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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 8036ca47e27c22055cf8d708358b2e48b2a63e3b / . / 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
374<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]375define i32 %main() { <i>; i32()* </i>
376 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]377 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]378 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]379
380 <i>; Call puts function to write out the string to stdout...</i>
381 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]382 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]383 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]384 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]385
386<p>This example is made up of a <a href="#globalvars">global variable</a>
387named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
388function, and a <a href="#functionstructure">function definition</a>
389for "<tt>main</tt>".</p>
390
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]391<p>In general, a module is made up of a list of global values,
392where both functions and global variables are global values. Global values are
393represented by a pointer to a memory location (in this case, a pointer to an
394array of char, and a pointer to a function), and have one of the following <a
395href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]396
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]397</div>
398
399<!-- ======================================================================= -->
400<div class="doc_subsection">
401 <a name="linkage">Linkage Types</a>
402</div>
403
404<div class="doc_text">
405
406<p>
407All Global Variables and Functions have one of the following types of linkage:
408</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]409
410<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
414 <dd>Global values with internal linkage are only directly accessible by
415 objects in the current module. In particular, linking code into a module with
416 an internal global value may cause the internal to be renamed as necessary to
417 avoid collisions. Because the symbol is internal to the module, all
418 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]419 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420 </dd>
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_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]424 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
425 the same name when linkage occurs. This is typically used to implement
426 inline functions, templates, or other code which must be generated in each
427 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
428 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]429 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]430
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]431 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]432
433 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
434 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]435 used for globals that may be emitted in multiple translation units, but that
436 are not guaranteed to be emitted into every translation unit that uses them.
437 One example of this are common globals in C, such as "<tt>int X;</tt>" at
438 global scope.
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_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
443 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
444 pointer to array type. When two global variables with appending linkage are
445 linked together, the two global arrays are appended together. This is the
446 LLVM, typesafe, equivalent of having the system linker append together
447 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]448 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]449
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]450 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
451 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
452 until linked, if not linked, the symbol becomes null instead of being an
453 undefined reference.
454 </dd>
455</dl>
456
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]457 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]458
459 <dd>If none of the above identifiers are used, the global is externally
460 visible, meaning that it participates in linkage and can be used to resolve
461 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]462 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]463
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]464 <p>
465 The next two types of linkage are targeted for Microsoft Windows platform
466 only. They are designed to support importing (exporting) symbols from (to)
467 DLLs.
468 </p>
469
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]470 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
472
473 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
474 or variable via a global pointer to a pointer that is set up by the DLL
475 exporting the symbol. On Microsoft Windows targets, the pointer name is
476 formed by combining <code>_imp__</code> and the function or variable name.
477 </dd>
478
479 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
480
481 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
482 pointer to a pointer in a DLL, so that it can be referenced with the
483 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
484 name is formed by combining <code>_imp__</code> and the function or variable
485 name.
486 </dd>
487
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488</dl>
489
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]490<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]491variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
492variable and was linked with this one, one of the two would be renamed,
493preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
494external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]495outside of the current module.</p>
496<p>It is illegal for a function <i>declaration</i>
497to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]498or <tt>extern_weak</tt>.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]499
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]500</div>
501
502<!-- ======================================================================= -->
503<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]504 <a name="callingconv">Calling Conventions</a>
505</div>
506
507<div class="doc_text">
508
509<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
510and <a href="#i_invoke">invokes</a> can all have an optional calling convention
511specified for the call. The calling convention of any pair of dynamic
512caller/callee must match, or the behavior of the program is undefined. The
513following calling conventions are supported by LLVM, and more may be added in
514the future:</p>
515
516<dl>
517 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
518
519 <dd>This calling convention (the default if no other calling convention is
520 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]521 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]522 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]523 </dd>
524
525 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
526
527 <dd>This calling convention attempts to make calls as fast as possible
528 (e.g. by passing things in registers). This calling convention allows the
529 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]530 without having to conform to an externally specified ABI. Implementations of
531 this convention should allow arbitrary tail call optimization to be supported.
532 This calling convention does not support varargs and requires the prototype of
533 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]534 </dd>
535
536 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
537
538 <dd>This calling convention attempts to make code in the caller as efficient
539 as possible under the assumption that the call is not commonly executed. As
540 such, these calls often preserve all registers so that the call does not break
541 any live ranges in the caller side. This calling convention does not support
542 varargs and requires the prototype of all callees to exactly match the
543 prototype of the function definition.
544 </dd>
545
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]546 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]547
548 <dd>Any calling convention may be specified by number, allowing
549 target-specific calling conventions to be used. Target specific calling
550 conventions start at 64.
551 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]552</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]553
554<p>More calling conventions can be added/defined on an as-needed basis, to
555support pascal conventions or any other well-known target-independent
556convention.</p>
557
558</div>
559
560<!-- ======================================================================= -->
561<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]562 <a name="visibility">Visibility Styles</a>
563</div>
564
565<div class="doc_text">
566
567<p>
568All Global Variables and Functions have one of the following visibility styles:
569</p>
570
571<dl>
572 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
573
574 <dd>On ELF, default visibility means that the declaration is visible to other
575 modules and, in shared libraries, means that the declared entity may be
576 overridden. On Darwin, default visibility means that the declaration is
577 visible to other modules. Default visibility corresponds to "external
578 linkage" in the language.
579 </dd>
580
581 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
582
583 <dd>Two declarations of an object with hidden visibility refer to the same
584 object if they are in the same shared object. Usually, hidden visibility
585 indicates that the symbol will not be placed into the dynamic symbol table,
586 so no other module (executable or shared library) can reference it
587 directly.
588 </dd>
589
590</dl>
591
592</div>
593
594<!-- ======================================================================= -->
595<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]596 <a name="globalvars">Global Variables</a>
597</div>
598
599<div class="doc_text">
600
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]601<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]602instead of run-time. Global variables may optionally be initialized, may have
603an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]604have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]605variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]606contents of the variable will <b>never</b> be modified (enabling better
607optimization, allowing the global data to be placed in the read-only section of
608an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]609cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]610
611<p>
612LLVM explicitly allows <em>declarations</em> of global variables to be marked
613constant, even if the final definition of the global is not. This capability
614can be used to enable slightly better optimization of the program, but requires
615the language definition to guarantee that optimizations based on the
616'constantness' are valid for the translation units that do not include the
617definition.
618</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]619
620<p>As SSA values, global variables define pointer values that are in
621scope (i.e. they dominate) all basic blocks in the program. Global
622variables always define a pointer to their "content" type because they
623describe a region of memory, and all memory objects in LLVM are
624accessed through pointers.</p>
625
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]626<p>LLVM allows an explicit section to be specified for globals. If the target
627supports it, it will emit globals to the section specified.</p>
628
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]629<p>An explicit alignment may be specified for a global. If not present, or if
630the alignment is set to zero, the alignment of the global is set by the target
631to whatever it feels convenient. If an explicit alignment is specified, the
632global is forced to have at least that much alignment. All alignments must be
633a power of 2.</p>
634
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]635<p>For example, the following defines a global with an initializer, section,
636 and alignment:</p>
637
638<pre>
639 %G = constant float 1.0, section "foo", align 4
640</pre>
641
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]642</div>
643
644
645<!-- ======================================================================= -->
646<div class="doc_subsection">
647 <a name="functionstructure">Functions</a>
648</div>
649
650<div class="doc_text">
651
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]652<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
653an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]654<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]655<a href="#callingconv">calling convention</a>, a return type, an optional
656<a href="#paramattrs">parameter attribute</a> for the return type, a function
657name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]658<a href="#paramattrs">parameter attributes</a>), an optional section, an
659optional alignment, an opening curly brace, a list of basic blocks, and a
660closing curly brace.
661
662LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
663optional <a href="#linkage">linkage type</a>, an optional
664<a href="#visibility">visibility style</a>, an optional
665<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]666<a href="#paramattrs">parameter attribute</a> for the return type, a function
667name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]668
669<p>A function definition contains a list of basic blocks, forming the CFG for
670the function. Each basic block may optionally start with a label (giving the
671basic block a symbol table entry), contains a list of instructions, and ends
672with a <a href="#terminators">terminator</a> instruction (such as a branch or
673function return).</p>
674
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]675<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]676executed on entrance to the function, and it is not allowed to have predecessor
677basic blocks (i.e. there can not be any branches to the entry block of a
678function). Because the block can have no predecessors, it also cannot have any
679<a href="#i_phi">PHI nodes</a>.</p>
680
681<p>LLVM functions are identified by their name and type signature. Hence, two
682functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]683considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]684appropriately.</p>
685
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]686<p>LLVM allows an explicit section to be specified for functions. If the target
687supports it, it will emit functions to the section specified.</p>
688
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]689<p>An explicit alignment may be specified for a function. If not present, or if
690the alignment is set to zero, the alignment of the function is set by the target
691to whatever it feels convenient. If an explicit alignment is specified, the
692function is forced to have at least that much alignment. All alignments must be
693a power of 2.</p>
694
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]695</div>
696
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]697<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]698<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
699<div class="doc_text">
700 <p>The return type and each parameter of a function type may have a set of
701 <i>parameter attributes</i> associated with them. Parameter attributes are
702 used to communicate additional information about the result or parameters of
703 a function. Parameter attributes are considered to be part of the function
704 type so two functions types that differ only by the parameter attributes
705 are different function types.</p>
706
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]707 <p>Parameter attributes are simple keywords that follow the type specified. If
708 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]709 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]710 %someFunc = i16 (i8 sext %someParam) zext
711 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]712 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]713 a different attribute (sext in the first one, zext in the second). Also note
714 that the attribute for the function result (zext) comes immediately after the
715 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]716
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]717 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]718 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]719 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]720 <dd>This indicates that the parameter should be zero extended just before
721 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]722 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]723 <dd>This indicates that the parameter should be sign extended just before
724 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]725 <dt><tt>inreg</tt></dt>
726 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]727 possible) during assembling function call. Support for this attribute is
728 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]729 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]730 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]731 that is the return value of the function in the source program.</dd>
Reid Spencer2dc52012007-03-22 02:18:56 +0000[diff] [blame]732 <dt><tt>noreturn</tt></dt>
733 <dd>This function attribute indicates that the function never returns. This
734 indicates to LLVM that every call to this function should be treated as if
735 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]736 <dt><tt>nounwind</tt></dt>
737 <dd>This function attribute indicates that the function type does not use
738 the unwind instruction and does not allow stack unwinding to propagate
739 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]740 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]741
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]742</div>
743
744<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]745<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]746 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]747</div>
748
749<div class="doc_text">
750<p>
751Modules may contain "module-level inline asm" blocks, which corresponds to the
752GCC "file scope inline asm" blocks. These blocks are internally concatenated by
753LLVM and treated as a single unit, but may be separated in the .ll file if
754desired. The syntax is very simple:
755</p>
756
757<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]758 module asm "inline asm code goes here"
759 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]760</pre></div>
761
762<p>The strings can contain any character by escaping non-printable characters.
763 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
764 for the number.
765</p>
766
767<p>
768 The inline asm code is simply printed to the machine code .s file when
769 assembly code is generated.
