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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c2df07095c21382e304036d1d9310ee88fe2e660 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]29 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]30 </ol>
31 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]32 <li><a href="#typesystem">Type System</a>
33 <ol>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]34 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]35 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]37 </ol>
38 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]39 <li><a href="#t_derived">Derived Types</a>
40 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]42 <li><a href="#t_function">Function Type</a></li>
43 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]44 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]45 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]46 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]47 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]48 </ol>
49 </li>
50 </ol>
51 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]52 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]53 <ol>
54 <li><a href="#simpleconstants">Simple Constants</a>
55 <li><a href="#aggregateconstants">Aggregate Constants</a>
56 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
57 <li><a href="#undefvalues">Undefined Values</a>
58 <li><a href="#constantexprs">Constant Expressions</a>
59 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]60 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]61 <li><a href="#othervalues">Other Values</a>
62 <ol>
63 <li><a href="#inlineasm">Inline Assembler Expressions</a>
64 </ol>
65 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#instref">Instruction Reference</a>
67 <ol>
68 <li><a href="#terminators">Terminator Instructions</a>
69 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]70 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
71 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]72 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
73 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]74 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]75 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]76 </ol>
77 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]78 <li><a href="#binaryops">Binary Operations</a>
79 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
81 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
82 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]83 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
84 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
85 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]86 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
87 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
88 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]89 </ol>
90 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]91 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
92 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]93 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
94 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
95 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]96 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]97 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]98 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </ol>
100 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]101 <li><a href="#vectorops">Vector Operations</a>
102 <ol>
103 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
104 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
105 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]106 </ol>
107 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]108 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]109 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
111 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
112 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]113 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
114 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
115 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]118 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]119 <ol>
120 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
121 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]125 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
126 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
127 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]129 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
130 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]131 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]132 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]133 <li><a href="#otherops">Other Operations</a>
134 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]135 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
136 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]138 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]139 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]140 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]141 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]143 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]144 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]145 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]146 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]147 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
148 <ol>
149 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
151 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
152 </ol>
153 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]154 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
155 <ol>
156 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
158 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
159 </ol>
160 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]161 <li><a href="#int_codegen">Code Generator Intrinsics</a>
162 <ol>
163 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
164 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]165 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
166 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]167 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]168 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]169 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]170 </ol>
171 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]172 <li><a href="#int_libc">Standard C Library Intrinsics</a>
173 <ol>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]174 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
176 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]177 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]178 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]179 </ol>
180 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]181 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]182 <ol>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]183 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]184 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]187 </ol>
188 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]189 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]190 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]191 </ol>
192 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]193</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]194
195<div class="doc_author">
196 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
197 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]198</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]199
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]200<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]201<div class="doc_section"> <a name="abstract">Abstract </a></div>
202<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]203
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]204<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]205<p>This document is a reference manual for the LLVM assembly language.
206LLVM is an SSA based representation that provides type safety,
207low-level operations, flexibility, and the capability of representing
208'all' high-level languages cleanly. It is the common code
209representation used throughout all phases of the LLVM compilation
210strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]211</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214<div class="doc_section"> <a name="introduction">Introduction</a> </div>
215<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]216
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]217<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]218
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]219<p>The LLVM code representation is designed to be used in three
220different forms: as an in-memory compiler IR, as an on-disk bytecode
221representation (suitable for fast loading by a Just-In-Time compiler),
222and as a human readable assembly language representation. This allows
223LLVM to provide a powerful intermediate representation for efficient
224compiler transformations and analysis, while providing a natural means
225to debug and visualize the transformations. The three different forms
226of LLVM are all equivalent. This document describes the human readable
227representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]228
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]229<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]230while being expressive, typed, and extensible at the same time. It
231aims to be a "universal IR" of sorts, by being at a low enough level
232that high-level ideas may be cleanly mapped to it (similar to how
233microprocessors are "universal IR's", allowing many source languages to
234be mapped to them). By providing type information, LLVM can be used as
235the target of optimizations: for example, through pointer analysis, it
236can be proven that a C automatic variable is never accessed outside of
237the current function... allowing it to be promoted to a simple SSA
238value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]239
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]240</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]241
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]242<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]243<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]244
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]245<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]246
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]247<p>It is important to note that this document describes 'well formed'
248LLVM assembly language. There is a difference between what the parser
249accepts and what is considered 'well formed'. For example, the
250following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]251
252<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]253 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]254</pre>
255
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]256<p>...because the definition of <tt>%x</tt> does not dominate all of
257its uses. The LLVM infrastructure provides a verification pass that may
258be used to verify that an LLVM module is well formed. This pass is
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]259automatically run by the parser after parsing input assembly and by
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]260the optimizer before it outputs bytecode. The violations pointed out
261by the verifier pass indicate bugs in transformation passes or input to
262the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]263
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]264<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]265
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]266<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]267<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]268<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]269
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]270<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]271
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]272<p>LLVM uses three different forms of identifiers, for different
273purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]275<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]276 <li>Named values are represented as a string of characters with a '%' prefix.
277 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
278 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
279 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]280 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]281 in a name.</li>
282
283 <li>Unnamed values are represented as an unsigned numeric value with a '%'
284 prefix. For example, %12, %2, %44.</li>
285
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]286 <li>Constants, which are described in a <a href="#constants">section about
287 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]288</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]289
290<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
291don't need to worry about name clashes with reserved words, and the set of
292reserved words may be expanded in the future without penalty. Additionally,
293unnamed identifiers allow a compiler to quickly come up with a temporary
294variable without having to avoid symbol table conflicts.</p>
295
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]296<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]297languages. There are keywords for different opcodes
298('<tt><a href="#i_add">add</a></tt>',
299 '<tt><a href="#i_bitcast">bitcast</a></tt>',
300 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]301href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]302and others. These reserved words cannot conflict with variable names, because
303none of them start with a '%' character.</p>
304
305<p>Here is an example of LLVM code to multiply the integer variable
306'<tt>%X</tt>' by 8:</p>
307
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]308<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]309
310<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]311 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]312</pre>
313
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]314<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]315
316<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]317 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]318</pre>
319
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]321
322<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]323 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
324 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
325 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]326</pre>
327
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]328<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
329important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]330
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]331<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]332
333 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
334 line.</li>
335
336 <li>Unnamed temporaries are created when the result of a computation is not
337 assigned to a named value.</li>
338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]339 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]340
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]341</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]342
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]343<p>...and it also shows a convention that we follow in this document. When
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]344demonstrating instructions, we will follow an instruction with a comment that
345defines the type and name of value produced. Comments are shown in italic
346text.</p>
347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]348</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]349
350<!-- *********************************************************************** -->
351<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
352<!-- *********************************************************************** -->
353
354<!-- ======================================================================= -->
355<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
356</div>
357
358<div class="doc_text">
359
360<p>LLVM programs are composed of "Module"s, each of which is a
361translation unit of the input programs. Each module consists of
362functions, global variables, and symbol table entries. Modules may be
363combined together with the LLVM linker, which merges function (and
364global variable) definitions, resolves forward declarations, and merges
365symbol table entries. Here is an example of the "hello world" module:</p>
366
367<pre><i>; Declare the string constant as a global constant...</i>
368<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]369 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]370
371<i>; External declaration of the puts function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]372<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]373
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]374<i>; Global variable / Function body section separator</i>
375implementation
376
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]377<i>; Definition of main function</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]378define i32 %main() { <i>; i32()* </i>
379 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]380 %cast210 = <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]381 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]382
383 <i>; Call puts function to write out the string to stdout...</i>
384 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]386 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]387 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]388
389<p>This example is made up of a <a href="#globalvars">global variable</a>
390named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
391function, and a <a href="#functionstructure">function definition</a>
392for "<tt>main</tt>".</p>
393
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]394<p>In general, a module is made up of a list of global values,
395where both functions and global variables are global values. Global values are
396represented by a pointer to a memory location (in this case, a pointer to an
397array of char, and a pointer to a function), and have one of the following <a
398href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]399
Chris Lattner81c01f02006-06-13 03:05:47 +0000[diff] [blame]400<p>Due to a limitation in the current LLVM assembly parser (it is limited by
401one-token lookahead), modules are split into two pieces by the "implementation"
402keyword. Global variable prototypes and definitions must occur before the
403keyword, and function definitions must occur after it. Function prototypes may
404occur either before or after it. In the future, the implementation keyword may
405become a noop, if the parser gets smarter.</p>
406
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]407</div>
408
409<!-- ======================================================================= -->
410<div class="doc_subsection">
411 <a name="linkage">Linkage Types</a>
412</div>
413
414<div class="doc_text">
415
416<p>
417All Global Variables and Functions have one of the following types of linkage:
418</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]419
420<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]421
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]422 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]423
424 <dd>Global values with internal linkage are only directly accessible by
425 objects in the current module. In particular, linking code into a module with
426 an internal global value may cause the internal to be renamed as necessary to
427 avoid collisions. Because the symbol is internal to the module, all
428 references can be updated. This corresponds to the notion of the
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]429 '<tt>static</tt>' keyword in C.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]430 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]431
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]432 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]433
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]434 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
435 the same name when linkage occurs. This is typically used to implement
436 inline functions, templates, or other code which must be generated in each
437 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
438 allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]439 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]440
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]441 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442
443 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
444 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]445 used for globals that may be emitted in multiple translation units, but that
446 are not guaranteed to be emitted into every translation unit that uses them.
447 One example of this are common globals in C, such as "<tt>int X;</tt>" at
448 global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]449 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]450
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]451 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]452
453 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
454 pointer to array type. When two global variables with appending linkage are
455 linked together, the two global arrays are appended together. This is the
456 LLVM, typesafe, equivalent of having the system linker append together
457 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]458 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]459
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]460 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
461 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
462 until linked, if not linked, the symbol becomes null instead of being an
463 undefined reference.
464 </dd>
465</dl>
466
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]467 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]468
469 <dd>If none of the above identifiers are used, the global is externally
470 visible, meaning that it participates in linkage and can be used to resolve
471 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]472 </dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]473
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]474 <p>
475 The next two types of linkage are targeted for Microsoft Windows platform
476 only. They are designed to support importing (exporting) symbols from (to)
477 DLLs.
478 </p>
479
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]480 <dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]481 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
482
483 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
484 or variable via a global pointer to a pointer that is set up by the DLL
485 exporting the symbol. On Microsoft Windows targets, the pointer name is
486 formed by combining <code>_imp__</code> and the function or variable name.
487 </dd>
488
489 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
490
491 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
492 pointer to a pointer in a DLL, so that it can be referenced with the
493 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
494 name is formed by combining <code>_imp__</code> and the function or variable
495 name.
496 </dd>
497
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]498</dl>
499
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]500<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]501variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
502variable and was linked with this one, one of the two would be renamed,
503preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
504external (i.e., lacking any linkage declarations), they are accessible
Reid Spencerac8d2762007-01-05 00:59:10 +0000[diff] [blame]505outside of the current module.</p>
506<p>It is illegal for a function <i>declaration</i>
507to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]508or <tt>extern_weak</tt>.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]509
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]510</div>
511
512<!-- ======================================================================= -->
513<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]514 <a name="callingconv">Calling Conventions</a>
515</div>
516
517<div class="doc_text">
518
519<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
520and <a href="#i_invoke">invokes</a> can all have an optional calling convention
521specified for the call. The calling convention of any pair of dynamic
522caller/callee must match, or the behavior of the program is undefined. The
523following calling conventions are supported by LLVM, and more may be added in
524the future:</p>
525
526<dl>
527 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
528
529 <dd>This calling convention (the default if no other calling convention is
530 specified) matches the target C calling conventions. This calling convention
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]531 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencerc28d2bc2006-12-31 21:30:18 +0000[diff] [blame]532 prototype and implemented declaration of the function (as does normal C).
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]533 </dd>
534
535 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
536
537 <dd>This calling convention attempts to make calls as fast as possible
538 (e.g. by passing things in registers). This calling convention allows the
539 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]540 without having to conform to an externally specified ABI. Implementations of
541 this convention should allow arbitrary tail call optimization to be supported.
542 This calling convention does not support varargs and requires the prototype of
543 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]544 </dd>
545
546 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
547
548 <dd>This calling convention attempts to make code in the caller as efficient
549 as possible under the assumption that the call is not commonly executed. As
550 such, these calls often preserve all registers so that the call does not break
551 any live ranges in the caller side. This calling convention does not support
552 varargs and requires the prototype of all callees to exactly match the
553 prototype of the function definition.
554 </dd>
555
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]556 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]557
558 <dd>Any calling convention may be specified by number, allowing
559 target-specific calling conventions to be used. Target specific calling
560 conventions start at 64.
561 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]562</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]563
564<p>More calling conventions can be added/defined on an as-needed basis, to
565support pascal conventions or any other well-known target-independent
566convention.</p>
567
568</div>
569
570<!-- ======================================================================= -->
571<div class="doc_subsection">
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]572 <a name="visibility">Visibility Styles</a>
573</div>
574
575<div class="doc_text">
576
577<p>
578All Global Variables and Functions have one of the following visibility styles:
579</p>
580
581<dl>
582 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
583
584 <dd>On ELF, default visibility means that the declaration is visible to other
585 modules and, in shared libraries, means that the declared entity may be
586 overridden. On Darwin, default visibility means that the declaration is
587 visible to other modules. Default visibility corresponds to "external
588 linkage" in the language.
