code generation for some algorithms.
4415</p>
4416
4417</div>
4418
4419<!-- _______________________________________________________________________ -->
4420<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4421 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4422</div>
4423
4424<div class="doc_text">
4425
4426<h5>Syntax:</h5>
4427<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4428 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4429 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4430 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4431</pre>
4432
4433<h5>Overview:</h5>
4434
4435<p>
4436The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
443764 bit quantity. These are useful for performing operations on data that is not
4438in the target's native byte order.
4439</p>
4440
4441<h5>Semantics:</h5>
4442
4443<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4444The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4445and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4446intrinsic returns an i32 value that has the four bytes of the input i32
4447swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4448i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4449intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4450</p>
4451
4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4456 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4457</div>
4458
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
4462<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4463 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4464 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4465 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4466 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4467</pre>
4468
4469<h5>Overview:</h5>
4470
4471<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4472The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4473value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4474</p>
4475
4476<h5>Arguments:</h5>
4477
4478<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4479The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4480integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4481</p>
4482
4483<h5>Semantics:</h5>
4484
4485<p>
4486The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4487</p>
4488</div>
4489
4490<!-- _______________________________________________________________________ -->
4491<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4492 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4493</div>
4494
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4499 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4500 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4501 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4502 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4503</pre>
4504
4505<h5>Overview:</h5>
4506
4507<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4508The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4509leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4510</p>
4511
4512<h5>Arguments:</h5>
4513
4514<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4515The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4516integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4517</p>
4518
4519<h5>Semantics:</h5>
4520
4521<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4522The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4523in 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]4524of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4525</p>
4526</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4527
4528
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4529
4530<!-- _______________________________________________________________________ -->
4531<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4532 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4533</div>
4534
4535<div class="doc_text">
4536
4537<h5>Syntax:</h5>
4538<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4539 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4540 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4541 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4542 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4543</pre>
4544
4545<h5>Overview:</h5>
4546
4547<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4548The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4549trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4550</p>
4551
4552<h5>Arguments:</h5>
4553
4554<p>
4555The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4556integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4557</p>
4558
4559<h5>Semantics:</h5>
4560
4561<p>
4562The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4563in a variable. If the src == 0 then the result is the size in bits of the type
4564of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4565</p>
4566</div>
4567
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4568<!-- ======================================================================= -->
4569<div class="doc_subsection">
4570 <a name="int_debugger">Debugger Intrinsics</a>
4571</div>
4572
4573<div class="doc_text">
4574<p>
4575The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4576are described in the <a
4577href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4578Debugging</a> document.
4579</p>
4580</div>
4581
4582
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4583<!-- ======================================================================= -->
4584<div class="doc_subsection">
4585 <a name="int_eh">Exception Handling Intrinsics</a>
4586</div>
4587
4588<div class="doc_text">
4589<p> The LLVM exception handling intrinsics (which all start with
4590<tt>llvm.eh.</tt> prefix), are described in the <a
4591href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4592Handling</a> document. </p>
4593</div>
4594
4595
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4596<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4597<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4598<address>
4599 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4600 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4601 <a href="http://validator.w3.org/check/referer"><img
4602 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4603
4604 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4605 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4606 Last modified: $Date$
4607</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4608</body>
4609</html>