770</p>
771</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]772
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]773<!-- ======================================================================= -->
774<div class="doc_subsection">
775 <a name="datalayout">Data Layout</a>
776</div>
777
778<div class="doc_text">
779<p>A module may specify a target specific data layout string that specifies how
780data is to be laid out in memory. The syntax for the data layout is simply:<br/>
781<pre> target datalayout = "<i>layout specification</i>"
782</pre>
783The <i>layout specification</i> consists of a list of specifications separated
784by the minus sign character ('-'). Each specification starts with a letter
785and may include other information after the letter to define some aspect of the
786data layout. The specifications accepted are as follows: </p>
787<dl>
788 <dt><tt>E</tt></dt>
789 <dd>Specifies that the target lays out data in big-endian form. That is, the
790 bits with the most significance have the lowest address location.</dd>
791 <dt><tt>e</tt></dt>
792 <dd>Specifies that hte target lays out data in little-endian form. That is,
793 the bits with the least significance have the lowest address location.</dd>
794 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
795 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
796 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
797 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
798 too.</dd>
799 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
800 <dd>This specifies the alignment for an integer type of a given bit
801 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
802 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
803 <dd>This specifies the alignment for a vector type of a given bit
804 <i>size</i>.</dd>
805 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
806 <dd>This specifies the alignment for a floating point type of a given bit
807 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
808 (double).</dd>
809 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
810 <dd>This specifies the alignment for an aggregate type of a given bit
811 <i>size</i>.</dd>
812</dl>
813<p>When constructing the data layout for a given target, LLVM starts with a
814default set of specifications which are then (possibly) overriden by the
815specifications in the <tt>datalayout</tt> keyword. The default specifications
816are given in this list:</p>
817<ul>
818 <li><tt>E</tt> - big endian</li>
819 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
820 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
821 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
822 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
823 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
824 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
825 alignment of 64-bits</li>
826 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
827 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
828 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
829 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
830 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
831</ul>
832<p>When llvm is determining the alignment for a given type, it uses the
833following rules:
834<ol>
835 <li>If the type sought is an exact match for one of the specifications, that
836 specification is used.</li>
837 <li>If no match is found, and the type sought is an integer type, then the
838 smallest integer type that is larger than the bitwidth of the sought type is
839 used. If none of the specifications are larger than the bitwidth then the the
840 largest integer type is used. For example, given the default specifications
841 above, the i7 type will use the alignment of i8 (next largest) while both
842 i65 and i256 will use the alignment of i64 (largest specified).</li>
843 <li>If no match is found, and the type sought is a vector type, then the
844 largest vector type that is smaller than the sought vector type will be used
845 as a fall back. This happens because <128 x double> can be implemented in
846 terms of 64 <2 x double>, for example.</li>
847</ol>
848</div>
Reid Spencerc10f0af2007-03-28 02:46:29 +0000[diff] [blame]849<!-- ======================================================================= -->
850<div class="doc_subsection">
851 <a name="datalayout">Data Layout</a>
852</div>
853<div class="doc_text">
854 <p>At the top level, the keyword <tt>checkpoint</tt> may be used to force the
855 assembler to check point the types and values it has defined so far. Any
856 unresolved types or references will generate error messages. This is useful
857 as an assertion point or for debugging.</p>
858</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]859
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]860<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]861<div class="doc_section"> <a name="typesystem">Type System</a> </div>
862<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]863
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]864<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]865
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]866<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]867intermediate representation. Being typed enables a number of
868optimizations to be performed on the IR directly, without having to do
869extra analyses on the side before the transformation. A strong type
870system makes it easier to read the generated code and enables novel
871analyses and transformations that are not feasible to perform on normal
872three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]873
874</div>
875
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]876<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]877<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]878<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]879<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]880system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]881
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]882<table class="layout">
883 <tr class="layout">
884 <td class="left">
885 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]886 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]887 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]888 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]889 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
890 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]891 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]892 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]893 </tbody>
894 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]895 </td>
896 <td class="right">
897 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]898 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]899 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]900 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]901 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
902 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]903 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]904 </tbody>
905 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]906 </td>
907 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]908</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]909</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]910
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]911<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]912<div class="doc_subsubsection"> <a name="t_classifications">Type
913Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]914<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]915<p>These different primitive types fall into a few useful
916classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]917
918<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]919 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]920 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]921 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]922 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]923 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]924 </tr>
925 <tr>
926 <td><a name="t_floating">floating point</a></td>
927 <td><tt>float, double</tt></td>
928 </tr>
929 <tr>
930 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]931 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]932 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]933 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934 </tr>
935 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]936</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]937
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]938<p>The <a href="#t_firstclass">first class</a> types are perhaps the
939most important. Values of these types are the only ones which can be
940produced by instructions, passed as arguments, or used as operands to
941instructions. This means that all structures and arrays must be
942manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]943</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]944
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]945<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]946<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]947
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]948<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]949
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]950<p>The real power in LLVM comes from the derived types in the system.
951This is what allows a programmer to represent arrays, functions,
952pointers, and other useful types. Note that these derived types may be
953recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]954
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]955</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]956
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]957<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]958<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]960<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]961
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]962<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]963
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]964<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]965sequentially in memory. The array type requires a size (number of
966elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]967
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]968<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]969
970<pre>
971 [&lt;# elements&gt; x &lt;elementtype&gt;]
972</pre>
973
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]974<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]975be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]976
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]977<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]978<table class="layout">
979 <tr class="layout">
980 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]981 <tt>[40 x i32 ]</tt><br/>
982 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]983 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]984 </td>
985 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]986 Array of 40 32-bit integer values.<br/>
987 Array of 41 32-bit integer values.<br/>
988 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]989 </td>
990 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]991</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]992<p>Here are some examples of multidimensional arrays:</p>
993<table class="layout">
994 <tr class="layout">
995 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]997 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]998 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]999 </td>
1000 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1001 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1002 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1003 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1004 </td>
1005 </tr>
1006</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1007
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1008<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1009length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1010LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1011As a special case, however, zero length arrays are recognized to be variable
1012length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1013type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1014
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1015</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1016
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1017<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1018<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1019<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1020<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1021<p>The function type can be thought of as a function signature. It
1022consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1023Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1024(which are structures of pointers to functions), for indirect function
1025calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1026<p>
1027The return type of a function type cannot be an aggregate type.
1028</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1029<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1030<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1031<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]1032specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1033which indicates that the function takes a variable number of arguments.
1034Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1035 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1036<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1037<table class="layout">
1038 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1039 <td class="left"><tt>i32 (i32)</tt></td>
1040 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1041 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1042 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1043 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1044 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1045 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1046 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1047 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1048 <tt>float</tt>.
1049 </td>
1050 </tr><tr class="layout">
1051 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1052 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1053 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1054 which returns an integer. This is the signature for <tt>printf</tt> in
1055 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1056 </td>
1057 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1058</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1059
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1060</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1061<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1062<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1063<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1064<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1065<p>The structure type is used to represent a collection of data members
1066together in memory. The packing of the field types is defined to match
1067the ABI of the underlying processor. The elements of a structure may
1068be any type that has a size.</p>
1069<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1070and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1071field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1072instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1073<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1074<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1075<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1076<table class="layout">
1077 <tr class="layout">
1078 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079 <tt>{ i32, i32, i32 }</tt><br/>
1080 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1081 </td>
1082 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1083 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1084 A pair, where the first element is a <tt>float</tt> and the second element
1085 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]1086 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1087 </td>
1088 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1089</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1090</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1091
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1092<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1093<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1094</div>
1095<div class="doc_text">
1096<h5>Overview:</h5>
1097<p>The packed structure type is used to represent a collection of data members
1098together in memory. There is no padding between fields. Further, the alignment
1099of a packed structure is 1 byte. The elements of a packed structure may
1100be any type that has a size.</p>
1101<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1102and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1103field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1104instruction.</p>
1105<h5>Syntax:</h5>
1106<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1107<h5>Examples:</h5>
1108<table class="layout">
1109 <tr class="layout">
1110 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1111 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1112 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1113 </td>
1114 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1115 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1116 A pair, where the first element is a <tt>float</tt> and the second element
1117 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]1118 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1119 </td>
1120 </tr>
1121</table>
1122</div>
1123
1124<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1125<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1126<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1127<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1128<p>As in many languages, the pointer type represents a pointer or
1129reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1130<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1131<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1132<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1133<table class="layout">
1134 <tr class="layout">
1135 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1136 <tt>[4x i32]*</tt><br/>
1137 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1138 </td>
1139 <td class="left">
1140 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]1141 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1142 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1143 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1144 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1145 </td>
1146 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1147</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1148</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1149
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1150<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1151<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1152<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1153
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1154<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1155
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1156<p>A vector type is a simple derived type that represents a vector
1157of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1158are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1159A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1160elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1161of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1162considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1163
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1164<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1165
1166<pre>
1167 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1168</pre>
1169
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1170<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1171be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1172
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1173<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1174
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1175<table class="layout">
1176 <tr class="layout">
1177 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1178 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1179 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1180 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1181 </td>
1182 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1183 Vector of 4 32-bit integer values.<br/>
1184 Vector of 8 floating-point values.<br/>
1185 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1186 </td>
1187 </tr>
1188</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1189</div>
1190
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1191<!-- _______________________________________________________________________ -->
1192<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1193<div class="doc_text">
1194
1195<h5>Overview:</h5>
1196
1197<p>Opaque types are used to represent unknown types in the system. This
1198corresponds (for example) to the C notion of a foward declared structure type.
1199In LLVM, opaque types can eventually be resolved to any type (not just a
1200structure type).</p>
1201
1202<h5>Syntax:</h5>
1203
1204<pre>
1205 opaque
1206</pre>
1207
1208<h5>Examples:</h5>
1209
1210<table class="layout">
1211 <tr class="layout">
1212 <td class="left">
1213 <tt>opaque</tt>
1214 </td>
1215 <td class="left">
1216 An opaque type.<br/>
1217 </td>
1218 </tr>
1219</table>
1220</div>
1221
1222
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1223<!-- *********************************************************************** -->
1224<div class="doc_section"> <a name="constants">Constants</a> </div>
1225<!-- *********************************************************************** -->
1226
1227<div class="doc_text">
1228
1229<p>LLVM has several different basic types of constants. This section describes
1230them all and their syntax.</p>
1231
1232</div>
1233
1234<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1235<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1236
1237<div class="doc_text">
1238
1239<dl>
1240 <dt><b>Boolean constants</b></dt>
1241
1242 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1243 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1244 </dd>
1245
1246 <dt><b>Integer constants</b></dt>
1247
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1248 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1249 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1250 integer types.
1251 </dd>
1252
1253 <dt><b>Floating point constants</b></dt>
1254
1255 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1256 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1257 notation (see below). Floating point constants must have a <a
1258 href="#t_floating">floating point</a> type. </dd>
1259
1260 <dt><b>Null pointer constants</b></dt>
1261
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1262 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1263 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1264
1265</dl>
1266
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1267<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1268of floating point constants. For example, the form '<tt>double
12690x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12704.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1271(and the only time that they are generated by the disassembler) is when a
1272floating point constant must be emitted but it cannot be represented as a
1273decimal floating point number. For example, NaN's, infinities, and other
1274special values are represented in their IEEE hexadecimal format so that
1275assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1276
1277</div>
1278
1279<!-- ======================================================================= -->
1280<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1281</div>
1282
1283<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1284<p>Aggregate constants arise from aggregation of simple constants
1285and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1286
1287<dl>
1288 <dt><b>Structure constants</b></dt>
1289
1290 <dd>Structure constants are represented with notation similar to structure
1291 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1292 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1293 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]1294 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1295 types of elements must match those specified by the type.