589 </dd>
590
591 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
592
593 <dd>Two declarations of an object with hidden visibility refer to the same
594 object if they are in the same shared object. Usually, hidden visibility
595 indicates that the symbol will not be placed into the dynamic symbol table,
596 so no other module (executable or shared library) can reference it
597 directly.
598 </dd>
599
600</dl>
601
602</div>
603
604<!-- ======================================================================= -->
605<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]606 <a name="globalvars">Global Variables</a>
607</div>
608
609<div class="doc_text">
610
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]611<p>Global variables define regions of memory allocated at compilation time
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]612instead of run-time. Global variables may optionally be initialized, may have
613an explicit section to be placed in, and may
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]614have an optional explicit alignment specified. A
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]615variable may be defined as a global "constant," which indicates that the
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]616contents of the variable will <b>never</b> be modified (enabling better
617optimization, allowing the global data to be placed in the read-only section of
618an executable, etc). Note that variables that need runtime initialization
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]619cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]620
621<p>
622LLVM explicitly allows <em>declarations</em> of global variables to be marked
623constant, even if the final definition of the global is not. This capability
624can be used to enable slightly better optimization of the program, but requires
625the language definition to guarantee that optimizations based on the
626'constantness' are valid for the translation units that do not include the
627definition.
628</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]629
630<p>As SSA values, global variables define pointer values that are in
631scope (i.e. they dominate) all basic blocks in the program. Global
632variables always define a pointer to their "content" type because they
633describe a region of memory, and all memory objects in LLVM are
634accessed through pointers.</p>
635
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]636<p>LLVM allows an explicit section to be specified for globals. If the target
637supports it, it will emit globals to the section specified.</p>
638
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]639<p>An explicit alignment may be specified for a global. If not present, or if
640the alignment is set to zero, the alignment of the global is set by the target
641to whatever it feels convenient. If an explicit alignment is specified, the
642global is forced to have at least that much alignment. All alignments must be
643a power of 2.</p>
644
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]645<p>For example, the following defines a global with an initializer, section,
646 and alignment:</p>
647
648<pre>
649 %G = constant float 1.0, section "foo", align 4
650</pre>
651
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]652</div>
653
654
655<!-- ======================================================================= -->
656<div class="doc_subsection">
657 <a name="functionstructure">Functions</a>
658</div>
659
660<div class="doc_text">
661
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]662<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
663an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]664<a href="#visibility">visibility style</a>, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]665<a href="#callingconv">calling convention</a>, a return type, an optional
666<a href="#paramattrs">parameter attribute</a> for the return type, a function
667name, a (possibly empty) argument list (each with optional
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]668<a href="#paramattrs">parameter attributes</a>), an optional section, an
669optional alignment, an opening curly brace, a list of basic blocks, and a
670closing curly brace.
671
672LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
673optional <a href="#linkage">linkage type</a>, an optional
674<a href="#visibility">visibility style</a>, an optional
675<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]676<a href="#paramattrs">parameter attribute</a> for the return type, a function
677name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]678
679<p>A function definition contains a list of basic blocks, forming the CFG for
680the function. Each basic block may optionally start with a label (giving the
681basic block a symbol table entry), contains a list of instructions, and ends
682with a <a href="#terminators">terminator</a> instruction (such as a branch or
683function return).</p>
684
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]685<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]686executed on entrance to the function, and it is not allowed to have predecessor
687basic blocks (i.e. there can not be any branches to the entry block of a
688function). Because the block can have no predecessors, it also cannot have any
689<a href="#i_phi">PHI nodes</a>.</p>
690
691<p>LLVM functions are identified by their name and type signature. Hence, two
692functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]693considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]694appropriately.</p>
695
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]696<p>LLVM allows an explicit section to be specified for functions. If the target
697supports it, it will emit functions to the section specified.</p>
698
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]699<p>An explicit alignment may be specified for a function. If not present, or if
700the alignment is set to zero, the alignment of the function is set by the target
701to whatever it feels convenient. If an explicit alignment is specified, the
702function is forced to have at least that much alignment. All alignments must be
703a power of 2.</p>
704
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]705</div>
706
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]707<!-- ======================================================================= -->
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]708<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
709<div class="doc_text">
710 <p>The return type and each parameter of a function type may have a set of
711 <i>parameter attributes</i> associated with them. Parameter attributes are
712 used to communicate additional information about the result or parameters of
713 a function. Parameter attributes are considered to be part of the function
714 type so two functions types that differ only by the parameter attributes
715 are different function types.</p>
716
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]717 <p>Parameter attributes are simple keywords that follow the type specified. If
718 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]719 example:</p><pre>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]720 %someFunc = i16 (i8 sext %someParam) zext
721 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]722 <p>Note that the two function types above are unique because the parameter has
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]723 a different attribute (sext in the first one, zext in the second). Also note
724 that the attribute for the function result (zext) comes immediately after the
725 argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]726
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]727 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]728 <dl>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]729 <dt><tt>zext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]730 <dd>This indicates that the parameter should be zero extended just before
731 a call to this function.</dd>
Reid Spencer950e9f82007-01-15 18:27:39 +0000[diff] [blame]732 <dt><tt>sext</tt></dt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]733 <dd>This indicates that the parameter should be sign extended just before
734 a call to this function.</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]735 <dt><tt>inreg</tt></dt>
736 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]737 possible) during assembling function call. Support for this attribute is
738 target-specific</dd>
Anton Korobeynikov34d6dea2007-01-28 14:30:45 +0000[diff] [blame]739 <dt><tt>sret</tt></dt>
Anton Korobeynikov66a8c8c2007-01-28 15:27:21 +0000[diff] [blame]740 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer67606122007-03-22 02:02:11 +0000[diff] [blame]741 that is the return value of the function in the source program.</dd>
742 <dt><tt>nounwind</tt></dt>
743 <dd>This function attribute indicates that the function type does not use
744 the unwind instruction and does not allow stack unwinding to propagate
745 through it.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]746 </dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]747
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]748</div>
749
750<!-- ======================================================================= -->
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]751<div class="doc_subsection">
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]752 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]753</div>
754
755<div class="doc_text">
756<p>
757Modules may contain "module-level inline asm" blocks, which corresponds to the
758GCC "file scope inline asm" blocks. These blocks are internally concatenated by
759LLVM and treated as a single unit, but may be separated in the .ll file if
760desired. The syntax is very simple:
761</p>
762
763<div class="doc_code"><pre>
Chris Lattner52599e12006-01-24 00:37:20 +0000[diff] [blame]764 module asm "inline asm code goes here"
765 module asm "more can go here"
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]766</pre></div>
767
768<p>The strings can contain any character by escaping non-printable characters.
769 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
770 for the number.
771</p>
772
773<p>
774 The inline asm code is simply printed to the machine code .s file when
775 assembly code is generated.
776</p>
777</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]778
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]779<!-- ======================================================================= -->
780<div class="doc_subsection">
781 <a name="datalayout">Data Layout</a>
782</div>
783
784<div class="doc_text">
785<p>A module may specify a target specific data layout string that specifies how
786data is to be laid out in memory. The syntax for the data layout is simply:<br/>
787<pre> target datalayout = "<i>layout specification</i>"
788</pre>
789The <i>layout specification</i> consists of a list of specifications separated
790by the minus sign character ('-'). Each specification starts with a letter
791and may include other information after the letter to define some aspect of the
792data layout. The specifications accepted are as follows: </p>
793<dl>
794 <dt><tt>E</tt></dt>
795 <dd>Specifies that the target lays out data in big-endian form. That is, the
796 bits with the most significance have the lowest address location.</dd>
797 <dt><tt>e</tt></dt>
798 <dd>Specifies that hte target lays out data in little-endian form. That is,
799 the bits with the least significance have the lowest address location.</dd>
800 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
801 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
802 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
803 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
804 too.</dd>
805 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
806 <dd>This specifies the alignment for an integer type of a given bit
807 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
808 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
809 <dd>This specifies the alignment for a vector type of a given bit
810 <i>size</i>.</dd>
811 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
812 <dd>This specifies the alignment for a floating point type of a given bit
813 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
814 (double).</dd>
815 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
816 <dd>This specifies the alignment for an aggregate type of a given bit
817 <i>size</i>.</dd>
818</dl>
819<p>When constructing the data layout for a given target, LLVM starts with a
820default set of specifications which are then (possibly) overriden by the
821specifications in the <tt>datalayout</tt> keyword. The default specifications
822are given in this list:</p>
823<ul>
824 <li><tt>E</tt> - big endian</li>
825 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
826 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
827 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
828 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
829 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
830 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
831 alignment of 64-bits</li>
832 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
833 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
834 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
835 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
836 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
837</ul>
838<p>When llvm is determining the alignment for a given type, it uses the
839following rules:
840<ol>
841 <li>If the type sought is an exact match for one of the specifications, that
842 specification is used.</li>
843 <li>If no match is found, and the type sought is an integer type, then the
844 smallest integer type that is larger than the bitwidth of the sought type is
845 used. If none of the specifications are larger than the bitwidth then the the
846 largest integer type is used. For example, given the default specifications
847 above, the i7 type will use the alignment of i8 (next largest) while both
848 i65 and i256 will use the alignment of i64 (largest specified).</li>
849 <li>If no match is found, and the type sought is a vector type, then the
850 largest vector type that is smaller than the sought vector type will be used
851 as a fall back. This happens because <128 x double> can be implemented in
852 terms of 64 <2 x double>, for example.</li>
853</ol>
854</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]855
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]856<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]857<div class="doc_section"> <a name="typesystem">Type System</a> </div>
858<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]859
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]860<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]861
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]862<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]863intermediate representation. Being typed enables a number of
864optimizations to be performed on the IR directly, without having to do
865extra analyses on the side before the transformation. A strong type
866system makes it easier to read the generated code and enables novel
867analyses and transformations that are not feasible to perform on normal
868three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]869
870</div>
871
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]872<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]873<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]874<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]875<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]876system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]877
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]878<table class="layout">
879 <tr class="layout">
880 <td class="left">
881 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]882 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]883 <tr><th>Type</th><th>Description</th></tr>
884 <tr><td><tt>void</tt></td><td>No value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]885 <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
886 <tr><td><tt>i32</tt></td><td>32-bit value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]887 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]888 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]889 </tbody>
890 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]891 </td>
892 <td class="right">
893 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]894 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]895 <tr><th>Type</th><th>Description</th></tr>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]896 <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]897 <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
898 <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]899 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]900 </tbody>
901 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]902 </td>
903 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]904</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]905</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]906
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]907<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]908<div class="doc_subsubsection"> <a name="t_classifications">Type
909Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]910<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]911<p>These different primitive types fall into a few useful
912classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]913
914<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]915 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]916 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]917 <tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]918 <td><a name="t_integer">integer</a></td>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]919 <td><tt>i1, i8, i16, i32, i64</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]920 </tr>
921 <tr>
922 <td><a name="t_floating">floating point</a></td>
923 <td><tt>float, double</tt></td>
924 </tr>
925 <tr>
926 <td><a name="t_firstclass">first class</a></td>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]927 <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]928 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]929 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]930 </tr>
931 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]932</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]933
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]934<p>The <a href="#t_firstclass">first class</a> types are perhaps the
935most important. Values of these types are the only ones which can be
936produced by instructions, passed as arguments, or used as operands to
937instructions. This means that all structures and arrays must be
938manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]939</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]940
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]941<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]942<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]943
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]944<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]945
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]946<p>The real power in LLVM comes from the derived types in the system.
947This is what allows a programmer to represent arrays, functions,
948pointers, and other useful types. Note that these derived types may be
949recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]950
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]951</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]952
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]953<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]954<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]955
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]956<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]957
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]958<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]959
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]960<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]961sequentially in memory. The array type requires a size (number of
962elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]963
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]964<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]965
966<pre>
967 [&lt;# elements&gt; x &lt;elementtype&gt;]
968</pre>
969
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]970<p>The number of elements is a constant integer value; elementtype may
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]971be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]972
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]973<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]974<table class="layout">
975 <tr class="layout">
976 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]977 <tt>[40 x i32 ]</tt><br/>
978 <tt>[41 x i32 ]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]979 <tt>[40 x i8]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]980 </td>
981 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]982 Array of 40 32-bit integer values.<br/>
983 Array of 41 32-bit integer values.<br/>
984 Array of 40 8-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]985 </td>
986 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]987</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]988<p>Here are some examples of multidimensional arrays:</p>
989<table class="layout">
990 <tr class="layout">
991 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]992 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]993 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]994 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]995 </td>
996 <td class="left">
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]997 3x4 array of 32-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]998 12x10 array of single precision floating point values.<br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]999 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1000 </td>
1001 </tr>
1002</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1003
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1004<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1005length array. Normally, accesses past the end of an array are undefined in
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1006LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1007As a special case, however, zero length arrays are recognized to be variable
1008length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1009type "{ i32, [0 x float]}", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1010
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1011</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1012
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1013<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1014<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1015<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1016<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1017<p>The function type can be thought of as a function signature. It
1018consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1019Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1020(which are structures of pointers to functions), for indirect function
1021calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]1022<p>
1023The return type of a function type cannot be an aggregate type.
1024</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1025<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1026<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]1027<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]1028specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1029which indicates that the function takes a variable number of arguments.