1296 </dd>
1297
1298 <dt><b>Array constants</b></dt>
1299
1300 <dd>Array constants are represented with notation similar to array type
1301 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1302 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1303 constants must have <a href="#t_array">array type</a>, and the number and
1304 types of elements must match those specified by the type.
1305 </dd>
1306
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1307 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1308
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1309 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1310 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1311 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]1312 i32 11, i32 74, i32 100 &gt;</tt>". VEctor constants must have <a
1313 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1314 match those specified by the type.
1315 </dd>
1316
1317 <dt><b>Zero initialization</b></dt>
1318
1319 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1320 value to zero of <em>any</em> type, including scalar and aggregate types.
1321 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]1322 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1323 initializers.
1324 </dd>
1325</dl>
1326
1327</div>
1328
1329<!-- ======================================================================= -->
1330<div class="doc_subsection">
1331 <a name="globalconstants">Global Variable and Function Addresses</a>
1332</div>
1333
1334<div class="doc_text">
1335
1336<p>The addresses of <a href="#globalvars">global variables</a> and <a
1337href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1338constants. These constants are explicitly referenced when the <a
1339href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1340href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1341file:</p>
1342
1343<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1344 %X = global i32 17
1345 %Y = global i32 42
1346 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1347</pre>
1348
1349</div>
1350
1351<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1352<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1353<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1354 <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]1355 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1356 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1357
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1358 <p>Undefined values indicate to the compiler that the program is well defined
1359 no matter what value is used, giving the compiler more freedom to optimize.
1360 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1361</div>
1362
1363<!-- ======================================================================= -->
1364<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1365</div>
1366
1367<div class="doc_text">
1368
1369<p>Constant expressions are used to allow expressions involving other constants
1370to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1371href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1372that does not have side effects (e.g. load and call are not supported). The
1373following is the syntax for constant expressions:</p>
1374
1375<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1376 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1377 <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]1378 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1379
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1380 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1381 <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]1382 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]1383
1384 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1385 <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]1386 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]1387
1388 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1389 <dd>Truncate a floating point constant to another floating point type. The
1390 size of CST must be larger than the size of TYPE. Both types must be
1391 floating point.</dd>
1392
1393 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1394 <dd>Floating point extend a constant to another type. The size of CST must be
1395 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1396
1397 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1398 <dd>Convert a floating point constant to the corresponding unsigned integer
1399 constant. TYPE must be an integer type. CST must be floating point. If the
1400 value won't fit in the integer type, the results are undefined.</dd>
1401
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1402 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1403 <dd>Convert a floating point constant to the corresponding signed integer
1404 constant. TYPE must be an integer type. CST must be floating point. If the
1405 value won't fit in the integer type, the results are undefined.</dd>
1406
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1407 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1408 <dd>Convert an unsigned integer constant to the corresponding floating point
1409 constant. TYPE must be floating point. CST must be of integer type. If the
1410 value won't fit in the floating point type, the results are undefined.</dd>
1411
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1412 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1413 <dd>Convert a signed integer constant to the corresponding floating point
1414 constant. TYPE must be floating point. CST must be of integer type. If the
1415 value won't fit in the floating point type, the results are undefined.</dd>
1416
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1417 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1418 <dd>Convert a pointer typed constant to the corresponding integer constant
1419 TYPE must be an integer type. CST must be of pointer type. The CST value is
1420 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1421
1422 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1423 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1424 pointer type. CST must be of integer type. The CST value is zero extended,
1425 truncated, or unchanged to make it fit in a pointer size. This one is
1426 <i>really</i> dangerous!</dd>
1427
1428 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1429 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1430 identical (same number of bits). The conversion is done as if the CST value
1431 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]1432 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1433 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]1434 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1435 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1436
1437 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1438
1439 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1440 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1441 instruction, the index list may have zero or more indexes, which are required
1442 to make sense for the type of "CSTPTR".</dd>
1443
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1444 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1445
1446 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1447 constants.</dd>
1448
1449 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1450 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1451
1452 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1453 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1454
1455 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1456
1457 <dd>Perform the <a href="#i_extractelement">extractelement
1458 operation</a> on constants.
1459
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1460 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1461
1462 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1463 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1464
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1465
1466 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1467
1468 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1469 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1470
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1471 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1472
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1473 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1474 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1475 binary</a> operations. The constraints on operands are the same as those for
1476 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1477 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1478</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1479</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1480
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1481<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1482<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1483<!-- *********************************************************************** -->
1484
1485<!-- ======================================================================= -->
1486<div class="doc_subsection">
1487<a name="inlineasm">Inline Assembler Expressions</a>
1488</div>
1489
1490<div class="doc_text">
1491
1492<p>
1493LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1494Module-Level Inline Assembly</a>) through the use of a special value. This
1495value represents the inline assembler as a string (containing the instructions
1496to emit), a list of operand constraints (stored as a string), and a flag that
1497indicates whether or not the inline asm expression has side effects. An example
1498inline assembler expression is:
1499</p>
1500
1501<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1502 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1503</pre>
1504
1505<p>
1506Inline assembler expressions may <b>only</b> be used as the callee operand of
1507a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1508</p>
1509
1510<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1511 %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]1512</pre>
1513
1514<p>
1515Inline asms with side effects not visible in the constraint list must be marked
1516as having side effects. This is done through the use of the
1517'<tt>sideeffect</tt>' keyword, like so:
1518</p>
1519
1520<pre>
1521 call void asm sideeffect "eieio", ""()
1522</pre>
1523
1524<p>TODO: The format of the asm and constraints string still need to be
1525documented here. Constraints on what can be done (e.g. duplication, moving, etc
1526need to be documented).
1527</p>
1528
1529</div>
1530
1531<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1532<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1533<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1534
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1535<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1536
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1537<p>The LLVM instruction set consists of several different
1538classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1539instructions</a>, <a href="#binaryops">binary instructions</a>,
1540<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1541 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1542instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1543
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1544</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1545
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1546<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1547<div class="doc_subsection"> <a name="terminators">Terminator
1548Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1549
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1550<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1551
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1552<p>As mentioned <a href="#functionstructure">previously</a>, every
1553basic block in a program ends with a "Terminator" instruction, which
1554indicates which block should be executed after the current block is
1555finished. These terminator instructions typically yield a '<tt>void</tt>'
1556value: they produce control flow, not values (the one exception being
1557the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1558<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1559 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1560instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1561the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1562 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1563 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1564
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1565</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1566
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1567<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1568<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1569Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1570<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1572<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]1573 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1574</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1575<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1576<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1577value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1578<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1579returns a value and then causes control flow, and one that just causes
1580control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1581<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1582<p>The '<tt>ret</tt>' instruction may return any '<a
1583 href="#t_firstclass">first class</a>' type. Notice that a function is
1584not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1585instruction inside of the function that returns a value that does not
1586match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1587<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1588<p>When the '<tt>ret</tt>' instruction is executed, control flow
1589returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1590 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1591the instruction after the call. If the caller was an "<a
1592 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1593at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1594returns a value, that value shall set the call or invoke instruction's
1595return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1596<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1597<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1598 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1599</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1600</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1601<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1602<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1603<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1605<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]1606</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1607<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1608<p>The '<tt>br</tt>' instruction is used to cause control flow to
1609transfer to a different basic block in the current function. There are
1610two forms of this instruction, corresponding to a conditional branch
1611and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1612<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1613<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1614single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1615unconditional form of the '<tt>br</tt>' instruction takes a single
1616'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1617<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1618<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1619argument is evaluated. If the value is <tt>true</tt>, control flows
1620to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1621control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1622<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1623<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]1624 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]1625</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1626<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1627<div class="doc_subsubsection">
1628 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1629</div>
1630
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1631<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1632<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1633
1634<pre>
1635 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1636</pre>
1637
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1638<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1639
1640<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1641several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1642instruction, allowing a branch to occur to one of many possible
1643destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1644
1645
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1646<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1647
1648<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1649comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1650an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1651table is not allowed to contain duplicate constant entries.</p>
1652
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1654
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1655<p>The <tt>switch</tt> instruction specifies a table of values and
1656destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1657table is searched for the given value. If the value is found, control flow is
1658transfered to the corresponding destination; otherwise, control flow is
1659transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1661<h5>Implementation:</h5>
1662
1663<p>Depending on properties of the target machine and the particular
1664<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1665ways. For example, it could be generated as a series of chained conditional
1666branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1667
1668<h5>Example:</h5>
1669
1670<pre>
1671 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1672 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1673 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1674
1675 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1676 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1677
1678 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1679 switch i32 %val, label %otherwise [ i32 0, label %onzero
1680 i32 1, label %onone
1681 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1682</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1683</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1685<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1686<div class="doc_subsubsection">
1687 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1688</div>
1689
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1690<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1691
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1692<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1693
1694<pre>
1695 &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]1696 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1697</pre>
1698
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1699<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1700
1701<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1702function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1703'<tt>normal</tt>' label or the
1704'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1705"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1706"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1707href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1708continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1710<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1712<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1714<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1715 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]1716 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1717 convention</a> the call should use. If none is specified, the call defaults
1718 to using C calling conventions.
1719 </li>
1720 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1721 function value being invoked. In most cases, this is a direct function
1722 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1723 an arbitrary pointer to function value.