1030Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1031 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1032<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1033<table class="layout">
1034 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1035 <td class="left"><tt>i32 (i32)</tt></td>
1036 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1037 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1038 </tr><tr class="layout">
Reid Spencer7bf214d2007-01-15 18:28:34 +0000[diff] [blame]1039 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]1040 </tt></td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1041 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1042 an <tt>i16</tt> that should be sign extended and a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1043 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1044 <tt>float</tt>.
1045 </td>
1046 </tr><tr class="layout">
1047 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1048 <td class="left">A vararg function that takes at least one
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1049 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]1050 which returns an integer. This is the signature for <tt>printf</tt> in
1051 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1052 </td>
1053 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1054</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1055
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1056</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1057<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1058<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1059<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1060<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1061<p>The structure type is used to represent a collection of data members
1062together in memory. The packing of the field types is defined to match
1063the ABI of the underlying processor. The elements of a structure may
1064be any type that has a size.</p>
1065<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1066and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1067field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1068instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1069<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1070<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1071<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1072<table class="layout">
1073 <tr class="layout">
1074 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1075 <tt>{ i32, i32, i32 }</tt><br/>
1076 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1077 </td>
1078 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1079 a triple of three <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1080 A pair, where the first element is a <tt>float</tt> and the second element
1081 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]1082 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1083 </td>
1084 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1085</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1086</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1087
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1088<!-- _______________________________________________________________________ -->
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1089<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1090</div>
1091<div class="doc_text">
1092<h5>Overview:</h5>
1093<p>The packed structure type is used to represent a collection of data members
1094together in memory. There is no padding between fields. Further, the alignment
1095of a packed structure is 1 byte. The elements of a packed structure may
1096be any type that has a size.</p>
1097<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1098and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1099field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1100instruction.</p>
1101<h5>Syntax:</h5>
1102<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1103<h5>Examples:</h5>
1104<table class="layout">
1105 <tr class="layout">
1106 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1107 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1108 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1109 </td>
1110 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1111 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1112 A pair, where the first element is a <tt>float</tt> and the second element
1113 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]1114 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]1115 </td>
1116 </tr>
1117</table>
1118</div>
1119
1120<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1121<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1122<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1123<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1124<p>As in many languages, the pointer type represents a pointer or
1125reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1126<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1127<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1128<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1129<table class="layout">
1130 <tr class="layout">
1131 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1132 <tt>[4x i32]*</tt><br/>
1133 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1134 </td>
1135 <td class="left">
1136 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]1137 four <tt>i32</tt> values<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1138 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1139 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1140 <tt>i32</tt>.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1141 </td>
1142 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1143</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1144</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1145
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1146<!-- _______________________________________________________________________ -->
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1147<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1148<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1149
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1150<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1151
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1152<p>A vector type is a simple derived type that represents a vector
1153of elements. Vector types are used when multiple primitive data
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1154are operated in parallel using a single instruction (SIMD).
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1155A vector type requires a size (number of
Chris Lattnerb8d172f2005-11-10 01:44:22 +0000[diff] [blame]1156elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1157of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1158considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1159
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1160<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1161
1162<pre>
1163 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1164</pre>
1165
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1166<p>The number of elements is a constant integer value; elementtype may
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]1167be any integer or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1168
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1169<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1170
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1171<table class="layout">
1172 <tr class="layout">
1173 <td class="left">
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1174 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1175 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1176 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1177 </td>
1178 <td class="left">
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1179 Vector of 4 32-bit integer values.<br/>
1180 Vector of 8 floating-point values.<br/>
1181 Vector of 2 64-bit integer values.<br/>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1182 </td>
1183 </tr>
1184</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1185</div>
1186
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]1187<!-- _______________________________________________________________________ -->
1188<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1189<div class="doc_text">
1190
1191<h5>Overview:</h5>
1192
1193<p>Opaque types are used to represent unknown types in the system. This
1194corresponds (for example) to the C notion of a foward declared structure type.
1195In LLVM, opaque types can eventually be resolved to any type (not just a
1196structure type).</p>
1197
1198<h5>Syntax:</h5>
1199
1200<pre>
1201 opaque
1202</pre>
1203
1204<h5>Examples:</h5>
1205
1206<table class="layout">
1207 <tr class="layout">
1208 <td class="left">
1209 <tt>opaque</tt>
1210 </td>
1211 <td class="left">
1212 An opaque type.<br/>
1213 </td>
1214 </tr>
1215</table>
1216</div>
1217
1218
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1219<!-- *********************************************************************** -->
1220<div class="doc_section"> <a name="constants">Constants</a> </div>
1221<!-- *********************************************************************** -->
1222
1223<div class="doc_text">
1224
1225<p>LLVM has several different basic types of constants. This section describes
1226them all and their syntax.</p>
1227
1228</div>
1229
1230<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1231<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1232
1233<div class="doc_text">
1234
1235<dl>
1236 <dt><b>Boolean constants</b></dt>
1237
1238 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1239 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1240 </dd>
1241
1242 <dt><b>Integer constants</b></dt>
1243
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1244 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1245 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1246 integer types.
1247 </dd>
1248
1249 <dt><b>Floating point constants</b></dt>
1250
1251 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1252 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1253 notation (see below). Floating point constants must have a <a
1254 href="#t_floating">floating point</a> type. </dd>
1255
1256 <dt><b>Null pointer constants</b></dt>
1257
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1258 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1259 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1260
1261</dl>
1262
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1263<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1264of floating point constants. For example, the form '<tt>double
12650x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
12664.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]1267(and the only time that they are generated by the disassembler) is when a
1268floating point constant must be emitted but it cannot be represented as a
1269decimal floating point number. For example, NaN's, infinities, and other
1270special values are represented in their IEEE hexadecimal format so that
1271assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1272
1273</div>
1274
1275<!-- ======================================================================= -->
1276<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1277</div>
1278
1279<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1280<p>Aggregate constants arise from aggregation of simple constants
1281and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1282
1283<dl>
1284 <dt><b>Structure constants</b></dt>
1285
1286 <dd>Structure constants are represented with notation similar to structure
1287 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1288 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1289 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]1290 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1291 types of elements must match those specified by the type.
1292 </dd>
1293
1294 <dt><b>Array constants</b></dt>
1295
1296 <dd>Array constants are represented with notation similar to array type
1297 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1298 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1299 constants must have <a href="#t_array">array type</a>, and the number and
1300 types of elements must match those specified by the type.
1301 </dd>
1302
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1303 <dt><b>Vector constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1304
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1305 <dd>Vector constants are represented with notation similar to vector type
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1306 definitions (a comma separated list of elements, surrounded by
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1307 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]1308 i32 11, i32 74, i32 100 &gt;</tt>". VEctor constants must have <a
1309 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1310 match those specified by the type.
1311 </dd>
1312
1313 <dt><b>Zero initialization</b></dt>
1314
1315 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1316 value to zero of <em>any</em> type, including scalar and aggregate types.
1317 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]1318 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1319 initializers.
1320 </dd>
1321</dl>
1322
1323</div>
1324
1325<!-- ======================================================================= -->
1326<div class="doc_subsection">
1327 <a name="globalconstants">Global Variable and Function Addresses</a>
1328</div>
1329
1330<div class="doc_text">
1331
1332<p>The addresses of <a href="#globalvars">global variables</a> and <a
1333href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1334constants. These constants are explicitly referenced when the <a
1335href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1336href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1337file:</p>
1338
1339<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1340 %X = global i32 17
1341 %Y = global i32 42
1342 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1343</pre>
1344
1345</div>
1346
1347<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1348<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1349<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1350 <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]1351 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1352 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1353
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1354 <p>Undefined values indicate to the compiler that the program is well defined
1355 no matter what value is used, giving the compiler more freedom to optimize.
1356 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1357</div>
1358
1359<!-- ======================================================================= -->
1360<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1361</div>
1362
1363<div class="doc_text">
1364
1365<p>Constant expressions are used to allow expressions involving other constants
1366to be used as constants. Constant expressions may be of any <a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1367href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1368that does not have side effects (e.g. load and call are not supported). The
1369following is the syntax for constant expressions:</p>
1370
1371<dl>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1372 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1373 <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]1374 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1375
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1376 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1377 <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]1378 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1379
1380 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1381 <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]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>fptrunc ( CST to TYPE )</tt></b></dt>
1385 <dd>Truncate a floating point constant to another floating point type. The
1386 size of CST must be larger than the size of TYPE. Both types must be
1387 floating point.</dd>
1388
1389 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1390 <dd>Floating point extend a constant to another type. The size of CST must be
1391 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1392
1393 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1394 <dd>Convert a floating point constant to the corresponding unsigned integer
1395 constant. TYPE must be an integer type. CST must be floating point. If the
1396 value won't fit in the integer type, the results are undefined.</dd>
1397
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1398 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1399 <dd>Convert a floating point constant to the corresponding signed integer
1400 constant. TYPE must be an integer type. CST must be floating point. If the
1401 value won't fit in the integer type, the results are undefined.</dd>
1402
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1403 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1404 <dd>Convert an unsigned integer constant to the corresponding floating point
1405 constant. TYPE must be floating point. CST must be of integer type. If the
1406 value won't fit in the floating point type, the results are undefined.</dd>
1407
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]1408 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1409 <dd>Convert a signed integer constant to the corresponding floating point
1410 constant. TYPE must be floating point. CST must be of integer type. If the
1411 value won't fit in the floating point type, the results are undefined.</dd>
1412
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]1413 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1414 <dd>Convert a pointer typed constant to the corresponding integer constant
1415 TYPE must be an integer type. CST must be of pointer type. The CST value is
1416 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1417
1418 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1419 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1420 pointer type. CST must be of integer type. The CST value is zero extended,
1421 truncated, or unchanged to make it fit in a pointer size. This one is
1422 <i>really</i> dangerous!</dd>
1423
1424 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1425 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1426 identical (same number of bits). The conversion is done as if the CST value
1427 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]1428 with this operator, just the type. This can be used for conversion of
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1429 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]1430 pointers it is only valid to cast to another pointer type.
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]1431 </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1432
1433 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1434
1435 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1436 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1437 instruction, the index list may have zero or more indexes, which are required
1438 to make sense for the type of "CSTPTR".</dd>
1439
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1440 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1441
1442 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1443 constants.</dd>
1444
1445 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1446 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1447
1448 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1449 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]1450
1451 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1452
1453 <dd>Perform the <a href="#i_extractelement">extractelement
1454 operation</a> on constants.
1455
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1456 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1457
1458 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1459 operation</a> on constants.</dd>
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]1460
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1461
1462 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1463
1464 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]1465 operation</a> on constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]1466
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1467 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1468
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1469 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1470 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1471 binary</a> operations. The constraints on operands are the same as those for
1472 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1473 values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1474</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1475</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1476
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1477<!-- *********************************************************************** -->
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1478<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1479<!-- *********************************************************************** -->
1480
1481<!-- ======================================================================= -->
1482<div class="doc_subsection">
1483<a name="inlineasm">Inline Assembler Expressions</a>
1484</div>
1485
1486<div class="doc_text">
1487
1488<p>
1489LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1490Module-Level Inline Assembly</a>) through the use of a special value. This
1491value represents the inline assembler as a string (containing the instructions
1492to emit), a list of operand constraints (stored as a string), and a flag that
1493indicates whether or not the inline asm expression has side effects. An example
1494inline assembler expression is:
1495</p>
1496
1497<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1498 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]1499</pre>
1500
1501<p>
1502Inline assembler expressions may <b>only</b> be used as the callee operand of
1503a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1504</p>
1505
1506<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1507 %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]1508</pre>
1509
1510<p>
1511Inline asms with side effects not visible in the constraint list must be marked
1512as having side effects. This is done through the use of the
1513'<tt>sideeffect</tt>' keyword, like so:
1514</p>
1515
1516<pre>
1517 call void asm sideeffect "eieio", ""()
1518</pre>
1519
1520<p>TODO: The format of the asm and constraints string still need to be
1521documented here. Constraints on what can be done (e.g. duplication, moving, etc
1522need to be documented).