1724 </li>
1725
1726 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1727 function to be invoked. </li>
1728
1729 <li>'<tt>function args</tt>': argument list whose types match the function
1730 signature argument types. If the function signature indicates the function
1731 accepts a variable number of arguments, the extra arguments can be
1732 specified. </li>
1733
1734 <li>'<tt>normal label</tt>': the label reached when the called function
1735 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1736
1737 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1738 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1739
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1741
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1743
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1744<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1745href="#i_call">call</a></tt>' instruction in most regards. The primary
1746difference is that it establishes an association with a label, which is used by
1747the runtime library to unwind the stack.</p>
1748
1749<p>This instruction is used in languages with destructors to ensure that proper
1750cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1751exception. Additionally, this is important for implementation of
1752'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1755<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1756 %retval = invoke i32 %Test(i32 15) to label %Continue
1757 unwind label %TestCleanup <i>; {i32}:retval set</i>
1758 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1759 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1760</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1761</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1762
1763
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1764<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1765
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1766<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1767Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1768
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1769<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1770
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1771<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1772<pre>
1773 unwind
1774</pre>
1775
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1776<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1777
1778<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1779at the first callee in the dynamic call stack which used an <a
1780href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1781primarily used to implement exception handling.</p>
1782
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1783<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1784
1785<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1786immediately halt. The dynamic call stack is then searched for the first <a
1787href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1788execution continues at the "exceptional" destination block specified by the
1789<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1790dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1791</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1792
1793<!-- _______________________________________________________________________ -->
1794
1795<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1796Instruction</a> </div>
1797
1798<div class="doc_text">
1799
1800<h5>Syntax:</h5>
1801<pre>
1802 unreachable
1803</pre>
1804
1805<h5>Overview:</h5>
1806
1807<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1808instruction is used to inform the optimizer that a particular portion of the
1809code is not reachable. This can be used to indicate that the code after a
1810no-return function cannot be reached, and other facts.</p>
1811
1812<h5>Semantics:</h5>
1813
1814<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1815</div>
1816
1817
1818
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1819<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1820<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1821<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1822<p>Binary operators are used to do most of the computation in a
1823program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1824produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1825multiple 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]1826The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1828<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1829</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1830<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1831<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1832Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1833<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1835<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]1836</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1838<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1839<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1840<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1841 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1842 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]1843Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1845<p>The value produced is the integer or floating point sum of the two
1846operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1847<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1848<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]1849</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1851<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1853Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1854<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1855<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<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]1857</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1858<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1859<p>The '<tt>sub</tt>' instruction returns the difference of its two
1860operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1862instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1863<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1865 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1866values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1867This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1868Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1869<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1870<p>The value produced is the integer or floating point difference of
1871the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1872<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1873<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1874 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1875</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1876</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1879Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1880<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1881<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1882<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]1883</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1884<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885<p>The '<tt>mul</tt>' instruction returns the product of its two
1886operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1887<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1888<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1889 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1890values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1891This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1892Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1893<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1894<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1895two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1896<p>Because the operands are the same width, the result of an integer
1897multiplication is the same whether the operands should be deemed unsigned or
1898signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1899<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1900<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]1901</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1902</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1903<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1904<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1905</a></div>
1906<div class="doc_text">
1907<h5>Syntax:</h5>
1908<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1909</pre>
1910<h5>Overview:</h5>
1911<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1912operands.</p>
1913<h5>Arguments:</h5>
1914<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1915<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1916types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1917of the values in which case the elements must be integers.</p>
1918<h5>Semantics:</h5>
1919<p>The value produced is the unsigned integer quotient of the two operands. This
1920instruction always performs an unsigned division operation, regardless of
1921whether the arguments are unsigned or not.</p>
1922<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1923<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]1924</pre>
1925</div>
1926<!-- _______________________________________________________________________ -->
1927<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1928</a> </div>
1929<div class="doc_text">
1930<h5>Syntax:</h5>
1931<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1932</pre>
1933<h5>Overview:</h5>
1934<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1935operands.</p>
1936<h5>Arguments:</h5>
1937<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1938<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1939types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1940of the values in which case the elements must be integers.</p>
1941<h5>Semantics:</h5>
1942<p>The value produced is the signed integer quotient of the two operands. This
1943instruction always performs a signed division operation, regardless of whether
1944the arguments are signed or not.</p>
1945<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1946<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]1947</pre>
1948</div>
1949<!-- _______________________________________________________________________ -->
1950<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1951Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1952<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1953<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1954<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]1955</pre>
1956<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1957<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1958operands.</p>
1959<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1960<p>The two arguments to the '<tt>div</tt>' instruction must be
1961<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1962identical types. This instruction can also take <a href="#t_vector">vector</a>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1963versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1964<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1965<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1966<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1967<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]1968</pre>
1969</div>
1970<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1971<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1972</div>
1973<div class="doc_text">
1974<h5>Syntax:</h5>
1975<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1976</pre>
1977<h5>Overview:</h5>
1978<p>The '<tt>urem</tt>' instruction returns the remainder from the
1979unsigned division of its two arguments.</p>
1980<h5>Arguments:</h5>
1981<p>The two arguments to the '<tt>urem</tt>' instruction must be
1982<a href="#t_integer">integer</a> values. Both arguments must have identical
1983types.</p>
1984<h5>Semantics:</h5>
1985<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1986This instruction always performs an unsigned division to get the remainder,
1987regardless of whether the arguments are unsigned or not.</p>
1988<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1989<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]1990</pre>
1991
1992</div>
1993<!-- _______________________________________________________________________ -->
1994<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1995Instruction</a> </div>
1996<div class="doc_text">
1997<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1998<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]1999</pre>
2000<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2001<p>The '<tt>srem</tt>' instruction returns the remainder from the
2002signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2003<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2004<p>The two arguments to the '<tt>srem</tt>' instruction must be
2005<a href="#t_integer">integer</a> values. Both arguments must have identical
2006types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2007<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2008<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2009has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2010operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2011a value. For more information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2012 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2013Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencer64f5c6c2007-03-24 22:40:44 +0000[diff] [blame]2014please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencerc9fdfc82007-03-24 22:23:39 +0000[diff] [blame]2015Wikipedia: modulo operation</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2016<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2017<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]2018</pre>
2019
2020</div>
2021<!-- _______________________________________________________________________ -->
2022<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2023Instruction</a> </div>
2024<div class="doc_text">
2025<h5>Syntax:</h5>
2026<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2027</pre>
2028<h5>Overview:</h5>
2029<p>The '<tt>frem</tt>' instruction returns the remainder from the
2030division of its two operands.</p>
2031<h5>Arguments:</h5>
2032<p>The two arguments to the '<tt>frem</tt>' instruction must be
2033<a href="#t_floating">floating point</a> values. Both arguments must have
2034identical types.</p>
2035<h5>Semantics:</h5>
2036<p>This instruction returns the <i>remainder</i> of a division.</p>
2037<h5>Example:</h5>
2038<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]2039</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2040</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2041
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2042<!-- ======================================================================= -->
2043<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2044Operations</a> </div>
2045<div class="doc_text">
2046<p>Bitwise binary operators are used to do various forms of
2047bit-twiddling in a program. They are generally very efficient
2048instructions and can commonly be strength reduced from other
2049instructions. They require two operands, execute an operation on them,
2050and produce a single value. The resulting value of the bitwise binary
2051operators is always the same type as its first operand.</p>
2052</div>
2053
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2054<!-- _______________________________________________________________________ -->
2055<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2056Instruction</a> </div>
2057<div class="doc_text">
2058<h5>Syntax:</h5>
2059<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2060</pre>
2061<h5>Overview:</h5>
2062<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2063the left a specified number of bits.</p>
2064<h5>Arguments:</h5>
2065<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2066 href="#t_integer">integer</a> type.</p>
2067<h5>Semantics:</h5>
2068<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2069<h5>Example:</h5><pre>
2070 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2071 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2072 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2073</pre>
2074</div>
2075<!-- _______________________________________________________________________ -->
2076<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2077Instruction</a> </div>
2078<div class="doc_text">
2079<h5>Syntax:</h5>
2080<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2081</pre>
2082
2083<h5>Overview:</h5>
2084<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2085operand shifted to the right a specified number of bits.</p>
2086
2087<h5>Arguments:</h5>
2088<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2089<a href="#t_integer">integer</a> type.</p>
2090
2091<h5>Semantics:</h5>
2092<p>This instruction always performs a logical shift right operation. The most
2093significant bits of the result will be filled with zero bits after the
2094shift.</p>
2095
2096<h5>Example:</h5>
2097<pre>
2098 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2099 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2100 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2101 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2102</pre>
2103</div>
2104
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2105<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2106<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2107Instruction</a> </div>
2108<div class="doc_text">
2109
2110<h5>Syntax:</h5>
2111<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2112</pre>
2113
2114<h5>Overview:</h5>
2115<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2116operand shifted to the right a specified number of bits.</p>
2117
2118<h5>Arguments:</h5>
2119<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2120<a href="#t_integer">integer</a> type.</p>
2121
2122<h5>Semantics:</h5>
2123<p>This instruction always performs an arithmetic shift right operation,
2124The most significant bits of the result will be filled with the sign bit
2125of <tt>var1</tt>.</p>
2126
2127<h5>Example:</h5>
2128<pre>
2129 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2130 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2131 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2132 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2133</pre>
2134</div>
2135
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2136<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2137<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2138Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2139<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2140<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2141<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]2142</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2143<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2144<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2145its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2146<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2147<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2148 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2149identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2150<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2151<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2152<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2153<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2154<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2155 <tbody>
2156 <tr>
2157 <td>In0</td>
2158 <td>In1</td>
2159 <td>Out</td>
2160 </tr>
2161 <tr>
2162 <td>0</td>
2163 <td>0</td>
2164 <td>0</td>
2165 </tr>
2166 <tr>
2167 <td>0</td>
2168 <td>1</td>
2169 <td>0</td>
2170 </tr>
2171 <tr>
2172 <td>1</td>
2173 <td>0</td>
2174 <td>0</td>
2175 </tr>
2176 <tr>
2177 <td>1</td>
2178 <td>1</td>
2179 <td>1</td>
2180 </tr>
2181 </tbody>
2182</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2183</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2184<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2185<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2186 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2187 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2188</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2189</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2190<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2191<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2192<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2193<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2194<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]2195</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2196<h5>Overview:</h5>
2197<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2198or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2199<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2200<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2201 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2202identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2203<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2204<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2205<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2206<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2207<table border="1" cellspacing="0" cellpadding="4">
2208 <tbody>
2209 <tr>
2210 <td>In0</td>
2211 <td>In1</td>
2212 <td>Out</td>
2213 </tr>
2214 <tr>
2215 <td>0</td>
2216 <td>0</td>
2217 <td>0</td>
2218 </tr>
2219 <tr>
2220 <td>0</td>
2221 <td>1</td>
2222 <td>1</td>
2223 </tr>
2224 <tr>
2225 <td>1</td>
2226 <td>0</td>
2227 <td>1</td>
2228 </tr>
2229 <tr>
2230 <td>1</td>
2231 <td>1</td>
2232 <td>1</td>
2233 </tr>
2234 </tbody>
2235</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2236</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2237<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2238<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2239 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2240 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2241</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2242</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2243<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2244<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2245Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2246<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2247<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2248<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]2249</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2250<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2251<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2252or of its two operands. The <tt>xor</tt> is used to implement the
2253"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2254<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2255<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2256 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2257identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2258<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2259<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2260<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2261<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2262<table border="1" cellspacing="0" cellpadding="4">
2263 <tbody>
2264 <tr>
2265 <td>In0</td>
2266 <td>In1</td>
2267 <td>Out</td>
2268 </tr>
2269 <tr>
2270 <td>0</td>
2271 <td>0</td>
2272 <td>0</td>
2273 </tr>
2274 <tr>
2275 <td>0</td>
2276 <td>1</td>
2277 <td>1</td>
2278 </tr>
2279 <tr>
2280 <td>1</td>
2281 <td>0</td>
2282 <td>1</td>
2283 </tr>
2284 <tr>
2285 <td>1</td>
2286 <td>1</td>
2287 <td>0</td>
2288 </tr>
2289 </tbody>
2290</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2291</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2292<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2293<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2294<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2295 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2296 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2297 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2298</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2299</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2301<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2302<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2303 <a name="vectorops">Vector Operations</a>
2304</div>
2305
2306<div class="doc_text">
2307
2308<p>LLVM supports several instructions to represent vector operations in a
2309target-independent manner. This instructions cover the element-access and
2310vector-specific operations needed to process vectors effectively. While LLVM
2311does directly support these vector operations, many sophisticated algorithms
2312will want to use target-specific intrinsics to take full advantage of a specific
2313target.</p>
2314
2315</div>
2316
2317<!-- _______________________________________________________________________ -->
2318<div class="doc_subsubsection">
2319 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2320</div>
2321
2322<div class="doc_text">
2323
2324<h5>Syntax:</h5>
2325
2326<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2327 &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]2328</pre>
2329
2330<h5>Overview:</h5>
2331
2332<p>
2333The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2334element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2335</p>
2336
2337
2338<h5>Arguments:</h5>
2339
2340<p>
2341The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2342value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2343an index indicating the position from which to extract the element.
2344The index may be a variable.</p>
2345
2346<h5>Semantics:</h5>
2347
2348<p>
2349The result is a scalar of the same type as the element type of
2350<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2351<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2352results are undefined.