1523</p>
1524
1525</div>
1526
1527<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1528<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1529<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1530
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1531<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1532
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1533<p>The LLVM instruction set consists of several different
1534classifications of instructions: <a href="#terminators">terminator
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1535instructions</a>, <a href="#binaryops">binary instructions</a>,
1536<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1537 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1538instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1539
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1540</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1541
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1542<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1543<div class="doc_subsection"> <a name="terminators">Terminator
1544Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1545
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1546<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1547
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1548<p>As mentioned <a href="#functionstructure">previously</a>, every
1549basic block in a program ends with a "Terminator" instruction, which
1550indicates which block should be executed after the current block is
1551finished. These terminator instructions typically yield a '<tt>void</tt>'
1552value: they produce control flow, not values (the one exception being
1553the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1554<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1555 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1556instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1557the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1558 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1559 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1561</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1562
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1563<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1564<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1565Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1566<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1567<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1568<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]1569 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1570</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1572<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1573value) from a function back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1574<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1575returns a value and then causes control flow, and one that just causes
1576control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1577<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1578<p>The '<tt>ret</tt>' instruction may return any '<a
1579 href="#t_firstclass">first class</a>' type. Notice that a function is
1580not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1581instruction inside of the function that returns a value that does not
1582match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1583<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1584<p>When the '<tt>ret</tt>' instruction is executed, control flow
1585returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1586 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1587the instruction after the call. If the caller was an "<a
1588 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1589at the beginning of the "normal" destination block. If the instruction
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1590returns a value, that value shall set the call or invoke instruction's
1591return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1593<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1594 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1595</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1596</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1597<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1598<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1599<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1600<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1601<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]1602</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1603<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1604<p>The '<tt>br</tt>' instruction is used to cause control flow to
1605transfer to a different basic block in the current function. There are
1606two forms of this instruction, corresponding to a conditional branch
1607and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1609<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1610single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1611unconditional form of the '<tt>br</tt>' instruction takes a single
1612'<tt>label</tt>' value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1613<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1614<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1615argument is evaluated. If the value is <tt>true</tt>, control flows
1616to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1617control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1618<h5>Example:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1619<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]1620 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]1621</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1622<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1623<div class="doc_subsubsection">
1624 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1625</div>
1626
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1627<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1628<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1629
1630<pre>
1631 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1632</pre>
1633
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1634<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1635
1636<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1637several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1638instruction, allowing a branch to occur to one of many possible
1639destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1640
1641
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1643
1644<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1645comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1646an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1647table is not allowed to contain duplicate constant entries.</p>
1648
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1649<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1650
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1651<p>The <tt>switch</tt> instruction specifies a table of values and
1652destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1653table is searched for the given value. If the value is found, control flow is
1654transfered to the corresponding destination; otherwise, control flow is
1655transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1656
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1657<h5>Implementation:</h5>
1658
1659<p>Depending on properties of the target machine and the particular
1660<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1661ways. For example, it could be generated as a series of chained conditional
1662branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1663
1664<h5>Example:</h5>
1665
1666<pre>
1667 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]1668 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1669 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1670
1671 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1672 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1673
1674 <i>; Implement a jump table:</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1675 switch i32 %val, label %otherwise [ i32 0, label %onzero
1676 i32 1, label %onone
1677 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1678</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1679</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1680
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1681<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1682<div class="doc_subsubsection">
1683 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1684</div>
1685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1687
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1688<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1689
1690<pre>
1691 &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]1692 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1693</pre>
1694
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1695<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1696
1697<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1698function, with the possibility of control flow transfer to either the
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1699'<tt>normal</tt>' label or the
1700'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1701"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1702"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswelle4c57cc2005-05-12 16:52:32 +0000[diff] [blame]1703href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1704continued at the dynamically nearest "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1706<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1707
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1708<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1709
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1710<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1711 <li>
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]1712 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1713 convention</a> the call should use. If none is specified, the call defaults
1714 to using C calling conventions.
1715 </li>
1716 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1717 function value being invoked. In most cases, this is a direct function
1718 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1719 an arbitrary pointer to function value.
1720 </li>
1721
1722 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1723 function to be invoked. </li>
1724
1725 <li>'<tt>function args</tt>': argument list whose types match the function
1726 signature argument types. If the function signature indicates the function
1727 accepts a variable number of arguments, the extra arguments can be
1728 specified. </li>
1729
1730 <li>'<tt>normal label</tt>': the label reached when the called function
1731 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1732
1733 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1734 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1735
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1736</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1737
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1739
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1740<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1741href="#i_call">call</a></tt>' instruction in most regards. The primary
1742difference is that it establishes an association with a label, which is used by
1743the runtime library to unwind the stack.</p>
1744
1745<p>This instruction is used in languages with destructors to ensure that proper
1746cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1747exception. Additionally, this is important for implementation of
1748'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1749
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1751<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1752 %retval = invoke i32 %Test(i32 15) to label %Continue
1753 unwind label %TestCleanup <i>; {i32}:retval set</i>
1754 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1755 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1756</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1757</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1758
1759
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1760<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1761
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1762<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1763Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1764
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1765<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1766
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1768<pre>
1769 unwind
1770</pre>
1771
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1772<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1773
1774<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1775at the first callee in the dynamic call stack which used an <a
1776href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1777primarily used to implement exception handling.</p>
1778
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1779<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1780
1781<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1782immediately halt. The dynamic call stack is then searched for the first <a
1783href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1784execution continues at the "exceptional" destination block specified by the
1785<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1786dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1788
1789<!-- _______________________________________________________________________ -->
1790
1791<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1792Instruction</a> </div>
1793
1794<div class="doc_text">
1795
1796<h5>Syntax:</h5>
1797<pre>
1798 unreachable
1799</pre>
1800
1801<h5>Overview:</h5>
1802
1803<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1804instruction is used to inform the optimizer that a particular portion of the
1805code is not reachable. This can be used to indicate that the code after a
1806no-return function cannot be reached, and other facts.</p>
1807
1808<h5>Semantics:</h5>
1809
1810<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1811</div>
1812
1813
1814
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1815<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1816<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1817<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1818<p>Binary operators are used to do most of the computation in a
1819program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1820produce a single value. The operands might represent
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1821multiple 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]1822The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1823necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1824<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1825</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1826<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1827<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1828Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1829<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1830<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1831<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]1832</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1833<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1834<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1835<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1836<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1837 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1838 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]1839Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1840<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1841<p>The value produced is the integer or floating point sum of the two
1842operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1843<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1844<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]1845</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1846</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1847<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1848<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1849Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1851<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852<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]1853</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1854<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1855<p>The '<tt>sub</tt>' instruction returns the difference of its two
1856operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1857<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1858instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1859<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1860<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1861 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1862values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1863This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1864Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1866<p>The value produced is the integer or floating point difference of
1867the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1868<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1869<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1870 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1871</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1872</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1873<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1874<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1875Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1876<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1878<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]1879</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1880<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1881<p>The '<tt>mul</tt>' instruction returns the product of its two
1882operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1883<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1884<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1885 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1886values.
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1887This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1888Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1889<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1890<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1891two operands.</p>
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]1892<p>Because the operands are the same width, the result of an integer
1893multiplication is the same whether the operands should be deemed unsigned or
1894signed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1895<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1896<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]1897</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1898</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1899<!-- _______________________________________________________________________ -->
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1900<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1901</a></div>
1902<div class="doc_text">
1903<h5>Syntax:</h5>
1904<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1905</pre>
1906<h5>Overview:</h5>
1907<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1908operands.</p>
1909<h5>Arguments:</h5>
1910<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1911<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1912types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1913of the values in which case the elements must be integers.</p>
1914<h5>Semantics:</h5>
1915<p>The value produced is the unsigned integer quotient of the two operands. This
1916instruction always performs an unsigned division operation, regardless of
1917whether the arguments are unsigned or not.</p>
1918<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1919<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]1920</pre>
1921</div>
1922<!-- _______________________________________________________________________ -->
1923<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1924</a> </div>
1925<div class="doc_text">
1926<h5>Syntax:</h5>
1927<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1928</pre>
1929<h5>Overview:</h5>
1930<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1931operands.</p>
1932<h5>Arguments:</h5>
1933<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1934<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1935types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1936of the values in which case the elements must be integers.</p>
1937<h5>Semantics:</h5>
1938<p>The value produced is the signed integer quotient of the two operands. This
1939instruction always performs a signed division operation, regardless of whether
1940the arguments are signed or not.</p>
1941<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1942<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]1943</pre>
1944</div>
1945<!-- _______________________________________________________________________ -->
1946<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1947Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1948<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1949<h5>Syntax:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1950<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]1951</pre>
1952<h5>Overview:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1953<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1954operands.</p>
1955<h5>Arguments:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1956<p>The two arguments to the '<tt>div</tt>' instruction must be
1957<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]1958identical types. This instruction can also take <a href="#t_vector">vector</a>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1959versions of the values in which case the elements must be floating point.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1960<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1961<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1962<h5>Example:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]1963<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]1964</pre>
1965</div>
1966<!-- _______________________________________________________________________ -->
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1967<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1968</div>
1969<div class="doc_text">
1970<h5>Syntax:</h5>
1971<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1972</pre>
1973<h5>Overview:</h5>
1974<p>The '<tt>urem</tt>' instruction returns the remainder from the
1975unsigned division of its two arguments.</p>
1976<h5>Arguments:</h5>
1977<p>The two arguments to the '<tt>urem</tt>' instruction must be
1978<a href="#t_integer">integer</a> values. Both arguments must have identical
1979types.</p>
1980<h5>Semantics:</h5>
1981<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1982This instruction always performs an unsigned division to get the remainder,
1983regardless of whether the arguments are unsigned or not.</p>
1984<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1985<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]1986</pre>
1987
1988</div>
1989<!-- _______________________________________________________________________ -->
1990<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1991Instruction</a> </div>
1992<div class="doc_text">
1993<h5>Syntax:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1994<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]1995</pre>
1996<h5>Overview:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]1997<p>The '<tt>srem</tt>' instruction returns the remainder from the
1998signed division of its two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1999<h5>Arguments:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2000<p>The two arguments to the '<tt>srem</tt>' instruction must be
2001<a href="#t_integer">integer</a> values. Both arguments must have identical
2002types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2003<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]2004<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2005has the same sign as the divisor), not the <i>modulus</i> (where the
2006result has the same sign as the dividend) of a value. For more
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2007information about the difference, see <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2008 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2009Math Forum</a>.</p>
2010<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2011<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]2012</pre>
2013
2014</div>
2015<!-- _______________________________________________________________________ -->
2016<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2017Instruction</a> </div>
2018<div class="doc_text">
2019<h5>Syntax:</h5>
2020<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2021</pre>
2022<h5>Overview:</h5>
2023<p>The '<tt>frem</tt>' instruction returns the remainder from the
2024division of its two operands.</p>
2025<h5>Arguments:</h5>
2026<p>The two arguments to the '<tt>frem</tt>' instruction must be
2027<a href="#t_floating">floating point</a> values. Both arguments must have
2028identical types.</p>
2029<h5>Semantics:</h5>
2030<p>This instruction returns the <i>remainder</i> of a division.</p>
2031<h5>Example:</h5>
2032<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]2033</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2034</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]2035
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2036<!-- ======================================================================= -->
2037<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2038Operations</a> </div>
2039<div class="doc_text">
2040<p>Bitwise binary operators are used to do various forms of
2041bit-twiddling in a program. They are generally very efficient
2042instructions and can commonly be strength reduced from other
2043instructions. They require two operands, execute an operation on them,
2044and produce a single value. The resulting value of the bitwise binary
2045operators is always the same type as its first operand.</p>
2046</div>
2047
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2048<!-- _______________________________________________________________________ -->
2049<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2050Instruction</a> </div>
2051<div class="doc_text">
2052<h5>Syntax:</h5>
2053<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2054</pre>
2055<h5>Overview:</h5>
2056<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2057the left a specified number of bits.</p>
2058<h5>Arguments:</h5>
2059<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2060 href="#t_integer">integer</a> type.</p>
2061<h5>Semantics:</h5>
2062<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2063<h5>Example:</h5><pre>
2064 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2065 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2066 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2067</pre>
2068</div>
2069<!-- _______________________________________________________________________ -->
2070<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2071Instruction</a> </div>
2072<div class="doc_text">
2073<h5>Syntax:</h5>
2074<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2075</pre>
2076
2077<h5>Overview:</h5>
2078<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2079operand shifted to the right a specified number of bits.</p>
2080
2081<h5>Arguments:</h5>
2082<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2083<a href="#t_integer">integer</a> type.</p>
2084
2085<h5>Semantics:</h5>
2086<p>This instruction always performs a logical shift right operation. The most
2087significant bits of the result will be filled with zero bits after the
2088shift.</p>
2089
2090<h5>Example:</h5>
2091<pre>
2092 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2093 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2094 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2095 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2096</pre>
2097</div>
2098
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]2099<!-- _______________________________________________________________________ -->
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]2100<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2101Instruction</a> </div>
2102<div class="doc_text">
2103
2104<h5>Syntax:</h5>
2105<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2106</pre>
2107
2108<h5>Overview:</h5>
2109<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2110operand shifted to the right a specified number of bits.</p>
2111
2112<h5>Arguments:</h5>
2113<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2114<a href="#t_integer">integer</a> type.</p>
2115
2116<h5>Semantics:</h5>
2117<p>This instruction always performs an arithmetic shift right operation,
2118The most significant bits of the result will be filled with the sign bit
2119of <tt>var1</tt>.</p>
2120
2121<h5>Example:</h5>
2122<pre>
2123 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2124 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2125 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2126 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2127</pre>
2128</div>
2129
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2130<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2131<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2132Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2133<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2134<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2135<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]2136</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2137<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2138<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2139its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2140<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2141<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2142 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2143identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2144<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2145<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2146<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2147<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2148<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2149 <tbody>
2150 <tr>
2151 <td>In0</td>
2152 <td>In1</td>
2153 <td>Out</td>
2154 </tr>
2155 <tr>
2156 <td>0</td>
2157 <td>0</td>
2158 <td>0</td>
2159 </tr>
2160 <tr>
2161 <td>0</td>
2162 <td>1</td>
2163 <td>0</td>
2164 </tr>
2165 <tr>
2166 <td>1</td>
2167 <td>0</td>
2168 <td>0</td>
2169 </tr>
2170 <tr>
2171 <td>1</td>
2172 <td>1</td>
2173 <td>1</td>
2174 </tr>
2175 </tbody>
2176</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2177</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2178<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2179<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2180 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2181 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2182</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2183</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2184<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2185<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2186<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2187<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2188<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]2189</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2190<h5>Overview:</h5>
2191<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2192or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2193<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2194<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2195 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2196identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2197<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2198<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2199<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2200<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2201<table border="1" cellspacing="0" cellpadding="4">
2202 <tbody>
2203 <tr>
2204 <td>In0</td>
2205 <td>In1</td>
2206 <td>Out</td>
2207 </tr>
2208 <tr>
2209 <td>0</td>
2210 <td>0</td>
2211 <td>0</td>
2212 </tr>
2213 <tr>
2214 <td>0</td>
2215 <td>1</td>
2216 <td>1</td>
2217 </tr>
2218 <tr>
2219 <td>1</td>
2220 <td>0</td>
2221 <td>1</td>
2222 </tr>
2223 <tr>
2224 <td>1</td>
2225 <td>1</td>
2226 <td>1</td>
2227 </tr>
2228 </tbody>
2229</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2230</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2231<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2232<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2233 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2234 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2235</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2236</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2237<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2238<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2239Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2240<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2241<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2242<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]2243</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2244<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2245<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2246or of its two operands. The <tt>xor</tt> is used to implement the
2247"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2248<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2249<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2250 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2251identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2252<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2253<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2254<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2255<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2256<table border="1" cellspacing="0" cellpadding="4">
2257 <tbody>
2258 <tr>
2259 <td>In0</td>
2260 <td>In1</td>
2261 <td>Out</td>
2262 </tr>
2263 <tr>
2264 <td>0</td>
2265 <td>0</td>
2266 <td>0</td>
2267 </tr>
2268 <tr>
2269 <td>0</td>
2270 <td>1</td>
2271 <td>1</td>
2272 </tr>
2273 <tr>
2274 <td>1</td>
2275 <td>0</td>
2276 <td>1</td>
2277 </tr>
2278 <tr>
2279 <td>1</td>
2280 <td>1</td>
2281 <td>0</td>
2282 </tr>
2283 </tbody>
2284</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2285</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2286<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2287<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2288<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2289 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2290 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2291 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2292</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2293</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2295<!-- ======================================================================= -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2296<div class="doc_subsection">
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2297 <a name="vectorops">Vector Operations</a>
2298</div>
2299
2300<div class="doc_text">
2301
2302<p>LLVM supports several instructions to represent vector operations in a
2303target-independent manner. This instructions cover the element-access and
2304vector-specific operations needed to process vectors effectively. While LLVM
2305does directly support these vector operations, many sophisticated algorithms
2306will want to use target-specific intrinsics to take full advantage of a specific
2307target.</p>
2308
2309</div>
2310
2311<!-- _______________________________________________________________________ -->
2312<div class="doc_subsubsection">
2313 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2314</div>
2315
2316<div class="doc_text">
2317
2318<h5>Syntax:</h5>
2319
2320<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2321 &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]2322</pre>
2323
2324<h5>Overview:</h5>
2325
2326<p>
2327The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2328element from a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2329</p>
2330
2331
2332<h5>Arguments:</h5>
2333
2334<p>
2335The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2336value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2337an index indicating the position from which to extract the element.
2338The index may be a variable.</p>
2339
2340<h5>Semantics:</h5>
2341
2342<p>
2343The result is a scalar of the same type as the element type of
2344<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2345<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2346results are undefined.
2347</p>
2348
2349<h5>Example:</h5>
2350
2351<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2352 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2353</pre>
2354</div>
2355
2356
2357<!-- _______________________________________________________________________ -->
2358<div class="doc_subsubsection">
2359 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2360</div>
2361
2362<div class="doc_text">
2363
2364<h5>Syntax:</h5>
2365
2366<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2367 &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]2368</pre>
2369
2370<h5>Overview:</h5>
2371
2372<p>
2373The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2374element into a vector at a specified index.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2375</p>
2376
2377
2378<h5>Arguments:</h5>
2379
2380<p>
2381The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2382value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2383scalar value whose type must equal the element type of the first
2384operand. The third operand is an index indicating the position at
2385which to insert the value. The index may be a variable.</p>
2386
2387<h5>Semantics:</h5>
2388
2389<p>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2390The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2391element values are those of <tt>val</tt> except at position
2392<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2393exceeds the length of <tt>val</tt>, the results are undefined.
2394</p>
2395
2396<h5>Example:</h5>
2397
2398<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2399 %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]2400</pre>
2401</div>
2402
2403<!-- _______________________________________________________________________ -->
2404<div class="doc_subsubsection">
2405 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2406</div>
2407
2408<div class="doc_text">
2409
2410<h5>Syntax:</h5>
2411
2412<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2413 &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]2414</pre>
2415
2416<h5>Overview:</h5>
2417
2418<p>
2419The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2420from two input vectors, returning a vector of the same type.
2421</p>
2422
2423<h5>Arguments:</h5>
2424
2425<p>
2426The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2427with types that match each other and types that match the result of the
2428instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2429of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2430</p>
2431
2432<p>
2433The shuffle mask operand is required to be a constant vector with either
2434constant integer or undef values.
2435</p>
2436
2437<h5>Semantics:</h5>
2438
2439<p>
2440The elements of the two input vectors are numbered from left to right across
2441both of the vectors. The shuffle mask operand specifies, for each element of
2442the result vector, which element of the two input registers the result element
2443gets. The element selector may be undef (meaning "don't care") and the second
2444operand may be undef if performing a shuffle from only one vector.
2445</p>
2446
2447<h5>Example:</h5>
2448
2449<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2450 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2451 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2452 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2453 &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]2454</pre>
2455</div>
2456
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]2457
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]2458<!-- ======================================================================= -->
2459<div class="doc_subsection">
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2460 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2461</div>
2462
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2463<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2464
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2465<p>A key design point of an SSA-based representation is how it
2466represents memory. In LLVM, no memory locations are in SSA form, which
2467makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2468allocate, and free memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2469
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2470</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2471
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2472<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2473<div class="doc_subsubsection">
2474 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2475</div>
2476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2477<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2478
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2480
2481<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2482 &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]2483</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2484
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2485<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2486
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2487<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2488heap and returns a pointer to it.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2489
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2490<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2491
2492<p>The '<tt>malloc</tt>' instruction allocates
2493<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]2494bytes of memory from the operating system and returns a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2495appropriate type to the program. If "NumElements" is specified, it is the
2496number of elements allocated. If an alignment is specified, the value result
2497of the allocation is guaranteed to be aligned to at least that boundary. If
2498not specified, or if zero, the target can choose to align the allocation on any
2499convenient boundary.</p>
2500
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2501<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2502
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2503<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2504
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2505<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2506a pointer is returned.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2507
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2508<h5>Example:</h5>
2509
2510<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2511 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2512
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2513 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2514 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2515 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2516 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2517 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2518</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2519</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2520
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2521<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2522<div class="doc_subsubsection">
2523 <a name="i_free">'<tt>free</tt>' Instruction</a>
2524</div>
2525
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2526<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2527
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2528<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2529
2530<pre>
2531 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2532</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2533
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2534<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2535
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2536<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2537memory heap to be reallocated in the future.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2538
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2539<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2540
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2541<p>'<tt>value</tt>' shall be a pointer value that points to a value
2542that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2543instruction.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2544
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2545<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2546
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2547<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2548after this instruction executes.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2549
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2550<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2551
2552<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2553 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2554 free [4 x i8]* %array
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2555</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2556</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2557
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2558<!-- _______________________________________________________________________ -->
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2559<div class="doc_subsubsection">
2560 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2561</div>
2562
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2563<div class="doc_text">
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2564
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2565<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2566
2567<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2568 &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]2569</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2570
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2571<h5>Overview:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2572
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2573<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2574stack frame of the procedure that is live until the current function
2575returns to its caller.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2576
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2577<h5>Arguments:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2578
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2579<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2580bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2581appropriate type to the program. If "NumElements" is specified, it is the
2582number of elements allocated. If an alignment is specified, the value result
2583of the allocation is guaranteed to be aligned to at least that boundary. If
2584not specified, or if zero, the target can choose to align the allocation on any
2585convenient boundary.</p>
2586
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2587<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2588
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2589<h5>Semantics:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2590
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2591<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2592memory is automatically released when the function returns. The '<tt>alloca</tt>'
2593instruction is commonly used to represent automatic variables that must
2594have an address available. When the function returns (either with the <tt><a
John Criswelldae2e932005-05-12 16:55:34 +0000[diff] [blame]2595 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]2596instructions), the memory is reclaimed.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2597
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2598<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2599
2600<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2601 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2602 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2603 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2604 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2605</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2606</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]2607
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2608<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2609<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2610Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2611<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2612<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2613<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]2614<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2615<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2616<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2617<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2618address from which to load. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]2619 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2620marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2621the number or order of execution of this <tt>load</tt> with other
2622volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2623instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2624<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2625<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2626<h5>Examples:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2627<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2628 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2629 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2630 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2631</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2632</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2633<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2634<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2635Instruction</a> </div>
Reid Spencer035ab572006-11-09 21:18:01 +0000[diff] [blame]2636<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2637<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2638<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]2639 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]2640</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2641<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2642<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2643<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2644<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2645to 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]2646operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2647operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2648optimizer is not allowed to modify the number or order of execution of
2649this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2650 href="#i_store">store</a></tt> instructions.</p>
2651<h5>Semantics:</h5>
2652<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2653at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2654<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2655<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2656 <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2657 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2658 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2659</pre>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2660</div>
2661
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]2662<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2663<div class="doc_subsubsection">
2664 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2665</div>
2666
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2667<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2668<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2669<pre>
2670 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2671</pre>
2672
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2673<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2674
2675<p>
2676The '<tt>getelementptr</tt>' instruction is used to get the address of a
2677subelement of an aggregate data structure.</p>
2678
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2679<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2680
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2681<p>This instruction takes a list of integer operands that indicate what
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2682elements of the aggregate object to index to. The actual types of the arguments
2683provided depend on the type of the first pointer argument. The
2684'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]2685levels 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]2686structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2687into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2688be sign extended to 64-bit values.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2689
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2690<p>For example, let's consider a C code fragment and how it gets
2691compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2692
2693<pre>
2694 struct RT {
2695 char A;
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2696 i32 B[10][20];
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2697 char C;
2698 };
2699 struct ST {
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2700 i32 X;
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2701 double Y;
2702 struct RT Z;
2703 };
2704
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2705 define i32 *foo(struct ST *s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2706 return &amp;s[1].Z.B[5][13];
2707 }
2708</pre>
2709
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2710<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2711
2712<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2713 %RT = type { i8 , [10 x [20 x i32]], i8 }
2714 %ST = type { i32, double, %RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2715
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2716 implementation
2717
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2718 define i32* %foo(%ST* %s) {
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]2719 entry:
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2720 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2721 ret i32* %reg
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2722 }
2723</pre>
2724
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2725<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2726
2727<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswellc1f786c2005-05-13 22:25:59 +0000[diff] [blame]2728on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencer85f5b5b2006-12-04 21:29:24 +0000[diff] [blame]2729and <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]2730<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]2731to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencer42ddd842006-12-03 16:53:48 +0000[diff] [blame]2732<b>constants</b>.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2733
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2734<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]2735type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2736}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2737the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2738i8 }</tt>' type, another structure. The third index indexes into the second
2739element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2740array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2741'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2742to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2743
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2744<p>Note that it is perfectly legal to index partially through a
2745structure, returning a pointer to an inner element. Because of this,
2746the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2747
2748<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2749 define i32* %foo(%ST* %s) {
2750 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2751 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2752 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2753 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2754 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2755 ret i32* %t5
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2756 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2757</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2758
2759<p>Note that it is undefined to access an array out of bounds: array and
2760pointer indexes must always be within the defined bounds of the array type.