2353</p>
2354
2355<h5>Example:</h5>
2356
2357<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2358 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2359</pre>
2360</div>
2361
2362
2363<!-- _______________________________________________________________________ -->
2364<div class="doc_subsubsection">
2365 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2366</div>
2367
2368<div class="doc_text">
2369
2370<h5>Syntax:</h5>
2371
2372<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2373 &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]2374</pre>
2375
2376<h5>Overview:</h5>
2377
2378<p>
2379The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2380element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2381</p>
2382
2383
2384<h5>Arguments:</h5>
2385
2386<p>
2387The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2388value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2389scalar value whose type must equal the element type of the first
2390operand. The third operand is an index indicating the position at
2391which to insert the value. The index may be a variable.</p>
2392
2393<h5>Semantics:</h5>
2394
2395<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2396The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2397element values are those of <tt>val</tt> except at position
2398<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2399exceeds the length of <tt>val</tt>, the results are undefined.
2400</p>
2401
2402<h5>Example:</h5>
2403
2404<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2405 %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]2406</pre>
2407</div>
2408
2409<!-- _______________________________________________________________________ -->
2410<div class="doc_subsubsection">
2411 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2412</div>
2413
2414<div class="doc_text">
2415
2416<h5>Syntax:</h5>
2417
2418<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2419 &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]2420</pre>
2421
2422<h5>Overview:</h5>
2423
2424<p>
2425The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2426from two input vectors, returning a vector of the same type.
2427</p>
2428
2429<h5>Arguments:</h5>
2430
2431<p>
2432The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2433with types that match each other and types that match the result of the
2434instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2435of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2436</p>
2437
2438<p>
2439The shuffle mask operand is required to be a constant vector with either
2440constant integer or undef values.
2441</p>
2442
2443<h5>Semantics:</h5>
2444
2445<p>
2446The elements of the two input vectors are numbered from left to right across
2447both of the vectors. The shuffle mask operand specifies, for each element of
2448the result vector, which element of the two input registers the result element
2449gets. The element selector may be undef (meaning "don't care") and the second
2450operand may be undef if performing a shuffle from only one vector.
2451</p>
2452
2453<h5>Example:</h5>
2454
2455<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2456 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2457 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2458 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2459 &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]2460</pre>
2461</div>
2462
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2463
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2464<!-- ======================================================================= -->
2465<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2466 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2467</div>
2468
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2469<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2470
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2471<p>A key design point of an SSA-based representation is how it
2472represents memory. In LLVM, no memory locations are in SSA form, which
2473makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2474allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2476</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2477
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2478<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2479<div class="doc_subsubsection">
2480 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2481</div>
2482
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2483<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2485<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2486
2487<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2488 &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]2489</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2490
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2491<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2492
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2493<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2494heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2495
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2496<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2497
2498<p>The '<tt>malloc</tt>' instruction allocates
2499<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2500bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2501appropriate type to the program. If "NumElements" is specified, it is the
2502number of elements allocated. If an alignment is specified, the value result
2503of the allocation is guaranteed to be aligned to at least that boundary. If
2504not specified, or if zero, the target can choose to align the allocation on any
2505convenient boundary.</p>
2506
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2507<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2508
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2509<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2510
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2511<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2512a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2513
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2514<h5>Example:</h5>
2515
2516<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2517 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2518
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2519 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2520 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2521 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2522 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2523 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2524</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2525</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2527<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2528<div class="doc_subsubsection">
2529 <a name="i_free">'<tt>free</tt>' Instruction</a>
2530</div>
2531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2532<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2534<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2535
2536<pre>
2537 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2538</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2539
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2540<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2541
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2542<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2543memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2546
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2547<p>'<tt>value</tt>' shall be a pointer value that points to a value
2548that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2549instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2550
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2551<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2552
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2553<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2554after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2555
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2556<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2557
2558<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2559 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2560 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2561</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2562</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2563
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2564<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2565<div class="doc_subsubsection">
2566 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2567</div>
2568
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2569<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2570
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2571<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2572
2573<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2574 &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]2575</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2577<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2578
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2579<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2580stack frame of the procedure that is live until the current function
2581returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2582
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2583<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2584
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2585<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2586bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2587appropriate type to the program. If "NumElements" is specified, it is the
2588number of elements allocated. If an alignment is specified, the value result
2589of the allocation is guaranteed to be aligned to at least that boundary. If
2590not specified, or if zero, the target can choose to align the allocation on any
2591convenient boundary.</p>
2592
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2593<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2594
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2595<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2596
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2597<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2598memory is automatically released when the function returns. The '<tt>alloca</tt>'
2599instruction is commonly used to represent automatic variables that must
2600have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2601 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]2602instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2603
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2604<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2605
2606<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2607 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2608 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2609 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2610 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2611</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2612</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2613
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2614<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2615<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2616Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2617<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2618<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2619<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]2620<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2621<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2622<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2623<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2624address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2625 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2626marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2627the number or order of execution of this <tt>load</tt> with other
2628volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2629instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2630<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2631<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2632<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2633<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2634 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2635 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2636 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2637</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2638</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2639<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2640<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2641Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2642<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2643<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2644<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]2645 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]2646</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2647<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2648<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2649<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2650<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2651to 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]2652operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2653operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2654optimizer is not allowed to modify the number or order of execution of
2655this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2656 href="#i_store">store</a></tt> instructions.</p>
2657<h5>Semantics:</h5>
2658<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2659at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2660<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2661<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2662 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2663 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2664 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2665</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2666</div>
2667
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2668<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2669<div class="doc_subsubsection">
2670 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2671</div>
2672
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2673<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2674<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2675<pre>
2676 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2677</pre>
2678
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2679<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2680
2681<p>
2682The '<tt>getelementptr</tt>' instruction is used to get the address of a
2683subelement of an aggregate data structure.</p>
2684
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2685<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2686
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2687<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2688elements of the aggregate object to index to. The actual types of the arguments
2689provided depend on the type of the first pointer argument. The
2690'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2691levels 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]2692structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2693into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2694be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2695
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2696<p>For example, let's consider a C code fragment and how it gets
2697compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2698
2699<pre>
2700 struct RT {
2701 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2702 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2703 char C;
2704 };
2705 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2706 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2707 double Y;
2708 struct RT Z;
2709 };
2710
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2711 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2712 return &amp;s[1].Z.B[5][13];
2713 }
2714</pre>
2715
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2716<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2717
2718<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2719 %RT = type { i8 , [10 x [20 x i32]], i8 }
2720 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2721
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2722 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2723 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2724 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2725 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2726 }
2727</pre>
2728
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2729<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2730
2731<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2732on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2733and <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]2734<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]2735to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2736<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2737
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2738<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]2739type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2740}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2741the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2742i8 }</tt>' type, another structure. The third index indexes into the second
2743element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2744array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2745'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2746to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2747
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2748<p>Note that it is perfectly legal to index partially through a
2749structure, returning a pointer to an inner element. Because of this,
2750the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2751
2752<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2753 define i32* %foo(%ST* %s) {
2754 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2755 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2756 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2757 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2758 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2759 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2760 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2761</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2762
2763<p>Note that it is undefined to access an array out of bounds: array and
2764pointer indexes must always be within the defined bounds of the array type.
2765The one exception for this rules is zero length arrays. These arrays are
2766defined to be accessible as variable length arrays, which requires access
2767beyond the zero'th element.</p>
2768
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2769<p>The getelementptr instruction is often confusing. For some more insight
2770into how it works, see <a href="GetElementPtr.html">the getelementptr
2771FAQ</a>.</p>
2772
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2773<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2774
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2775<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2776 <i>; yields [12 x i8]*:aptr</i>
2777 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2778</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2779</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2780
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2781<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2782<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2783</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2784<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2785<p>The instructions in this category are the conversion instructions (casting)
2786which all take a single operand and a type. They perform various bit conversions
2787on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2788</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2789
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2790<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2791<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2792 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2793</div>
2794<div class="doc_text">
2795
2796<h5>Syntax:</h5>
2797<pre>
2798 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2799</pre>
2800
2801<h5>Overview:</h5>
2802<p>
2803The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2804</p>
2805
2806<h5>Arguments:</h5>
2807<p>
2808The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2809be 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]2810and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2811type. The bit size of <tt>value</tt> must be larger than the bit size of
2812<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2813
2814<h5>Semantics:</h5>
2815<p>
2816The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2817and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2818larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2819It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2820
2821<h5>Example:</h5>
2822<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2823 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2824 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2825 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2826</pre>
2827</div>
2828
2829<!-- _______________________________________________________________________ -->
2830<div class="doc_subsubsection">
2831 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2832</div>
2833<div class="doc_text">
2834
2835<h5>Syntax:</h5>
2836<pre>
2837 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2838</pre>
2839
2840<h5>Overview:</h5>
2841<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2842<tt>ty2</tt>.</p>
2843
2844
2845<h5>Arguments:</h5>
2846<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]2847<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2848also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2849<tt>value</tt> must be smaller than the bit size of the destination type,
2850<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2851
2852<h5>Semantics:</h5>
2853<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2854bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2855the operand and the type are the same size, no bit filling is done and the
2856cast is considered a <i>no-op cast</i> because no bits change (only the type
2857changes).</p>
2858
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2859<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]2860
2861<h5>Example:</h5>
2862<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2863 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2864 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2865</pre>
2866</div>
2867
2868<!-- _______________________________________________________________________ -->
2869<div class="doc_subsubsection">
2870 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2871</div>
2872<div class="doc_text">
2873
2874<h5>Syntax:</h5>
2875<pre>
2876 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2877</pre>
2878
2879<h5>Overview:</h5>
2880<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2881
2882<h5>Arguments:</h5>
2883<p>
2884The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2885<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2886also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2887<tt>value</tt> must be smaller than the bit size of the destination type,
2888<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2889
2890<h5>Semantics:</h5>
2891<p>
2892The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2893bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2894the type <tt>ty2</tt>. When the the operand and the type are the same size,
2895no bit filling is done and the cast is considered a <i>no-op cast</i> because
2896no bits change (only the type changes).</p>
2897
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2898<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]2899
2900<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2901<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2902 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2903 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2904</pre>
2905</div>
2906
2907<!-- _______________________________________________________________________ -->
2908<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2909 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2910</div>
2911
2912<div class="doc_text">
2913
2914<h5>Syntax:</h5>
2915
2916<pre>
2917 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2918</pre>
2919
2920<h5>Overview:</h5>
2921<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2922<tt>ty2</tt>.</p>
2923
2924
2925<h5>Arguments:</h5>
2926<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2927 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2928cast it to. The size of <tt>value</tt> must be larger than the size of
2929<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2930<i>no-op cast</i>.</p>
2931
2932<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2933<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2934<a href="#t_floating">floating point</a> type to a smaller
2935<a href="#t_floating">floating point</a> type. If the value cannot fit within
2936the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2937
2938<h5>Example:</h5>
2939<pre>
2940 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2941 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2942</pre>
2943</div>
2944
2945<!-- _______________________________________________________________________ -->
2946<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2947 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2948</div>
2949<div class="doc_text">
2950
2951<h5>Syntax:</h5>
2952<pre>
2953 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2954</pre>
2955
2956<h5>Overview:</h5>
2957<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2958floating point value.</p>
2959
2960<h5>Arguments:</h5>
2961<p>The '<tt>fpext</tt>' instruction takes a
2962<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2963and a <a href="#t_floating">floating point</a> type to cast it to. The source
2964type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2965
2966<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2967<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]2968<a href="#t_floating">floating point</a> type to a larger
2969<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2970used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2971<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]2972
2973<h5>Example:</h5>
2974<pre>
2975 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2976 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2977</pre>
2978</div>
2979
2980<!-- _______________________________________________________________________ -->
2981<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]2982 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2983</div>
2984<div class="doc_text">
2985
2986<h5>Syntax:</h5>
2987<pre>
2988 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2989</pre>
2990
2991<h5>Overview:</h5>
2992<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2993unsigned integer equivalent of type <tt>ty2</tt>.
2994</p>
2995
2996<h5>Arguments:</h5>
2997<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2998<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]2999must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3000
3001<h5>Semantics:</h5>
3002<p> The '<tt>fp2uint</tt>' instruction converts its
3003<a href="#t_floating">floating point</a> operand into the nearest (rounding
3004towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3005the results are undefined.</p>
3006
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3007<p>When converting to i1, the conversion is done as a comparison against
3008zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3009If 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]3010
3011<h5>Example:</h5>
3012<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3013 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3014 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3015 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3016</pre>
3017</div>
3018
3019<!-- _______________________________________________________________________ -->
3020<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3021 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3022</div>
3023<div class="doc_text">
3024
3025<h5>Syntax:</h5>
3026<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3027 &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]3028</pre>
3029
3030<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3031<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3032<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]3033</p>
3034
3035
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3036<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3037<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]3038<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]3039must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3040
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3041<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3042<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3043<a href="#t_floating">floating point</a> operand into the nearest (rounding
3044towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3045the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3046
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3047<p>When converting to i1, the conversion is done as a comparison against
3048zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3049If 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]3050
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3051<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3052<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3053 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3054 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3055 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3056</pre>
3057</div>
3058
3059<!-- _______________________________________________________________________ -->
3060<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3061 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3062</div>
3063<div class="doc_text">
3064
3065<h5>Syntax:</h5>
3066<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3067 &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]3068</pre>
3069
3070<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3071<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3072integer and converts that value to the <tt>ty2</tt> type.</p>
3073
3074
3075<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3076<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]3077<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]3078be a <a href="#t_floating">floating point</a> type.</p>
3079
3080<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3081<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3082integer quantity and converts it to the corresponding floating point value. If
3083the value cannot fit in the floating point value, the results are undefined.</p>
3084
3085
3086<h5>Example:</h5>
3087<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3088 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3089 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3090</pre>
3091</div>
3092
3093<!-- _______________________________________________________________________ -->
3094<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3095 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3096</div>
3097<div class="doc_text">
3098
3099<h5>Syntax:</h5>
3100<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3101 &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]3102</pre>
3103
3104<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3105<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3106integer and converts that value to the <tt>ty2</tt> type.</p>
3107
3108<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3109<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]3110<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]3111a <a href="#t_floating">floating point</a> type.</p>
3112
3113<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3114<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3115integer quantity and converts it to the corresponding floating point value. If
3116the value cannot fit in the floating point value, the results are undefined.</p>
3117
3118<h5>Example:</h5>
3119<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3120 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3121 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3122</pre>
3123</div>
3124
3125<!-- _______________________________________________________________________ -->
3126<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3127 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3128</div>
3129<div class="doc_text">
3130
3131<h5>Syntax:</h5>
3132<pre>
3133 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3134</pre>
3135
3136<h5>Overview:</h5>
3137<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3138the integer type <tt>ty2</tt>.</p>
3139
3140<h5>Arguments:</h5>
3141<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]3142must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3143<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3144
3145<h5>Semantics:</h5>
3146<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3147<tt>ty2</tt> by interpreting the pointer value as an integer and either
3148truncating or zero extending that value to the size of the integer type. If
3149<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3150<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3151are the same size, then nothing is done (<i>no-op cast</i>).</p>
3152
3153<h5>Example:</h5>
3154<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3155 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3156 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3157</pre>
3158</div>
3159
3160<!-- _______________________________________________________________________ -->
3161<div class="doc_subsubsection">
3162 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3163</div>
3164<div class="doc_text">
3165
3166<h5>Syntax:</h5>
3167<pre>
3168 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3169</pre>
3170
3171<h5>Overview:</h5>
3172<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3173a pointer type, <tt>ty2</tt>.</p>
3174
3175<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]3176<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3177value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3178<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3179
3180<h5>Semantics:</h5>
3181<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3182<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3183the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3184size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3185the size of a pointer then a zero extension is done. If they are the same size,
3186nothing is done (<i>no-op cast</i>).</p>
3187
3188<h5>Example:</h5>
3189<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3190 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3191 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3192 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3193</pre>
3194</div>
3195
3196<!-- _______________________________________________________________________ -->
3197<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3198 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3199</div>
3200<div class="doc_text">
3201
3202<h5>Syntax:</h5>
3203<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3204 &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]3205</pre>
3206
3207<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3208<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3209<tt>ty2</tt> without changing any bits.</p>
3210
3211<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3212<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3213a first class value, and a type to cast it to, which must also be a <a
3214 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3215and the destination type, <tt>ty2</tt>, must be identical. If the source
3216type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3217
3218<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3219<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3220<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3221this conversion. The conversion is done as if the <tt>value</tt> had been
3222stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3223converted to other pointer types with this instruction. To convert pointers to
3224other types, use the <a href="#i_inttoptr">inttoptr</a> or
3225<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3226
3227<h5>Example:</h5>
3228<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3229 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3230 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3231 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3232</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3233</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3234
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3235<!-- ======================================================================= -->
3236<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3237<div class="doc_text">
3238<p>The instructions in this category are the "miscellaneous"
3239instructions, which defy better classification.</p>
3240</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3241
3242<!-- _______________________________________________________________________ -->
3243<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3244</div>
3245<div class="doc_text">
3246<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3247<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3248<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3249</pre>
3250<h5>Overview:</h5>
3251<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3252of its two integer operands.</p>
3253<h5>Arguments:</h5>
3254<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3255the condition code which indicates the kind of comparison to perform. It is not
3256a value, just a keyword. The possibilities for the condition code are:
3257<ol>
3258 <li><tt>eq</tt>: equal</li>
3259 <li><tt>ne</tt>: not equal </li>
3260 <li><tt>ugt</tt>: unsigned greater than</li>
3261 <li><tt>uge</tt>: unsigned greater or equal</li>
3262 <li><tt>ult</tt>: unsigned less than</li>
3263 <li><tt>ule</tt>: unsigned less or equal</li>
3264 <li><tt>sgt</tt>: signed greater than</li>
3265 <li><tt>sge</tt>: signed greater or equal</li>
3266 <li><tt>slt</tt>: signed less than</li>
3267 <li><tt>sle</tt>: signed less or equal</li>
3268</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3269<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3270<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3271<h5>Semantics:</h5>
3272<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3273the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3274yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3275<ol>
3276 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3277 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3278 </li>
3279 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3280 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3281 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3282 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3283 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3284 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3285 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3286 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3287 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3288 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3289 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3290 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3291 <li><tt>sge</tt>: interprets the operands as signed values and yields
3292 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3293 <li><tt>slt</tt>: interprets the operands as signed values and yields
3294 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3295 <li><tt>sle</tt>: interprets the operands as signed values and yields
3296 <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]3297</ol>
3298<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3299values are treated as integers and then compared.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3300
3301<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3302<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3303 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3304 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3305 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3306 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3307 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3308</pre>
3309</div>
3310
3311<!-- _______________________________________________________________________ -->
3312<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3313</div>
3314<div class="doc_text">
3315<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3316<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3317<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3318</pre>
3319<h5>Overview:</h5>
3320<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3321of its floating point operands.</p>
3322<h5>Arguments:</h5>
3323<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3324the condition code which indicates the kind of comparison to perform. It is not
3325a value, just a keyword. The possibilities for the condition code are:
3326<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3327 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3328 <li><tt>oeq</tt>: ordered and equal</li>
3329 <li><tt>ogt</tt>: ordered and greater than </li>
3330 <li><tt>oge</tt>: ordered and greater than or equal</li>
3331 <li><tt>olt</tt>: ordered and less than </li>
3332 <li><tt>ole</tt>: ordered and less than or equal</li>
3333 <li><tt>one</tt>: ordered and not equal</li>
3334 <li><tt>ord</tt>: ordered (no nans)</li>
3335 <li><tt>ueq</tt>: unordered or equal</li>
3336 <li><tt>ugt</tt>: unordered or greater than </li>
3337 <li><tt>uge</tt>: unordered or greater than or equal</li>
3338 <li><tt>ult</tt>: unordered or less than </li>
3339 <li><tt>ule</tt>: unordered or less than or equal</li>
3340 <li><tt>une</tt>: unordered or not equal</li>
3341 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3342 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3343</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3344<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3345<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3346<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3347<a href="#t_floating">floating point</a> typed. They must have identical
3348types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3349<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3350<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3351<h5>Semantics:</h5>
3352<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3353the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3354yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3355<ol>
3356 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3357 <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]3358 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3359 <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]3360 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3361 <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]3362 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3363 <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]3364 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3365 <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]3366 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3367 <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]3368 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3369 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3370 <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]3371 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3372 <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]3373 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3374 <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]3375 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3376 <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]3377 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3378 <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]3379 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3380 <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]3381 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3382 <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]3383 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3384</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3385
3386<h5>Example:</h5>
3387<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3388 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3389 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3390 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3391</pre>
3392</div>
3393
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3394<!-- _______________________________________________________________________ -->
3395<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3396Instruction</a> </div>
3397<div class="doc_text">
3398<h5>Syntax:</h5>
3399<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3400<h5>Overview:</h5>
3401<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3402the SSA graph representing the function.</p>
3403<h5>Arguments:</h5>
3404<p>The type of the incoming values are specified with the first type
3405field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3406as arguments, with one pair for each predecessor basic block of the
3407current block. Only values of <a href="#t_firstclass">first class</a>
3408type may be used as the value arguments to the PHI node. Only labels
3409may be used as the label arguments.</p>
3410<p>There must be no non-phi instructions between the start of a basic
3411block and the PHI instructions: i.e. PHI instructions must be first in
3412a basic block.</p>
3413<h5>Semantics:</h5>
3414<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3415value specified by the parameter, depending on which basic block we
3416came from in the last <a href="#terminators">terminator</a> instruction.</p>
3417<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3418<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]3419</div>
3420
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection">
3423 <a name="i_select">'<tt>select</tt>' Instruction</a>
3424</div>
3425
3426<div class="doc_text">
3427
3428<h5>Syntax:</h5>
3429
3430<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3431 &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]3432</pre>
3433
3434<h5>Overview:</h5>
3435
3436<p>
3437The '<tt>select</tt>' instruction is used to choose one value based on a
3438condition, without branching.
3439</p>
3440
3441
3442<h5>Arguments:</h5>
3443
3444<p>
3445The '<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.
3446</p>
3447
3448<h5>Semantics:</h5>
3449
3450<p>
3451If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3452value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3453</p>
3454
3455<h5>Example:</h5>
3456
3457<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3458 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3459</pre>
3460</div>
3461
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3462
3463<!-- _______________________________________________________________________ -->
3464<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3465 <a name="i_call">'<tt>call</tt>' Instruction</a>
3466</div>
3467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3468<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3471<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3472 &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]3473</pre>
3474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3477<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3478
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3479<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3480
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3481<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3482
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3483<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3484 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3485 <p>The optional "tail" marker indicates whether the callee function accesses
3486 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3487 function call is eligible for tail call optimization. Note that calls may
3488 be marked "tail" even if they do not occur before a <a
3489 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3490 </li>
3491 <li>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]3492 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3493 convention</a> the call should use. If none is specified, the call defaults
3494 to using C calling conventions.