2761The one exception for this rules is zero length arrays. These arrays are
2762defined to be accessible as variable length arrays, which requires access
2763beyond the zero'th element.</p>
2764
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]2765<p>The getelementptr instruction is often confusing. For some more insight
2766into how it works, see <a href="GetElementPtr.html">the getelementptr
2767FAQ</a>.</p>
2768
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2769<h5>Example:</h5>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]2770
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2771<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2772 <i>; yields [12 x i8]*:aptr</i>
2773 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2774</pre>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]2775</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]2776
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2777<!-- ======================================================================= -->
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2778<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2779</div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2780<div class="doc_text">
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]2781<p>The instructions in this category are the conversion instructions (casting)
2782which all take a single operand and a type. They perform various bit conversions
2783on the operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2784</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2785
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2786<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2787<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2788 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2789</div>
2790<div class="doc_text">
2791
2792<h5>Syntax:</h5>
2793<pre>
2794 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2795</pre>
2796
2797<h5>Overview:</h5>
2798<p>
2799The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2800</p>
2801
2802<h5>Arguments:</h5>
2803<p>
2804The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2805be 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]2806and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2807type. The bit size of <tt>value</tt> must be larger than the bit size of
2808<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2809
2810<h5>Semantics:</h5>
2811<p>
2812The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2813and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2814larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2815It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2816
2817<h5>Example:</h5>
2818<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2819 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2820 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2821 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2822</pre>
2823</div>
2824
2825<!-- _______________________________________________________________________ -->
2826<div class="doc_subsubsection">
2827 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2828</div>
2829<div class="doc_text">
2830
2831<h5>Syntax:</h5>
2832<pre>
2833 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2834</pre>
2835
2836<h5>Overview:</h5>
2837<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2838<tt>ty2</tt>.</p>
2839
2840
2841<h5>Arguments:</h5>
2842<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]2843<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2844also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2845<tt>value</tt> must be smaller than the bit size of the destination type,
2846<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2847
2848<h5>Semantics:</h5>
2849<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2850bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2851the operand and the type are the same size, no bit filling is done and the
2852cast is considered a <i>no-op cast</i> because no bits change (only the type
2853changes).</p>
2854
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]2855<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]2856
2857<h5>Example:</h5>
2858<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2859 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2860 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2861</pre>
2862</div>
2863
2864<!-- _______________________________________________________________________ -->
2865<div class="doc_subsubsection">
2866 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2867</div>
2868<div class="doc_text">
2869
2870<h5>Syntax:</h5>
2871<pre>
2872 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2873</pre>
2874
2875<h5>Overview:</h5>
2876<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2877
2878<h5>Arguments:</h5>
2879<p>
2880The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]2881<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2882also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2883<tt>value</tt> must be smaller than the bit size of the destination type,
2884<tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2885
2886<h5>Semantics:</h5>
2887<p>
2888The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2889bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2890the type <tt>ty2</tt>. When the the operand and the type are the same size,
2891no bit filling is done and the cast is considered a <i>no-op cast</i> because
2892no bits change (only the type changes).</p>
2893
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2894<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]2895
2896<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2897<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2898 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]2899 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2900</pre>
2901</div>
2902
2903<!-- _______________________________________________________________________ -->
2904<div class="doc_subsubsection">
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2905 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2906</div>
2907
2908<div class="doc_text">
2909
2910<h5>Syntax:</h5>
2911
2912<pre>
2913 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2914</pre>
2915
2916<h5>Overview:</h5>
2917<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2918<tt>ty2</tt>.</p>
2919
2920
2921<h5>Arguments:</h5>
2922<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2923 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2924cast it to. The size of <tt>value</tt> must be larger than the size of
2925<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2926<i>no-op cast</i>.</p>
2927
2928<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2929<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2930<a href="#t_floating">floating point</a> type to a smaller
2931<a href="#t_floating">floating point</a> type. If the value cannot fit within
2932the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]2933
2934<h5>Example:</h5>
2935<pre>
2936 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2937 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2938</pre>
2939</div>
2940
2941<!-- _______________________________________________________________________ -->
2942<div class="doc_subsubsection">
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2943 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2944</div>
2945<div class="doc_text">
2946
2947<h5>Syntax:</h5>
2948<pre>
2949 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2950</pre>
2951
2952<h5>Overview:</h5>
2953<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2954floating point value.</p>
2955
2956<h5>Arguments:</h5>
2957<p>The '<tt>fpext</tt>' instruction takes a
2958<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2959and a <a href="#t_floating">floating point</a> type to cast it to. The source
2960type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2961
2962<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]2963<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2964<a href="t_floating">floating point</a> type to a larger
2965<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2966used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2967<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]2968
2969<h5>Example:</h5>
2970<pre>
2971 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2972 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2973</pre>
2974</div>
2975
2976<!-- _______________________________________________________________________ -->
2977<div class="doc_subsubsection">
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]2978 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2979</div>
2980<div class="doc_text">
2981
2982<h5>Syntax:</h5>
2983<pre>
2984 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2985</pre>
2986
2987<h5>Overview:</h5>
2988<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2989unsigned integer equivalent of type <tt>ty2</tt>.
2990</p>
2991
2992<h5>Arguments:</h5>
2993<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2994<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]2995must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2996
2997<h5>Semantics:</h5>
2998<p> The '<tt>fp2uint</tt>' instruction converts its
2999<a href="#t_floating">floating point</a> operand into the nearest (rounding
3000towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3001the results are undefined.</p>
3002
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3003<p>When converting to i1, the conversion is done as a comparison against
3004zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3005If 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]3006
3007<h5>Example:</h5>
3008<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3009 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3010 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3011 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3012</pre>
3013</div>
3014
3015<!-- _______________________________________________________________________ -->
3016<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3017 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3018</div>
3019<div class="doc_text">
3020
3021<h5>Syntax:</h5>
3022<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3023 &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]3024</pre>
3025
3026<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3027<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3028<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]3029</p>
3030
3031
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3032<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3033<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]3034<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]3035must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3036
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3037<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3038<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3039<a href="#t_floating">floating point</a> operand into the nearest (rounding
3040towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3041the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3042
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3043<p>When converting to i1, the conversion is done as a comparison against
3044zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3045If 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]3046
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3047<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3048<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3049 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3050 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3051 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3052</pre>
3053</div>
3054
3055<!-- _______________________________________________________________________ -->
3056<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3057 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3058</div>
3059<div class="doc_text">
3060
3061<h5>Syntax:</h5>
3062<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3063 &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]3064</pre>
3065
3066<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3067<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3068integer and converts that value to the <tt>ty2</tt> type.</p>
3069
3070
3071<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3072<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]3073<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]3074be a <a href="#t_floating">floating point</a> type.</p>
3075
3076<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3077<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3078integer quantity and converts it to the corresponding floating point value. If
3079the value cannot fit in the floating point value, the results are undefined.</p>
3080
3081
3082<h5>Example:</h5>
3083<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3084 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3085 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3086</pre>
3087</div>
3088
3089<!-- _______________________________________________________________________ -->
3090<div class="doc_subsubsection">
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3091 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3092</div>
3093<div class="doc_text">
3094
3095<h5>Syntax:</h5>
3096<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3097 &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]3098</pre>
3099
3100<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3101<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3102integer and converts that value to the <tt>ty2</tt> type.</p>
3103
3104<h5>Arguments:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3105<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]3106<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]3107a <a href="#t_floating">floating point</a> type.</p>
3108
3109<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]3110<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3111integer quantity and converts it to the corresponding floating point value. If
3112the value cannot fit in the floating point value, the results are undefined.</p>
3113
3114<h5>Example:</h5>
3115<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3116 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3117 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3118</pre>
3119</div>
3120
3121<!-- _______________________________________________________________________ -->
3122<div class="doc_subsubsection">
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3123 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3124</div>
3125<div class="doc_text">
3126
3127<h5>Syntax:</h5>
3128<pre>
3129 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3130</pre>
3131
3132<h5>Overview:</h5>
3133<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3134the integer type <tt>ty2</tt>.</p>
3135
3136<h5>Arguments:</h5>
3137<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3138must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3139<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3140
3141<h5>Semantics:</h5>
3142<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3143<tt>ty2</tt> by interpreting the pointer value as an integer and either
3144truncating or zero extending that value to the size of the integer type. If
3145<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3146<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3147are the same size, then nothing is done (<i>no-op cast</i>).</p>
3148
3149<h5>Example:</h5>
3150<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3151 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3152 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3153</pre>
3154</div>
3155
3156<!-- _______________________________________________________________________ -->
3157<div class="doc_subsubsection">
3158 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3159</div>
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163<pre>
3164 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3165</pre>
3166
3167<h5>Overview:</h5>
3168<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3169a pointer type, <tt>ty2</tt>.</p>
3170
3171<h5>Arguments:</h5>
3172<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3173value to cast, and a type to cast it to, which must be a
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]3174<a href="#t_pointer">pointer</a> type.
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3175
3176<h5>Semantics:</h5>
3177<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3178<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3179the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3180size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3181the size of a pointer then a zero extension is done. If they are the same size,
3182nothing is done (<i>no-op cast</i>).</p>
3183
3184<h5>Example:</h5>
3185<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3186 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3187 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3188 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3189</pre>
3190</div>
3191
3192<!-- _______________________________________________________________________ -->
3193<div class="doc_subsubsection">
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3194 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3195</div>
3196<div class="doc_text">
3197
3198<h5>Syntax:</h5>
3199<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3200 &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]3201</pre>
3202
3203<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3204<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3205<tt>ty2</tt> without changing any bits.</p>
3206
3207<h5>Arguments:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3208<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3209a first class value, and a type to cast it to, which must also be a <a
3210 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencer19b569f2007-01-09 20:08:58 +0000[diff] [blame]3211and the destination type, <tt>ty2</tt>, must be identical. If the source
3212type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3213
3214<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]3215<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]3216<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3217this conversion. The conversion is done as if the <tt>value</tt> had been
3218stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3219converted to other pointer types with this instruction. To convert pointers to
3220other types, use the <a href="#i_inttoptr">inttoptr</a> or
3221<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]3222
3223<h5>Example:</h5>
3224<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3225 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3226 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3227 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]3228</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3229</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3230
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3231<!-- ======================================================================= -->
3232<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3233<div class="doc_text">
3234<p>The instructions in this category are the "miscellaneous"
3235instructions, which defy better classification.</p>
3236</div>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3237
3238<!-- _______________________________________________________________________ -->
3239<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3240</div>
3241<div class="doc_text">
3242<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3243<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3244<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3245</pre>
3246<h5>Overview:</h5>
3247<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3248of its two integer operands.</p>
3249<h5>Arguments:</h5>
3250<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3251the condition code which indicates the kind of comparison to perform. It is not
3252a value, just a keyword. The possibilities for the condition code are:
3253<ol>
3254 <li><tt>eq</tt>: equal</li>
3255 <li><tt>ne</tt>: not equal </li>
3256 <li><tt>ugt</tt>: unsigned greater than</li>
3257 <li><tt>uge</tt>: unsigned greater or equal</li>
3258 <li><tt>ult</tt>: unsigned less than</li>
3259 <li><tt>ule</tt>: unsigned less or equal</li>
3260 <li><tt>sgt</tt>: signed greater than</li>
3261 <li><tt>sge</tt>: signed greater or equal</li>
3262 <li><tt>slt</tt>: signed less than</li>
3263 <li><tt>sle</tt>: signed less or equal</li>
3264</ol>
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]3265<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3266<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3267<h5>Semantics:</h5>
3268<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3269the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3270yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3271<ol>
3272 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3273 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3274 </li>
3275 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3276 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3277 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3278 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3279 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3280 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3281 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3282 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3283 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3284 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3285 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3286 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3287 <li><tt>sge</tt>: interprets the operands as signed values and yields
3288 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3289 <li><tt>slt</tt>: interprets the operands as signed values and yields
3290 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3291 <li><tt>sle</tt>: interprets the operands as signed values and yields
3292 <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]3293</ol>
3294<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3295values are treated as integers and then compared.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3296
3297<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3298<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3299 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3300 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3301 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3302 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3303 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3304</pre>
3305</div>
3306
3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3309</div>
3310<div class="doc_text">
3311<h5>Syntax:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3312<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;
3313<i>; yields {i1}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3314</pre>
3315<h5>Overview:</h5>
3316<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3317of its floating point operands.</p>
3318<h5>Arguments:</h5>
3319<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3320the condition code which indicates the kind of comparison to perform. It is not
3321a value, just a keyword. The possibilities for the condition code are:
3322<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3323 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3324 <li><tt>oeq</tt>: ordered and equal</li>
3325 <li><tt>ogt</tt>: ordered and greater than </li>
3326 <li><tt>oge</tt>: ordered and greater than or equal</li>
3327 <li><tt>olt</tt>: ordered and less than </li>
3328 <li><tt>ole</tt>: ordered and less than or equal</li>
3329 <li><tt>one</tt>: ordered and not equal</li>
3330 <li><tt>ord</tt>: ordered (no nans)</li>
3331 <li><tt>ueq</tt>: unordered or equal</li>
3332 <li><tt>ugt</tt>: unordered or greater than </li>
3333 <li><tt>uge</tt>: unordered or greater than or equal</li>
3334 <li><tt>ult</tt>: unordered or less than </li>
3335 <li><tt>ule</tt>: unordered or less than or equal</li>
3336 <li><tt>une</tt>: unordered or not equal</li>
3337 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3338 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3339</ol>
Reid Spencer93a49852006-12-06 07:08:07 +0000[diff] [blame]3340<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3341<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer350f8aa2007-01-04 05:19:58 +0000[diff] [blame]3342<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3343<a href="#t_floating">floating point</a> typed. They must have identical
3344types.</p>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3345<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3346<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3347<h5>Semantics:</h5>
3348<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3349the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3350yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3351<ol>
3352 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3353 <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]3354 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3355 <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]3356 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3357 <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]3358 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3359 <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]3360 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3361 <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]3362 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3363 <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]3364 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3365 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3366 <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]3367 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3368 <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]3369 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3370 <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]3371 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3372 <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]3373 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3374 <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]3375 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3376 <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]3377 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]3378 <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]3379 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3380</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]3381
3382<h5>Example:</h5>
3383<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3384 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3385 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3386 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3387</pre>
3388</div>
3389
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]3390<!-- _______________________________________________________________________ -->
3391<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3392Instruction</a> </div>
3393<div class="doc_text">
3394<h5>Syntax:</h5>
3395<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3396<h5>Overview:</h5>
3397<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3398the SSA graph representing the function.</p>
3399<h5>Arguments:</h5>
3400<p>The type of the incoming values are specified with the first type
3401field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3402as arguments, with one pair for each predecessor basic block of the
3403current block. Only values of <a href="#t_firstclass">first class</a>
3404type may be used as the value arguments to the PHI node. Only labels
3405may be used as the label arguments.</p>
3406<p>There must be no non-phi instructions between the start of a basic
3407block and the PHI instructions: i.e. PHI instructions must be first in
3408a basic block.</p>
3409<h5>Semantics:</h5>
3410<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3411value specified by the parameter, depending on which basic block we
3412came from in the last <a href="#terminators">terminator</a> instruction.</p>
3413<h5>Example:</h5>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3414<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]3415</div>
3416
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3417<!-- _______________________________________________________________________ -->
3418<div class="doc_subsubsection">
3419 <a name="i_select">'<tt>select</tt>' Instruction</a>
3420</div>
3421
3422<div class="doc_text">
3423
3424<h5>Syntax:</h5>
3425
3426<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3427 &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]3428</pre>
3429
3430<h5>Overview:</h5>
3431
3432<p>
3433The '<tt>select</tt>' instruction is used to choose one value based on a
3434condition, without branching.
3435</p>
3436
3437
3438<h5>Arguments:</h5>
3439
3440<p>
3441The '<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.
3442</p>
3443
3444<h5>Semantics:</h5>
3445
3446<p>
3447If the boolean condition evaluates to true, the instruction returns the first
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3448value argument; otherwise, it returns the second value argument.
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3449</p>
3450
3451<h5>Example:</h5>
3452
3453<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3454 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]3455</pre>
3456</div>
3457
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]3458
3459<!-- _______________________________________________________________________ -->
3460<div class="doc_subsubsection">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3461 <a name="i_call">'<tt>call</tt>' Instruction</a>
3462</div>
3463
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3464<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3465
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3466<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3467<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3468 &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]3469</pre>
3470
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3471<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3472
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3473<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3474
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3475<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3476
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3477<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3478
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3479<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3480 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3481 <p>The optional "tail" marker indicates whether the callee function accesses
3482 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3483 function call is eligible for tail call optimization. Note that calls may
3484 be marked "tail" even if they do not occur before a <a
3485 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3486 </li>
3487 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3488 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3489 convention</a> the call should use. If none is specified, the call defaults
3490 to using C calling conventions.
3491 </li>
3492 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3493 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3494 being invoked. The argument types must match the types implied by this
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3495 signature. This type can be omitted if the function is not varargs and
3496 if the function type does not return a pointer to a function.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3497 </li>
3498 <li>
3499 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3500 be invoked. In most cases, this is a direct function invocation, but
3501 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3502 to function value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3503 </li>
3504 <li>
3505 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]3506 function signature argument types. All arguments must be of
3507 <a href="#t_firstclass">first class</a> type. If the function signature
3508 indicates the function accepts a variable number of arguments, the extra
3509 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3510 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3511</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3512
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3513<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3514
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3515<p>The '<tt>call</tt>' instruction is used to cause control flow to
3516transfer to a specified function, with its incoming arguments bound to
3517the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3518instruction in the called function, control flow continues with the
3519instruction after the function call, and the return value of the
3520function is bound to the result argument. This is a simpler case of
3521the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3522
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3523<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3524
3525<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3526 %retval = call i32 %test(i32 %argc)
3527 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3528 %X = tail call i32 %foo()
3529 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]3530</pre>
3531
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3532</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3533
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3534<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3535<div class="doc_subsubsection">
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3536 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3537</div>
3538
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3539<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3540
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3541<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3542
3543<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3544 &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]3545</pre>
3546
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3547<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3548
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3549<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3550the "variable argument" area of a function call. It is used to implement the
3551<tt>va_arg</tt> macro in C.</p>
3552
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3553<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3554
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3555<p>This instruction takes a <tt>va_list*</tt> value and the type of
3556the argument. It returns a value of the specified argument type and
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]3557increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3558actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3559
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3560<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3561
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3562<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3563type from the specified <tt>va_list</tt> and causes the
3564<tt>va_list</tt> to point to the next argument. For more information,
3565see the variable argument handling <a href="#int_varargs">Intrinsic
3566Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3567
3568<p>It is legal for this instruction to be called in a function which does not
3569take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3570function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3571
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3572<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3573href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3574argument.</p>
3575
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]3576<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]3577
3578<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3579
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3580</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3581
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3582<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3583<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3584<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3585
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3586<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3587
3588<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3589well known names and semantics and are required to follow certain
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3590restrictions. Overall, these instructions represent an extension mechanism for
3591the LLVM language that does not require changing all of the transformations in
3592LLVM to add to the language (or the bytecode reader/writer, the parser,
3593etc...).</p>
3594
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3595<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3596prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3597this. Intrinsic functions must always be external functions: you cannot define
3598the body of intrinsic functions. Intrinsic functions may only be used in call
3599or invoke instructions: it is illegal to take the address of an intrinsic
3600function. Additionally, because intrinsic functions are part of the LLVM
3601language, it is required that they all be documented here if any are added.</p>
3602
3603
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]3604<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner590cff32005-05-11 03:35:57 +0000[diff] [blame]3605href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3606</p>
3607
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3608</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3609
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3610<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3611<div class="doc_subsection">
3612 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3613</div>
3614
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3615<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3616
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3617<p>Variable argument support is defined in LLVM with the <a
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]3618 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3619intrinsic functions. These functions are related to the similarly
3620named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3621
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3622<p>All of these functions operate on arguments that use a
3623target-specific value type "<tt>va_list</tt>". The LLVM assembly
3624language reference manual does not define what this type is, so all
3625transformations should be prepared to handle intrinsics with any type
3626used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3627
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]3628<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]3629instruction and the variable argument handling intrinsic functions are
3630used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3631
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3632<pre>
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3633define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3634 ; Initialize variable argument processing
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3635 %ap = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3636 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3637 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3638
3639 ; Read a single integer argument
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3640 %tmp = va_arg i8 ** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3641
3642 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3643 %aq = alloca i8 *
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3644 %aq2 = bitcast i8** %aq to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3645 call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
3646 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3647
3648 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3649 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3650 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3651}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]3652
3653declare void @llvm.va_start(i8*)
3654declare void @llvm.va_copy(i8*, i8*)
3655declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3656</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3657</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3658
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3659<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3660<div class="doc_subsubsection">
3661 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3662</div>
3663
3664
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3665<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3666<h5>Syntax:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3667<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3668<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3669<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3670<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3671href="#i_va_arg">va_arg</a></tt>.</p>
3672
3673<h5>Arguments:</h5>
3674
3675<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3676
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3677<h5>Semantics:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3678
3679<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3680macro available in C. In a target-dependent way, it initializes the
3681<tt>va_list</tt> element the argument points to, so that the next call to
3682<tt>va_arg</tt> will produce the first variable argument passed to the function.
3683Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3684last argument of the function, the compiler can figure that out.</p>
3685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3686</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3687
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3688<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3689<div class="doc_subsubsection">
3690 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3691</div>
3692
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3693<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3694<h5>Syntax:</h5>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3695<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3696<h5>Overview:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3697
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3698<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3699which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3700or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3701
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3702<h5>Arguments:</h5>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3703
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3704<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3705
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3706<h5>Semantics:</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 '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3709macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3710Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3711 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3712with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]3713
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3714</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3715
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3716<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3717<div class="doc_subsubsection">
3718 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3719</div>
3720
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3721<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3722
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3723<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3724
3725<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3726 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3727</pre>
3728
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3729<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3730
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3731<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3732the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3733
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3734<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3735
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3736<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]3737The 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]3738
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3739
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]3740<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3741
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]3742<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3743available in C. In a target-dependent way, it copies the source
3744<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3745because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3746arbitrarily complex and require memory allocation, for example.</p>
3747
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3748</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3749
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3750<!-- ======================================================================= -->
3751<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3752 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3753</div>
3754
3755<div class="doc_text">
3756
3757<p>
3758LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3759Collection</a> requires the implementation and generation of these intrinsics.
3760These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3761stack</a>, as well as garbage collector implementations that require <a
3762href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3763Front-ends for type-safe garbage collected languages should generate these
3764intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3765href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3766</p>
3767</div>
3768
3769<!-- _______________________________________________________________________ -->
3770<div class="doc_subsubsection">
3771 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3772</div>
3773
3774<div class="doc_text">
3775
3776<h5>Syntax:</h5>
3777
3778<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3779 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3780</pre>
3781
3782<h5>Overview:</h5>
3783
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]3784<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]3785the code generator, and allows some metadata to be associated with it.</p>
3786
3787<h5>Arguments:</h5>
3788
3789<p>The first argument specifies the address of a stack object that contains the
3790root pointer. The second pointer (which must be either a constant or a global
3791value address) contains the meta-data to be associated with the root.</p>
3792
3793<h5>Semantics:</h5>
3794
3795<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3796location. At compile-time, the code generator generates information to allow
3797the runtime to find the pointer at GC safe points.
3798</p>
3799
3800</div>
3801
3802
3803<!-- _______________________________________________________________________ -->
3804<div class="doc_subsubsection">
3805 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3806</div>
3807
3808<div class="doc_text">
3809
3810<h5>Syntax:</h5>
3811
3812<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3813 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3814</pre>
3815
3816<h5>Overview:</h5>
3817
3818<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3819locations, allowing garbage collector implementations that require read
3820barriers.</p>
3821
3822<h5>Arguments:</h5>
3823
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3824<p>The second argument is the address to read from, which should be an address
3825allocated from the garbage collector. The first object is a pointer to the
3826start of the referenced object, if needed by the language runtime (otherwise
3827null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3828
3829<h5>Semantics:</h5>
3830
3831<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3832instruction, but may be replaced with substantially more complex code by the
3833garbage collector runtime, as needed.</p>
3834
3835</div>
3836
3837
3838<!-- _______________________________________________________________________ -->
3839<div class="doc_subsubsection">
3840 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3841</div>
3842
3843<div class="doc_text">
3844
3845<h5>Syntax:</h5>
3846
3847<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3848 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3849</pre>
3850
3851<h5>Overview:</h5>
3852
3853<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3854locations, allowing garbage collector implementations that require write
3855barriers (such as generational or reference counting collectors).</p>
3856
3857<h5>Arguments:</h5>
3858
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]3859<p>The first argument is the reference to store, the second is the start of the
3860object to store it to, and the third is the address of the field of Obj to
3861store to. If the runtime does not require a pointer to the object, Obj may be
3862null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]3863
3864<h5>Semantics:</h5>
3865
3866<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3867instruction, but may be replaced with substantially more complex code by the
3868garbage collector runtime, as needed.</p>
3869
3870</div>
3871
3872
3873
3874<!-- ======================================================================= -->
3875<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3876 <a name="int_codegen">Code Generator Intrinsics</a>
3877</div>
3878
3879<div class="doc_text">
3880<p>
3881These intrinsics are provided by LLVM to expose special features that may only
3882be implemented with code generator support.
3883</p>
3884
3885</div>
3886
3887<!-- _______________________________________________________________________ -->
3888<div class="doc_subsubsection">
3889 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3890</div>
3891
3892<div class="doc_text">
3893
3894<h5>Syntax:</h5>
3895<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3896 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3897</pre>
3898
3899<h5>Overview:</h5>
3900
3901<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3902The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3903target-specific value indicating the return address of the current function
3904or one of its callers.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3905</p>
3906
3907<h5>Arguments:</h5>
3908
3909<p>
3910The argument to this intrinsic indicates which function to return the address
3911for. Zero indicates the calling function, one indicates its caller, etc. The
3912argument is <b>required</b> to be a constant integer value.
3913</p>
3914
3915<h5>Semantics:</h5>
3916
3917<p>
3918The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3919the return address of the specified call frame, or zero if it cannot be
3920identified. The value returned by this intrinsic is likely to be incorrect or 0
3921for arguments other than zero, so it should only be used for debugging purposes.
3922</p>
3923
3924<p>
3925Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3926aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3927source-language caller.
3928</p>
3929</div>
3930
3931
3932<!-- _______________________________________________________________________ -->
3933<div class="doc_subsubsection">
3934 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3935</div>
3936
3937<div class="doc_text">
3938
3939<h5>Syntax:</h5>
3940<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3941 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3942</pre>
3943
3944<h5>Overview:</h5>
3945
3946<p>
Chris Lattner32b5d712006-10-15 20:05:59 +0000[diff] [blame]3947The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3948target-specific frame pointer value for the specified stack frame.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3949</p>
3950
3951<h5>Arguments:</h5>
3952
3953<p>
3954The argument to this intrinsic indicates which function to return the frame
3955pointer for. Zero indicates the calling function, one indicates its caller,
3956etc. The argument is <b>required</b> to be a constant integer value.
3957</p>
3958
3959<h5>Semantics:</h5>
3960
3961<p>
3962The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3963the frame address of the specified call frame, or zero if it cannot be
3964identified. The value returned by this intrinsic is likely to be incorrect or 0
3965for arguments other than zero, so it should only be used for debugging purposes.
3966</p>
3967
3968<p>
3969Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]3970aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3971source-language caller.
3972</p>
3973</div>
3974
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]3975<!-- _______________________________________________________________________ -->
3976<div class="doc_subsubsection">
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3977 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3978</div>
3979
3980<div class="doc_text">
3981
3982<h5>Syntax:</h5>
3983<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]3984 declare i8 *@llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]3985</pre>
3986
3987<h5>Overview:</h5>
3988
3989<p>
3990The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3991the function stack, for use with <a href="#i_stackrestore">
3992<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3993features like scoped automatic variable sized arrays in C99.