3495 </li>
3496 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3497 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3498 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3499 signature. This type can be omitted if the function is not varargs and
3500 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3501 </li>
3502 <li>
3503 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3504 be invoked. In most cases, this is a direct function invocation, but
3505 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3506 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3507 </li>
3508 <li>
3509 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3510 function signature argument types. All arguments must be of
3511 <a href="#t_firstclass">first class</a> type. If the function signature
3512 indicates the function accepts a variable number of arguments, the extra
3513 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3514 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3515</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3516
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3517<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3518
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3519<p>The '<tt>call</tt>' instruction is used to cause control flow to
3520transfer to a specified function, with its incoming arguments bound to
3521the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3522instruction in the called function, control flow continues with the
3523instruction after the function call, and the return value of the
3524function is bound to the result argument. This is a simpler case of
3525the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3526
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3527<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3528
3529<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3530 %retval = call i32 %test(i32 %argc)
3531 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3532 %X = tail call i32 %foo()
3533 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3534</pre>
3535
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3536</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3537
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3538<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3539<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3540 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3541</div>
3542
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3543<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3544
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3545<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3546
3547<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3548 &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]3549</pre>
3550
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3551<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3552
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3553<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3554the "variable argument" area of a function call. It is used to implement the
3555<tt>va_arg</tt> macro in C.</p>
3556
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3557<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3558
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3559<p>This instruction takes a <tt>va_list*</tt> value and the type of
3560the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3561increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3562actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3563
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3564<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3565
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3566<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3567type from the specified <tt>va_list</tt> and causes the
3568<tt>va_list</tt> to point to the next argument. For more information,
3569see the variable argument handling <a href="#int_varargs">Intrinsic
3570Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3571
3572<p>It is legal for this instruction to be called in a function which does not
3573take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3574function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3575
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3576<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3577href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3578argument.</p>
3579
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3580<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3581
3582<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3583
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3584</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3585
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3586<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3587<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3588<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3589
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3590<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3591
3592<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3593well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3594restrictions. Overall, these instructions represent an extension mechanism for
3595the LLVM language that does not require changing all of the transformations in
3596LLVM to add to the language (or the bytecode reader/writer, the parser,
3597etc...).</p>
3598
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3599<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3600prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3601this. Intrinsic functions must always be external functions: you cannot define
3602the body of intrinsic functions. Intrinsic functions may only be used in call
3603or invoke instructions: it is illegal to take the address of an intrinsic
3604function. Additionally, because intrinsic functions are part of the LLVM
3605language, it is required that they all be documented here if any are added.</p>
3606
3607
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3608<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3609href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3610</p>
3611
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3612</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3613
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3614<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3615<div class="doc_subsection">
3616 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3617</div>
3618
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3619<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3620
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3621<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3622 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3623intrinsic functions. These functions are related to the similarly
3624named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3625
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3626<p>All of these functions operate on arguments that use a
3627target-specific value type "<tt>va_list</tt>". The LLVM assembly
3628language reference manual does not define what this type is, so all
3629transformations should be prepared to handle intrinsics with any type
3630used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3631
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3632<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]3633instruction and the variable argument handling intrinsic functions are
3634used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3635
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3636<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3637define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3638 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3639 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3640 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3641 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3642
3643 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3644 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3645
3646 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3647 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3648 %aq2 = bitcast i8** %aq to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3649 call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
3650 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3651
3652 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3653 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3654 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3655}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3656
3657declare void @llvm.va_start(i8*)
3658declare void @llvm.va_copy(i8*, i8*)
3659declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3660</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3661</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3662
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3663<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3664<div class="doc_subsubsection">
3665 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3666</div>
3667
3668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3669<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3670<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3671<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3672<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3673<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3674<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3675href="#i_va_arg">va_arg</a></tt>.</p>
3676
3677<h5>Arguments:</h5>
3678
3679<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3680
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3681<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3682
3683<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3684macro available in C. In a target-dependent way, it initializes the
3685<tt>va_list</tt> element the argument points to, so that the next call to
3686<tt>va_arg</tt> will produce the first variable argument passed to the function.
3687Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3688last argument of the function, the compiler can figure that out.</p>
3689
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3690</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3691
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3692<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3693<div class="doc_subsubsection">
3694 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3695</div>
3696
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3697<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3698<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3699<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3700<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3701
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3702<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3703which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3704or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3705
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3706<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3707
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3708<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3709
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3710<h5>Semantics:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3712<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]3713macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3714Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3715 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3716with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3717
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3718</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3719
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3720<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3721<div class="doc_subsubsection">
3722 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3723</div>
3724
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3725<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3726
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3727<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3728
3729<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3730 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3731</pre>
3732
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3733<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3734
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3735<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3736the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3737
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3738<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3739
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3740<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]3741The 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]3742
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3743
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3744<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3745
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3746<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3747available in C. In a target-dependent way, it copies the source
3748<tt>va_list</tt> element into the destination list. This intrinsic is necessary
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]3749because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3750arbitrarily complex and require memory allocation, for example.</p>
3751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3752</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3753
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3754<!-- ======================================================================= -->
3755<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3756 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3757</div>
3758
3759<div class="doc_text">
3760
3761<p>
3762LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3763Collection</a> requires the implementation and generation of these intrinsics.
3764These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3765stack</a>, as well as garbage collector implementations that require <a
3766href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3767Front-ends for type-safe garbage collected languages should generate these
3768intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3769href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3770</p>
3771</div>
3772
3773<!-- _______________________________________________________________________ -->
3774<div class="doc_subsubsection">
3775 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3776</div>
3777
3778<div class="doc_text">
3779
3780<h5>Syntax:</h5>
3781
3782<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3783 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3784</pre>
3785
3786<h5>Overview:</h5>
3787
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3788<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]3789the code generator, and allows some metadata to be associated with it.</p>
3790
3791<h5>Arguments:</h5>
3792
3793<p>The first argument specifies the address of a stack object that contains the
3794root pointer. The second pointer (which must be either a constant or a global
3795value address) contains the meta-data to be associated with the root.</p>
3796
3797<h5>Semantics:</h5>
3798
3799<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3800location. At compile-time, the code generator generates information to allow
3801the runtime to find the pointer at GC safe points.
3802</p>
3803
3804</div>
3805
3806
3807<!-- _______________________________________________________________________ -->
3808<div class="doc_subsubsection">
3809 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3810</div>
3811
3812<div class="doc_text">
3813
3814<h5>Syntax:</h5>
3815
3816<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3817 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3818</pre>
3819
3820<h5>Overview:</h5>
3821
3822<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3823locations, allowing garbage collector implementations that require read
3824barriers.</p>
3825
3826<h5>Arguments:</h5>
3827
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3828<p>The second argument is the address to read from, which should be an address
3829allocated from the garbage collector. The first object is a pointer to the
3830start of the referenced object, if needed by the language runtime (otherwise
3831null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3832
3833<h5>Semantics:</h5>
3834
3835<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3836instruction, but may be replaced with substantially more complex code by the
3837garbage collector runtime, as needed.</p>
3838
3839</div>
3840
3841
3842<!-- _______________________________________________________________________ -->
3843<div class="doc_subsubsection">
3844 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3845</div>
3846
3847<div class="doc_text">
3848
3849<h5>Syntax:</h5>
3850
3851<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3852 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3853</pre>
3854
3855<h5>Overview:</h5>
3856
3857<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3858locations, allowing garbage collector implementations that require write
3859barriers (such as generational or reference counting collectors).</p>
3860
3861<h5>Arguments:</h5>
3862
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3863<p>The first argument is the reference to store, the second is the start of the
3864object to store it to, and the third is the address of the field of Obj to
3865store to. If the runtime does not require a pointer to the object, Obj may be
3866null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3867
3868<h5>Semantics:</h5>
3869
3870<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3871instruction, but may be replaced with substantially more complex code by the
3872garbage collector runtime, as needed.</p>
3873
3874</div>
3875
3876
3877
3878<!-- ======================================================================= -->
3879<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3880 <a name="int_codegen">Code Generator Intrinsics</a>
3881</div>
3882
3883<div class="doc_text">
3884<p>
3885These intrinsics are provided by LLVM to expose special features that may only
3886be implemented with code generator support.
3887</p>
3888
3889</div>
3890
3891<!-- _______________________________________________________________________ -->
3892<div class="doc_subsubsection">
3893 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3894</div>
3895
3896<div class="doc_text">
3897
3898<h5>Syntax:</h5>
3899<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3900 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3901</pre>
3902
3903<h5>Overview:</h5>
3904
3905<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3906The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3907target-specific value indicating the return address of the current function
3908or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3909</p>
3910
3911<h5>Arguments:</h5>
3912
3913<p>
3914The argument to this intrinsic indicates which function to return the address
3915for. Zero indicates the calling function, one indicates its caller, etc. The
3916argument is <b>required</b> to be a constant integer value.
3917</p>
3918
3919<h5>Semantics:</h5>
3920
3921<p>
3922The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3923the return address of the specified call frame, or zero if it cannot be
3924identified. The value returned by this intrinsic is likely to be incorrect or 0
3925for arguments other than zero, so it should only be used for debugging purposes.
3926</p>
3927
3928<p>
3929Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3930aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3931source-language caller.
3932</p>
3933</div>
3934
3935
3936<!-- _______________________________________________________________________ -->
3937<div class="doc_subsubsection">
3938 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3939</div>
3940
3941<div class="doc_text">
3942
3943<h5>Syntax:</h5>
3944<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3945 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3946</pre>
3947
3948<h5>Overview:</h5>
3949
3950<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3951The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3952target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3953</p>
3954
3955<h5>Arguments:</h5>
3956
3957<p>
3958The argument to this intrinsic indicates which function to return the frame
3959pointer for. Zero indicates the calling function, one indicates its caller,
3960etc. The argument is <b>required</b> to be a constant integer value.
3961</p>
3962
3963<h5>Semantics:</h5>
3964
3965<p>
3966The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3967the frame address of the specified call frame, or zero if it cannot be
3968identified. The value returned by this intrinsic is likely to be incorrect or 0
3969for arguments other than zero, so it should only be used for debugging purposes.
3970</p>
3971
3972<p>
3973Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3974aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3975source-language caller.
3976</p>
3977</div>
3978
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3979<!-- _______________________________________________________________________ -->
3980<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3981 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3982</div>
3983
3984<div class="doc_text">
3985
3986<h5>Syntax:</h5>
3987<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3988 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3989</pre>
3990
3991<h5>Overview:</h5>
3992
3993<p>
3994The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3995the function stack, for use with <a href="#i_stackrestore">
3996<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3997features like scoped automatic variable sized arrays in C99.
3998</p>
3999
4000<h5>Semantics:</h5>
4001
4002<p>
4003This intrinsic returns a opaque pointer value that can be passed to <a
4004href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4005<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4006<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4007state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4008practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4009that were allocated after the <tt>llvm.stacksave</tt> was executed.
4010</p>
4011
4012</div>
4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
4016 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4017</div>
4018
4019<div class="doc_text">
4020
4021<h5>Syntax:</h5>
4022<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4023 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4024</pre>
4025
4026<h5>Overview:</h5>
4027
4028<p>
4029The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4030the function stack to the state it was in when the corresponding <a
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame^]4031href="#i_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4032useful for implementing language features like scoped automatic variable sized
4033arrays in C99.