3994</p>
3995
3996<h5>Semantics:</h5>
3997
3998<p>
3999This intrinsic returns a opaque pointer value that can be passed to <a
4000href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4001<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4002<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4003state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4004practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4005that were allocated after the <tt>llvm.stacksave</tt> was executed.
4006</p>
4007
4008</div>
4009
4010<!-- _______________________________________________________________________ -->
4011<div class="doc_subsubsection">
4012 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4013</div>
4014
4015<div class="doc_text">
4016
4017<h5>Syntax:</h5>
4018<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4019 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]4020</pre>
4021
4022<h5>Overview:</h5>
4023
4024<p>
4025The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4026the function stack to the state it was in when the corresponding <a
4027href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4028useful for implementing language features like scoped automatic variable sized
4029arrays in C99.
4030</p>
4031
4032<h5>Semantics:</h5>
4033
4034<p>
4035See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
4036</p>
4037
4038</div>
4039
4040
4041<!-- _______________________________________________________________________ -->
4042<div class="doc_subsubsection">
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4043 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4044</div>
4045
4046<div class="doc_text">
4047
4048<h5>Syntax:</h5>
4049<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4050 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4051 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4052</pre>
4053
4054<h5>Overview:</h5>
4055
4056
4057<p>
4058The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4059a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4060no
4061effect on the behavior of the program but can change its performance
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]4062characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4063</p>
4064
4065<h5>Arguments:</h5>
4066
4067<p>
4068<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4069determining if the fetch should be for a read (0) or write (1), and
4070<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]4071locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]4072<tt>locality</tt> arguments must be constant integers.
4073</p>
4074
4075<h5>Semantics:</h5>
4076
4077<p>
4078This intrinsic does not modify the behavior of the program. In particular,
4079prefetches cannot trap and do not produce a value. On targets that support this
4080intrinsic, the prefetch can provide hints to the processor cache for better
4081performance.
4082</p>
4083
4084</div>
4085
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4086<!-- _______________________________________________________________________ -->
4087<div class="doc_subsubsection">
4088 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4089</div>
4090
4091<div class="doc_text">
4092
4093<h5>Syntax:</h5>
4094<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4095 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4096</pre>
4097
4098<h5>Overview:</h5>
4099
4100
4101<p>
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4102The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4103(PC) in a region of
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4104code to simulators and other tools. The method is target specific, but it is
4105expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohen25d4f7e2005-11-11 02:15:27 +0000[diff] [blame]4106The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnerd07c3f42005-11-15 06:07:55 +0000[diff] [blame]4107after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb3e7afd2006-03-24 07:16:10 +0000[diff] [blame]4108optimizations. The intended use is to be inserted after optimizations to allow
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]4109correlations of simulation runs.
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]4110</p>
4111
4112<h5>Arguments:</h5>
4113
4114<p>
4115<tt>id</tt> is a numerical id identifying the marker.
4116</p>
4117
4118<h5>Semantics:</h5>
4119
4120<p>
4121This intrinsic does not modify the behavior of the program. Backends that do not
4122support this intrinisic may ignore it.
4123</p>
4124
4125</div>
4126
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4127<!-- _______________________________________________________________________ -->
4128<div class="doc_subsubsection">
4129 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4130</div>
4131
4132<div class="doc_text">
4133
4134<h5>Syntax:</h5>
4135<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4136 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]4137</pre>
4138
4139<h5>Overview:</h5>
4140
4141
4142<p>
4143The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4144counter register (or similar low latency, high accuracy clocks) on those targets
4145that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4146As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4147should only be used for small timings.
4148</p>
4149
4150<h5>Semantics:</h5>
4151
4152<p>
4153When directly supported, reading the cycle counter should not modify any memory.
4154Implementations are allowed to either return a application specific value or a
4155system wide value. On backends without support, this is lowered to a constant 0.
4156</p>
4157
4158</div>
4159
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4160<!-- ======================================================================= -->
4161<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4162 <a name="int_libc">Standard C Library Intrinsics</a>
4163</div>
4164
4165<div class="doc_text">
4166<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4167LLVM provides intrinsics for a few important standard C library functions.
4168These intrinsics allow source-language front-ends to pass information about the
4169alignment of the pointer arguments to the code generator, providing opportunity
4170for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4171</p>
4172
4173</div>
4174
4175<!-- _______________________________________________________________________ -->
4176<div class="doc_subsubsection">
4177 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4178</div>
4179
4180<div class="doc_text">
4181
4182<h5>Syntax:</h5>
4183<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4184 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4185 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4186 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4187 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4188</pre>
4189
4190<h5>Overview:</h5>
4191
4192<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4193The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4194location to the destination location.
4195</p>
4196
4197<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4198Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4199intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4200</p>
4201
4202<h5>Arguments:</h5>
4203
4204<p>
4205The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4206the source. The third argument is an integer argument
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4207specifying the number of bytes to copy, and the fourth argument is the alignment
4208of the source and destination locations.
4209</p>
4210
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4211<p>
4212If 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]4213the caller guarantees that both the source and destination pointers are aligned
4214to that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4215</p>
4216
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4217<h5>Semantics:</h5>
4218
4219<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4220The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]4221location to the destination location, which are not allowed to overlap. It
4222copies "len" bytes of memory over. If the argument is known to be aligned to
4223some boundary, this can be specified as the fourth argument, otherwise it should
4224be set to 0 or 1.
4225</p>
4226</div>
4227
4228
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4229<!-- _______________________________________________________________________ -->
4230<div class="doc_subsubsection">
4231 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4232</div>
4233
4234<div class="doc_text">
4235
4236<h5>Syntax:</h5>
4237<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4238 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4239 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4240 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4241 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4242</pre>
4243
4244<h5>Overview:</h5>
4245
4246<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4247The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4248location to the destination location. It is similar to the
4249'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4250</p>
4251
4252<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4253Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4254intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4255</p>
4256
4257<h5>Arguments:</h5>
4258
4259<p>
4260The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4261the source. The third argument is an integer argument
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4262specifying the number of bytes to copy, and the fourth argument is the alignment
4263of the source and destination locations.
4264</p>
4265
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4266<p>
4267If 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]4268the caller guarantees that the source and destination pointers are aligned to
4269that boundary.
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]4270</p>
4271
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4272<h5>Semantics:</h5>
4273
4274<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4275The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]4276location to the destination location, which may overlap. It
4277copies "len" bytes of memory over. If the argument is known to be aligned to
4278some boundary, this can be specified as the fourth argument, otherwise it should
4279be set to 0 or 1.
4280</p>
4281</div>
4282
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4283
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4284<!-- _______________________________________________________________________ -->
4285<div class="doc_subsubsection">
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4286 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4287</div>
4288
4289<div class="doc_text">
4290
4291<h5>Syntax:</h5>
4292<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4293 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4294 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4295 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4296 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4297</pre>
4298
4299<h5>Overview:</h5>
4300
4301<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4302The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4303byte value.
4304</p>
4305
4306<p>
4307Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4308does not return a value, and takes an extra alignment argument.
4309</p>
4310
4311<h5>Arguments:</h5>
4312
4313<p>
4314The first argument is a pointer to the destination to fill, the second is the
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4315byte value to fill it with, the third argument is an integer
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4316argument specifying the number of bytes to fill, and the fourth argument is the
4317known alignment of destination location.
4318</p>
4319
4320<p>
4321If 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]4322the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4323</p>
4324
4325<h5>Semantics:</h5>
4326
4327<p>
Chris Lattner5b310c32006-03-03 00:07:20 +0000[diff] [blame]4328The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4329the
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]4330destination location. If the argument is known to be aligned to some boundary,
4331this can be specified as the fourth argument, otherwise it should be set to 0 or
43321.
4333</p>
4334</div>
4335
4336
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4337<!-- _______________________________________________________________________ -->
4338<div class="doc_subsubsection">
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4339 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4340</div>
4341
4342<div class="doc_text">
4343
4344<h5>Syntax:</h5>
4345<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4346 declare float @llvm.sqrt.f32(float %Val)
4347 declare double @llvm.sqrt.f64(double %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4348</pre>
4349
4350<h5>Overview:</h5>
4351
4352<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4353The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]4354returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4355<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4356negative numbers (which allows for better optimization).
4357</p>
4358
4359<h5>Arguments:</h5>
4360
4361<p>
4362The argument and return value are floating point numbers of the same type.
4363</p>
4364
4365<h5>Semantics:</h5>
4366
4367<p>
4368This function returns the sqrt of the specified operand if it is a positive
4369floating point number.
4370</p>
4371</div>
4372
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4373<!-- _______________________________________________________________________ -->
4374<div class="doc_subsubsection">
4375 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4376</div>
4377
4378<div class="doc_text">
4379
4380<h5>Syntax:</h5>
4381<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4382 declare float @llvm.powi.f32(float %Val, i32 %power)
4383 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]4384</pre>
4385
4386<h5>Overview:</h5>
4387
4388<p>
4389The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4390specified (positive or negative) power. The order of evaluation of
4391multiplications is not defined.
4392</p>
4393
4394<h5>Arguments:</h5>
4395
4396<p>
4397The second argument is an integer power, and the first is a value to raise to
4398that power.
4399</p>
4400
4401<h5>Semantics:</h5>
4402
4403<p>
4404This function returns the first value raised to the second power with an
4405unspecified sequence of rounding operations.</p>
4406</div>
4407
4408
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4409<!-- ======================================================================= -->
4410<div class="doc_subsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4411 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4412</div>
4413
4414<div class="doc_text">
4415<p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4416LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4417These allow efficient code generation for some algorithms.
4418</p>
4419
4420</div>
4421
4422<!-- _______________________________________________________________________ -->
4423<div class="doc_subsubsection">
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4424 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4425</div>
4426
4427<div class="doc_text">
4428
4429<h5>Syntax:</h5>
4430<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4431 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4432 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4433 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4434</pre>
4435
4436<h5>Overview:</h5>
4437
4438<p>
4439The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
444064 bit quantity. These are useful for performing operations on data that is not
4441in the target's native byte order.
4442</p>
4443
4444<h5>Semantics:</h5>
4445
4446<p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4447The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4448and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4449intrinsic returns an i32 value that has the four bytes of the input i32
4450swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4451i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4452intrinsic extends this concept to 64 bits.
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]4453</p>
4454
4455</div>
4456
4457<!-- _______________________________________________________________________ -->
4458<div class="doc_subsubsection">
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4459 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4460</div>
4461
4462<div class="doc_text">
4463
4464<h5>Syntax:</h5>
4465<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4466 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4467 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
4468 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
4469 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4470</pre>
4471
4472<h5>Overview:</h5>
4473
4474<p>
Chris Lattnerec6cb612006-01-16 22:38:59 +0000[diff] [blame]4475The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4476value.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4477</p>
4478
4479<h5>Arguments:</h5>
4480
4481<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4482The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4483integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4484</p>
4485
4486<h5>Semantics:</h5>
4487
4488<p>
4489The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4490</p>
4491</div>
4492
4493<!-- _______________________________________________________________________ -->
4494<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4495 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4496</div>
4497
4498<div class="doc_text">
4499
4500<h5>Syntax:</h5>
4501<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4502 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4503 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
4504 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
4505 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4506</pre>
4507
4508<h5>Overview:</h5>
4509
4510<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4511The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4512leading zeros in a variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4513</p>
4514
4515<h5>Arguments:</h5>
4516
4517<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]4518The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4519integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4520</p>
4521
4522<h5>Semantics:</h5>
4523
4524<p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4525The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4526in 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]4527of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]4528</p>
4529</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]4530
4531
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4532
4533<!-- _______________________________________________________________________ -->
4534<div class="doc_subsubsection">
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]4535 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4536</div>
4537
4538<div class="doc_text">
4539
4540<h5>Syntax:</h5>
4541<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]4542 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4543 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
4544 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
4545 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4546</pre>
4547
4548<h5>Overview:</h5>
4549
4550<p>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]4551The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4552trailing zeros.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4553</p>
4554
4555<h5>Arguments:</h5>
4556
4557<p>
4558The only argument is the value to be counted. The argument may be of any
Reid Spencera5173382007-01-04 16:43:23 +0000[diff] [blame]4559integer type. The return type must match the argument type.
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]4560</p>
4561
4562<h5>Semantics:</h5>
4563
4564<p>
4565The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4566in a variable. If the src == 0 then the result is the size in bits of the type
4567of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4568</p>
4569</div>
4570
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]4571<!-- ======================================================================= -->
4572<div class="doc_subsection">
4573 <a name="int_debugger">Debugger Intrinsics</a>
4574</div>
4575
4576<div class="doc_text">
4577<p>
4578The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4579are described in the <a
4580href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4581Debugging</a> document.
4582</p>
4583</div>
4584
4585
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]4586<!-- ======================================================================= -->
4587<div class="doc_subsection">
4588 <a name="int_eh">Exception Handling Intrinsics</a>
4589</div>
4590
4591<div class="doc_text">
4592<p> The LLVM exception handling intrinsics (which all start with
4593<tt>llvm.eh.</tt> prefix), are described in the <a
4594href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4595Handling</a> document. </p>
4596</div>
4597
4598
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4599<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4600<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4601<address>
4602 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4603 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4604 <a href="http://validator.w3.org/check/referer"><img
4605 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4606
4607 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]4608 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]4609 Last modified: $Date$
4610</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4611</body>
4612</html>