4034</p>
4035
4036<h5>Semantics:</h5>
4037
4038<p>
4039See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
4040</p>
4041
4042</div>
4043
4044
4045<!-- _______________________________________________________________________ -->
4046<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4047 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4048</div>
4049
4050<div class="doc_text">
4051
4052<h5>Syntax:</h5>
4053<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4054 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4055 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4056</pre>
4057
4058<h5>Overview:</h5>
4059
4060
4061<p>
4062The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4063a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4064no
4065effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4066characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4067</p>
4068
4069<h5>Arguments:</h5>
4070
4071<p>
4072<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4073determining if the fetch should be for a read (0) or write (1), and
4074<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4075locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4076<tt>locality</tt> arguments must be constant integers.
4077</p>
4078
4079<h5>Semantics:</h5>
4080
4081<p>
4082This intrinsic does not modify the behavior of the program. In particular,
4083prefetches cannot trap and do not produce a value. On targets that support this
4084intrinsic, the prefetch can provide hints to the processor cache for better
4085performance.
4086</p>
4087
4088</div>
4089
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4090<!-- _______________________________________________________________________ -->
4091<div class="doc_subsubsection">
4092 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4093</div>
4094
4095<div class="doc_text">
4096
4097<h5>Syntax:</h5>
4098<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4099 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4100</pre>
4101
4102<h5>Overview:</h5>
4103
4104
4105<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4106The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4107(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4108code to simulators and other tools. The method is target specific, but it is
4109expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4110The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4111after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4112optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4113correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4114</p>
4115
4116<h5>Arguments:</h5>
4117
4118<p>
4119<tt>id</tt> is a numerical id identifying the marker.
4120</p>
4121
4122<h5>Semantics:</h5>
4123
4124<p>
4125This intrinsic does not modify the behavior of the program. Backends that do not
4126support this intrinisic may ignore it.
4127</p>
4128
4129</div>
4130
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4131<!-- _______________________________________________________________________ -->
4132<div class="doc_subsubsection">
4133 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4134</div>
4135
4136<div class="doc_text">
4137
4138<h5>Syntax:</h5>
4139<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4140 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4141</pre>
4142
4143<h5>Overview:</h5>
4144
4145
4146<p>
4147The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4148counter register (or similar low latency, high accuracy clocks) on those targets
4149that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4150As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4151should only be used for small timings.
4152</p>
4153
4154<h5>Semantics:</h5>
4155
4156<p>
4157When directly supported, reading the cycle counter should not modify any memory.
4158Implementations are allowed to either return a application specific value or a
4159system wide value. On backends without support, this is lowered to a constant 0.
4160</p>
4161
4162</div>
4163
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4164<!-- ======================================================================= -->
4165<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4166 <a name="int_libc">Standard C Library Intrinsics</a>
4167</div>
4168
4169<div class="doc_text">
4170<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4171LLVM provides intrinsics for a few important standard C library functions.
4172These intrinsics allow source-language front-ends to pass information about the
4173alignment of the pointer arguments to the code generator, providing opportunity
4174for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4175</p>
4176
4177</div>
4178
4179<!-- _______________________________________________________________________ -->
4180<div class="doc_subsubsection">
4181 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4182</div>
4183
4184<div class="doc_text">
4185
4186<h5>Syntax:</h5>
4187<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4188 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4189 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4190 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4191 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4192</pre>
4193
4194<h5>Overview:</h5>
4195
4196<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4197The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4198location to the destination location.
4199</p>
4200
4201<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4202Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4203intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4204</p>
4205
4206<h5>Arguments:</h5>
4207
4208<p>
4209The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4210the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4211specifying the number of bytes to copy, and the fourth argument is the alignment
4212of the source and destination locations.
4213</p>
4214
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4215<p>
4216If 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]4217the caller guarantees that both the source and destination pointers are aligned
4218to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4219</p>
4220
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4221<h5>Semantics:</h5>
4222
4223<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4224The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4225location to the destination location, which are not allowed to overlap. It
4226copies "len" bytes of memory over. If the argument is known to be aligned to
4227some boundary, this can be specified as the fourth argument, otherwise it should
4228be set to 0 or 1.
4229</p>
4230</div>
4231
4232
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4236</div>
4237
4238<div class="doc_text">
4239
4240<h5>Syntax:</h5>
4241<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4242 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4243 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4244 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4245 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4246</pre>
4247
4248<h5>Overview:</h5>
4249
4250<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4251The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4252location to the destination location. It is similar to the
4253'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4254</p>
4255
4256<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4257Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4258intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4259</p>
4260
4261<h5>Arguments:</h5>
4262
4263<p>
4264The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4265the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4266specifying the number of bytes to copy, and the fourth argument is the alignment
4267of the source and destination locations.
4268</p>
4269
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4270<p>
4271If 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]4272the caller guarantees that the source and destination pointers are aligned to
4273that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4274</p>
4275
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4276<h5>Semantics:</h5>
4277
4278<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4279The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4280location to the destination location, which may overlap. It
4281copies "len" bytes of memory over. If the argument is known to be aligned to
4282some boundary, this can be specified as the fourth argument, otherwise it should
4283be set to 0 or 1.
4284</p>
4285</div>
4286
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4287
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4288<!-- _______________________________________________________________________ -->
4289<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4290 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4291</div>
4292
4293<div class="doc_text">
4294
4295<h5>Syntax:</h5>
4296<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4297 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4298 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4299 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4300 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4301</pre>
4302
4303<h5>Overview:</h5>
4304
4305<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4306The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4307byte value.
4308</p>
4309
4310<p>
4311Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4312does not return a value, and takes an extra alignment argument.
4313</p>
4314
4315<h5>Arguments:</h5>
4316
4317<p>
4318The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4319byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4320argument specifying the number of bytes to fill, and the fourth argument is the
4321known alignment of destination location.
4322</p>
4323
4324<p>
4325If 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]4326the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4327</p>
4328
4329<h5>Semantics:</h5>
4330
4331<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4332The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4333the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4334destination location. If the argument is known to be aligned to some boundary,
4335this can be specified as the fourth argument, otherwise it should be set to 0 or
43361.
4337</p>
4338</div>
4339
4340
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4341<!-- _______________________________________________________________________ -->
4342<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4343 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4344</div>
4345
4346<div class="doc_text">
4347
4348<h5>Syntax:</h5>
4349<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4350 declare float @llvm.sqrt.f32(float %Val)
4351 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4352</pre>
4353
4354<h5>Overview:</h5>
4355
4356<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4357The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4358returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4359<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4360negative numbers (which allows for better optimization).
4361</p>
4362
4363<h5>Arguments:</h5>
4364
4365<p>
4366The argument and return value are floating point numbers of the same type.
4367</p>
4368
4369<h5>Semantics:</h5>
4370
4371<p>
4372This function returns the sqrt of the specified operand if it is a positive
4373floating point number.
4374</p>
4375</div>
4376
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4377<!-- _______________________________________________________________________ -->
4378<div class="doc_subsubsection">
4379 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4380</div>
4381
4382<div class="doc_text">
4383
4384<h5>Syntax:</h5>
4385<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4386 declare float @llvm.powi.f32(float %Val, i32 %power)
4387 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4388</pre>
4389
4390<h5>Overview:</h5>
4391
4392<p>
4393The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4394specified (positive or negative) power. The order of evaluation of
4395multiplications is not defined.
4396</p>
4397
4398<h5>Arguments:</h5>
4399
4400<p>
4401The second argument is an integer power, and the first is a value to raise to
4402that power.
4403</p>
4404
4405<h5>Semantics:</h5>
4406
4407<p>
4408This function returns the first value raised to the second power with an
4409unspecified sequence of rounding operations.</p>
4410</div>
4411
4412
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4413<!-- ======================================================================= -->
4414<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4415 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4416</div>
4417
4418<div class="doc_text">
4419<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4420LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4421These allow efficient code generation for some algorithms.
4422</p>
4423
4424</div>
4425
4426<!-- _______________________________________________________________________ -->
4427<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4428 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4429</div>
4430
4431<div class="doc_text">
4432
4433<h5>Syntax:</h5>
4434<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4435 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4436 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4437 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4438</pre>
4439
4440<h5>Overview:</h5>
4441
4442<p>
4443The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
444464 bit quantity. These are useful for performing operations on data that is not
4445in the target's native byte order.
4446</p>
4447
4448<h5>Semantics:</h5>
4449
4450<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4451The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4452and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4453intrinsic returns an i32 value that has the four bytes of the input i32
4454swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4455i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4456intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4457</p>
4458
4459</div>
4460
4461<!-- _______________________________________________________________________ -->
4462<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4463 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4464</div>
4465
4466<div class="doc_text">
4467
4468<h5>Syntax:</h5>
4469<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4470 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4471 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
4472 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
4473 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4474</pre>
4475
4476<h5>Overview:</h5>
4477
4478<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4479The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4480value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4481</p>
4482
4483<h5>Arguments:</h5>
4484
4485<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4486The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4487integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4488</p>
4489
4490<h5>Semantics:</h5>
4491
4492<p>
4493The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4494</p>
4495</div>
4496
4497<!-- _______________________________________________________________________ -->
4498<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4499 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4500</div>
4501
4502<div class="doc_text">
4503
4504<h5>Syntax:</h5>
4505<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4506 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4507 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
4508 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
4509 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4510</pre>
4511
4512<h5>Overview:</h5>
4513
4514<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4515The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4516leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4517</p>
4518
4519<h5>Arguments:</h5>
4520
4521<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4522The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4523integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4524</p>
4525
4526<h5>Semantics:</h5>
4527
4528<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4529The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4530in 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]4531of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4532</p>
4533</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4534
4535
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4536
4537<!-- _______________________________________________________________________ -->
4538<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4539 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4540</div>
4541
4542<div class="doc_text">
4543
4544<h5>Syntax:</h5>
4545<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4546 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4547 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
4548 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
4549 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4550</pre>
4551
4552<h5>Overview:</h5>
4553
4554<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4555The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4556trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4557</p>
4558
4559<h5>Arguments:</h5>
4560
4561<p>
4562The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4563integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4564</p>
4565
4566<h5>Semantics:</h5>
4567
4568<p>
4569The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4570in a variable. If the src == 0 then the result is the size in bits of the type
4571of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4572</p>
4573</div>
4574
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4575<!-- ======================================================================= -->
4576<div class="doc_subsection">
4577 <a name="int_debugger">Debugger Intrinsics</a>
4578</div>
4579
4580<div class="doc_text">
4581<p>
4582The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4583are described in the <a
4584href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4585Debugging</a> document.
4586</p>
4587</div>
4588
4589
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4590<!-- ======================================================================= -->
4591<div class="doc_subsection">
4592 <a name="int_eh">Exception Handling Intrinsics</a>
4593</div>
4594
4595<div class="doc_text">
4596<p> The LLVM exception handling intrinsics (which all start with
4597<tt>llvm.eh.</tt> prefix), are described in the <a
4598href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4599Handling</a> document. </p>
4600</div>
4601
4602
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4603<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4604<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4605<address>
4606 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4607 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4608 <a href="http://validator.w3.org/check/referer"><img
4609 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4610
4611 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4612 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4613 Last modified: $Date$
4614</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4615</body>
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